Background Natural and synthetic plant growth regulators are essential for plant health,likewise these regulators also play a role in increasing organic production productivity and improving quality and yield stabilit...Background Natural and synthetic plant growth regulators are essential for plant health,likewise these regulators also play a role in increasing organic production productivity and improving quality and yield stability.In the present study,we have evaluated the effects of foliar applied plant growth regulators,i.e.,moringa leaf extract(MLE)and mepiquat chloride(MC)alone and in combination MC and MLE on the conventional cotton cultivar(CIM 573)and transgenic one(CIM 598).The growth regulators were applied at the start of bloom,45 and 90 days after blooming.Results The application of MC and MLE at 90 days after blooming significantly improved the relative growth rate,net assimilation rate,the number of bolls per plant,and seed cotton yield.Likewise,the combined application of MLE and MC at 90 days after blooming significantly boosted the nitrogen uptake in locules,as well as the phosphorus and potassium uptake in the leaves of both cotton cultivars.The application of MLE alone has considerably improved the nitrogen uptake in leaves,and phosphorus and potassium contents in locules of Bt and conventional cotton cultivars.Similarly,Bt cotton treated with MLE at 90 days after blooming produced significantly higher ginning out turn and oil contents.Treatment in combination(MLE+MC)at 90 days after blooming produced considerably higher micronaire value,fiber strength,and staple length in conventional cultivar.Conclusion The natural growth enhancer,MLE is a rich source of minerals and zeatin,improving the nutrient absorption and quality of cotton fiber in both conventional and Bt cotton cultivars.展开更多
Automated over-tree sprinkler irrigation systems were developed and tested in two orchards located in two separate locations in southern Iran (a 0.17 ha peach orchard and a 0.24 ha orange orchard) to protect peach b...Automated over-tree sprinkler irrigation systems were developed and tested in two orchards located in two separate locations in southern Iran (a 0.17 ha peach orchard and a 0.24 ha orange orchard) to protect peach blossoms and orange trees leaves and fruits from low temperature damage. The experiment used a system that monitored the trees and air temperatures using two thermistors. The water application rate by the irrigation system was determined by an energy balance as implemented by the software FROSTPRO, In the peach orchard, the system was tested during three frost events during the spring of 2003 and three other events during the spring of 2004. The system successfully kept peach flowers above the critical temperature, i.e., -4.0℃ in spring 2004 (control block -4.12℃, and sprinkled block +0.5℃) during all events. Similar results were obtained in the orange orchard during three frost events in the winter of 2004, during which the tree temperatures were at least 2.5℃ above the critical temperature. Results from field tests show that the system can effectively protect the peach blossoms from damage. Determination done after the frost events showed a 12% blossom kill in the sprinkled blocks while in the unsprinkled control block a 41.5% blossom kill. Calculations indicated that when using variable application rates, the amount of water used can be reduced by 54.3%. Spatial distribution of minimum temperatures during the three frosts was also studied in Jahrom, Iran. Results showed a significant temperature control in the experimental block, especially in the central part of the orchard, but the block margins (about 3.6% of the total area) were at the risk of low temperature due to the wind drift effects.展开更多
Field experiments were carried out at the National Research Center farm, Nubaria area, Behura Governorate, Egypt, to study the effect of nitrogen source, flushing schedule and irrigation method on emitter clogging. Pe...Field experiments were carried out at the National Research Center farm, Nubaria area, Behura Governorate, Egypt, to study the effect of nitrogen source, flushing schedule and irrigation method on emitter clogging. Peanut Giza 5 variety (Arachishy pogaea L.) was planted in sandy soil during two successive growing seasons (2010-2011) in the 1st week of May and harvested after 130 days. Treatments used are: 1) two irrigation methods: surface drip irrigation and sub-surface drip irrigation (SDI;SSDI), 2) nitrogen source (NS):NH4NO3, (NH4)2SO4 and Ca(NO3)2 (NS1, NS2 and NS3) and 3) flushing number (FL) 0, 1 and 4 (FL1, FL2;FL3). The experiments design was split-split plot and three replicates were used. Data obtained were subjected to statistical analysis. The main effects of treatments used on clogging per cent could be written the following ascending orders: SDI 3 2 1, NS1 2 3. Concerning the 1st interaction the following ascending orders denote their effects on clogging percent: SDI × FL3 2 1, SDI × NS1 2 3, SSDI × FL3 2 1, SSDI × NS1 2 3, FL1 × NS1 1 × NS2 1 × NS3, FL2 × NS1 2 × NS2 2 × NS3 and FL3 × NS1 3 × NS2 3 × NS3. The differences between any two treatments and/or any two interactions in clogging percent were significant at the 5% level. The effect of the 2nd interaction on clogging percent was significant at the 5% level. The maximum value of clogging (20.18%) and the lowest one (3.9%) were archived in the interactions: SSDI × FL1 × NS3 and SDI × FL3 × NS1, respectively.展开更多
The field experiments were conducted at the experimental farm of Faculty of agricultural, southern Illinois University SIUC, USA. The project makes the irrigation automated. With the use of low cost sensors and the si...The field experiments were conducted at the experimental farm of Faculty of agricultural, southern Illinois University SIUC, USA. The project makes the irrigation automated. With the use of low cost sensors and the simple circuitry makes currently project a low cost product, which can be bought even by a poor farmer. This research work is best suited for places where water is scares and has to be used in limited quantity and this proposal is a model to modernize the agriculture industries at a mass scale with optimum expenditure. In the field of agricultural engineering, use of sensor method of irrigation operation is important and it is well known that closed circuits of Mini-sprinkler irrigation system are very economical and efficient. Closed circuits are considered one of the modifications of Mini-sprinkler irrigation system, and added advantages to Mini-sprinkler irrigation system because it can relieve low operating pressures problem at the end of the lateral lines. In the conventional closed circuits of Mini-sprinkler irrigation system, the farmer has to keep watch on irrigation timetable, which is different for different crops. Using this system, one can save manpower, water to improve production and ultimately profit. The data could be summarized in following: Irrigation methods under study when using lateral length 60 mcould be ranked in the following ascending order according the values of the predicted and measured head losses CM1M-SIS CM2M-SIS.The correlation (Corr.) coefficients were used to compare the predicted and measured head losses along the lateral lines of all the closed circuits designs. Generally, the values of correlation analysis were (>0.90) were obtained with 0% field slope60 mlength (experimental conditions) for all closed circuits.The interaction between irrigation methods: at the start there are significant differences between CM2M-SIS and CM1M-SIS.展开更多
Drought stress (DS) is an important limiting factor for crop growth and production in some regions of the world. Limitation in water availability precludes optimal irrigation in some production regions. Therefore, inv...Drought stress (DS) is an important limiting factor for crop growth and production in some regions of the world. Limitation in water availability precludes optimal irrigation in some production regions. Therefore, investigations on the interaction of other factors to mitigate the DS to varying degree are important. Two field experiments were conducted in the experimental farm of the National Research Centre, Shalakan, Kalubia Governorate, Egypt, during 2004 and 2005 summer seasons to evaluate the interactions between N, P, K rates and optimal vs. deficit irrigation regimes on biomass yield as well as water use efficiency (WUE) of forage sorghum. Omission of the 4th irrigation significantly decreased the biomass of sorghum c.v. Pioneer, as compared to that of the plants receiving optimal irrigation or subject to omission of the 2nd irrigation. The biomass yield increased with an increase in NPK fertilizer rates. Plant height and leaf area also decreased by omitting the 2nd irrigation as compared to that of the plants under optimal irrigation, and further declined with omission of the 4th irrigation. The biomass of the plants (dry weight basis) that received the high N, P, K rates was greater by 26%, 29%, and 35% as compared to that of the plants that received no N, P, K fertilizers, under optimal irrigation, omission of the 2nd, and omission of the 4th irrigation, respectively. The corresponding increases in water use efficiency (based on fresh weight yield) were 37%, 42%, and 55%.展开更多
Field experiment was conducted for one growing season (2012) in clay loam soil at the Experimental Farm of Faculty of Agriculture, Southern Illinois University at Carbondale (SIUC), USA on soybean crop to study the ef...Field experiment was conducted for one growing season (2012) in clay loam soil at the Experimental Farm of Faculty of Agriculture, Southern Illinois University at Carbondale (SIUC), USA on soybean crop to study the effect of: 1) the closed drip irrigation system: closed circuits with one and two a manifolds for lateral lines (CM1DIS;CM2DIS) and traditional drip irrigation system (TDIS) as a control;and 2) lateral lines length (LLL): LLL1, LLL2 and LLL3 (40, 60,80 m) on soybean growth, yield, oil, protein content and water use efficiency. Plants were drip irrigated every 4 days. N, K2O and P2O5 fertilizers were added via irrigation water. Data obtained could be outlined as follows: 1) According to the mean values of soybean crop growth (leaf area;plant height), yield (grain and straw), both oil and protein content and water use efficiency, the treatment used could be ranked in the following ascending orders: TDIS < CM1DIS < CM2DIS and LLL3 < LLL2 < LLL1;2) Differences in the means of the studied data among treatments used were significant at the 1% level;3) The effects of the DIC × LLL on the data obtained were significant at the 1 % level;And 4) the highest values of the obtained data and the lowest ones were achieved in the following interactions: CM2DIS × LLL1;TDIS × LLL3, respectively.展开更多
This study examined changes in some soil hydrophysical, chemical properties and wheat yield (grain;straw yield, N, P, K, Protein and carbohydrates contents) as trends under two cultivated period 10 and 25 year and Far...This study examined changes in some soil hydrophysical, chemical properties and wheat yield (grain;straw yield, N, P, K, Protein and carbohydrates contents) as trends under two cultivated period 10 and 25 year and Farm Yard manure (FYM) addition under sprinkler irrigation system on a newly reclaimed soils, Nubaria, Beheira Governorate, Egypt. Obtained results noticed that cultivation period has more pronounced effect than FYM addition on soil water content at field capacity, wilting point and available water with increase percent 15.1%, 9.3%;19.0% and 25.7%, 19.5% and 30.0% for FYM and cultivation period comparing with control one. Hydraulic conductivity values were strongly affected by cultivation period and FYM addition and significantly decreased values by about 18.9% and 12.1% in same sequences. Wheat straw content from protein had a superior effect under 25 than 10 years cultivated periods with values 61.9 and 6.7 comparing with control, respectively as affected by FYM addition, while FYM alone improved protein content in straw by about 31.9% comparing with untreated one. Slightly increase in straw protein content was attained relative to the increase of cultivated period by about 7.8%. Nutrients content in grain is more than FYM, where the increase percentage were 5.2%, 13.5%;3.8% and 26.5, 21.3;22.6 comparing cultivated periods 25 with 10 years and FYM addition with control, respectively. FYM individually under two studied cultivated periods is more effective under 10 years (28.0%, 25.2%;15.1%) than the 2nd one (25.1%, 25.2%;15.1%) comparing with untreated FYM plots. While N, P and K content in wheat straw had unclear trend and the increase were 6.8, 23.23;56.5% and 62.9, 6.0;29.8 as a result of FYM addition under 10 and 25 years cultivated periods, respectively. The highest values of protein and carbohydrates content in wheat grains as affected by studied factors were 12.86% and 67.43%) were obtained under cultivated period 25 years after FYM addition. Cultivated periods had a highly significant effect on the field water use efficiency values of grain more than the effect of FYM. The highest values of grain and straw yield were recorded at 10 years cultivated periods + treated FYM (2966.8 kg/fed) and 25 years cultivated periods treated with FYM (3835.6 kg/fed). Cultivated periods increased grain and straw yield of wheat crop by about 57.6% and 8.3%. Whereas, FYM increased grain and straw yield by about 39.8% and 58.8% relative to the control, respectively.展开更多
Two field experiments were carried out during growing seasons 2010 and 2011, it executed in research farm of national research center in Nubaryia region, Egypt to study the effect of pulse drip irrigation and mulching...Two field experiments were carried out during growing seasons 2010 and 2011, it executed in research farm of national research center in Nubaryia region, Egypt to study the effect of pulse drip irrigation and mulching systems for saving water, increasing and improving yield of soybean. The study factors were, pulse drip irrigation technology (adding of daily water requirements on 4 times, 8 times, 12 times compared with adding of daily water requirements on 1 time) and mulching systems (covering the soil with black plastic mulch “BPM”, rice straw mulch “RSM” and the control treatment was soil surface without mulch “WM”). The following parameters were studied to evaluate the effect of pulse drip irrigation and mulching systems: 1) Soil moisture distribution in root zone, 2) Growth characters of soybean plant, 3) Yield of soybean, 4) Irrigation water use efficiency of soybean “IWUE soybean”, and 5) Oil content and oil yield, 6) Protein content and protein yield, 7) Economical parameter. According to the economical view and the results of statistical analysis for effect of pulse drip irrigation and mulching systems on yield, quality traits and IWUE soybean indicated that, applying the irrigation requirements on 8 pulses/day with using BPM is the best conditions because under these conditions was occurred the highest value of yield, quality traits and IWUE soybean and there was significant deference between this case and other treatments. Where, pulse irrigation technique increase from water movement in horizontal direction than vertical direction hence improve from soil moisture distribution and wetted soil volume in root zone and using BPM decrease from evaporation process rate from soil surface hence decreasing of salts accumulation in addition to decreasing of weed growth in the root zone. All traits at AIR on 12 pulses/ day are decreased by increasing of pulses, this may be due to irrigation water was very small with every pulse at AIR on 12 pulses/day in addition increasing the total time of time-off, this mean, un-sufficient application for irrigation water to remove water stress in the root zone.展开更多
Irrigation with high salinity water influences plant growth, production of photosynthetic pigments and total phenols, leading to reduction in crop yield and quality. The objective of this study was to investigate the ...Irrigation with high salinity water influences plant growth, production of photosynthetic pigments and total phenols, leading to reduction in crop yield and quality. The objective of this study was to investigate the effects of potassium (K) foliar application in mitigating the negative effects of salt stress on pepper plants. A greenhouse experiment was conducted to investigate the effects of foliar application of potassium (K) on pepper plants grown with different salinity water irrigation (3000 and 6000 ppm as compared to tap water with salinity level of 300 ppm). Irrigation using high salinity water decreased plant height, biomass production, and fruit yield as compared to those of the plants irrigated by tap water. Photosynthetic pigments and total phenols increased in the former as compared to those of the latter plants. The most serious affect was for the plants under highest salinity irrigation (6000 ppm) as compared to that of the plants under moderate salinity irrigation (3000 ppm). Foliar application of potassium mono phosphate (KMP) at 200ppm concentration increased the plant growth, biomass production, and fruit yield. Chlorophyll_a content and total phenols increased significantly with foliar application of 100 ppm KMP. Further increase in foliar KMP concentration to 200 ppm had no significant benefits on photosynthetic pigments and total phenols content. This study demonstrated that foliar application of KMP, to some extent, mitigated the negative effects of high salinity water irrigation on pepper plant growth and fruit yield.展开更多
Waterlogging and low application efficiency are the main problems inherent with surface irrigation in the Nile Delta. Develop surface irrigation using gated pipes (GP) is a new method to be used to distribute water in...Waterlogging and low application efficiency are the main problems inherent with surface irrigation in the Nile Delta. Develop surface irrigation using gated pipes (GP) is a new method to be used to distribute water into furrow irrigated fields as strategy based on water saving. Laboratory calibration was conducted out to evaluate the hydraulic characteristics of pipe gates. Field experiments were conducted at the Experimental Farm of the Agriculture Faculty, Minufiya University during 2013 and 2014 seasons to evaluate the performance of utilize gated pipes technique for irrigating five maize varieties (S.C 10, S.C 130, S.C 131, S.C 2031 and T.W.C 321). The results revealed that the highest amount of water applied was with traditional surface irrigation (6423.81 m3·ha-1. Use of gated pipes system GP1 as compared to traditional irrigation reduced water application by 923.81 m3·ha-1 with grain and stover yields increases of 5.7% and 3.4%, respectively. Traditional irrigation system achieved lowest irrigation performance parameters compared to gated pipes systems. Maize physiological attributes, yield, water use efficiency (WUE) and nitrogen accumulation were significantly decreased by either deficit or surplus irrigation than of GP1 rate. S.C 2031 variety significantly surpassed other varieties in abovementioned traits. Significant interaction effects were detected in both seasons. Maize varieties respond differently to irrigation systems. The highest values of grain yield (11062.6 and 10911.8 kg·ha-1 and stover yield (13639.0 and 13902.2 kg·ha-1) were obtained by S.C 2031 irrigated with GP1 system in both seasons. From the above mentioned results, it is concluded that the gated pipes technique is better than traditional irrigation for improving WUE and maize productivity under Nile Delta conditions.展开更多
Two field experiments were carried out during growing seasons 2011 and 2012. It was executed in research farm of National Research Center in Nubaryia region, Egypt to study the effect of irrigation systems, fertigatio...Two field experiments were carried out during growing seasons 2011 and 2012. It was executed in research farm of National Research Center in Nubaryia region, Egypt to study the effect of irrigation systems, fertigation rates by using the wastewater of fish farms “WWFF” in irrigation of potato. Study factors were irrigation systems (sprinkler irrigation system “SIS” and trickle irrigation system “TIS”), water quality (traditional irrigation water “TIW” and WWFF) and fertigation rates “FR” (20%, 40%, 60%, 80% and 100% NPK). The following parameters were studied to evaluate the effect of study factors: 1) Calculating the total amount of WWFF per season;2) Chemical and biological description of WWFF;3) Clogging ratio of emitters;4) Yield of potato;5) Irrigation water use efficiency of potato “IWUEpotato”. Statistical analysis indicated that, maximum values were obtained of yield under SIS × FR100% NPK × WWFF, also, there were no significant differences for yield values under the following conditions: SIS × FR100% NPK × WWFF > SIS × FR80% NPK × WWFF > SIS × FR60% NPK × WWFF > TIS × FR100% NPK × TIW. This means that, using WWFF in the irrigation can save at least 40% from mineral fertilizers and 100% from irrigation water under sprinkler irrigation system.展开更多
A two-year study was carried out at Ismailia Agricultural Research Station, Egypt during 2016 and 2017 summer seasons to evaluate competitive effects of intercropping sunflower and peanut under different drip irrigati...A two-year study was carried out at Ismailia Agricultural Research Station, Egypt during 2016 and 2017 summer seasons to evaluate competitive effects of intercropping sunflower and peanut under different drip irrigation water amounts and K fertilizer rates for increasing farmer profitability. Three irrigation amounts (70%, 100% and 120% ETo), three K fertilizer levels (57, 86 and 114 K2O kg/ha) and four intercropping patterns of sunflower and peanut (different spatial arrangements) were implemented. The experimental design was strip split plot with three replications. The results showed that there were no significant differences between 100% and 120% ETo on most of yield traits of the intercrops. The highest K fertilizer level had the highest values of most yield traits of the intercrops. The highest values of peanut and sunflower traits were obtained from intercropping sunflower with peanut, where peanut seeds were sown on both sides of all the raised beds, sunflower seeds were sown on one row above the raised beds and the following bed was left without intercropping (P1). Thus, to attain the highest yield of intercrops and water equivalent ratio (WER), the lowest competitive pressure and the highest farmer profitability, 120% ETo, 114 K2O kg/ha and P1 intercropping pattern should be implemented. This research found that the result of competitiveness was consistent with the result of profitability.展开更多
In order to examine the application of different soil and foliar organic fertilizers as well as biofertilizing flax under sandy soil conditions, two field experiments were carried out at the Research and Production St...In order to examine the application of different soil and foliar organic fertilizers as well as biofertilizing flax under sandy soil conditions, two field experiments were carried out at the Research and Production Station of the National Research Centre (NRC), Al Nubaria district, El-Behaira Governorate, Egypt during 2012/2013 and 2013/2014 winter seasons. The trials aimed to study the effect of humic acid (HA) as low cost natural fertilizer, inoculation with mycorrhiza, and biocharcoal on on yield, quality and water use efficiency of flax variety (Amon) under newly reclaimed sandy soil. The treatments consisted of HA (25 kg/feddan), inoculation with mycorrhiza (1 kg/ feddan), and biochar (4 tons/feddan) and all the combinations among the treatments. Results showed that the treatment combination of (humic acid + mycorrhiza + biochar) was significantly superior compared to all the other treatments in number of capsules/plant, biological yield/plant (g), seed yield/plant (g), seed yield (kg/feddan), straw yield (tons/feddan), oil percent (%), and oil yield (kg/feddan). However, it gave the highest fruiting zone length (cm) but not significantly different from (mycorrhiza + biochar) and (humic acid + biochar), also it gave the highest seed index (g) but not significantly different from humic acid and (humic acid + mycorrhiza). The treatment combination of (humic acid + biochar) gave the highest plant height (cm), technical stem length (cm), and number of branches/plant.展开更多
This study highlights the influence of freezing-thawing processes on soil erosion in an alpine mine restoration area. Accordingly, a series of simulation experiments were conducted to investigate runoff, sediment, and...This study highlights the influence of freezing-thawing processes on soil erosion in an alpine mine restoration area. Accordingly, a series of simulation experiments were conducted to investigate runoff, sediment, and nutrient losses, and potential influencing factors under freeze-thaw(FT) conditions. Three FT treatments(i.e., 0, 3, and 5 FT cycles), and two soil moisture contents(SMCs;i.e., 10% and 20% SMC on a gravimetric basis) were assessed. The runoff, sediment yield, ammonia nitrogen(AN), nitrate nitrogen(NN), total phosphorus(TP), and dissolved phosphorus(DP) losses from runoff were characterized under different rainfall durations. The fitting results indicated that the runoff rate and sediment rate, AN, NN, TP, and DP concentrations in runoff could be described by exponential functions. FT action increased the total runoff volume and sediment yield by 14.6%–26.0% and 8.8%–35.2%, respectively. The runoff rate and sediment rate increased rapidly with the increment of FT cycles before stabilizing. At 20% SMC, the total runoff volume and sediment yield were significantly higher than those at 10% SMC. The loss curves of AN and NN concentrations varied due to differences in their chemical properties. FT action and high SMC promoted AN and NN losses, whereas the FT cycles had little effect. FT action increased TP and DP losses by 60.2%–220.1% and 48.4%–129.8%, respectively, compared to cases with no FT action;the highest TP and DP losses were recorded at 20% SMC. This study provides a deep understanding of freezing-thawing mechanisms in the soils of alpine mine restoration areas and the influencing factors of these mechanisms on soil erosion, thereby supporting the development of erosion prevention and control measures in alpine mine restoration areas.展开更多
In recent years Jatropha curcas L. has emerged as a biofuel crop with potential for its production in marginal land with application of treated sewage water. Since this is a new crop for its profitable cultivation, ad...In recent years Jatropha curcas L. has emerged as a biofuel crop with potential for its production in marginal land with application of treated sewage water. Since this is a new crop for its profitable cultivation, additional research is needed to develop optimal management programs, including macro and micronutrients applications. A pot experiment was conducted in a Greenhouse at the National Research Center, Dokki, Cairo, Egypt, during 2010 summer to evaluate effects of varying concentrations of iron (Fe), manganese (Mn), and zinc (Zn) in irrigation water (0, 50, 100, 150, 200 and 250 ppm) on the growth, biomass production, photosynthetic pigments, and mineral nutrients status in the plants. Increasing concentrations of Fe, Mn, and Zn in irrigation water up to 150 ppm increased the biomass weight, photosynthetic pigments, and nutrient uptake by Jatropha plants. Further increase in concentrations of micronutrients showed negative effects on the above response parameters. Therefore, this study demonstrates that Jatropha can be grown under irrigation using waste water containing reasonable concentrations of micronutrients and heavy metals. This property of Jatropha provides some support for potential use of this crop for phytoremediation of metal contaminated soils. However, long term field research is needed to further verify both the above beneficial effects.展开更多
Salinity stress impacts crop growth as well as production. The need for increased food production to feed the increasing population and the limited resources, i.e. optimal quality land and water, require developing st...Salinity stress impacts crop growth as well as production. The need for increased food production to feed the increasing population and the limited resources, i.e. optimal quality land and water, require developing strategies to mitigate marginal stresses, including salinity stress, for reasonable expectation of crop production. A pot experiment was conducted in a greenhouse at the National Research Centre, Dokki, Cairo, Egypt in the summer season of 2005 to evaluate the effects of foliar application of ascorbic acid alone or in combination with zinc sulfate on the growth and photosynthetic pigments of millet plants irrigated by tap water (250 ppm, 0.39 dS·m-1) or moderate to high salinity irrigation water [2500 ppm (3.9 dS·m-1) and 5000 ppm (7.8 dS·m-1)]. Increased salinity in the irrigation water decreased the plant growth, biomass, and carotenoid content. Foliar application of ascorbic acid alone increased number of leaves and leaf area, while in combination with zinc sulfate increased the plant height and total plant biomass. However, these treatments had no significant effects on the photosynthetic pigments. This study demonstrates that exogenous application of ascorbic acid can enhance foliar growth which may contribute to increased plant biomass and yield.展开更多
<span style="font-family:;" "=""><span style="font-family:Verdana;">Methane is released from waste disposal areas as a result from anaerobic decay of food. Methane causes...<span style="font-family:;" "=""><span style="font-family:Verdana;">Methane is released from waste disposal areas as a result from anaerobic decay of food. Methane causes more greenhouse effects than carbon dioxide so a methane monitoring system is required to warn its release from gas emitting environments. The low explosive limit of methane is 5% in ambient air, so gas leakage is dangerous and can produce explosions. An entire head monitoring system was built around a MQ-4 methane gas sensor as it is cheap and reliable. The design proves to be flexible enough as it can measure CH</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> emissions in ducts, CH</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> in landfills at different depths and even in cattle barns. The measuring system head consists of a suction pump, solenoids, and a methane sensor. Measurements are taken 13 seconds after methane gas sucking. </span><span style="font-family:Verdana;">A timing of 100 seconds is required for purging the chamber before the</span><span style="font-family:Verdana;"> second solenoid is turned-on. Devices temperature during operation was sampled with a thermal Flir-One camera and solenoid coil temperature was of 24.9</span></span><span style="font-family:;" "=""><span style="font-family:Verdana;"><span style="white-space:nowrap;">˚</span>C </span><span style="font-family:Verdana;">after a continuous operation of 30 seconds. As hoses for emission sampling</span><span style="font-family:Verdana;"> become larger time for sampling increases as well as energy consumption.</span></span>展开更多
The saline wetlands,or'saladas',of Monegros Desert,NE Spain,contain biodiversity that depends on the estab- lishment of a prognostic monitoring system that can warn of approaching irreversible damage.In the co...The saline wetlands,or'saladas',of Monegros Desert,NE Spain,contain biodiversity that depends on the estab- lishment of a prognostic monitoring system that can warn of approaching irreversible damage.In the context of a lack of existing biodiversity inventories for the saladas,we determined their state of conservation and vulnerability using seven physical indicators:escarpment continuity,cropping,stone dumping,size,water occurrence,distance to roads,and proximity to irrigated areas.These features were combined into three meaningful indexes,i.e.,conservation,current vulnerability,and future vulnerability,thus creating an assessment of the preservation or degradation of saladas in the context of encroaching agricultural irrigation projects.The proposed indexes produced consistent results and showed that a great number of the Monegros wetlands were threatened,regardless of their size or frequency of water occurrence.Only 20% of the saladas studied were classified as being in a good or very good conservation,whereas 50% were in bad or very bad shape.A high current vulnerability was found for 60% of the saladas.For saladas located in land to be irrigated, we predicted that 73% would have a high or very high future vulnerability.Currently,58% of the saladas were in bad or very bad condition and fully 65% of the saladas,variable in size,presented a bad or very bad prognosis.Our approach provides a monitoring strategy for the conservation of saline wetlands threatened by agricultural intensification,especially irrigation.展开更多
Phenylalanin ammonia-lyase(PAL) plays a pivotal role in the production of phenolic compounds,which are responsible for the success of the defense strategies in harsh environments in response to different stimuli.Measu...Phenylalanin ammonia-lyase(PAL) plays a pivotal role in the production of phenolic compounds,which are responsible for the success of the defense strategies in harsh environments in response to different stimuli.Measurements of the PAL activity,total phenolics,total flavonoids and anthocyanin contents were performed in flowers,leaves and fruits of three pistachio cultivars "Ahmadaghaii","Ohadi" and "Kallehghuchi".The results showed that PAL activity was different in cultivars and in plant organs of pistachio trees(flowers,leaves and fruits).The highest activity rate of their compounds was observed in Ahmadaghaii cultivar.A positive correlation was observed between PAL activity,total phenolics and total flavonoids in leaves,and a negative correlation between PAL activity and anthocyanin contents in leaves and flowers of Ahmadaghaii cultivar.PAL activity and total phenolics in fruits of pistachio suffered a decrease when the maturation processes began.It is suggested that the hulls of the pistachio fruits,containing high level of phenolic compounds(especially in Ahmadaghaii cultivar),may function as a protective layer of defense chemicals against ultraviolet radiation and pathogens.The final concentration of phenolic compounds,flavonoids and antocyanins in the kernel depend on PAL activity in the kernel's cultivar.The results led to the conclusion that increase in PAL activity,phenolic compounds and flavonoids in Ahmadaghaii can help the plant to cope with the stresses better than the other cultivars.Since phenolic compounds are antioxidant and scavenge free oxygen,it is postulated that Ahmadaghaii is the most resistant cultivar to the environmental stresses.展开更多
Most of infrastructure projects around the world have to focus on a clear understanding of geological model which may be determined from various sources of information. The limitation in geotechnical data and budget a...Most of infrastructure projects around the world have to focus on a clear understanding of geological model which may be determined from various sources of information. The limitation in geotechnical data and budget affects the accuracy of the geological model, particularly for projects of long and deep tunnel of which accessibility to the excavation points is difficult and far reaching. Therefore, an approach adopted for interpretation plays an important role in the level of uncertainty of the derived geological model. This paper focuses on the determination of the geological models at the site of a long water diversion tunnel project in a complex geologic setting in northern Thailand from an approach to understand the relationship between regional tectonic setting and local tectonic condition so that geological structures and rock mass conditions along the tunnel alignment can be assessed for a better planning of tunnel design and construction. The paper describes tectonic settings at regional scale (Northern Thailand and Eastern Myanmar), tectonic features and geologic condition in project area, geotechnical investigation and data along tunnel alignment and predicted tunnel ground behavior.展开更多
文摘Background Natural and synthetic plant growth regulators are essential for plant health,likewise these regulators also play a role in increasing organic production productivity and improving quality and yield stability.In the present study,we have evaluated the effects of foliar applied plant growth regulators,i.e.,moringa leaf extract(MLE)and mepiquat chloride(MC)alone and in combination MC and MLE on the conventional cotton cultivar(CIM 573)and transgenic one(CIM 598).The growth regulators were applied at the start of bloom,45 and 90 days after blooming.Results The application of MC and MLE at 90 days after blooming significantly improved the relative growth rate,net assimilation rate,the number of bolls per plant,and seed cotton yield.Likewise,the combined application of MLE and MC at 90 days after blooming significantly boosted the nitrogen uptake in locules,as well as the phosphorus and potassium uptake in the leaves of both cotton cultivars.The application of MLE alone has considerably improved the nitrogen uptake in leaves,and phosphorus and potassium contents in locules of Bt and conventional cotton cultivars.Similarly,Bt cotton treated with MLE at 90 days after blooming produced significantly higher ginning out turn and oil contents.Treatment in combination(MLE+MC)at 90 days after blooming produced considerably higher micronaire value,fiber strength,and staple length in conventional cultivar.Conclusion The natural growth enhancer,MLE is a rich source of minerals and zeatin,improving the nutrient absorption and quality of cotton fiber in both conventional and Bt cotton cultivars.
文摘Automated over-tree sprinkler irrigation systems were developed and tested in two orchards located in two separate locations in southern Iran (a 0.17 ha peach orchard and a 0.24 ha orange orchard) to protect peach blossoms and orange trees leaves and fruits from low temperature damage. The experiment used a system that monitored the trees and air temperatures using two thermistors. The water application rate by the irrigation system was determined by an energy balance as implemented by the software FROSTPRO, In the peach orchard, the system was tested during three frost events during the spring of 2003 and three other events during the spring of 2004. The system successfully kept peach flowers above the critical temperature, i.e., -4.0℃ in spring 2004 (control block -4.12℃, and sprinkled block +0.5℃) during all events. Similar results were obtained in the orange orchard during three frost events in the winter of 2004, during which the tree temperatures were at least 2.5℃ above the critical temperature. Results from field tests show that the system can effectively protect the peach blossoms from damage. Determination done after the frost events showed a 12% blossom kill in the sprinkled blocks while in the unsprinkled control block a 41.5% blossom kill. Calculations indicated that when using variable application rates, the amount of water used can be reduced by 54.3%. Spatial distribution of minimum temperatures during the three frosts was also studied in Jahrom, Iran. Results showed a significant temperature control in the experimental block, especially in the central part of the orchard, but the block margins (about 3.6% of the total area) were at the risk of low temperature due to the wind drift effects.
文摘Field experiments were carried out at the National Research Center farm, Nubaria area, Behura Governorate, Egypt, to study the effect of nitrogen source, flushing schedule and irrigation method on emitter clogging. Peanut Giza 5 variety (Arachishy pogaea L.) was planted in sandy soil during two successive growing seasons (2010-2011) in the 1st week of May and harvested after 130 days. Treatments used are: 1) two irrigation methods: surface drip irrigation and sub-surface drip irrigation (SDI;SSDI), 2) nitrogen source (NS):NH4NO3, (NH4)2SO4 and Ca(NO3)2 (NS1, NS2 and NS3) and 3) flushing number (FL) 0, 1 and 4 (FL1, FL2;FL3). The experiments design was split-split plot and three replicates were used. Data obtained were subjected to statistical analysis. The main effects of treatments used on clogging per cent could be written the following ascending orders: SDI 3 2 1, NS1 2 3. Concerning the 1st interaction the following ascending orders denote their effects on clogging percent: SDI × FL3 2 1, SDI × NS1 2 3, SSDI × FL3 2 1, SSDI × NS1 2 3, FL1 × NS1 1 × NS2 1 × NS3, FL2 × NS1 2 × NS2 2 × NS3 and FL3 × NS1 3 × NS2 3 × NS3. The differences between any two treatments and/or any two interactions in clogging percent were significant at the 5% level. The effect of the 2nd interaction on clogging percent was significant at the 5% level. The maximum value of clogging (20.18%) and the lowest one (3.9%) were archived in the interactions: SSDI × FL1 × NS3 and SDI × FL3 × NS1, respectively.
文摘The field experiments were conducted at the experimental farm of Faculty of agricultural, southern Illinois University SIUC, USA. The project makes the irrigation automated. With the use of low cost sensors and the simple circuitry makes currently project a low cost product, which can be bought even by a poor farmer. This research work is best suited for places where water is scares and has to be used in limited quantity and this proposal is a model to modernize the agriculture industries at a mass scale with optimum expenditure. In the field of agricultural engineering, use of sensor method of irrigation operation is important and it is well known that closed circuits of Mini-sprinkler irrigation system are very economical and efficient. Closed circuits are considered one of the modifications of Mini-sprinkler irrigation system, and added advantages to Mini-sprinkler irrigation system because it can relieve low operating pressures problem at the end of the lateral lines. In the conventional closed circuits of Mini-sprinkler irrigation system, the farmer has to keep watch on irrigation timetable, which is different for different crops. Using this system, one can save manpower, water to improve production and ultimately profit. The data could be summarized in following: Irrigation methods under study when using lateral length 60 mcould be ranked in the following ascending order according the values of the predicted and measured head losses CM1M-SIS CM2M-SIS.The correlation (Corr.) coefficients were used to compare the predicted and measured head losses along the lateral lines of all the closed circuits designs. Generally, the values of correlation analysis were (>0.90) were obtained with 0% field slope60 mlength (experimental conditions) for all closed circuits.The interaction between irrigation methods: at the start there are significant differences between CM2M-SIS and CM1M-SIS.
文摘Drought stress (DS) is an important limiting factor for crop growth and production in some regions of the world. Limitation in water availability precludes optimal irrigation in some production regions. Therefore, investigations on the interaction of other factors to mitigate the DS to varying degree are important. Two field experiments were conducted in the experimental farm of the National Research Centre, Shalakan, Kalubia Governorate, Egypt, during 2004 and 2005 summer seasons to evaluate the interactions between N, P, K rates and optimal vs. deficit irrigation regimes on biomass yield as well as water use efficiency (WUE) of forage sorghum. Omission of the 4th irrigation significantly decreased the biomass of sorghum c.v. Pioneer, as compared to that of the plants receiving optimal irrigation or subject to omission of the 2nd irrigation. The biomass yield increased with an increase in NPK fertilizer rates. Plant height and leaf area also decreased by omitting the 2nd irrigation as compared to that of the plants under optimal irrigation, and further declined with omission of the 4th irrigation. The biomass of the plants (dry weight basis) that received the high N, P, K rates was greater by 26%, 29%, and 35% as compared to that of the plants that received no N, P, K fertilizers, under optimal irrigation, omission of the 2nd, and omission of the 4th irrigation, respectively. The corresponding increases in water use efficiency (based on fresh weight yield) were 37%, 42%, and 55%.
文摘Field experiment was conducted for one growing season (2012) in clay loam soil at the Experimental Farm of Faculty of Agriculture, Southern Illinois University at Carbondale (SIUC), USA on soybean crop to study the effect of: 1) the closed drip irrigation system: closed circuits with one and two a manifolds for lateral lines (CM1DIS;CM2DIS) and traditional drip irrigation system (TDIS) as a control;and 2) lateral lines length (LLL): LLL1, LLL2 and LLL3 (40, 60,80 m) on soybean growth, yield, oil, protein content and water use efficiency. Plants were drip irrigated every 4 days. N, K2O and P2O5 fertilizers were added via irrigation water. Data obtained could be outlined as follows: 1) According to the mean values of soybean crop growth (leaf area;plant height), yield (grain and straw), both oil and protein content and water use efficiency, the treatment used could be ranked in the following ascending orders: TDIS < CM1DIS < CM2DIS and LLL3 < LLL2 < LLL1;2) Differences in the means of the studied data among treatments used were significant at the 1% level;3) The effects of the DIC × LLL on the data obtained were significant at the 1 % level;And 4) the highest values of the obtained data and the lowest ones were achieved in the following interactions: CM2DIS × LLL1;TDIS × LLL3, respectively.
文摘This study examined changes in some soil hydrophysical, chemical properties and wheat yield (grain;straw yield, N, P, K, Protein and carbohydrates contents) as trends under two cultivated period 10 and 25 year and Farm Yard manure (FYM) addition under sprinkler irrigation system on a newly reclaimed soils, Nubaria, Beheira Governorate, Egypt. Obtained results noticed that cultivation period has more pronounced effect than FYM addition on soil water content at field capacity, wilting point and available water with increase percent 15.1%, 9.3%;19.0% and 25.7%, 19.5% and 30.0% for FYM and cultivation period comparing with control one. Hydraulic conductivity values were strongly affected by cultivation period and FYM addition and significantly decreased values by about 18.9% and 12.1% in same sequences. Wheat straw content from protein had a superior effect under 25 than 10 years cultivated periods with values 61.9 and 6.7 comparing with control, respectively as affected by FYM addition, while FYM alone improved protein content in straw by about 31.9% comparing with untreated one. Slightly increase in straw protein content was attained relative to the increase of cultivated period by about 7.8%. Nutrients content in grain is more than FYM, where the increase percentage were 5.2%, 13.5%;3.8% and 26.5, 21.3;22.6 comparing cultivated periods 25 with 10 years and FYM addition with control, respectively. FYM individually under two studied cultivated periods is more effective under 10 years (28.0%, 25.2%;15.1%) than the 2nd one (25.1%, 25.2%;15.1%) comparing with untreated FYM plots. While N, P and K content in wheat straw had unclear trend and the increase were 6.8, 23.23;56.5% and 62.9, 6.0;29.8 as a result of FYM addition under 10 and 25 years cultivated periods, respectively. The highest values of protein and carbohydrates content in wheat grains as affected by studied factors were 12.86% and 67.43%) were obtained under cultivated period 25 years after FYM addition. Cultivated periods had a highly significant effect on the field water use efficiency values of grain more than the effect of FYM. The highest values of grain and straw yield were recorded at 10 years cultivated periods + treated FYM (2966.8 kg/fed) and 25 years cultivated periods treated with FYM (3835.6 kg/fed). Cultivated periods increased grain and straw yield of wheat crop by about 57.6% and 8.3%. Whereas, FYM increased grain and straw yield by about 39.8% and 58.8% relative to the control, respectively.
文摘Two field experiments were carried out during growing seasons 2010 and 2011, it executed in research farm of national research center in Nubaryia region, Egypt to study the effect of pulse drip irrigation and mulching systems for saving water, increasing and improving yield of soybean. The study factors were, pulse drip irrigation technology (adding of daily water requirements on 4 times, 8 times, 12 times compared with adding of daily water requirements on 1 time) and mulching systems (covering the soil with black plastic mulch “BPM”, rice straw mulch “RSM” and the control treatment was soil surface without mulch “WM”). The following parameters were studied to evaluate the effect of pulse drip irrigation and mulching systems: 1) Soil moisture distribution in root zone, 2) Growth characters of soybean plant, 3) Yield of soybean, 4) Irrigation water use efficiency of soybean “IWUE soybean”, and 5) Oil content and oil yield, 6) Protein content and protein yield, 7) Economical parameter. According to the economical view and the results of statistical analysis for effect of pulse drip irrigation and mulching systems on yield, quality traits and IWUE soybean indicated that, applying the irrigation requirements on 8 pulses/day with using BPM is the best conditions because under these conditions was occurred the highest value of yield, quality traits and IWUE soybean and there was significant deference between this case and other treatments. Where, pulse irrigation technique increase from water movement in horizontal direction than vertical direction hence improve from soil moisture distribution and wetted soil volume in root zone and using BPM decrease from evaporation process rate from soil surface hence decreasing of salts accumulation in addition to decreasing of weed growth in the root zone. All traits at AIR on 12 pulses/ day are decreased by increasing of pulses, this may be due to irrigation water was very small with every pulse at AIR on 12 pulses/day in addition increasing the total time of time-off, this mean, un-sufficient application for irrigation water to remove water stress in the root zone.
文摘Irrigation with high salinity water influences plant growth, production of photosynthetic pigments and total phenols, leading to reduction in crop yield and quality. The objective of this study was to investigate the effects of potassium (K) foliar application in mitigating the negative effects of salt stress on pepper plants. A greenhouse experiment was conducted to investigate the effects of foliar application of potassium (K) on pepper plants grown with different salinity water irrigation (3000 and 6000 ppm as compared to tap water with salinity level of 300 ppm). Irrigation using high salinity water decreased plant height, biomass production, and fruit yield as compared to those of the plants irrigated by tap water. Photosynthetic pigments and total phenols increased in the former as compared to those of the latter plants. The most serious affect was for the plants under highest salinity irrigation (6000 ppm) as compared to that of the plants under moderate salinity irrigation (3000 ppm). Foliar application of potassium mono phosphate (KMP) at 200ppm concentration increased the plant growth, biomass production, and fruit yield. Chlorophyll_a content and total phenols increased significantly with foliar application of 100 ppm KMP. Further increase in foliar KMP concentration to 200 ppm had no significant benefits on photosynthetic pigments and total phenols content. This study demonstrated that foliar application of KMP, to some extent, mitigated the negative effects of high salinity water irrigation on pepper plant growth and fruit yield.
文摘Waterlogging and low application efficiency are the main problems inherent with surface irrigation in the Nile Delta. Develop surface irrigation using gated pipes (GP) is a new method to be used to distribute water into furrow irrigated fields as strategy based on water saving. Laboratory calibration was conducted out to evaluate the hydraulic characteristics of pipe gates. Field experiments were conducted at the Experimental Farm of the Agriculture Faculty, Minufiya University during 2013 and 2014 seasons to evaluate the performance of utilize gated pipes technique for irrigating five maize varieties (S.C 10, S.C 130, S.C 131, S.C 2031 and T.W.C 321). The results revealed that the highest amount of water applied was with traditional surface irrigation (6423.81 m3·ha-1. Use of gated pipes system GP1 as compared to traditional irrigation reduced water application by 923.81 m3·ha-1 with grain and stover yields increases of 5.7% and 3.4%, respectively. Traditional irrigation system achieved lowest irrigation performance parameters compared to gated pipes systems. Maize physiological attributes, yield, water use efficiency (WUE) and nitrogen accumulation were significantly decreased by either deficit or surplus irrigation than of GP1 rate. S.C 2031 variety significantly surpassed other varieties in abovementioned traits. Significant interaction effects were detected in both seasons. Maize varieties respond differently to irrigation systems. The highest values of grain yield (11062.6 and 10911.8 kg·ha-1 and stover yield (13639.0 and 13902.2 kg·ha-1) were obtained by S.C 2031 irrigated with GP1 system in both seasons. From the above mentioned results, it is concluded that the gated pipes technique is better than traditional irrigation for improving WUE and maize productivity under Nile Delta conditions.
文摘Two field experiments were carried out during growing seasons 2011 and 2012. It was executed in research farm of National Research Center in Nubaryia region, Egypt to study the effect of irrigation systems, fertigation rates by using the wastewater of fish farms “WWFF” in irrigation of potato. Study factors were irrigation systems (sprinkler irrigation system “SIS” and trickle irrigation system “TIS”), water quality (traditional irrigation water “TIW” and WWFF) and fertigation rates “FR” (20%, 40%, 60%, 80% and 100% NPK). The following parameters were studied to evaluate the effect of study factors: 1) Calculating the total amount of WWFF per season;2) Chemical and biological description of WWFF;3) Clogging ratio of emitters;4) Yield of potato;5) Irrigation water use efficiency of potato “IWUEpotato”. Statistical analysis indicated that, maximum values were obtained of yield under SIS × FR100% NPK × WWFF, also, there were no significant differences for yield values under the following conditions: SIS × FR100% NPK × WWFF > SIS × FR80% NPK × WWFF > SIS × FR60% NPK × WWFF > TIS × FR100% NPK × TIW. This means that, using WWFF in the irrigation can save at least 40% from mineral fertilizers and 100% from irrigation water under sprinkler irrigation system.
文摘A two-year study was carried out at Ismailia Agricultural Research Station, Egypt during 2016 and 2017 summer seasons to evaluate competitive effects of intercropping sunflower and peanut under different drip irrigation water amounts and K fertilizer rates for increasing farmer profitability. Three irrigation amounts (70%, 100% and 120% ETo), three K fertilizer levels (57, 86 and 114 K2O kg/ha) and four intercropping patterns of sunflower and peanut (different spatial arrangements) were implemented. The experimental design was strip split plot with three replications. The results showed that there were no significant differences between 100% and 120% ETo on most of yield traits of the intercrops. The highest K fertilizer level had the highest values of most yield traits of the intercrops. The highest values of peanut and sunflower traits were obtained from intercropping sunflower with peanut, where peanut seeds were sown on both sides of all the raised beds, sunflower seeds were sown on one row above the raised beds and the following bed was left without intercropping (P1). Thus, to attain the highest yield of intercrops and water equivalent ratio (WER), the lowest competitive pressure and the highest farmer profitability, 120% ETo, 114 K2O kg/ha and P1 intercropping pattern should be implemented. This research found that the result of competitiveness was consistent with the result of profitability.
文摘In order to examine the application of different soil and foliar organic fertilizers as well as biofertilizing flax under sandy soil conditions, two field experiments were carried out at the Research and Production Station of the National Research Centre (NRC), Al Nubaria district, El-Behaira Governorate, Egypt during 2012/2013 and 2013/2014 winter seasons. The trials aimed to study the effect of humic acid (HA) as low cost natural fertilizer, inoculation with mycorrhiza, and biocharcoal on on yield, quality and water use efficiency of flax variety (Amon) under newly reclaimed sandy soil. The treatments consisted of HA (25 kg/feddan), inoculation with mycorrhiza (1 kg/ feddan), and biochar (4 tons/feddan) and all the combinations among the treatments. Results showed that the treatment combination of (humic acid + mycorrhiza + biochar) was significantly superior compared to all the other treatments in number of capsules/plant, biological yield/plant (g), seed yield/plant (g), seed yield (kg/feddan), straw yield (tons/feddan), oil percent (%), and oil yield (kg/feddan). However, it gave the highest fruiting zone length (cm) but not significantly different from (mycorrhiza + biochar) and (humic acid + biochar), also it gave the highest seed index (g) but not significantly different from humic acid and (humic acid + mycorrhiza). The treatment combination of (humic acid + biochar) gave the highest plant height (cm), technical stem length (cm), and number of branches/plant.
基金supported by the National Natural Science Foundation of China(U1703244)Bingtuan Science and Technology Program(2021DB019)Science and Technology project of Alar City(2018TF01)。
文摘This study highlights the influence of freezing-thawing processes on soil erosion in an alpine mine restoration area. Accordingly, a series of simulation experiments were conducted to investigate runoff, sediment, and nutrient losses, and potential influencing factors under freeze-thaw(FT) conditions. Three FT treatments(i.e., 0, 3, and 5 FT cycles), and two soil moisture contents(SMCs;i.e., 10% and 20% SMC on a gravimetric basis) were assessed. The runoff, sediment yield, ammonia nitrogen(AN), nitrate nitrogen(NN), total phosphorus(TP), and dissolved phosphorus(DP) losses from runoff were characterized under different rainfall durations. The fitting results indicated that the runoff rate and sediment rate, AN, NN, TP, and DP concentrations in runoff could be described by exponential functions. FT action increased the total runoff volume and sediment yield by 14.6%–26.0% and 8.8%–35.2%, respectively. The runoff rate and sediment rate increased rapidly with the increment of FT cycles before stabilizing. At 20% SMC, the total runoff volume and sediment yield were significantly higher than those at 10% SMC. The loss curves of AN and NN concentrations varied due to differences in their chemical properties. FT action and high SMC promoted AN and NN losses, whereas the FT cycles had little effect. FT action increased TP and DP losses by 60.2%–220.1% and 48.4%–129.8%, respectively, compared to cases with no FT action;the highest TP and DP losses were recorded at 20% SMC. This study provides a deep understanding of freezing-thawing mechanisms in the soils of alpine mine restoration areas and the influencing factors of these mechanisms on soil erosion, thereby supporting the development of erosion prevention and control measures in alpine mine restoration areas.
文摘In recent years Jatropha curcas L. has emerged as a biofuel crop with potential for its production in marginal land with application of treated sewage water. Since this is a new crop for its profitable cultivation, additional research is needed to develop optimal management programs, including macro and micronutrients applications. A pot experiment was conducted in a Greenhouse at the National Research Center, Dokki, Cairo, Egypt, during 2010 summer to evaluate effects of varying concentrations of iron (Fe), manganese (Mn), and zinc (Zn) in irrigation water (0, 50, 100, 150, 200 and 250 ppm) on the growth, biomass production, photosynthetic pigments, and mineral nutrients status in the plants. Increasing concentrations of Fe, Mn, and Zn in irrigation water up to 150 ppm increased the biomass weight, photosynthetic pigments, and nutrient uptake by Jatropha plants. Further increase in concentrations of micronutrients showed negative effects on the above response parameters. Therefore, this study demonstrates that Jatropha can be grown under irrigation using waste water containing reasonable concentrations of micronutrients and heavy metals. This property of Jatropha provides some support for potential use of this crop for phytoremediation of metal contaminated soils. However, long term field research is needed to further verify both the above beneficial effects.
文摘Salinity stress impacts crop growth as well as production. The need for increased food production to feed the increasing population and the limited resources, i.e. optimal quality land and water, require developing strategies to mitigate marginal stresses, including salinity stress, for reasonable expectation of crop production. A pot experiment was conducted in a greenhouse at the National Research Centre, Dokki, Cairo, Egypt in the summer season of 2005 to evaluate the effects of foliar application of ascorbic acid alone or in combination with zinc sulfate on the growth and photosynthetic pigments of millet plants irrigated by tap water (250 ppm, 0.39 dS·m-1) or moderate to high salinity irrigation water [2500 ppm (3.9 dS·m-1) and 5000 ppm (7.8 dS·m-1)]. Increased salinity in the irrigation water decreased the plant growth, biomass, and carotenoid content. Foliar application of ascorbic acid alone increased number of leaves and leaf area, while in combination with zinc sulfate increased the plant height and total plant biomass. However, these treatments had no significant effects on the photosynthetic pigments. This study demonstrates that exogenous application of ascorbic acid can enhance foliar growth which may contribute to increased plant biomass and yield.
文摘<span style="font-family:;" "=""><span style="font-family:Verdana;">Methane is released from waste disposal areas as a result from anaerobic decay of food. Methane causes more greenhouse effects than carbon dioxide so a methane monitoring system is required to warn its release from gas emitting environments. The low explosive limit of methane is 5% in ambient air, so gas leakage is dangerous and can produce explosions. An entire head monitoring system was built around a MQ-4 methane gas sensor as it is cheap and reliable. The design proves to be flexible enough as it can measure CH</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> emissions in ducts, CH</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> in landfills at different depths and even in cattle barns. The measuring system head consists of a suction pump, solenoids, and a methane sensor. Measurements are taken 13 seconds after methane gas sucking. </span><span style="font-family:Verdana;">A timing of 100 seconds is required for purging the chamber before the</span><span style="font-family:Verdana;"> second solenoid is turned-on. Devices temperature during operation was sampled with a thermal Flir-One camera and solenoid coil temperature was of 24.9</span></span><span style="font-family:;" "=""><span style="font-family:Verdana;"><span style="white-space:nowrap;">˚</span>C </span><span style="font-family:Verdana;">after a continuous operation of 30 seconds. As hoses for emission sampling</span><span style="font-family:Verdana;"> become larger time for sampling increases as well as energy consumption.</span></span>
基金Project supported by the Ministry of Education and Science,Spain (No.AGL2006-01283)the European Regional Development Fund (No.EX2006-0347).
文摘The saline wetlands,or'saladas',of Monegros Desert,NE Spain,contain biodiversity that depends on the estab- lishment of a prognostic monitoring system that can warn of approaching irreversible damage.In the context of a lack of existing biodiversity inventories for the saladas,we determined their state of conservation and vulnerability using seven physical indicators:escarpment continuity,cropping,stone dumping,size,water occurrence,distance to roads,and proximity to irrigated areas.These features were combined into three meaningful indexes,i.e.,conservation,current vulnerability,and future vulnerability,thus creating an assessment of the preservation or degradation of saladas in the context of encroaching agricultural irrigation projects.The proposed indexes produced consistent results and showed that a great number of the Monegros wetlands were threatened,regardless of their size or frequency of water occurrence.Only 20% of the saladas studied were classified as being in a good or very good conservation,whereas 50% were in bad or very bad shape.A high current vulnerability was found for 60% of the saladas.For saladas located in land to be irrigated, we predicted that 73% would have a high or very high future vulnerability.Currently,58% of the saladas were in bad or very bad condition and fully 65% of the saladas,variable in size,presented a bad or very bad prognosis.Our approach provides a monitoring strategy for the conservation of saline wetlands threatened by agricultural intensification,especially irrigation.
基金Shahid Bahonar University for providing research funds and Iran's Pistachio Research Institute (IPRI) for providing the research material
文摘Phenylalanin ammonia-lyase(PAL) plays a pivotal role in the production of phenolic compounds,which are responsible for the success of the defense strategies in harsh environments in response to different stimuli.Measurements of the PAL activity,total phenolics,total flavonoids and anthocyanin contents were performed in flowers,leaves and fruits of three pistachio cultivars "Ahmadaghaii","Ohadi" and "Kallehghuchi".The results showed that PAL activity was different in cultivars and in plant organs of pistachio trees(flowers,leaves and fruits).The highest activity rate of their compounds was observed in Ahmadaghaii cultivar.A positive correlation was observed between PAL activity,total phenolics and total flavonoids in leaves,and a negative correlation between PAL activity and anthocyanin contents in leaves and flowers of Ahmadaghaii cultivar.PAL activity and total phenolics in fruits of pistachio suffered a decrease when the maturation processes began.It is suggested that the hulls of the pistachio fruits,containing high level of phenolic compounds(especially in Ahmadaghaii cultivar),may function as a protective layer of defense chemicals against ultraviolet radiation and pathogens.The final concentration of phenolic compounds,flavonoids and antocyanins in the kernel depend on PAL activity in the kernel's cultivar.The results led to the conclusion that increase in PAL activity,phenolic compounds and flavonoids in Ahmadaghaii can help the plant to cope with the stresses better than the other cultivars.Since phenolic compounds are antioxidant and scavenge free oxygen,it is postulated that Ahmadaghaii is the most resistant cultivar to the environmental stresses.
文摘Most of infrastructure projects around the world have to focus on a clear understanding of geological model which may be determined from various sources of information. The limitation in geotechnical data and budget affects the accuracy of the geological model, particularly for projects of long and deep tunnel of which accessibility to the excavation points is difficult and far reaching. Therefore, an approach adopted for interpretation plays an important role in the level of uncertainty of the derived geological model. This paper focuses on the determination of the geological models at the site of a long water diversion tunnel project in a complex geologic setting in northern Thailand from an approach to understand the relationship between regional tectonic setting and local tectonic condition so that geological structures and rock mass conditions along the tunnel alignment can be assessed for a better planning of tunnel design and construction. The paper describes tectonic settings at regional scale (Northern Thailand and Eastern Myanmar), tectonic features and geologic condition in project area, geotechnical investigation and data along tunnel alignment and predicted tunnel ground behavior.