Background Stocker cattle diet and management influence beef cattle performance during the finishing stage,but knowledge of the dynamics of the rumen microbiome associated with the host are lacking.A longitudinal stud...Background Stocker cattle diet and management influence beef cattle performance during the finishing stage,but knowledge of the dynamics of the rumen microbiome associated with the host are lacking.A longitudinal study was conducted to determine how the feeding strategy from the stocker to the finishing stages of production affects the temporal dynamics of rumen microbiota.During the stocker phase,either dry hay or wheat pasture were provided,and three levels of monensin were administrated.All calves were then transported to a feedlot and received similar finishing diets with or without monensin.Rumen microbial samples were collected on d 0,28,85 during the stocker stage(S0,S28 and S85)and d 0,14,28,56,30 d before slaughter and the end of the trial during the finishing stage(F0,F14,F28,F56,Pre-Ba,and Final).The V4 region of the bacterial 16S rRNA gene of 263 rumen samples was sequenced.Results Higher alpha diversity,including the number of observed bacterial features and the Shannon index,was observed in the stocker phase compared to the finishing phase.The bacterial amplicon sequence variants(ASVs)differentiating different sampling time points were identified.Dietary treatments during the stocker stage temporally impact the dynamics of rumen microbiota.For example,shared bacteria,including Bacteroidales(ASV19)and Streptococcus infantarius(ASV94),were significantly higher in hay rumen on S28,S85,and F0,while Bacteroidaceae(ASV11)and Limivicinus(ASV15)were more abundant in wheat.Monensin affected rumen microbial composition at a specific time.Transportation to feedlot significantly influenced microbiome structure and diversity in hay-fed calves.Bacterial taxa associated with body weight were classified,and core microbiotas interacted with each other during the trial.Conclusions In summary,the temporal dynamics of the rumen microbiome in cattle at the stocker and finishing stage are influenced by multiple factors of the feeding strategy.Diet at the stocker phase may temporarily affect the microbial composition during this stage.Modulating the rumen microbiome in the steers at the stocker stage affects the microbial interactions and performance in the finishing stage.展开更多
Integrated water and fertilizer management is important for promoting sustainable development of facility agriculture,and biochar plays an important role in guaranteeing food production,as well as alleviating water sh...Integrated water and fertilizer management is important for promoting sustainable development of facility agriculture,and biochar plays an important role in guaranteeing food production,as well as alleviating water shortages and the overuse of fertilizers.The field experiment had twelve treatments and a control(CK)trial including two irrigation amounts(I1,100%ETm;I2,60%ETm;where ETm is the maximum evapotranspiration),two nitrogen applications(N1,360 kg ha^(−1);N2,120 kg ha^(−1))and three biochar application levels(B1,60 t ha^(−1);B_(2),30 t ha^(−1)and B3,0 t ha^(−1)).A multi-objective synergistic irrigation-nitrogen-biochar application system for improving tomato yield,quality,water and nitrogen use efficiency,and greenhouse emissions was developed by integrating the techniques of experimentation and optimization.First,a coupled irrigation-nitrogen-biochar plot experiment was arranged.Then,tomato yield and fruit quality parameters were determined experimentally to establish the response relationships between irrigation-nitrogen-biochar dosage and yield,comprehensive quality of tomatoes(TCQ),irrigation water use efficiency(IWUE),partial factor productivity of nitrogen(PFPN),and net greenhouse gas emissions(NGE).Finally,a multi-objective dynamic optimization regulation model of irrigation-nitrogen-biochar resource allocation at different growth stages of tomato was constructed which was solved by the fuzzy programming method.The results showed that the application of irrigation and nitrogen to biochar promoted increase in yield,IWUE and PFPN,while it had an inhibitory effect on NGE.In addition,the optimal allocation amounts of water and fertilizer were different under different scenarios.The yield of the S1 scenario increased by 8.31%compared to the B_(1)I_(1)N_(2) treatment;TCQ of the S2 scenario increased by 5.14%compared to the B_(2)I_(2)N_(1) treatment;IWUE of the S3 scenario increased by 10.01%compared to the B1I2N2 treatment;PFPN of the S4 scenario increased by 9.35%compared to the B_(1)I_(1)N_(2) treatment;and NGE of the S5 scenario decreased by 11.23%compared to the B_(2)I1N1 treatment.The optimization model showed that the coordination of multiple objectives considering yield,TCQ,IWUE,PFPN,and NGE increased on average from 4.44 to 69.02%compared to each treatment when the irrigation-nitrogen-biochar dosage was 205.18 mm,186 kg ha^(−1)and 43.31 t ha^(−1),respectively.This study provides a guiding basis for the sustainable management of water and fertilizer in greenhouse tomato production under drip irrigation fertilization conditions.展开更多
The purpose of this paper is to investigate the spatial interpolation of rainfall variability with deterministic and geostatic inspections in the Prefecture of Kilkis (Greece). The precipitation data where recorded fr...The purpose of this paper is to investigate the spatial interpolation of rainfall variability with deterministic and geostatic inspections in the Prefecture of Kilkis (Greece). The precipitation data where recorded from 12 meteorological stations in the Prefecture of Kilkis for 36 hydrological years (1973-2008). The cumulative monthly values of rainfall were studied on an annual and seasonal basis as well as during the arid-dry season. In the deterministic tests, the I.D.W. and R.B.F. checks were inspected, while in the geostatic tests, Ordinary Kriging and Universal Kriging respectively. The selection of the optimum method was made based on the least Root Mean Square Error (R.M.S.E.), as well as on the Mean Error (M.E.), as assessed by the cross validation analysis. The geostatical Kriging also considered the impact of isotropy and anisotropy across all time periods of data collection. Moreover, for Universal Kriging, the study explored spherical, exponential and Gaussian models in various combinations. Geostatistical techniques consistently demonstrated greater reliability than deterministic techniques across all time periods of data collection. Specifically, during the annual period, anisotropy was the prevailing characteristic in geostatistical techniques. Moreover, the results for the irrigation and seasonal periods were generally comparable, with few exceptions where isotropic methods yielded lower (R.M.S.E.) in some seasonal observations.展开更多
Multifunctionality, as a feature of agriculture, is subject to different interpretations, depending on the state and context. The core concept of Multifunctionality of Agriculture (MFA) is that the agricultural sector...Multifunctionality, as a feature of agriculture, is subject to different interpretations, depending on the state and context. The core concept of Multifunctionality of Agriculture (MFA) is that the agricultural sector has multiple roles. These roles are not confined to food and fiber production, but also to the provision of several non-market commodities. In this study, we have interviewed 30 Syrian experts from different fields of sciences so as to examine their understanding of the concept of multifunctional agriculture and its elements and look closely into the importance of the elements of MFA in Syrian agricultural policy context from an expert’s point of view. The results show that wider roles of agriculture are highly acknowledged among the chosen experts but few of them are working on it. In its broadest sense, no undivided acceptance of the concept of multifunctionality has been found. The Syrian agriculture policies have elements which support and improve MFA, but it is not clearly recognized as such.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
This experiment aims to increase sweet pepper production sustainably by using manures and a combination of manure and fertilizer. Manures are well known to improve soil health and maintain crop production for a relati...This experiment aims to increase sweet pepper production sustainably by using manures and a combination of manure and fertilizer. Manures are well known to improve soil health and maintain crop production for a relatively long period. This study was conducted under a tunnel house at the National Agricultural Research and Extension Institute at Mon Repos East Coast Demerara, Guyana. Plots were arranged according to strip plot design with two treatments (Aristotle and Sunsation), four rates (R1: 0 g/plant), (R2: 350 kg NPK/ha + 10 t vermicompost/ha), (R3: 10 t poultry manure/ha + 10 t vermicompost/ha and (R4: 350 kg NPK/ha + 10 t poultry manure/ha) and replicated thrice. These nutrients were applied in a split application at four weeks before planting, and four, eight, and twelve-week intervals after planting. The varieties did not differ from one another for the vegetative parameters tested. Plants treated with Rate 2 achieved significantly better growth parameters such as plant height, plant spread, and number of branches than the other rates. Sunsation obtained a significantly higher yield of 21.4 t/ha at the 5% level as compared to Aristotle (19.9 t/ha). The various rates recorded significant differences in yield. Rate 2 obtained a significantly higher yield of 32.8 t/ha followed by Rate 4 with 24.9 t/ha, then Rate 3 (17.0 t/ha). The lowest yield of 7.8 t/ha was attained by Rate 1. The interaction of varieties and rates showed statistically significant differences in yield. The interaction of Sunsation and Aristotle with Rate 2 achieved a superior yield of 34.8 t/ha and 30.7 t/ha respectively than other rates. Rate 4 also obtained significant interaction with Sunsation and Aristotle to achieve a yield of 25.7 t/ha and 24.1 t/ha respectively than Rate 3. Rate 3 interacted significantly with Sunsation and Aristotle and obtained a yield of 16.5 t/ha and 17.5 t/ha compared to Rate 1. Rate 1 achieved the least interaction for both varieties tested. Rates differed significantly for fruit shelf-life at room temperature. Fruits obtained from Rate 3 recorded a significantly longer fruit shelf-life of 14.7 days for 50% decay when stored at room temperature (30.3˚C) than other rates. The lowest fruit shelf-life of 7.7 days was obtained from Rate 1. This study indicated that the Sunsation variety is better to cultivate because of superior improvement in growth and yield attributes. The application of Rate 2 can considerably increase yield and when combined with Sunsation variety superior yield and yield attributes can be obtained.展开更多
Natural regeneration is the interaction of natural processes to restore the forest ecosystem. Its dynamics are influenced by the intensity and extent of a series of abiotic and biotic factors, which may be intrinsic o...Natural regeneration is the interaction of natural processes to restore the forest ecosystem. Its dynamics are influenced by the intensity and extent of a series of abiotic and biotic factors, which may be intrinsic or extrinsic. Knowing the importance of establishing natural regeneration within forest ecosystems, this work aimed to evaluate whether litter depth and trail distance influenced seedling abundance and richness in a forest fragment undergoing natural restoration. The hypothesis tested in this research was that abiotic factors influence the natural regeneration of this forest since they are factors that are directly linked to seed germination and seedling establishment. 30 plots of 1 m2 were randomly analyzed within the forest located on the brown trail. A millimeter ruler was used to diagnose the litter depth and a measuring tape to measure the distance from the plot to the edge. In each plot the seedlings were morpho-specified and each morphospecies had the number of individuals counted. Linear regression tests were performed to assess the relationships between species richness and trail distance and litter depth. The same was done for species abundance. All results showed that there is no relationship pattern between any of the variables. Other factors also influence the regeneration of a forest, such as luminosity and seed bank. Furthermore, litter depth is related to the successional stage of the forest. It was concluded that the abiotic factors tested do not influence the regeneration of the study area.展开更多
The study evaluated the role of different substrates on water quality, growth and survival of Labeo victorianus fry. Random sampling was used to select 225 fry, stocked at 100/m<sup>3</sup> and fed on shel...The study evaluated the role of different substrates on water quality, growth and survival of Labeo victorianus fry. Random sampling was used to select 225 fry, stocked at 100/m<sup>3</sup> and fed on shell free artemia<sup>®</sup> (40% - 60% crude protein). Each treatment was carried out in triplicates using gravel and sand as substrates and water media without substrate (control). Growth and survival of the fry was monitored over 4 weeks period at a hatchery set-up. Physicochemical parameters were measured weekly while mortality was documented daily. Substrate type had an effect on water quality, growth and survival of fry. Dissolved Oxygen, growth and survival was higher in tanks under gravel substrate than sand and control while mortality was higher (22%) for sand (p ≤ 0.05) than gravel and sand treatments. Fry in gravel substrate had the best growth response (1.77 ± 0.92 g) while control and sand recorded 1.57 ± 0.90 g and 1.45 ± 0.97 g respectively. In contrast, growth was homogenous during the first 2 weeks of the trial but gravel substrate fry significantly out-grew sand and control in the remaining 3 weeks. However, fry in sand and control experienced compensatory growth towards the end of the study. Therefore, gravel substrate enhances L. victorianus performance and is recommended in the introduction of the species into aquaculture and re-stocking back to the wild.展开更多
Parasitic weeds are a major threat to food security in Africa and control measures mostly done by smallholder farmers are not effective in eradicating the parasites.This results in a yield loss up to 100%.Parasitic we...Parasitic weeds are a major threat to food security in Africa and control measures mostly done by smallholder farmers are not effective in eradicating the parasites.This results in a yield loss up to 100%.Parasitic weeds comprise Alectra vogelii,Striga spp.,Orobanche spp.,Rafflesia spp.,and Phoradendron spp.Parasitic attachment is successful when three necessary conditions have been fulfilled namely the compatible host,suitable environment,and parasitic weed.These species parasite plant species through special attachment features such as modified leaves,suckers,haustoria,or modified roots.In Africa,the variability of parasitic weeds is largely driven by environmental factors such as temperature,rainfall,soil type,and crop husbandry practices.Warmer temperatures create more hospitable conditions for certain parasitic weeds,and allowing them to spread to new areas.Parasitic weed control is vital for effective crop production and the control strategies can be achieved through integrated weed control method that embraces mechanical,cultural,chemical,and biological methods.However,the most effective and crucial method is the cultivation of resistant varieties that provide long-term protection against parasitic weeds.Studies have been done on host-parasite attachment where dodder can send out new roots to infected neighbouring plants and spread their parasitic behaviour.More insight and knowledge should offer new goals for control within the life cycle of the parasitic weeds and their metabolic activities.Lastly,disciplines such as agronomy,plant breeding,nutrition,economics,and IT should play their roles effectively in combating parasitic weeds.展开更多
Monogenic lines,which carried 23 genes for blast resistance were tested and used donors to transfer resistance genes by crossing method.The results under blast nursery revealed that 9 genes from 23 genes were suscepti...Monogenic lines,which carried 23 genes for blast resistance were tested and used donors to transfer resistance genes by crossing method.The results under blast nursery revealed that 9 genes from 23 genes were susceptible to highly susceptible under the three locations(Sakha,Gemmeza,and Zarzoura in Egypt);Pia,Pik,Pik-p,Piz-t,Pita,Pi b,Pi,Pi 19 and Pi 20.While,the genes Pii,Pik-s,Pik-h,Pi z,Piz-5,Pi sh,Pi 3,Pi 1,Pi 5,Pi 7,Pi 9,Pi 12,Pikm and Pita-2 were highly resistant at the same locations.Clustering analysis confirmed the results,which divided into two groups;the first one included all the susceptible genes,while the second one included the resistance genes.In the greenhouse test,the reaction pattern of five races produced 100%resistance under artificial inoculation with eight genes showing complete resistance to all isolates.The completely resistant genes:Pii,Pik-s,Piz,Piz-5(=bi2)(t),Pita(=Pi4)(t),Pita,Pi b and Pi1 as well as clustering analysis confirmed the results.In the F1 crosses,the results showed all the 25 crosses were resistant for leaf blast disease under field conditions.While,the results in F2 population showed seven crosses with segregation ratio of 15(R):1(S),two cross gave segregated ratio of 3 R:1 S and one gave 13:3.For the identification of blast resistance genes in the parental lines,the marker K3959,linked to Pik-s gene and the variety IRBLKS-F5 carry this gene,which was from the monogenic line.The results showed that four genotypes;Sakha 105,Sakha 103,Sakha 106 and IRBLKS-F5 were carrying Pik-s gene,while was absent in the Sakha 101,Sakha 104,IRBL5-M,IRBL9-W,IRBLTACP1 and IRBL9-W(R)genotypes.As for Pi 5 gene,the results showed that it was present in Sakha 103 and Sakha 104 varieties and absent in the rest of the genotypes.In addition,Pita-Pita-2 gene was found in the three Egyptian genotypes(Sakha 105,Sakha 101 and Sakha 104)plus IRBLTACP1 monogenetic.In F2 generation,six populations were used to study the inheritance of blast resistance and specific primers to confirm the ratio and identify the resistance genes.However,the ratios in molecular markers were the same of the ratio under field evaluation in the most population studies.These findings would facilitate in breeding programs for gene pyramiding and gene accumulation to produce durable resistance for blast using those genotypes.展开更多
North Africa is one of the most regions impacted by water shortage.The implementation of controlled drainage(CD)in the northern Nile River delta of Egypt is one strategy to decrease irrigation,thus alleviating the neg...North Africa is one of the most regions impacted by water shortage.The implementation of controlled drainage(CD)in the northern Nile River delta of Egypt is one strategy to decrease irrigation,thus alleviating the negative impact of water shortage.This study investigated the impacts of CD at different levels on drainage outflow,water table level,nitrate loss,grain yield,and water use efficiency(WUE)of various wheat cultivars.Two levels of CD,i.e.,0.4 m below the soil surface(CD-0.4)and 0.8 m below the soil surface(CD-0.8),were compared with subsurface free drainage(SFD)at 1.2 m below the soil surface(SFD-1.2).Under each drainage treatment,four wheat cultivars were grown for two growing seasons(November 2018–April 2019 and November 2019–April 2020).Compared with SFD-1.2,CD-0.4 and CD-0.8 decreased irrigation water by 42.0%and 19.9%,drainage outflow by 40.3%and 27.3%,and nitrate loss by 35.3%and 20.8%,respectively.Under CD treatments,plants absorbed a significant portion of their evapotranspiration from shallow groundwater(22.0%and 8.0%for CD-0.4 and CD-0.8,respectively).All wheat cultivars positively responded to CD treatments,and the highest grain yield and straw yield were obtained under CD-0.4 treatment.Using the initial soil salinity as a reference,the soil salinity under CD-0.4 treatment increased two-fold by the end of the second growing season without negative impacts on wheat yield.Modifying the drainage system by raising the outlet elevation and considering shallow groundwater contribution to crop evapotranspiration promoted water-saving and WUE.Different responses could be obtained based on the different plant tolerance to salinity and water stress,crop characteristics,and growth stage.Site-specific soil salinity management practices will be required to avoid soil salinization due to the adoption of long-term shallow groundwater in Egypt and other similar agroecosystems.展开更多
Plant growth-promoting bacteria(PGPB)play an important role in improving agricultural production under several abiotic stress factors.PGPB can be used to increase crop growth and development through hormonal balance a...Plant growth-promoting bacteria(PGPB)play an important role in improving agricultural production under several abiotic stress factors.PGPB can be used to increase crop growth and development through hormonal balance and increase nutrient uptake.The positive effect of PGPB may be due to its pivotal role in morphophysiological and biochemical characteristics like leaf number,leaf area,and stem length.Furthermore,relative water content,chlorophyll content,carotenoids,antioxidant enzymes,and plant hormones were improved with PGPB treatment.Crop yield and yield components were also increased with PGPB treatment in numerous crops.The anatomical structure of plant organs was increased such as lamina thickness,stem diameter,xylem vessel diameter,and number of xylem vessels as well as phloem thickness under treatment with PGPB.Additionally,PGPB can alleviate the negative effects of several abiotic stresses by regulating the antioxidant defense system to scavenge the reactive oxygen species resulting in an improvement of yield production in the stressed plants.Additionally,gene expressions were controlled by calcium ion modulation during secondary messengers that act upon calcium-dependent protein kinase and protein phosphatases.This includes many transcription factors such as MYB,AP2/ERF,bZIP,and NAC which regulate genes related to salinity stress signals.PGPB can demonstrate induction genes of signaling under abiotic stress conditions.This review gives an outline of the PGPB role in alleviating the harmful effects of abiotic factors such as salinity,drought,and heat associated with the improvement of the morpho-physiological and biochemical features especially,leaves and branches number,leaf area,antioxidant compounds,plant hormones,and relative water content.展开更多
Solar energy represents one of themost important renewable energy sources contributing to the energy transition process.Considering that the observation of daily global solar radiation(GSR)is not affordable in some pa...Solar energy represents one of themost important renewable energy sources contributing to the energy transition process.Considering that the observation of daily global solar radiation(GSR)is not affordable in some parts of the globe,there is an imperative need to develop alternative ways to predict it.Therefore,the main objective of this study is to evaluate the performance of different hybrid data-driven techniques in predicting daily GSR in semi-arid regions,such as the majority of Spanish territory.Here,four ensemble-based hybrid models were developed by hybridizing Additive Regression(AR)with Random Forest(RF),Locally Weighted Linear Regression(LWLR),Random Subspace(RS),and M5P.The base algorithms of the developed models are scarcely applied in previous studies to predict solar radiation.The testing phase outcomes demonstrated that the ARRF models outperform all other hybrid models.The provided models were validated by statisticalmetrics,such as the correlation coefficient(R)and root mean square error(RMSE).The results proved that Scenario#6,utilizing extraterrestrial solar radiation,relative humidity,wind speed,and mean,maximum,and minimum ambient air temperatures as the model inputs,leads to the most accurate predictions among all scenarios(R=0.968–0.988 and RMSE=1.274–1.403 MJ/m^(2)・d).Also,Scenario#3 stood in the next rank of accuracy for predicting the solar radiation in both validating stations.The AD-RF model was the best predictive,followed by AD-RS and AD-LWLR.Hence,this study recommends new effective methods to predict GSR in semiarid regions.展开更多
Pollution of residual plastic film in arable lands is a severe problem in China. In this study, the status of residual film and influential factors were investigated using the methods of farm survey in combination wit...Pollution of residual plastic film in arable lands is a severe problem in China. In this study, the status of residual film and influential factors were investigated using the methods of farm survey in combination with questionnaires and quadrat sampling at a large number of field sites in Xinjiang Uygur Autonomous Region, China. The results showed that the amount of film utilization increased largely and reached to 1.8×10~5 t in 2013. Similarly, the mulching area also substantially increased in recent decades, and reached to 2.7×10~5 ha in the same year. According to the current survey, 60.7% of the sites presented a greater mulch residue than the national film residue standard(75 kg ha^(–1)), and the maximum residual amount reached 502.2 kg ha^(–1) in Turpan, Xinjiang. The film thickness, the mulching time and the crop type all influenced mulch residue. The thickness of the film had significantly negative correlation with the amount of residual film(P0.05), while the mulching years had significantly positive correlation with it(P0.05). The total amount of residual film in Xinjiang was 3.43×105 t in 2011, which accounted for 15.3% of the cumulative dosage of mulching. Among all the crops, the cotton fields had the largest residual amount of mulch film(158.4 kg ha^(–1)), and also the largest contribution(2.6×10~5 tons) to the total amount of residual film in Xinjiang.展开更多
Winter wheat-maize rotations are dominant cropping systems on the North China Plain, where recently the use of organic manure with grain crops has almost disappeared. This could reduce soil fertility and crop producti...Winter wheat-maize rotations are dominant cropping systems on the North China Plain, where recently the use of organic manure with grain crops has almost disappeared. This could reduce soil fertility and crop productivity in the long run. A 20-year field experiment was conducted to 1) assess the effect of inorganic and organic nutrient sources on yield and yield trends of both winter wheat and maize, 2) monitor the changes in soil organic matter content under continuous wheat-maize cropping with different soil fertility management schemes, and 3) identify reasons for yield trends observed in Xuzhou City, Jiangsu Province, over a 20-year period. There were eight treatments applied to both wheat and maize seasons: a control treatment (C); three inorganic fertilizers, that is, nitrogen (N), nitrogen and phosphorus (NP), and nitrogen, phosphorus and potassium (NPK); and addition of farmyard manure (FYM) to these four treatments, that is, M, MN, MNP, and MNPK. At the end of the experiment the MN, MNP, and MNPK treatments had the highest yields, about 7 t wheat ha-1 and 7.5 t maize ha-1, with each about 1 t ha-1 more than the NPK treatments. Over 20 years with FYM soil organic matter increased by 80% compared to only 10% with NPK, which explained yield increases. However, from an environmental and agronomic perspective, manure application was not a superior strategy to NPK fertilizers. If manure was to be applied, though, it would be best applied to the wheat crop, which showed a better response than maize.展开更多
. Mostly based on assumptions derived from controlled-environment studies, predicted future atmospheric CO2 concen- trations [CO2] are expected to have considerable impacts on carbon (C) turnover in agro-ecosystems. I.... Mostly based on assumptions derived from controlled-environment studies, predicted future atmospheric CO2 concen- trations [CO2] are expected to have considerable impacts on carbon (C) turnover in agro-ecosystems. In order to allow the in situ examination of C-transformations in the plant-soil system of arable crop rotations under future [CO2], a free air carbon dioxide enrichment (FACE) experiment (550 μmol mol-1 CO2) was started at Braunschweig, Germany in 1999. The crop rotation under investigation comprised winter barley, a cover crop (ryegrass), sugar beets and winter wheat. Assessments of CO2 effects included the determination of above- and belowground biomass production, measurements of canopy CO2- and H2O- fluxes, soil microbial biomass and in situ soil respiration. The results obtained during the 1st crop rotation cycle (3 years) showed that for the selected crops elevated [CO2] entailed significant positive effects (P < 0.05) on aboveground (6%-14% stimulation) and belowground biomass production (up to 90% stimulation), while canopy evapotranspiration was reduced. This resulted in increased soil water content. Also, depending on crop type and season, high CO2 stimulated in situ soil respiration (up to 30%), while soil microbial biomass did not show significant responses to elevated [CO2] during the first rotation cycle.展开更多
基金the University of Arkansas Agricultural Experiment Station,Hatch Project No.AR002234,National Natural Science Foundation of China(32170430)Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding(2019B030301010)Key Laboratory of Animal Molecular Design and Precise Breeding of Guangdong Higher Education Institutes(2019KSYS011).
文摘Background Stocker cattle diet and management influence beef cattle performance during the finishing stage,but knowledge of the dynamics of the rumen microbiome associated with the host are lacking.A longitudinal study was conducted to determine how the feeding strategy from the stocker to the finishing stages of production affects the temporal dynamics of rumen microbiota.During the stocker phase,either dry hay or wheat pasture were provided,and three levels of monensin were administrated.All calves were then transported to a feedlot and received similar finishing diets with or without monensin.Rumen microbial samples were collected on d 0,28,85 during the stocker stage(S0,S28 and S85)and d 0,14,28,56,30 d before slaughter and the end of the trial during the finishing stage(F0,F14,F28,F56,Pre-Ba,and Final).The V4 region of the bacterial 16S rRNA gene of 263 rumen samples was sequenced.Results Higher alpha diversity,including the number of observed bacterial features and the Shannon index,was observed in the stocker phase compared to the finishing phase.The bacterial amplicon sequence variants(ASVs)differentiating different sampling time points were identified.Dietary treatments during the stocker stage temporally impact the dynamics of rumen microbiota.For example,shared bacteria,including Bacteroidales(ASV19)and Streptococcus infantarius(ASV94),were significantly higher in hay rumen on S28,S85,and F0,while Bacteroidaceae(ASV11)and Limivicinus(ASV15)were more abundant in wheat.Monensin affected rumen microbial composition at a specific time.Transportation to feedlot significantly influenced microbiome structure and diversity in hay-fed calves.Bacterial taxa associated with body weight were classified,and core microbiotas interacted with each other during the trial.Conclusions In summary,the temporal dynamics of the rumen microbiome in cattle at the stocker and finishing stage are influenced by multiple factors of the feeding strategy.Diet at the stocker phase may temporarily affect the microbial composition during this stage.Modulating the rumen microbiome in the steers at the stocker stage affects the microbial interactions and performance in the finishing stage.
基金supported by the National Natural Science Foundation of China(52222902 and 52079029)。
文摘Integrated water and fertilizer management is important for promoting sustainable development of facility agriculture,and biochar plays an important role in guaranteeing food production,as well as alleviating water shortages and the overuse of fertilizers.The field experiment had twelve treatments and a control(CK)trial including two irrigation amounts(I1,100%ETm;I2,60%ETm;where ETm is the maximum evapotranspiration),two nitrogen applications(N1,360 kg ha^(−1);N2,120 kg ha^(−1))and three biochar application levels(B1,60 t ha^(−1);B_(2),30 t ha^(−1)and B3,0 t ha^(−1)).A multi-objective synergistic irrigation-nitrogen-biochar application system for improving tomato yield,quality,water and nitrogen use efficiency,and greenhouse emissions was developed by integrating the techniques of experimentation and optimization.First,a coupled irrigation-nitrogen-biochar plot experiment was arranged.Then,tomato yield and fruit quality parameters were determined experimentally to establish the response relationships between irrigation-nitrogen-biochar dosage and yield,comprehensive quality of tomatoes(TCQ),irrigation water use efficiency(IWUE),partial factor productivity of nitrogen(PFPN),and net greenhouse gas emissions(NGE).Finally,a multi-objective dynamic optimization regulation model of irrigation-nitrogen-biochar resource allocation at different growth stages of tomato was constructed which was solved by the fuzzy programming method.The results showed that the application of irrigation and nitrogen to biochar promoted increase in yield,IWUE and PFPN,while it had an inhibitory effect on NGE.In addition,the optimal allocation amounts of water and fertilizer were different under different scenarios.The yield of the S1 scenario increased by 8.31%compared to the B_(1)I_(1)N_(2) treatment;TCQ of the S2 scenario increased by 5.14%compared to the B_(2)I_(2)N_(1) treatment;IWUE of the S3 scenario increased by 10.01%compared to the B1I2N2 treatment;PFPN of the S4 scenario increased by 9.35%compared to the B_(1)I_(1)N_(2) treatment;and NGE of the S5 scenario decreased by 11.23%compared to the B_(2)I1N1 treatment.The optimization model showed that the coordination of multiple objectives considering yield,TCQ,IWUE,PFPN,and NGE increased on average from 4.44 to 69.02%compared to each treatment when the irrigation-nitrogen-biochar dosage was 205.18 mm,186 kg ha^(−1)and 43.31 t ha^(−1),respectively.This study provides a guiding basis for the sustainable management of water and fertilizer in greenhouse tomato production under drip irrigation fertilization conditions.
文摘The purpose of this paper is to investigate the spatial interpolation of rainfall variability with deterministic and geostatic inspections in the Prefecture of Kilkis (Greece). The precipitation data where recorded from 12 meteorological stations in the Prefecture of Kilkis for 36 hydrological years (1973-2008). The cumulative monthly values of rainfall were studied on an annual and seasonal basis as well as during the arid-dry season. In the deterministic tests, the I.D.W. and R.B.F. checks were inspected, while in the geostatic tests, Ordinary Kriging and Universal Kriging respectively. The selection of the optimum method was made based on the least Root Mean Square Error (R.M.S.E.), as well as on the Mean Error (M.E.), as assessed by the cross validation analysis. The geostatical Kriging also considered the impact of isotropy and anisotropy across all time periods of data collection. Moreover, for Universal Kriging, the study explored spherical, exponential and Gaussian models in various combinations. Geostatistical techniques consistently demonstrated greater reliability than deterministic techniques across all time periods of data collection. Specifically, during the annual period, anisotropy was the prevailing characteristic in geostatistical techniques. Moreover, the results for the irrigation and seasonal periods were generally comparable, with few exceptions where isotropic methods yielded lower (R.M.S.E.) in some seasonal observations.
文摘Multifunctionality, as a feature of agriculture, is subject to different interpretations, depending on the state and context. The core concept of Multifunctionality of Agriculture (MFA) is that the agricultural sector has multiple roles. These roles are not confined to food and fiber production, but also to the provision of several non-market commodities. In this study, we have interviewed 30 Syrian experts from different fields of sciences so as to examine their understanding of the concept of multifunctional agriculture and its elements and look closely into the importance of the elements of MFA in Syrian agricultural policy context from an expert’s point of view. The results show that wider roles of agriculture are highly acknowledged among the chosen experts but few of them are working on it. In its broadest sense, no undivided acceptance of the concept of multifunctionality has been found. The Syrian agriculture policies have elements which support and improve MFA, but it is not clearly recognized as such.
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This experiment aims to increase sweet pepper production sustainably by using manures and a combination of manure and fertilizer. Manures are well known to improve soil health and maintain crop production for a relatively long period. This study was conducted under a tunnel house at the National Agricultural Research and Extension Institute at Mon Repos East Coast Demerara, Guyana. Plots were arranged according to strip plot design with two treatments (Aristotle and Sunsation), four rates (R1: 0 g/plant), (R2: 350 kg NPK/ha + 10 t vermicompost/ha), (R3: 10 t poultry manure/ha + 10 t vermicompost/ha and (R4: 350 kg NPK/ha + 10 t poultry manure/ha) and replicated thrice. These nutrients were applied in a split application at four weeks before planting, and four, eight, and twelve-week intervals after planting. The varieties did not differ from one another for the vegetative parameters tested. Plants treated with Rate 2 achieved significantly better growth parameters such as plant height, plant spread, and number of branches than the other rates. Sunsation obtained a significantly higher yield of 21.4 t/ha at the 5% level as compared to Aristotle (19.9 t/ha). The various rates recorded significant differences in yield. Rate 2 obtained a significantly higher yield of 32.8 t/ha followed by Rate 4 with 24.9 t/ha, then Rate 3 (17.0 t/ha). The lowest yield of 7.8 t/ha was attained by Rate 1. The interaction of varieties and rates showed statistically significant differences in yield. The interaction of Sunsation and Aristotle with Rate 2 achieved a superior yield of 34.8 t/ha and 30.7 t/ha respectively than other rates. Rate 4 also obtained significant interaction with Sunsation and Aristotle to achieve a yield of 25.7 t/ha and 24.1 t/ha respectively than Rate 3. Rate 3 interacted significantly with Sunsation and Aristotle and obtained a yield of 16.5 t/ha and 17.5 t/ha compared to Rate 1. Rate 1 achieved the least interaction for both varieties tested. Rates differed significantly for fruit shelf-life at room temperature. Fruits obtained from Rate 3 recorded a significantly longer fruit shelf-life of 14.7 days for 50% decay when stored at room temperature (30.3˚C) than other rates. The lowest fruit shelf-life of 7.7 days was obtained from Rate 1. This study indicated that the Sunsation variety is better to cultivate because of superior improvement in growth and yield attributes. The application of Rate 2 can considerably increase yield and when combined with Sunsation variety superior yield and yield attributes can be obtained.
文摘Natural regeneration is the interaction of natural processes to restore the forest ecosystem. Its dynamics are influenced by the intensity and extent of a series of abiotic and biotic factors, which may be intrinsic or extrinsic. Knowing the importance of establishing natural regeneration within forest ecosystems, this work aimed to evaluate whether litter depth and trail distance influenced seedling abundance and richness in a forest fragment undergoing natural restoration. The hypothesis tested in this research was that abiotic factors influence the natural regeneration of this forest since they are factors that are directly linked to seed germination and seedling establishment. 30 plots of 1 m2 were randomly analyzed within the forest located on the brown trail. A millimeter ruler was used to diagnose the litter depth and a measuring tape to measure the distance from the plot to the edge. In each plot the seedlings were morpho-specified and each morphospecies had the number of individuals counted. Linear regression tests were performed to assess the relationships between species richness and trail distance and litter depth. The same was done for species abundance. All results showed that there is no relationship pattern between any of the variables. Other factors also influence the regeneration of a forest, such as luminosity and seed bank. Furthermore, litter depth is related to the successional stage of the forest. It was concluded that the abiotic factors tested do not influence the regeneration of the study area.
文摘The study evaluated the role of different substrates on water quality, growth and survival of Labeo victorianus fry. Random sampling was used to select 225 fry, stocked at 100/m<sup>3</sup> and fed on shell free artemia<sup>®</sup> (40% - 60% crude protein). Each treatment was carried out in triplicates using gravel and sand as substrates and water media without substrate (control). Growth and survival of the fry was monitored over 4 weeks period at a hatchery set-up. Physicochemical parameters were measured weekly while mortality was documented daily. Substrate type had an effect on water quality, growth and survival of fry. Dissolved Oxygen, growth and survival was higher in tanks under gravel substrate than sand and control while mortality was higher (22%) for sand (p ≤ 0.05) than gravel and sand treatments. Fry in gravel substrate had the best growth response (1.77 ± 0.92 g) while control and sand recorded 1.57 ± 0.90 g and 1.45 ± 0.97 g respectively. In contrast, growth was homogenous during the first 2 weeks of the trial but gravel substrate fry significantly out-grew sand and control in the remaining 3 weeks. However, fry in sand and control experienced compensatory growth towards the end of the study. Therefore, gravel substrate enhances L. victorianus performance and is recommended in the introduction of the species into aquaculture and re-stocking back to the wild.
文摘Parasitic weeds are a major threat to food security in Africa and control measures mostly done by smallholder farmers are not effective in eradicating the parasites.This results in a yield loss up to 100%.Parasitic weeds comprise Alectra vogelii,Striga spp.,Orobanche spp.,Rafflesia spp.,and Phoradendron spp.Parasitic attachment is successful when three necessary conditions have been fulfilled namely the compatible host,suitable environment,and parasitic weed.These species parasite plant species through special attachment features such as modified leaves,suckers,haustoria,or modified roots.In Africa,the variability of parasitic weeds is largely driven by environmental factors such as temperature,rainfall,soil type,and crop husbandry practices.Warmer temperatures create more hospitable conditions for certain parasitic weeds,and allowing them to spread to new areas.Parasitic weed control is vital for effective crop production and the control strategies can be achieved through integrated weed control method that embraces mechanical,cultural,chemical,and biological methods.However,the most effective and crucial method is the cultivation of resistant varieties that provide long-term protection against parasitic weeds.Studies have been done on host-parasite attachment where dodder can send out new roots to infected neighbouring plants and spread their parasitic behaviour.More insight and knowledge should offer new goals for control within the life cycle of the parasitic weeds and their metabolic activities.Lastly,disciplines such as agronomy,plant breeding,nutrition,economics,and IT should play their roles effectively in combating parasitic weeds.
基金Authors extend their appreciation to Deanship of Scientific Research,King Faisal University,Saudi Arabia,for supporting this research(NA000112).
文摘Monogenic lines,which carried 23 genes for blast resistance were tested and used donors to transfer resistance genes by crossing method.The results under blast nursery revealed that 9 genes from 23 genes were susceptible to highly susceptible under the three locations(Sakha,Gemmeza,and Zarzoura in Egypt);Pia,Pik,Pik-p,Piz-t,Pita,Pi b,Pi,Pi 19 and Pi 20.While,the genes Pii,Pik-s,Pik-h,Pi z,Piz-5,Pi sh,Pi 3,Pi 1,Pi 5,Pi 7,Pi 9,Pi 12,Pikm and Pita-2 were highly resistant at the same locations.Clustering analysis confirmed the results,which divided into two groups;the first one included all the susceptible genes,while the second one included the resistance genes.In the greenhouse test,the reaction pattern of five races produced 100%resistance under artificial inoculation with eight genes showing complete resistance to all isolates.The completely resistant genes:Pii,Pik-s,Piz,Piz-5(=bi2)(t),Pita(=Pi4)(t),Pita,Pi b and Pi1 as well as clustering analysis confirmed the results.In the F1 crosses,the results showed all the 25 crosses were resistant for leaf blast disease under field conditions.While,the results in F2 population showed seven crosses with segregation ratio of 15(R):1(S),two cross gave segregated ratio of 3 R:1 S and one gave 13:3.For the identification of blast resistance genes in the parental lines,the marker K3959,linked to Pik-s gene and the variety IRBLKS-F5 carry this gene,which was from the monogenic line.The results showed that four genotypes;Sakha 105,Sakha 103,Sakha 106 and IRBLKS-F5 were carrying Pik-s gene,while was absent in the Sakha 101,Sakha 104,IRBL5-M,IRBL9-W,IRBLTACP1 and IRBL9-W(R)genotypes.As for Pi 5 gene,the results showed that it was present in Sakha 103 and Sakha 104 varieties and absent in the rest of the genotypes.In addition,Pita-Pita-2 gene was found in the three Egyptian genotypes(Sakha 105,Sakha 101 and Sakha 104)plus IRBLTACP1 monogenetic.In F2 generation,six populations were used to study the inheritance of blast resistance and specific primers to confirm the ratio and identify the resistance genes.However,the ratios in molecular markers were the same of the ratio under field evaluation in the most population studies.These findings would facilitate in breeding programs for gene pyramiding and gene accumulation to produce durable resistance for blast using those genotypes.
文摘North Africa is one of the most regions impacted by water shortage.The implementation of controlled drainage(CD)in the northern Nile River delta of Egypt is one strategy to decrease irrigation,thus alleviating the negative impact of water shortage.This study investigated the impacts of CD at different levels on drainage outflow,water table level,nitrate loss,grain yield,and water use efficiency(WUE)of various wheat cultivars.Two levels of CD,i.e.,0.4 m below the soil surface(CD-0.4)and 0.8 m below the soil surface(CD-0.8),were compared with subsurface free drainage(SFD)at 1.2 m below the soil surface(SFD-1.2).Under each drainage treatment,four wheat cultivars were grown for two growing seasons(November 2018–April 2019 and November 2019–April 2020).Compared with SFD-1.2,CD-0.4 and CD-0.8 decreased irrigation water by 42.0%and 19.9%,drainage outflow by 40.3%and 27.3%,and nitrate loss by 35.3%and 20.8%,respectively.Under CD treatments,plants absorbed a significant portion of their evapotranspiration from shallow groundwater(22.0%and 8.0%for CD-0.4 and CD-0.8,respectively).All wheat cultivars positively responded to CD treatments,and the highest grain yield and straw yield were obtained under CD-0.4 treatment.Using the initial soil salinity as a reference,the soil salinity under CD-0.4 treatment increased two-fold by the end of the second growing season without negative impacts on wheat yield.Modifying the drainage system by raising the outlet elevation and considering shallow groundwater contribution to crop evapotranspiration promoted water-saving and WUE.Different responses could be obtained based on the different plant tolerance to salinity and water stress,crop characteristics,and growth stage.Site-specific soil salinity management practices will be required to avoid soil salinization due to the adoption of long-term shallow groundwater in Egypt and other similar agroecosystems.
基金supported by the Deanship of Scientific Research,Vice Presidency for Graduate Studies and Scientific Research,King Faisal University,Saudi Arabia (Grant No.3783).
文摘Plant growth-promoting bacteria(PGPB)play an important role in improving agricultural production under several abiotic stress factors.PGPB can be used to increase crop growth and development through hormonal balance and increase nutrient uptake.The positive effect of PGPB may be due to its pivotal role in morphophysiological and biochemical characteristics like leaf number,leaf area,and stem length.Furthermore,relative water content,chlorophyll content,carotenoids,antioxidant enzymes,and plant hormones were improved with PGPB treatment.Crop yield and yield components were also increased with PGPB treatment in numerous crops.The anatomical structure of plant organs was increased such as lamina thickness,stem diameter,xylem vessel diameter,and number of xylem vessels as well as phloem thickness under treatment with PGPB.Additionally,PGPB can alleviate the negative effects of several abiotic stresses by regulating the antioxidant defense system to scavenge the reactive oxygen species resulting in an improvement of yield production in the stressed plants.Additionally,gene expressions were controlled by calcium ion modulation during secondary messengers that act upon calcium-dependent protein kinase and protein phosphatases.This includes many transcription factors such as MYB,AP2/ERF,bZIP,and NAC which regulate genes related to salinity stress signals.PGPB can demonstrate induction genes of signaling under abiotic stress conditions.This review gives an outline of the PGPB role in alleviating the harmful effects of abiotic factors such as salinity,drought,and heat associated with the improvement of the morpho-physiological and biochemical features especially,leaves and branches number,leaf area,antioxidant compounds,plant hormones,and relative water content.
基金supported by the Portuguese Foundation for Science and Technology(FCT)through the project PTDC/CTA-OHR/30561/2017(WinTherface).
文摘Solar energy represents one of themost important renewable energy sources contributing to the energy transition process.Considering that the observation of daily global solar radiation(GSR)is not affordable in some parts of the globe,there is an imperative need to develop alternative ways to predict it.Therefore,the main objective of this study is to evaluate the performance of different hybrid data-driven techniques in predicting daily GSR in semi-arid regions,such as the majority of Spanish territory.Here,four ensemble-based hybrid models were developed by hybridizing Additive Regression(AR)with Random Forest(RF),Locally Weighted Linear Regression(LWLR),Random Subspace(RS),and M5P.The base algorithms of the developed models are scarcely applied in previous studies to predict solar radiation.The testing phase outcomes demonstrated that the ARRF models outperform all other hybrid models.The provided models were validated by statisticalmetrics,such as the correlation coefficient(R)and root mean square error(RMSE).The results proved that Scenario#6,utilizing extraterrestrial solar radiation,relative humidity,wind speed,and mean,maximum,and minimum ambient air temperatures as the model inputs,leads to the most accurate predictions among all scenarios(R=0.968–0.988 and RMSE=1.274–1.403 MJ/m^(2)・d).Also,Scenario#3 stood in the next rank of accuracy for predicting the solar radiation in both validating stations.The AD-RF model was the best predictive,followed by AD-RS and AD-LWLR.Hence,this study recommends new effective methods to predict GSR in semiarid regions.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest from the Ministry of Agriculture,China(201003014)
文摘Pollution of residual plastic film in arable lands is a severe problem in China. In this study, the status of residual film and influential factors were investigated using the methods of farm survey in combination with questionnaires and quadrat sampling at a large number of field sites in Xinjiang Uygur Autonomous Region, China. The results showed that the amount of film utilization increased largely and reached to 1.8×10~5 t in 2013. Similarly, the mulching area also substantially increased in recent decades, and reached to 2.7×10~5 ha in the same year. According to the current survey, 60.7% of the sites presented a greater mulch residue than the national film residue standard(75 kg ha^(–1)), and the maximum residual amount reached 502.2 kg ha^(–1) in Turpan, Xinjiang. The film thickness, the mulching time and the crop type all influenced mulch residue. The thickness of the film had significantly negative correlation with the amount of residual film(P0.05), while the mulching years had significantly positive correlation with it(P0.05). The total amount of residual film in Xinjiang was 3.43×105 t in 2011, which accounted for 15.3% of the cumulative dosage of mulching. Among all the crops, the cotton fields had the largest residual amount of mulch film(158.4 kg ha^(–1)), and also the largest contribution(2.6×10~5 tons) to the total amount of residual film in Xinjiang.
基金Project supported by the National Natural Science Foundation of China (No. 30030090)the National High-Tech Research and Development Program of China (863 Program) (No. 2003AA209030).
文摘Winter wheat-maize rotations are dominant cropping systems on the North China Plain, where recently the use of organic manure with grain crops has almost disappeared. This could reduce soil fertility and crop productivity in the long run. A 20-year field experiment was conducted to 1) assess the effect of inorganic and organic nutrient sources on yield and yield trends of both winter wheat and maize, 2) monitor the changes in soil organic matter content under continuous wheat-maize cropping with different soil fertility management schemes, and 3) identify reasons for yield trends observed in Xuzhou City, Jiangsu Province, over a 20-year period. There were eight treatments applied to both wheat and maize seasons: a control treatment (C); three inorganic fertilizers, that is, nitrogen (N), nitrogen and phosphorus (NP), and nitrogen, phosphorus and potassium (NPK); and addition of farmyard manure (FYM) to these four treatments, that is, M, MN, MNP, and MNPK. At the end of the experiment the MN, MNP, and MNPK treatments had the highest yields, about 7 t wheat ha-1 and 7.5 t maize ha-1, with each about 1 t ha-1 more than the NPK treatments. Over 20 years with FYM soil organic matter increased by 80% compared to only 10% with NPK, which explained yield increases. However, from an environmental and agronomic perspective, manure application was not a superior strategy to NPK fertilizers. If manure was to be applied, though, it would be best applied to the wheat crop, which showed a better response than maize.
基金Project supported by the German Ministry of Consumer Protection, Food and Agriculture (BMVEL) and the German Science Foundation (DFG) (No.WE 1839/1-1)
文摘. Mostly based on assumptions derived from controlled-environment studies, predicted future atmospheric CO2 concen- trations [CO2] are expected to have considerable impacts on carbon (C) turnover in agro-ecosystems. In order to allow the in situ examination of C-transformations in the plant-soil system of arable crop rotations under future [CO2], a free air carbon dioxide enrichment (FACE) experiment (550 μmol mol-1 CO2) was started at Braunschweig, Germany in 1999. The crop rotation under investigation comprised winter barley, a cover crop (ryegrass), sugar beets and winter wheat. Assessments of CO2 effects included the determination of above- and belowground biomass production, measurements of canopy CO2- and H2O- fluxes, soil microbial biomass and in situ soil respiration. The results obtained during the 1st crop rotation cycle (3 years) showed that for the selected crops elevated [CO2] entailed significant positive effects (P < 0.05) on aboveground (6%-14% stimulation) and belowground biomass production (up to 90% stimulation), while canopy evapotranspiration was reduced. This resulted in increased soil water content. Also, depending on crop type and season, high CO2 stimulated in situ soil respiration (up to 30%), while soil microbial biomass did not show significant responses to elevated [CO2] during the first rotation cycle.