Effects of drip and flood irrigation on carbon dioxide exchange and crop growth in the maize ecosystem in the Hetao Irrigation District,China

Drip irrigation and flood irrigation are major irrigation methods for maize crops in the Hetao Irrigation District,Inner Mongolia Autonomous Region,China.This research delves into the effects of these irrigation methods on carbon dioxide(CO_(2))exchange and crop growth in this region.The experimental site was divided into drip and flood irrigation zones.The irrigation schedules of this study aligned with the local commonly used irrigation schedule.We employed a developed chamber system to measure the diurnal CO_(2)exchange of maize plants during various growth stages under both drip and flood irrigation methods.From May to September in 2020 and 2021,two sets of repeated experiments were conducted.In each experiment,a total of nine measurements of CO_(2)exchange were performed to obtain carbon exchange data at different growth stages of maize crop.During each CO_(2)exchange measurement event,CO_(2)flux data were collected every two hours over a day-long period to capture the diurnal variations in CO_(2)exchange.During each CO_(2)exchange measurement event,the biological parameters(aboveground biomass and crop growth rate)of maize and environmental parameters(including air humidity,air temperature,precipitation,soil water content,and photosynthetically active radiation)were measured.The results indicated a V-shaped trend in net ecosystem CO_(2)exchange in daytime,reducing slowly at night,while the net assimilation rate(net primary productivity)exhibited a contrasting trend.Notably,compared with flood irrigation,drip irrigation demonstrated significantly higher average daily soil CO_(2)emission and greater average daily CO_(2)absorption by maize plants.Consequently,within the maize ecosystem,drip irrigation appeared more conducive to absorbing atmospheric CO_(2).Furthermore,drip irrigation demonstrated a faster crop growth rate and increased aboveground biomass compared with flood irrigation.A strong linear relationship existed between leaf area index and light utilization efficiency,irrespective of the irrigation method.Notably,drip irrigation displayed superior light use efficiency compared with flood irrigation.The final yield results corroborated these findings,indicating that drip irrigation yielded higher harvest index and overall yield than flood irrigation.The results of this study provide a basis for the selection of optimal irrigation methods commonly used in the Hetao Irrigation District.This research also serves as a reference for future irrigation studies that consider measurements of both carbon emissions and yield simultaneously.

Expert consensus on irrigation and intracanal medication in root canal therapy

Chemical cleaning and disinfection are crucial steps for eliminating infection in root canal treatment. However, irrigant selection or irrigation procedures are far from clear. The vapor lock effect in the apical region has yet to be solved, impeding irrigation efficacy and resulting in residual infections and compromised treatment outcomes.

Irrigation and nitrogen fertiliser optimisation in protected vegetable fields of northern China:Achieving environmental and agronomic sustainability

Globally,sub-optimal use of nitrogen (N) fertiliser and elevated N irrigation groundwater have led to high leached nitrate (NO_(3)^(–)) losses from protected vegetable field systems.Optimising fertiliser and irrigation management in different soil types is crucial to reduce future N loads from such systems.The present 4-year study examined leached N loads from lysimeter monitoring arrays set up across 18 protected vegetable system sites encompassing the dominant soil types of northern China.The treatments applied at each field site were:1) a high N and high irrigation input treatment (HNHI);2) a low N but high irrigation input treatment (LNHI) and 3) a low N with low irrigation input treatment (LNLI).Results showed that the mean annual leached total nitrogen loads from the HNHI,LNHI and LNLI treatments were 325,294 and 257 kg N ha^(–1) in the fluvo-aquic soil,114,100 and 78 kg N ha^(–1) in the cinnamon soil and 79,68 and 57 kg N ha^(–1) in the black soil,respectively.The N dissolved in irrigation water in the fluvo-aquic soil areas was 8.26-fold higher than in the cinnamon areas.A structural equation model showed that N fertiliser inputs and leaching water amounts explained 14.7 and 81.8%of the variation of leached N loads,respectively.Correspondingly,reducing irrigation water by 21.5%decreased leached N loads by 20.9%,while reducing manure N and chemical N inputs by 22 and 25%decreased leached N loads by only 9.5%. This study highlights that protected vegetable fields dominated by fluvo-aquic soil need management to curtail leached N losses in northern China.

Effect of Water Application Rate on Growth Parameters of Farro 44 Rice Grown in a Selected Irrigation Scheme in Niger State, Nigeria

Water and land are the necessary agricultural inputs, and both are scarce these days. This study aims to determine the effect of water application rate on selected planting and crop parameters of Farro 44 rice during dry season farming and its growth response. The randomised complete block design was employed for the Farro 44 rice variety, with each plot size 4 m2 (2 m × 2 m) for ease of monitoring. A 0.3 m bound space separated each plot. The crop spacing was 0.2 m × 0.3 m, 0.3 m × 0.3 m, and 0.3 m × 0.4 m, respectively, for the row-to-row and plant-to-plant distance. The data collected were statistically analysed. The height of the faro 44 variety of rice ranged between 35.50 cm to 44.00 cm for plots with 2 tillers per hill, while that of 4 and 6 tillers per hill ranged between 35.50 cm to 41.40 cm and 35.50 cm to 39.30 cm, respectively. Minimum damage of 2.32% was seen for plant hills of 2 tillers, while 9.21% and 11.89% were observed for tillers of 4 and 6, respectively. It was seen that plots with the highest spacing of 30 × 40 cm and tillers of 2 per hill were observed to perform better than those of the other plots within the experimental pots. Such plots had a maximum plant tiller of 37 when counted, with the height of the plants reaching 44 cm after 70 days of planting. In conclusion, farmers within the study area of the Kanko community in Niger State. Nigeria appears not to have any known knowledge of the soil they are cultivating and the water they use as a source of irrigation within the farming areas. It was further concluded that the rice crops would be produced maximally with minimal water application to the rice field.

A study of the soil water potential threshold values to trigger irrigation of ‘Shimizu Hakuto’ peach at pivotal fruit developmental stages

Water management is an important practice that affects fruit size and quality.Effective implementation of irrigation scheduling requires knowledge of the appropriate indicators and thresholds,which are established manly based on the effects of water deficits on final fruit quality.Few studies have focused on the real-time effects of water status on fruit and shoot growth.To establish soil water potential (ψ_(soil)) thresholds to trigger irrigation of peach at pivotal fruit developmental stages,photogrammetry,^(13)C labelling,and other techniques were used in this study to investigate real-time changes in stem diameter,fruit projected area,net leaf photosynthetic rate (P_(n)),and allocation of photoassimilates to fruit under soil water potential conditions ranging from saturation to stress in 6-year-old Shimizu hakuto’peach.Stem growth,fruit growth,and P_n exhibited gradually decreasing sensitivity to water deficits during fruit developmental stages I,II,and III.Stem diameter growth was significantly inhibited whenψ_(soil)dropped to-8.5,-7.6,and-5.4 k Pa,respectively.Fruit growth rate was low,reaching zero when theψ_(soil)was-9.0 to-23.1,-14.9 to-21.4,and-16.5 to-23.3 k Pa,respectively,and P_ndecreased significantly when theψ_(soil)reached-24.2,-22.7,and-20.4 kPa,respectively.In addition,more photoassimilates were allocated to fruit under moderateψ_(soil)conditions (-10.1 to-17.0 k Pa) than under otherψ_(soil)values.Our results revealed threeψ_(soil)thresholds,-10.0,-15.0,and-15.0 kPa,suitable for triggering irrigation during stages I,II,and III,respectively.These thresholds can be helpful for controlling excessive tree vigor,maintaining rapid fruit growth and leaf photosynthesis,and promoting the allocation of more photoassimilates to fruit.

Irrigation and Thermal Buffering Using Mathematical Modeling

Two methods of irrigation,drip,and sprinkler were studied to determine the response of the Javits green roof to irrigation.The control study was dry unirrigated plots.Drip irrigation consisted of irrigation tubes running through the green roof that would water the soil throughout and sprinkler irrigation used a sprinkler system to irrigate the green roof from above.In all cases,the irrigated roofs had increased the soil moisture,reduced temperatures of both the upper and lower surfaces,reduced growing medium temperatures and reduced air temperatures above the green roof relative to the unirrigated roof.The buffered temperature fluctuations were also studied via air conditioner energy consumption.There was a 28%reduction in air conditioner energy consumption and a 33%reduction in overall energy consumption between dry and irrigated plots.Values of thermal resistance or S were determined for accuracy and for this study,there was little change which is ideal.A series of infra-red and thermal probe measurements were used to determine temperatures in the air and sedum.It was determined that the sprinkler irrigation did a better job than the drip irrigation in keeping cooler temperatures within the green roof.A Mann-Whitney U test was performed to verify the variation in moisture temperatures buffering energy consumption.By getting a p-value<0.05,it indicates that the model is accurate for prediction and medium temperatures were statistically different.

Exploring the combination of biochar‐amended soil and automated irrigation technology for water regulation and preservation in green infrastructure

Biochar is a carbon sink material with the potential to improve water retention in various soils.However,for the long‐term maintenance of green infrastructure,there is an additional need to regulate the water contents in the covers to maintain vegetation growth in semiarid conditions.In this study,biochar‐amended soil was combined with subsurface drip irrigation,and the water preservation characteristics of this treatment were investigated through a series of one‐dimensional soil column tests.To ascertain the best treatment method specific to semiarid climatic conditions,the test soil was amended with 0%,1%,3%,and 5%biochar.Automatic irrigation devices equipped with soil moisture sensors were used to control the subsurface water content with the aim of enhancing vegetation growth.Each soil column test lasted 150 h,during which the volumetric water contents and soil suction data were recorded.The experimental results reveal that the soil specimen amended with 3%biochar is the most water‐saving regardless of the time cost.Soil with a higher biochar content(e.g.,5%)consumes a more significant amount of water due to the enhancement of the water‐holding capacity.Based on the experimental results,it can be concluded that the appropriate ratio can be determined within 1%–3%,which can reduce not only the amount of irrigated/used water but also the time cost.Such technology can be explored for water content regulation in green infrastructure and the development of barriers for protecting the environment around deep underground waste containment.

Grain-filling strategies of wheat of contrasting grain sizes under various planting patterns and irrigation levels

In a study comparing grain filling and yield in a large-and a small-grain-size wheat cultivar under two planting patterns and two irrigation regimes,plastic-covered ridge and furrow planting with sprinkler irrigation increased grain filling and yield in both cultivars.The largest contributors to grain yield were an extended active grain-filling period in Shuangda 1 and an increased mean grain-filling rate in XN538.

Effect of Supplementary Irrigation on the Yield of Sorghum (Sorghum bicolor L. Moench) in the Context of Climate Change in the Dry Savannahs of Togo

Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah region of Togo. A two-year trial was conducted in a controlled environment at AREJ, an agro-ecological center in Cinkassé. The plant material was sorghum variety Sorvato 28. The experimental design was a Completely Randomized Block with three replications and three treatments as follows: T0 control plot (rainfed conditions);T1 (supplementary irrigation from flowering to grain filling stage) and T2 (supplementary irrigation from planting to grain filling stage). Two irrigation techniques (furrow and Californian system) were used under each watering treatment. The results showed that irrigation technique significantly affected panicle length with no effect on 1000 grains mass. Panicle length and grain yields varied from 15.59 to 25.71 cm and 0.0 to 2.06 t∙h−1, respectively, with the highest values (25.66 cm and 2.06 t∙h−1, respectively) under the T2 treatment with the California system-based supplementary irrigation. The comparison of results obtained on treatment T0 and T2, shows that supplementary irrigation increased the yields by at least 68.62%. Supplementary irrigation during sowing and growing season (T2) improved sorghum yields in the dry savannahs of Togo, with a better performance of the California irrigation system.

Reform of the Irrigation Sector and Creation of Functional and Sustainable Irrigation Water Users Associations (AUEI) in Niger: Capitalization of the Experience of the Konni AHA

During the 1980s, as part of a policy of liberalization, following budgetary cuts linked to the implementation of structural adjustment programs, management responsibilities for AHAs were transferred from ONAHA to cooperatives concerned. Due to lack of financial resources, but also because of poor management, everywhere in Niger we are witnessing an accelerated deterioration of the irrigation infrastructure of hydro-agricultural developments. Institutional studies carried out on this situation led the State of Niger to initiate a reform of the governance of hydro-agricultural developments, by streng-thening the status of ONAHA, by creating an Association of Irrigation Water Users (AUEI) and by restructuring the old cooperatives. Indeed, this research aims to analyze the creation of functional and sustainable Irrigation Water User Associations (AUEI) in Niger in a context of reform of the irrigation sector, and based on the experience of the Konni AHA. It is based on a methodological approach which takes into account documentary research and the collection of data from 115 farmers, selected by reasoned choice and directly concerned by the management of the irrigated area. The data collected was analyzed and the results were analyzed using the systemic approach and the diagnostic process. The results show that the main mission of the AUEI is to ensure better management of water, hydraulic equipment and infrastructure on the hydro-agricultural developments of Konni. The creation of the Konni AUEI was possible thanks to massive support from the populations and authorities in the implementation process. After its establishment, the AUEI experienced a certain lethargy for some time due to the rehabilitation work of the AHA but currently it is functional and operational in terms of associative life and governance. Thus, the constraints linked to the legal system, the delay in the completion of the work, the uncertainties of access to irrigation water but also the problems linked to the change in mentality of certain ONAHA agents constitute the challenges that must be resolved in the short term for the operationalization of the Konni AUEI.

Spatio-temporal variation and relationship between agricultural efficiency and irrigation intensity in a semi-arid region of India

A surging population in Karnataka State,a semi-arid region in India,poses a threat to both food security and livelihood sustainability,necessitating a concentrated effort to bolster agricultural efficiency and achieve United Naton’s Sustainable Development Goal 2(zero hunger).Therefore,in order to address the pressing issue of food scarcity in Karnataka,this study meticulously examined the spatio-temporal variation of agricultural efficiency and irrigation intensity in Karnataka,uncovering its significant dependence of agricultural efficiency on irrigation intensity.Specifically,this study used a one-way analysis of variance(ANOVA)to ascertain significant differences in the means of agricultural efficiency and irrigation intensity during 2004-2005 and 2018-2019.This study showed that the maximum improvement in agricultural efficiency index was recorded in Belgaum(40.24),Gulbarga(24.77),and Yadgir districts(22.92)between 2004-2005 and 2018-2019,which indicated the progressing trend and better scope for agriculture extension.On the contrary,some districts expressed threat(a decline of above 20.00 of agricultural efficiency index)and needed special care for the improvement of agricultural efficiency in four northern districts(Bagalkot,Bidar,Raichur,and Bijapur),three southern districts(Chitradurga,Chikballapur and Hassan),and two southern districts(Koppal and Gadag)in Karnataka.During 2004-2005,irrigation intensity varied from 3.19%to 56.39%,with the lowest irrigation intensity in Kodagu District and the highest irrigation intensity in Shimoga District.During 2018-2019,irrigation intensity changed from 0.77%to 72.77%,with the lowest irrigation intensity in Kodagu District and the highest in Dakshin Kannad District.Moreover,the research scrutinized the complex relationship between agricultural efficiency and irrigation intensity,with the correlation coefficient increased from 0.162 during 2004-2005 to 0.255 during 2018-2019.It implies that in both periods,a low positive correlation existed between these two variables.Over time,several factors(high-yield seeds and chemical fertilizers)other than irrigation intensity gradually became essential for agricultural efficiency.This research offers a wealth of valuable insights for regional planners and policy-makers contending with comparable challenges in various regions of India and other developing countries.

Outcomes of early versus late irrigation and debridement of pediatric open long bone fractures

BACKGROUND Open long bone fractures are a major concern for pediatric patients due to the risk of surgical site infection(SSI).Early studies have recommended irrigation and debridement of open fractures within 6 hours-8 hours for the prevention of SSI.According to the American College of Surgeons(ACS)Best Practice Guidelines,in 2015,irrigation and debridement should be done within 24 hours.AIM To identify whether early irrigation and debridement,within 8 hours,vs late,between 8 hours and 24 hours,for pediatric open long bone fractures impacts rate of SSI.METHODS Using retrospective data review from the National Trauma Data Bank,Trauma Quality Improvement Project(TQIP)of 2019.TQIP database is own by the ACS and it is the largest database for trauma quality program in the world.Propensity matching analysis was performed for the study.RESULTS There were 390 pediatric patients with open long bone fractures who were incl-uded in the study.After completing propensity score matching,we had 176 patients in each category,irrigation and debridement within 8 hours and irrigation and debridement between 8 hours and 24 hours.We found no significant differences between each group for the rate of deep SSI which was 0.6%for patients who received surgical irrigation and debridement within 8 hours and 1.1%for those who received it after 8 hours[adjusted odd ratio(AOR):0.5,95%CI:0.268-30.909,P>0.99].For the secondary outcomes studied,in terms of length of hospital stay,patients who received irrigation and debridement within 8 hours stayed for an average of 3.5 days,and those who received it after 8 hours stayed for an average of 3 days,with no significant difference found,and there were also no sig-nificant differences found between the discharge dispositions of the patients.CONCLUSION Our findings support the recommendation for managing open long bone fractures from the ACS:Complete surgical irrigation and debridement within 24 hours.

Assessing the Water-Energy-Food-Ecosystems Nexus in Smart Irrigation: A Potato Farming Case Study in Lebanon

This study examines the Water-Energy-Food-Ecosystems (WEFE) nexus in Lebanese agriculture, with a focus on the shift from conventional surface irrigation techniques to advanced smart irrigation systems in the Bekaa region, specifically targeting potato cultivation. The study quantitatively analyzes the interaction among water, energy, and agricultural outputs at the farm scale using the WEFE Nexus framework for scenario analysis. It evaluates variations in water productivity, environmental effects, and economic outcomes, offering a detailed view of existing practices and their sustainable improvement potential. The WEFE Nexus assessment demonstrates that smart irrigation integration significantly decreased resource usage: water consumption was reduced by 58%, diesel fuel use for irrigation dropped by 57%, and the demand for labor and fertilizers decreased by 47% and 49%, respectively. This change led to enhanced crop yields and increased resource efficiency, demonstrating the potential of smart irrigation as a transformative strategy for sustainable agriculture in Lebanon and other arid areas. Economic analysis showed that farmers could recover the costs of installing the smart irrigation system within 3 months. The findings highlight the need for further research on integrating smart irrigation with renewable energy, showing potential for sustainable agricultural development. .

Impact of Seawater Irrigation on seed germination and seedling growth of Ten Bread Wheat(Triticum aestivum L.)Genotypes

Objective:Seawater leakage in Al-Jabal Al-Akhdar East Libya's coastal areas is one of the most biggest obstacles to farmers obtaining a highly productive crop.As a result,the experiment was conducted in a laboratory to find out the impact of irrigation with seawater on the salt tolerance of Acsad Bread wheat genotypes.Method:Ten genotypes(1398,1492,1514,1522,1524,1536,1538,1544,1550,and 1562),obtained from the Arab Center for the Studies of Arid Zones and Dry Lands Acsad,were used in the study,10 seeds of each genotype with three repetitions were germinated under four seawater concentrations(10,20,30 and 40%).Results:The results showed that there were highly significant(P≤0.05)differences in the genotypes’response to all salinity concentrations,Which led to decreasing germination percentage,delaying the average germination time,and decreasing radical/plumule length and seedling fresh/dry weight compared with a control.As noted genotypes(1524,1522 and 1514)were able to germinate in all concentrations of seawater,and gave the best average for all the studied traits.Also,the study indicated that a concentration of seawater of 40%was the most toxic for all wheat genotypes.The results of this study categorize the wheat genotypes into tolerant genotypes(1524,1522 and 1514),moderate tolerant(1492,1536),and sensitive(1398,1538,1544,1550 and 1562).Conclusion:The results concluded that the possibility of wheat crops agriculture into tolerant in Libyan coastal locations in which seawater concentration did not exceed 30%.

Effect of Continuous Double-Lumen Irrigation Drainage at Constant Temperature on the Control of Abdominal Infection After Surgery

Objective:To investigate the effect of continuous double-lumen irrigation drainage at constant temperature on the control of abdominal infection after surgery,providing a reference for clinical treatment.Methods:From December 2022 to August 2023,100 patients with abdominal infections after surgery were selected from Wendeng People's Hospital in Weihai.They were randomly divided into a control group(50 cases,using conventional single-hole rubber irrigation drainage)and an observation group(50 cases,using continuous double-lumen irrigation drainage at constant temperature).The inflammatory and immune indicators of the two groups were compared after different interventions,and the specific conditions of abdominal infection were statistically analyzed.Results:There was no significant difference in inflammatory indicators between the two groups before intervention(P>0.05).After the intervention,the inflammatory indicators of the observation group were significantly lower(P<0.05).There was no significant difference in immune function indicators between the two groups before intervention(P>0.05).After intervention,the immune function indicators of the observation group showed significant improvement(P<0.05).The control of abdominal infection in the observation group was better than in the control group(P<0.05).Conclusion:Continuous double-lumen rrigation drainage at constant temperature has a better effect on controlling abdominal infection after surgery,improving the infection condition,and enhancing the immune function of patients.

Seasonal Sodium Percentage (%NA), Absorption Ratio (SAR) and Irrigation Water Quality Index (IWQI) Determination for Irrigation Purposes Along River Ethiope, Southern Nigeria

The improvement of agriculture through irrigation farming is now of great need in the country Nigeria and Delta State. The country is going through a phase of famine and food insecurity caused by climate change and rain dependent agricultural practices. The aim of the study therefore, was to evaluate the quality of water from River Ethiope in Southern Nigeria for irrigation agriculture purposes using the percentage sodium (%Na), sodium-adsorption ratio (SAR) and irrigation-water quality index (IWQ1) techniques. The study deployed the experimental design and water samples were collected from different segments of the Ethiope River. A total of 144 water samples were collected and analysed for physicochemical parameters quality (EC, HCO3, Cl−, Na+, Mg2+, Ca2+ and K+) from January to December, 2022. The results showed that all the calculated values for %Na were within the classified rating of 20 < N ≤ 40 and 60 < Na ≤ 80;while SAR were within the range of 0 < SAR ≤ 10. The recorded values of IWQI were within the range of 70 - 55 and 55 - 40. This implies that the water is good to doubtful for %Na, excellent for SAR and of moderate and high restrictions for IWQI. Water was adjudged to be good for irrigation activities, and should be applicable in areas with moderate and high soil permeability. The routine testing of the water to ascertain physicochemical parameters quality regularly, in order not to affect its use for irrigation was among the recommendations. This finding herein shall be of use to Water Resources and Agriculture ministries in Nigeria.

Agricultural Water Footprint of Southern Highbush Blueberry Produced Commercially with Drip Irrigation and Sprinkler Frost Protection

A study was conducted from 2010 to 2017 to determine the water footprint for producing blueberries in the Entre Ríos province of Argentina. Three cultivars of southern highbush blueberry (hybrid cross of Vaccinium sp.) were evaluated in the study, including “Star”, “Emerald”, and “Snowchaser”. In each case, the plants were irrigated by drip and protected from frost using overhead sprinklers. Water requirements for irrigation and frost protection varied among the cultivars due to differences in the timing of flowering and fruit development. The annual water footprint for fruit production in each cultivar is expressed in units of cubic meters of water used to produce one ton of fresh fruit and ranged from 212 - 578 m3∙t−1 for “Star”, 296 - 985 m3∙t−1 for “Emerald”, and 536 - 4066 m3∙t−1 for “Snowchaser”. “Snowchaser” flowered earlier than the other cultivars and, therefore, needed more water for frost protection. “Star”, on the other hand, ripened the latest among the cultivars and required little to no water for frost protection. Frost protection required a minimum of 30 m3∙h−1 of water per hectare and in addition to drip irrigation was a major component of the water footprint.

Effect of fertigation frequency on soil nitrogen distribution and tomato yield under alternate partial root-zone drip irrigation

Alternate partial root-zone drip fertigation (ADF) is a combination of alternating irrigation and drip fertigation,with the potential to save water and increase nitrogen (N) fertilizer efficiency.A 2-year greenhouse experiment was conducted to evaluate the effect of different fertigation frequencies on the distribution of soil moisture and nutrients and tomato yield under ADF.The treatments included three ADF frequencies with intervals of 3 days (F3),6 days (F6) and 12 days (F12),and conventional drip fertigation as a control (CK),which was fertilized once every 6 days.For the ADF treatments,two drip tapes were placed 10 cm away on each side of the tomato row,and alternate drip irrigation was realized using a manual valve on the distribution tapes.For the CK treatment,a drip tape was located close to the roots of the tomato plants.The total N application rate of all treatments was 180 kg ha^(-1).The total irrigation amounts applied to the CK treatment were450.6 and 446.1 mm in 2019 and 2020,respectively;and the irrigation amounts applied to the ADF treatments were 60%of those of the CK treatment.The F3 treatment resulted in water and N being distributed mainly in the 0–40-cm soil layer with less water and N being distributed in the 40–60-cm soil layer.The F6 treatment led to 21.0 and 29.0%higher 2-year average concentration of mineral N in the 0–20 and 20–40-cm soil layer,respectively and a 23.0%lower N concentration in the 40–60-cm soil layer than in the CK treatment.The 2-year average tomato yields of the F3,F6,F12,and CK treatments were 107.5,102.6,87.2,and 98.7 t ha^(-1),respectively.The tomato yield of F3 was significantly higher (23.3%) than that in the F12 treatment,whereas there was no significant difference between the F3 and F6 treatment.The F6 treatment resulted in yield similar to the CK treatment,indicating that ADF could maintain tomato yield with a 40%saving in water use.Based on the distribution of water and N,and tomato yield,a fertigation frequency of 6 days under ADF should be considered as a water-saving strategy for greenhouse tomato production.

Integrating a novel irrigation approximation method with a process-based remote sensing model to estimate multi-years'winter wheat yield over the North China Plain

Accurate estimation of regional winter wheat yields is essential for understanding the food production status and ensuring national food security.However,using the existing remote sensing-based crop yield models to accurately reproduce the inter-annual and spatial variations in winter wheat yields remains challenging due to the limited ability to acquire irrigation information in water-limited regions.Thus,we proposed a new approach to approximating irrigations of winter wheat over the North China Plain(NCP),where irrigation occurs extensively during the winter wheat growing season.This approach used irrigation pattern parameters(IPPs)to define the irrigation frequency and timing.Then,they were incorporated into a newly-developed process-based and remote sensing-driven crop yield model for winter wheat(PRYM–Wheat),to improve the regional estimates of winter wheat over the NCP.The IPPs were determined using statistical yield data of reference years(2010–2015)over the NCP.Our findings showed that PRYM–Wheat with the optimal IPPs could improve the regional estimate of winter wheat yield,with an increase and decrease in the correlation coefficient(R)and root mean square error(RMSE)of 0.15(about 37%)and 0.90 t ha–1(about 41%),respectively.The data in validation years(2001–2009 and 2016–2019)were used to validate PRYM–Wheat.In addition,our findings also showed R(RMSE)of 0.80(0.62 t ha–1)on a site level,0.61(0.91 t ha–1)for Hebei Province on a county level,0.73(0.97 t ha–1)for Henan Province on a county level,and 0.55(0.75 t ha–1)for Shandong Province on a city level.Overall,PRYM–Wheat can offer a stable and robust approach to estimating regional winter wheat yield across multiple years,providing a scientific basis for ensuring regional food security.

Effects of water and nitrogen conditions under surge-root irrigation on growth and yield of apple trees

In order to explore the effects of different irrigation and nitrogen application on growth cha-racteristics and yield of apple trees under surge-root irrigation in mountainous areas of northern Shaanxi, field experiments were carried out with different apple trees. Three irrigation levels were applied: 85%-100%(H1), 70%-85%(H2) and 55%-70%(H3) of the field water capacity, respectively, and three nitrogen levels were N1(360 g/plant), N2(240 g/plant) and N3(120 g/plant). The results show that irrigation and nitrogen application has significant effects on new shoot length, flowering and fruit setting, fruit diameter, fruit volume and yield of apple. The leaf area index(LAI) shows a single trend during the growth period, and the peak value appears in the middle of July. Under the same irrigation level, compared with N3, N1 increases in yield, new shoot length, LAI, transverse diameter, longitudinal diameter, volume, flowering and fruit setting by 17.91%, 28.31%, 18.75%, 11.38%, 10.13%, 36.60%, 20.92% and 5.19%, respectively, while N2 also increases by 12.40%, 15.63%, 4.86%, 5.40%, 5.11%, 17.01%, 26.17% and 13.74%, respectively. The rate of flowering and fruit setting decreases with the increase of nitrogen application. Under the same nitrogen level, compared with H3, H1 increases in yield, new shoot length, LAI, transverse diameter, longitudinal diameter, volume, flowering and fruit setting by 34.65%, 15.49%, 30.77%, 3.93%, 4.95%, 12.86%, 33.15% and 28.62%, respectively, while H2 also increases by 33.67%, 16.42%, 67.52%, 3.81%, 2.97%, 11.57%, 43.45% and 27.26%, respectively. The rate of flowering and fruit setting decreases first and then increases with the increase of irrigation amount. Compared with H3N3, the yield of other treatments increases by 2.69%-52.20%, while H2N1 treatment has the highest yield(26 852.55 kg/ha). Considering from the point of view of promoting growth and increasing yield, the best water and nitrogen combination mode of mountain apple in northern Shaanxi is medium water deficit irrigation and high nitrogen(H2N1) treatment. The results from this study can provide a theoretical basis for apple water and nitrogen management in mountainous areas of northern Shaanxi.