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Agricultural Water Management
Elsevier
Agricultural Water Management

Elsevier

0378-3774

Agricultural Water Management/Journal Agricultural Water ManagementSCIISTPEI
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    Estimation of crop evapotranspiration from MODIS data by combining random forest and trapezoidal models

    Hao, PengyuDi, LipingGuo, Liying
    18页
    查看更多>>摘要：Evapotranspiration (ET) is an important parameter for crop growth monitoring and land surface modeling. This paper proposed a new workflow, namely ESVEP-RF, to calculate ET during the crop growing season using MODIS data by combining the advantages of the trapezoidal model and Random Forest (RF) algorithm. In ESVEP-RF, the endmember-based soil and vegetation energy partitioning (ESVEP) model was first used to calculate a series of parameters from MODIS and meteorological inputs, and then all parameters derived from remote sensing data, meteorological data and ESVEP models were used as inputs to the RF algorithm for latent heat flux (LE) calculation. In-situ data of 12 years (2003-2012, 2018 and 2019) from five flux towers located in Nebraska (NE) and Michigan (MI) were used to test the performance of ESVEP-RF, and results showed that ESVEP-RF had great potential to accurately calculate ET when the number of training samples was sufficient and representative. In 2010 and 2011, R-2 of LE were around 0.8 and RMSE were around 70 W/m(2), which outperformed original ESVEP model results. This indicated that the RF algorithm could better describe the non-linear correlation between in LST/FVC space endmembers and LE. Among all parameters, LAI, PLEv and R-vw had high contribution with percentage importance of 18.49%, 15.71% and 13.57%, respectively. Furthermore, all samples between 2003 and 2012 collected from the three NE sites were used to train RF models and then calculate LE for both NE and MI sites in 2018 and 2019. In NE sites, RMSE was around 65 W/m(2) and R-2 was around 0.8. In MI sites, it was noted that no samples from these sites were included in the training data set, and RMSE was around 70 W/m(2) and R-2 was higher than 0.7. These results showed the potential of ESVEP-RF for providing up-to-date ET information.
      原文链接:
    • NSTL
    • Elsevier

    Irrigation and grazing management affect leaching losses and soil nitrogen balance of lucerne

    Graham, Scott L.Laubach, JohannesHunt, John E.Mudge, Paul L....
    9页
    查看更多>>摘要：Intensification of agricultural management practices, including irrigation and addition of nitrogen (N) fertilizers, can lead to enhanced N leaching and loss of soil fertility. In New Zealand, expansion of the dairy industry has rapidly increased irrigated land area, particularly on shallow, stony soils of the Canterbury region that are prone to leaching, leading to degradation of surface- and ground-water quality and losses of soil N and carbon (C). In this study, we measure components of N balance for two adjacent fields of lucerne (Medicago sativa L., alfalfa) harvested for cut-and-carry feed and grazed in situ. One field was non-irrigated and one irrigated with both water and dairy effluent. Inputs from N fixation associated with the legume crop were quantified using a natural abundance isotopic approach. Drainage from the root zone and leaching were measured with 6 large lysimeters in each field. Leaching losses from non-irrigated lucerne were 7-30 kg N ha(-1) y(-1) with the largest losses occurring in a year with primarily grazing management. Losses from irrigated lucerne were 39-102 kg N ha(-1) y(-1) , with the largest losses resulting from summer drainage events exacerbated by irrigation. Fixation of N was the largest input to both systems, contributing 192-257 kg N ha(-1) y(-1) for non-irrigated lucerne. Under irrigation, biomass production increased, but N uptake from effluent and soil stocks contributed to biomass N to a greater extent and fixation was 262-286 kg N ha(-1) y(-1) . Management influenced N balance through inputs from animal excreta and effluent additions and exports through harvest and grazing removals. Management practices which reduce N losses from the soil are needed to minimize environmental impacts and protect soil fertility.
      原文链接:
    • NSTL
    • Elsevier

    Assessment of CERES-Maize model in simulating maize growth, yield and soil water content under rainfed, limited and full irrigation

    Amiri, E.Irmak, S.Araji, H. Ahmadzadeh
    13页
    查看更多>>摘要：CERES-Maize is a crop simulation model that can be applied as a tool to simulate grain yield, above-ground biomass, leaf area index (LAI), soil-water components (SWC), and other variables related to crop production. The model was calibrated and validated using long-term (2005-2010) field-measured data under full irrigation treatment (FIT), limited irrigation treatments (50%, 60% and 75% of FIT) and rainfed conditions in a transition zone between the subhumid and semi-arid climatic region in Nebraska, USA. Model performance was evaluated using the coefficient of determination (R-2), absolute and normalized root mean squared errors (RMSE and RMSEn, respectively) between simulated and measured data. The RMSE between model-simulated and observed data for days after planting to flowering (DAPF) and maturity day (DAPM) were 3 and 13 days, respectively. There was an acceptable agreement between simulated and observed LAI (RMSEn = 17% and R-2 = 0.79) and above-ground biomass (RMSEn = 16% and R-2 = 0.95). Grain yield estimates by the model showed moderately high R-2 (> 0.80) and moderate RMSEn (3-18%) values, confirming that the model simulated the grain yield accurately. The accuracy of the model in simulating SWC in FIT conditions was good, but with increasing water stress, the accuracy decreased. The cumulative drought stress index for photosynthesis (SIP) and drought stress index for leaf expansion (SIE) were also simulated and evaluated. There was an inverse relationship between grain yield and the SIP and SIE (R-2 >= 0.97), indicating the potential applicability of SIP and SIE for estimating maize grain yield. Both SIP and SIE were strongly affected by the irrigation treatments. The FIT treatment had a value of 2 for cumulative SIE, indicating that this treatment was rarely exposed to drought/water stress. The results showed that irrigation and early planting date together had synergistic effects on grain yield. Delaying planting dates for the FIT led to yield reduction of 1%, 3% and 11% after planting dates of April 30, May 10 and May 20, respectively. Delay in planting date under rainfed led to greater yield reduction of 6%, 10% and 18% after planting dates of April 30, May 10 and May 20, respectively. The CERES-Maize model simulated maize crop parameters relatively accurately under rainfed, full and limited irrigation management conditions under the experimental and climatic conditions presented in this study and can be a viable tool for simulating various management scenarios for increasing maize productivity.
      原文链接:
    • NSTL
    • Elsevier

    Simulating cucumber plant heights using optimized growth functions driven by water and accumulated temperature in a solar greenhouse

    Wang, RongYang, DongyanMa, LingSun, Zhaojun...
    10页
    查看更多>>摘要：Plant height is the main agronomic character used to measure the vertical growth and developmental abilities of plant. Cucumber is a popular greenhouse vegetable in Northwest China, and its production is principally limited by water and temperature. However, few studies have simulated water- and temperature-driven cucumber heights in solar greenhouses; in this paper, we explored these optimum growth functions to simulate cucumber height dynamics under different irrigation upper limits by conducting experiments between 2017 and 2019 in Wuzhong, Ningxia, China. First, we calculated the accumulated temperature during the growth period by measuring growth-stage base temperatures.We then calculated water impact factor parameters based on the perday plant height growth rate. We constructed functions (DWSTR(i)) of the factors affecting cucumber plant heights at different growth stages, then used these functions as multipliers; the accumulated temperature was taken as an independent variable in four functions (i.e., the Bertalanffy, Gompertz, Logistic and Mischerlich functions) to describe the water- and temperature-driven cucumber plant height growth dynamics. Consequently, an optimal function was selected among the four simulated functions defined as Mo-B, Mo-G, Mo-L and Mo-M. Impact factor functions were established with 2018 experimental data as y = 0.1753e0.0177x, y = 0.6332e0.0046x and y = 0.7241e0.0031x in the stretch-tendril period, initial flowering period, and early harvest period, respectively; the corresponding correlation coefficients were 0.9604, 0.9937 and 0.9191. These data were then used to assess the function-associated parameters. The models were calibrated with the 2017 and 2019 experimental data, and the Mo-L model obtained the best IA (0.993 and 0.998 in 2017 and 2019) and NRMSE (10.27 and 4.97 in 2017 and 2019) values among the four models. Further, the mean IA (0.995) and NRMSE (9.20) values of the Mo-L model were significantly higher than those of the Mo-B and Mo-M models between 2017 and 2019. The MoL model could be optimal for simulating the physiological cucumber height growth insolar greenhouses, and the model calibration showed good agreement between the simulated and measured results.
      原文链接:
    • NSTL
    • Elsevier

    Effects of anecic earthworms on runoff and erosion on the slope with soil from the Loess Plateau under a rainfall simulation experiment

    Wen, ShuhaiWang, JiaoLi, YanpeiShao, Ming'an...
    9页
    查看更多>>摘要：Earthworms are ecological engineers that play an important role in hydrological processes and soil erosion by their burrowing and casting activities. Little is known, however, about the ecological function of the activities of an anecic species (Metaphire guillelmi) from the Loess Plateau in China where the soil is severely eroded. We conducted rain-simulation experiments on artificial slopes (mesocosms) filled with soil from Loess Plateau. Two rain intensities (90 and 120 mm h(-1)) and slope gradients (5 degrees and 15 degrees) were used to investigate the influences of earthworm activity on runoff and soil loss under multiple conditions. Data from 15 d of earthworm activity and 1 h of rain indicated that earthworm activity significantly reduced runoff but aggravated soil erosion. Runoff initiation time increased 2.7-3.1-fold, contributing to the promotion of water infiltration, and the amounts and rates of runoff were 35.8-61.6% and 35.1-60.8% lower under earthworm activity than the controls, respectively. Earthworms greatly influenced the physical and chemical properties of the soil, and these properties were strongly correlated with runoff initiation time and cumulative runoff. The surface casts produced by the earthworms on the soil surface were completely dispersed, increasing the cumulative sediment by a maximum of 169%. Both rain intensity and slope gradient greatly influence runoff and soil detachment, but with earthworm activity, slope gradient was more influential due to its superior contribution to sediment transport. This study quantified the effects of M. guillelmi on runoff and soil erosion and provides basic data for developing a more integrated control of soil erosion on the Loess Plateau.
      原文链接:
    • NSTL
    • Elsevier

    Climate change impacts on water security elements of Kafr El-Sheikh governorate, Egypt

    Alkhawaga, AbdalmonemZeidan, BakenazElshemy, Mohamed
    10页
    查看更多>>摘要：Egypt faces great challenges to manage its limited freshwater resources. Shortage in freshwater, due to expected stresses of climatic changes and upper Nile projects, will have major impacts on Egypt's water and food security. About 85% of the annual total freshwater resource is consumed by agriculture. The objective of this work is to assess the future water security situation of Kafr El-Sheikh governorate, Nile Delta, Egypt, under climate change and urbanization stresses, compared to the current situation. Main investigated water security elements for this study were the irrigation water requirements and agricultural land areas. Two different reference evapotranspiration equations were used to calculate the future irrigation water requirements under three different Representative Concentration Pathways (RCP) (2.6, 4.5 and 8.5 scenarios) for the period 2010-2100, based on the intergovernmental panel on climate change's 5th assessment report. Remote sensing and Geographical Information System (GIS) were used to generate a land use classification map, which was used to estimate the losses in each land use category of the study area under 0.5 and 1.0 m relative sea level rise (SLR) estimates. Combined scenarios of future changes in irrigation water consumption and agricultural land area were analysed. The results show that the future water security situation of the governorate is highly sensitive to projected climatic changes. Moreover, most future scenarios revealed that the agricultural land area would decrease, which will cause serious food security problems. The maximum decrease by about 55.9% of the agricultural land area for year 2095 compared to year 2016 is estimated, due to the current annual decreasing rate of 0.4% and 1.0 m SLR, whatever the applied RCP scenario. While the maximum increase in the required irrigation water would be about 6% due to the RCP85 scenario, assuming no change in the irrigation land area, with a mixing ratio of 1.34 (freshwater): 1 (drainage water) which would affect the crop yield productivity. A regular assessment of water security elements for each of the Egyptian governorates should be managed and an urgent integrated plan for food security to adapt with the future climate change impacts is essential.
      原文链接:
    • NSTL
    • Elsevier

    Towards a sustainable viticulture: The combination of deficit irrigation strategies and agroecological practices in Mediterranean vineyards. A review and update

    Romero, PascualNavarro, Josefa MariaOrdaz, Pablo Botia
    30页
    查看更多>>摘要：In this study we review the state of the art of different physiologically-based water-saving irrigation strategies and methods used to improve productive water use efficiency (WUEyield) and berry and wine quality in vineyards. We also show how these irrigation practices, combined with more sustainable soil management and other agroecological practices, can help to mitigate the negative effects of climate change on wine grapes cultivation and make irrigated Mediterranean vineyards more resilient and sustainable. We analyse the deficit irrigation (DI) strategies used most often for different varieties and edaphoclimatic conditions. We review the latest advances in the application of regulated deficit irrigation (RDI) and partial root zone drying irrigation (PRI) strategies in grapevines (red and white grapes), as well as other irrigation methods used less frequently in vineyards to improve WUEyield, berry quality and irrigation efficiency, such as subsurface drip irrigation. We also analyze recent findings concerning the physiological response of the vine to water stress with more holistic approaches such as, hydraulic safety marging and stress distance, and discuss how to translate these physiological approaches into the practical application of RDI management in field conditions, according to the genotypic characteristics and degree of drought tolerance of the variety/rootstock combination. We review optimum vine water status ranges and the thresholds proposed for better deficit irrigation scheduling in vineyards. In addition, we consider sustainable soil management practices - such as cover crops, mulching, composting, reduced tillage, mutualistic plant-microorganisms interactions, and agroforestry - and their potential as beneficial agroecological practices to improve WUE, soil/vine performance, and other ecological services in RDI vineyards within a more sustainable farming system (organic farming). The idea is to design sustainable and climate-change-resilient agricultural systems (e.g. vineyards) in Mediterranean semi-arid areas.
      原文链接:
    • NSTL
    • Elsevier

    Effects of drip irrigation methods on yield and water productivity of maize in Northwest China

    Cao, YuxinCai, HuanjieSun, ShikunGu, Xiaobo...
    10页
    查看更多>>摘要：Water scarcity adversely affects the growth and yield of summer maize in the semi-arid region of Northwest China, and the application of irrigation technology to save water is an effective method for sustainable agricultural development in the area. In order to evaluate the potential of different drip methods for increasing grain yield and water productivity (WP), a 2-year (2018-19) field experiments was conducted to study the effects of various drip irrigation methods on the biomass accumulation and translocation and grain filling progress. The experiment involved three drip irrigation methods: conventional surface drip irrigation (CDI), subsurface drip irrigation (SDI) and alternate surface and subsurface drip irrigation in the soil vertical profile (ADI). The results showed that the ADI treatment had the highest above-ground accumulation of biomass at the maturity stage. However, no statistically significant differences were observed in all the treatments. The contribution of post-silking biomass to grain yield was ADI > SDI > CDI. Based on the two-year average analysis of data, the contribution of post-silking biomass to the grain yield in ADI was 3.6% and 7.0% higher than that in SDI and CDI, respectively. The maximum grain filling rate and the mean grain filling rate were the highest in the ADI, followed by SDI with CDI as the lowest. The active grain filling period and effective grain filling time were the highest under ADI and the lowest under CDI. There was a positive correlation between the active grain filling period and effective grain filling time. The ADI treatment decreased the grain number per spike but significantly increased the kernel weight. Two years of mean data demonstrated that the grain yield of the ADI was 6939.5 kg ha(-1), which corresponded to increases of 4.8% and 13.3% from 6625.0 and 6126.5 kg ha(-1) for SDI and CDI, respectively. For WP, the difference between treatments followed a similar pattern in 2018 and 2019, i.e., the ADI was significantly higher than the SDI, while the SDI was significantly higher than the CDI. Taken together, in addition to its potential for saving water, ADI has the additional advantage of promoting yield. Furthermore, the findings can contribute to a better understanding of the mechanism of biomass accumulation and grain filling process responses to drip irrigation methods.
      原文链接:
    • NSTL
    • Elsevier

    Managing water table depth thresholds for potato subirrigation

    Rens, Libby R.Zotarelli, LincolnSilva, Andre Luiz Biscaia Ribeiro daFerreira, Camila J. B....
    14页
    查看更多>>摘要：Subirrigation requires precise control of the water table level to provide adequate soil water content (SWC) for promoting plant growth. Optimizing water table level management has been shown to improve soil aeration, reduce N-leaching, and reduce risk of crop losses. The objectives of this study were to: i) assess if water table level and N-fertilizer rate impact potato growth, root development, plant N uptake, or tuber yield; and ii) estimate the optimum water table level threshold that provides sufficient soil upward water flux to meet plant water requirements. The study was conducted in 2013 and 2014 in Hastings, FL, USA. Water table level was automatically controlled in three independent irrigation zones of 1.4 ha at 36, 54, and 71 cm from the top of the hilled row, termed as high (HWT), medium (MWT), and low (LWT) water table treatments, respectively, and SWC measured at 22 cm depth was used as covariate to compare treatments. A randomized complete block with three replications was used to evaluate potato cultivars 'Atlantic' and 'FL1867 ' under 0, 112, 224, and 336 kg ha-1 of N-fertilizer within water table treatments. Marketable yield in 2013 was lower than 2014, owing to the high precipitation (421 mm) during tuber bulking that led to high SWC and tuber decay. Total and marketable tuber yields were maximized when N fertilizer rates ranged from 243 to 336 kg ha-1. The highest yield and proportion of large tubers occurred when SWC at 22 cm ranged from 0.13 to 0.16 m3 m- 3. The HWT significantly limited root length, diameter, and surface area, compared to the LWT. In 2014, variation of SWC at 22 cm depth had little effect on tuber yield. The HWT was not detrimental to tuber yield, but rather it compounded the negative effect that high precipitation rate had on fluctuating SWC in the root zone, resulting in reduced yield and tuber quality. Optimal SWC in the root zone can be achieved by adjusting the water table level and upward soil water flux throughout the season, according to the crop evapotranspiration for each crop stage, which reduces irrigation water requirements and minimizes the risks of soil water saturation and tuber yield losses.
      原文链接:
    • NSTL
    • Elsevier