Using EPIC model to manage irrigated cotton and maize

Simulation models are becoming of interest as a decision support system for management and assessment of crop water use and of crop production. The Environmental Policy Integrated Climate (EPIC) model was used to evaluate its application as a decision support tool for irrigation management of cotton and maize under South Texas conditions. Simulation of the model was performed to determine crop yield, crop water use, and the relationships between the yield and crop water use parameters such as crop evapotranspiration (ETc) and water use efficiency (WUE). We measured actual ETc using a weighing lysimeter and crop yields by field sampling, and then calibrated the model. The measured variables were compared with simulated variables using EPIC. Simulated ETc agreed with the lysimeter, in general, but some simulated ETc were biased compared with measured ETc. EPIC also simulated the variability in crop yields at different irrigation regimes. Furthermore, EPIC was used to simulate yield responses at various irrigation regimes with farm fields’ data. Maize required ∼700 mm of water input and ∼650 mm of ETc to achieve a maximum yield of 8.5 Mg ha⁻¹ while cotton required between 700 and 900 mm of water input and between 650 and 750 mm of ETc to achieve a maximum yield of 2.0-2.5 Mg ha⁻¹. The simulation results demonstrate that the EPIC model can be used as a decision support tool for the crops under full and deficit irrigation conditions in South Texas. EPIC appears to be effective in making long-term and pre-season decisions for irrigation management of crops, while reference ET and phenologically based crop coefficients can be used for in-season irrigation management.     

DéciBlé, a software package for wheat crop management simulation

DéciBlé is a simulation tool intended to support the design and evaluation of technical management for the wheat crop. Crop management is here considered from a strategic planning point of view, as the choice of technical decision rules for the whole growing period rather than day-by-day decisions for each operation. DéciBlé simulates the consequences for technical operations and crop production of a set of decision rules over a wide range of possible contexts (regions, year-to-year weather variation, fields, etc.). It is a simulation in which two models interact: a decision and a crop model. The decision model represents the decision rules through a specific formalisation and generates the operations for each context. The crop model is a set of modules simulating plant development, crop environment and yield accumulation implied by these operations in this context through the generation of loss functions or risk estimates. The crop model consists of a set of empirical models based on agronomic diagnosis and experimental references widely used in France. A general validation of DéciBlé is carried out using observed data from a network of field trials. The wheat development stages are simulated within 4 days of the observed dates in more than 80% of the cases and the yield components and final yield with differences of less than 15% from the real values in more than 75% of the cases. We discuss (i) the causes of unsatisfactory predictions and the prospects for improving the various modules of the crop model; (ii) the use of the simulator in some decision problems; and (iii) the position of DéciBlé among the existing models for crop management decision help, emphasising the originality of the method of decision representation.     

Water resources and water use efficiency in the North China Plain: Current status and agronomic management options

Serious water deficits and deteriorating environmental quality are threatening agricultural sustainability in the North China Plain (NCP). This paper addresses spatial and temporal availability of water resources in the NCP, identifies the effects of soil management, irrigation timing and amounts, and crop genetic improvement on water use efficiency (WUE), and then discusses knowledge gaps and research priorities to further improve WUE. Enhanced irrigation and soil nutrient (mainly nitrogen) management are the focal issues in the NCP for enhancing WUE, which are shown to increase WUE by 10-25% in a wheat-maize double cropping system. Crop breeding has also contributed to increased of WUE and is expected to play an important role in the future as genetic and environmental interactions are understood better. Agricultural system models and remote sensing have been used to evaluate and improve current agronomic management practices for increasing WUE at field and regional scales. The low WUE in farmer's fields compared with well-managed experimental sites indicates that more efforts are needed to transfer water-saving technologies to the farmers. We also identified several knowledge gaps for further increasing WUE in the NCP by: (1) increasing scientific understanding of the effects of agronomic management on WUE across various soil and climate conditions; (2) quantifying the interaction between soil water and nitrogen in water-limited agriculture for improving both water and nitrogen-use efficiency; (3) improving irrigation practices (timing and amounts) based on real-time monitoring of water status in soil-crop systems; and (4) maximizing regional WUE by managing water resources and allocation at regional scales.     

Management planning for winter wheat with multiple objectives (1): The BETHA system

Today, farmers have to fulfil the economic, technological and environmental requirements laid down by agro-industries or consumers, or government regulations. This makes designing crop management plans more complex. A tool specific for a wheat crop has therefore been devised: the BETHA system. First, BETHA generates feasible crop management plans from an agronomic model. This agronomic model includes simple relationships that link qualitative and quantitative production to the crop, the crop techniques and climate and soil characteristics. As BETHA is a knowledge-based system, the user can easily modify the agronomic model. BETHA then performs a multiple criteria analysis to classify the crop management plans according to their capacity to follow the competing requirements defined by the user. A non-totally compensatory method based on agreement and discordance principles has been used because these criteria may be very different and cannot be directly aggregated.     

A rule-based method for the development of crop management systems applied to grain sorghum in south-western France

A generic approach is proposed for the development and testing of crop management systems in contrasting situations of water availability. Ecophysiological knowledge, expertise, regional references and simulation models are combined to devise management strategies adapted to production targets and constraints. The next stage consists of converting these crop management strategies into logical and consistent sets of decision rules. Each rule describes the reasoning which is used to apply a technical decision by taking account of observed or simulated environmental conditions or predicted agronomic risks.

This approach was applied to design crop management systems for grain sorghum (Sorghum bicolor L. Moench.) in south-western France. For spring-sown crops, management (sowing date, plant density, varietal choice, N fertilizer rate and timing) was based on water availability, both for economic and environmental reasons. Specific sets of decision rules were written for irrigated and rainfed conditions. The establishment of rules was based on agronomic principles (e.g. for plant density) or on the application of a simulation model (e.g. for sowing date, variety). N fertilization and irrigation were applied using combined N and water dynamic models.

A novel methodology combining crop diagnosis, analytical trials and crop simulation was developed to evaluate the management systems. An irrigated and a rainfed rule-based management system were compared near Toulouse (S.W. France) from 1995 to 2002. The profitability of rainfed low-input management was confirmed for sorghum in spite of high yields under irrigation (up to 10 t ha⁻¹). The adaptation of sorghum management in rainfed conditions was mainly achieved through early maturing cultivars and by reducing N applications by 65%.     

农艺与物联网下的智慧农业

农业物联网在大棚控制系统中的运用实现了农作物增产、改善品质、调节生长周期和提高经济效益的目的。从物联网出发,结合农艺技术和物联网技术,提出了智慧农业系统结构总体框架,为用户实时监控农田并进行信息决策提供了技术支持,真正实现了农业管理的智能化,符合现代农业的发展。      

Use of available information at a European level to construct crop nitrogen response curves for the regions of the EU

Nowadays European agriculture is evolving in a context where policy-making and environmental concerns play a key role. To better assess agro-environmental policies, the AROPAj agricultural supply model needs to take into account the technical characteristics of crop management for different farms. A method to build up specific relationships between yield and nitrogen fertilization that takes into account agronomic techniques is proposed in this paper. The nitrogen response curve is based on an exponential function that integrates economic properties consistently from an agronomic point of view. In AROPAj, individual production systems (farm types) do not have a given location within a specified region and in databases technical information is scarce. The method involves determining technical and physical characteristics, inputs that allow the STICS crop model to assess the yield response to nitrogen of each crop on every farm type. From this information, a nitrogen response curve can be drawn up for each crop of each one of the farms. It can take into account both nitrogen from purchased fertilizer and nitrogen from animal effluents produced on farm. The method was designed to be adaptable to any European region, and tests carried out on two French regions covering a wide range of situations (crops, soils, climates and techniques) showed it was able to cope with varying prices and environments. The agronomic consistency of STICS inputs and curve shapes was also checked. When incorporated into the AROPAj economic model, the response curves can be used to render farms more sensitive to agricultural policy scenarios, by allowing their optimal fertilization level to be adjusted.     

Crop rotations in Argentina: Analysis of water balance and yield using crop models

Cropping schemes have developed in east-central Argentina for rainfed soybean (Glycine max Merr.) production that invariably employ no-tillage management. Often these schemes include growing soybean in a sequence of crops including wheat (Triticum aestivum L.) and maize (Zea mays L.). The full impact of various rotation schemes on soil water balance through a sequence of seasons has not been explored, although the value of these rotations has been studied experimentally. The objective of this work was to investigate through simulations, potential differences in temporal soil water status among rotations over five years. In this study, mechanistic models of soybean (Soy), maize (Maz), and wheat (Wht) were linked over a five-years period at Marcos Juárez, Argentina to simulate soil water status, crop growth, and yield of four no-till rotations (Soy/Soy, Soy/Wht, Soy/Maz, and Soy/Maz/Wht). Published data on sowing dates and initial soil water contents in the first year from a no-till rotation experiment were used as inputs to the model. After the first year, soil water status output from the model was used to initiate the next crop simulation in the sequence. The results of these simulations indicated a positive impact on soil water balance resulting from crop residue on the soil surface under no-till management. Continuous soybean and the two-year soybean/maize rotation did not efficiently use the available water from rainfall. Residue from maize was simulated to be especially effective in suppressing soil evaporation. Thus, the Soy/Maz simulation results indicated that this rotation resulted in enhanced soil water retention, increased deep water percolation, and increased soybean yields compared with continuous soybean crops. The simulated results matched well with experimental observations. The three-crop rotation of Soy/Maz/Wht did not increase simulated soybean yields, but the additional water retained as a result of decreased soil evaporation resulting from the maize residue allowed the addition of a wheat crop in this two-year rotation. Simulated soybean yields were poorly correlated with both the amount of soil water at sowing and the rainfall during the cropping period. These results highlight the importance of temporal distribution of rainfall on final yield. These models proved a valuable tool for assessing the consequences of various rotation schemes now being employed in Argentina on temporal soil water status, and ultimately crop yield.     

不同生育期水分胁迫对玉米农艺性状的影响

为了研究不同生育期玉米水分胁迫对玉米农艺性状的影响,为干旱、半干旱地区玉米抗旱提供理论依据。以玉米在苗期、拔节期、抽雄-吐丝、灌浆-成熟期进行水分胁迫,测量玉米株高、穗位高、叶面积、穗部性状,对比充分灌水与非充分灌溉下玉米农艺性状差异。利用Jensen模型求解出玉米各生育期水分敏感系数,验证水分胁迫对玉米产量的影响。结果表明在拔节期进行干旱处理的株高、穗位高、叶面积受影响较大,有明显的抑制作用。抽雄—吐丝期干旱胁迫对穗部性状的形成较为明显,并且对产量影响较大。     

Crop protection in European maize-based cropping systems: Current practices and recommendations for innovative Integrated Pest Management

Maize-based cropping systems (MBCSs), with different frequency of maize in the crop sequence, are common in European arable systems. Pesticide use differs according to the type of active ingredients and target organisms in different regions. Within the EU Network of Excellence ENDURE, two expert-based surveys were conducted focusing on four European study regions where experts were asked to identify MBCSs in their region, determine the current crop protection practices, propose advanced practices against major pests, weeds and diseases, and evaluate the potential agronomic, environmental, economic and social impact of innovative Integrated Pest Management (IPM) tools on the sustainability of MBCSs. In the northern region (Denmark and The Netherlands), maize is mostly cultivated as non-irrigated continuous silage maize or rotated with grass, while in the central-eastern region the major systems are non-irrigated continuous grain maize (Tolna county, Hungary) or grain maize grown in rotation with winter wheat, oilseed rape and sunflower (Békés county, Hungary). In the south-western (Ebro Valley, Spain) and southern (Po Valley, Italy) regions, continuous and irrigated grain maize, as well as irrigated grain and silage maize/winter wheat rotations are prevalent. Differences in current and proposed advanced crop protection practices for MBCSs were identified between regions due to specific pest, weed and disease problems. The tolerant/resistant non-GM maize cultivars, early detection methods, pest and disease forecasting models, precision/patch spraying using GPS spray maps and the community-based decisions through information sharing were commonly recommended for innovative IPM implementation in all regions. Deviations in the recommendations between regions were mainly caused by differences in the evaluation of economic or social impact of some tools (i.e. innovative mechanical weeding). Applied multi-disciplinary research and farmer incentives to encourage the adoption of innovative IPM strategies are essential for sustainable MBCSs development in Europe. The introduction of innovative tools into IPM strategies can contribute significantly to addressing the EU’s strategic commitment to the sustainable use of pesticides and, consequently, more environmentally sustainable MBCSs.     

Crop coefficients for winter wheat in a sub-humid climate regime

Estimations of evapotranspiration (ET) from natural surfaces are used in a large number of applications such as agricultural water management and water resources planning. Lack of reliable, cheap and easy-to-use instruments, associated with the chaotic and varying nature of the meteorological and plant physiological factors influencing ET cause these estimations to be based on calculated values rather than the measured ones. The two-step approach where ET from a reference crop is calculated and multiplied by empirical crop coefficients to obtain ET from a crop has gained wide acceptance. Daily coefficients for a winter wheat crop growing under standard conditions, i.e. not short of water and growing under optimal agronomic conditions, were estimated for a cold sub-humid climate regime. One of the two methods used to estimate ET from a reference crop required net radiation (R_n) as input. Two sets of coefficients were used for calculating R_n. Weather data from a meteorological station was used to estimate R_n and ET from the reference crop. The winter wheat ET was measured using an eddy covariance system during the main parts of the growing seasons 2004 and 2005. The meteorological data and field measurements were quality controlled and discarded from the analysis if flagged for errors. Daily values of ET from the reference crop and winter wheat calculated from hourly values were used to calculate the crop coefficients. Average daily crop coefficients were in the 1.1–1.15 range during mid-season with standard deviations ranging from 0.13 to 0.23 for both years. These values exceed values used in some sub-humid climate regime studies, but agree well with values from the international literature.     

用叶绿素测值(SPAD)评估夏玉米氮素状况的实验研究

比较了 2 0 0 0年北京永乐店夏玉米生长过程中 ,不同水分、氮素处理条件下反映叶片叶绿素含量的SPAD值的变化过程 ,并且就生育期内平均 SPAD值与作物产量 ,水分生理利用效率之间的关系进行了分析。结果表明 ,采用叶绿素仪可以较好的对夏玉米生长过程中作物氮素状况对生长的影响进行评价和预测。     

Maize yield response to deficit irrigation during low-sensitive growth stages and nitrogen rate under semi-arid climatic conditions

Knowledge of crop production in suboptimal environmental conditions not only helps to sustain crop production but also aids in the design of low-input systems. The objective of this study was to evaluate the effects of water stress imposed at low-sensitive growth stages (vegetative, reproductive, and both vegetative and reproductive) and level of nitrogen (N) supply (100 and 200 kg ha⁻¹) on the physiological and agronomic characteristics of two hybrids of maize (Zea mays L.). A two-site field experiment was carried out using a randomized complete block design with three replications and a split-factorial arrangement. A water deficit (WD) was induced by withholding irrigation at different stages of crop development. The results showed that proline content increased and the relative water content, leaf greenness, 100-kernel weight and grain yield decreased under conditions of WD. The highest IWUE was obtained when maize endured WD at vegetative stage at two sites. The limited irrigation imposed on maize during reproductive stage resulted in more yield reduction than that during vegetative stage, compared with fully irrigated treatment. The 100-kernel weight was the most sensitive yield component to determine the yield variation in maize plant when the WD treatments were imposed in low-sensitive growth stages. The results of the statistical regression analysis showed liner relationships between RGR during a period bracketing the V₈ or R₃ stages and 100-kernel weight in all the WD treatments. The increase of N supply improved yield and IWUE when maize plant endured once irrigation shortage at vegetative stage. But, the performance of high N fertilizer reduced and eliminated when water deficit imposed once at reproductive stage and twice at vegetative and reproductive stages, respectively. Furthermore, the response of T.C647 hybrid to increase of N supply was stronger than S.C647 hybrid.     

Simulating field-scale nitrogen management scenarios involving fertiliser and slurry applications

The long-term effects of nitrogen (N) fertiliser and slurry management practices in agricultural systems has been simulated using event driven physically based models. The Swedish soil water model SOIL and its associated nitrogen cycle model SOILN has been used to simulate the long-term impacts (over 12 years) of 360 management scenarios; three slurry applications with 10 spreading dates (involving single and split applications) for surface spreading and injection of slurry, and three fertiliser applications with two spreading dates. The effects of the N management scenarios on NO₃–N drainage flows, total gaseous N losses and crop yields for grass, winter and spring cereals is investigated. Furthermore, seven soils with varying degrees of drainage efficiency and three climatic conditions (East and West coast Scotland and Southern Ireland) are studied.The aim of this work is to produce N-budget tables for an expert agricultural decision system (ADS) which deals specifically with N best management practises for fertiliser and slurry applications. Simulations conducted in this study were based on input parameters calibrated for specific sites in previous studies on hydrology and NO₃–N transport to subsurface drains with associated crop growth.The results of this study show that increasing rates of N applications (in the form of slurry and fertiliser) resulted in a non-linear increase in both the N leached through subsurface drains and the N harvest yield. Surface spreading and injection of slurry gave similar trends. The most important decision about slurry spreading concerns the selection of spreading date and the selection of fields which are likely to produce only moderate leaching effects. Application of slurry in autumn (as a single or split loading), invariably leads to large losses through N leaching, with a single application always resulting in the highest loss. Significant differences are evident for N leaching from the seven soil types. Climatic variation as exemplified in the three meteorological data sets, produces noticeable and significant differences in both N leached and harvest crop totals. This study also aims to identify that a field environmental risk assessment (ERA) using a physically based model such as SOILN can be determined such that strategic agronomic decisions involving N management can be made. In practice this is so provided that a farm manager can recognise and match the actual soil type and drainage condition of the fields on which spreading is to occur with the simulated field types within a similar climate region.     

秸秆还田配施稳定性氮肥对麦玉轮作水氮利用的影响

为探究秸秆还田配施稳定性氮肥对关中地区麦玉轮作体系作物生长及水氮利用的综合影响,并确定合理的高产高效施肥管理措施,设置两种秸秆还田模式(秸秆不还田、秸秆全量还田)和两种施氮措施(常规尿素和减量施用稳定性氮肥),以无秸秆还田且不施肥作为对照,共5个处理,研究分析作物产量、地上部生物量、土壤氨挥发累积量、土壤含水率、土壤硝态氮残留量及水氮利用效率。结果表明：秸秆还田配施氮肥会分别显著提高夏玉米和冬小麦产量28.03%～39.63%和90.10%～112.52%、地上部生物量27.88%～34.00%和78.96%～107.64%;施用稳定性氮肥较施用常规尿素分别降低夏玉米季和冬小麦季全生育期土壤氨挥发累积量50.18%～59.32%和68.21%～73.43%;秸秆还田会显著提高夏玉米季0～10 cm土壤含水率6.29%～21.38%,显著提高冬小麦季0～10 cm土壤含水率6.80%～25.06%;相同施肥措施下,秸秆还田会显著降低夏玉米与冬小麦收获期0～100 cm土壤NO^-₃-N残留量7.34%～10.78%和6.57%～11.24%,在相...     

Assessing yield optimization and water reduction potential for summer-sown and spring-sown maize in Pakistan

Agricultural food production in arid and semi-arid regions faces the challenge to ensure high yields with limited supply of water. This raises the question to which extent irrigation supply can be reduced without detriment to yield. Our study focuses on the yield-water uptake relationship for maize in the moderate water stress range in order to determine the onset of stress-induced dry-matter and yield losses. Compensatory plant responses under moderate stress levels are discussed in relation to seasonal climatic conditions.Summer-sown and spring-sown maize were irrigated with a decreasing amount of water in a field experiment in Pakistan. Water supply ranged from 100% water required to maintain soil at field capacity (FC) to 40% of FC. The average dry-matter and yield levels were slightly higher for summer-sown (15.0 Mg ha⁻¹) compared to spring-sown maize (13.1 Mg ha⁻¹). The onset of significant dry-matter and yield reduction started at the least irrigation treatment in both seasons. The amount of water required to avoid production losses was 272 mm in the summer-sown maize during the autumn growing season, and 407 mm for the spring-sown maize in the summer season, when the evaporative demand of the atmosphere was +27% higher. Water use efficiency (WUE_ET), normalized by vapour pressure deficit, of the summer-sown maize which was 10.0 kg kPa m⁻³, was +15% higher compared to the spring-sown crop; while the irrigation water productivity (2.9 kg m⁻³) was +11% more. WUE_ET increased over the whole range of applied water deficits for summer-sown maize, while the spring-sown crop showed a decreasing WUE_ET in the less irrigated treatment. Due to the higher efficiency in summer-sown maize, the potential in irrigation reduction without production losses (129 mm) was higher compared to the spring-sown maize (57 mm). Our results showed that in Pakistan water saving irrigation practices can be applied without yield loss mainly during the cooler growing season when the crop can efficiently compensate a lower total water uptake by increased use efficiency. For spring-sown maize the increasing evaporative demand of the atmosphere towards summer implies a higher risk of yield losses and narrows the range to exploit higher irrigation water productivity under moderate water deficit conditions.     

2ZYS-2型玉米育苗滤水移栽机的研制

玉米是黑龙江省种植面积最大、分布范围最广、总产量最高的优势作物,其栽培模式长期以来以直播为主。玉米移栽技术是一项抗旱高产新型农艺栽培技术,相比传统的直播种植方式,移栽能够使玉米作物提高有效积温时间、减少春季低温伤害、提高抵抗病虫害的能力,从而确保纸筒秧苗存活率率,提高玉米的产量和品质。过去玉米移栽大都采用人工的方式进行,劳动力需求大,作业效率低下,移栽质量难以保证,无法进行大面积推广应用。玉米育苗滤水移栽机的研制成功为玉米机械化移栽提供有效机械载体,填补了我国在该类型农机装备方面的空白。     

Regional crop modelling in Europe: The impact of climatic conditions and farm characteristics on maize yields

Impacts of climate variability and climate change on regional crop yields are commonly assessed using process-based crop models. These models, however, simulate potential and water limited yields, which do not always relate to observed yields. The latter are largely influenced by crop management, which varies by farm and region. Data on specific management strategies may be obtained at the field level, but at the regional level information about the diversity in management strategies is rarely available and difficult to be considered adequately in process-based crop models. Alternatively, understanding the factors influencing management may provide helpful information to improve simulations at the regional level.In this study, we aim to identify factors at the regional level that explain differences between observed and simulated yields. Observed yield data were provided by the Farm Accountancy Data Network (FADN) and Eurostat. The Crop Growth Monitoring System (CGMS), based on the WOFOST model, was used to simulate potential and water limited maize yields in the EU15 (i.e., the old member states of the European Union). Differences between observed and simulated maize yields were analysed using regression models including: (i) climatic factors (temperature and precipitation), (ii) farm size, (iii) farm intensity, (iv) land use, (v) income and (vi) subsidies. We assumed that the highest yields observed in a region were close to the yield potential as determined by climate and considered the average regional yields as also influenced by management. Model performance was analysed with respect to spatial and temporal yield variability.Results indicate that for potential yield, the model performed unsatisfactory in southern regions, where high temperatures increased observed yields which was in contrast to model simulations. When considering management effects, we find that especially irrigation and the maize area explain much of the differences between observed and simulated yields across regions. Simulations of temporal yield variability also diverted from observed data of which about 80% could be explained by the climatic factors (35%) and farm characteristics (50%) considered in the analysis. However, effects of specific factors differed depending on the regions. Accordingly, we propose different groups of regions with factors related to management which should be considered to improve regional yield simulations with CGMS.     

土壤空间变异对水氮淋失和产量影响的模拟研究

基于CERES-Maize模型,研究了土壤空间变异和水文年型对半干旱地区土壤水氮淋失和玉米产量的影响.结果表明,土壤空间变异对作物产量和土壤水氮淋失的影响程度与降雨密切相关.丰水年水氮淋失量显著高于平水年和枯水年.降雨对作物产量和农田尺度水氮淋失的空间变异有明显影响,并能在一定程度上减弱土壤空间变异对产量和农田尺度水氮淋失的影响.随着土壤空间变异程度的增大,产量降低,产量的空间变异程度增加.水分渗漏和氮淋失量随土壤空间变异的增加呈增加趋势.当土壤黏粒和粉粒含量变异系数CV≥0.2时,在水氮管理中考虑土壤空间变异有利于提高作物产量,减轻水氮淋失.     

Energy balance and crop water stress in winter maize under phenology-based irrigation scheduling

In eastern India, cultivation of winter maize is getting popular after rainy season rice and farmers practice irrigation scheduling of this crop based on critical phenological stages. In this study, crop water stress index of winter maize at different critical stages wase determined to investigate if phenology-based irrigation scheduling could be optimized further. The components of the energy budget of the crop stand were computed. The stressed and non-stressed base lines were also developed (between canopy temperature and vapor pressure deficit) and with the help of base line equation, [(T _c − T _a) = −1.102 VPD − 3.772], crop water stress index (CWSI) was determined from the canopy-air temperature data collected frequently throughout the growing season. The values of CWSI (varied between 0.42 and 0.67) were noted just before the irrigations were applied at critical phenological stages. The soil moisture depletion was also measured throughout the crop growing period and plotted with CWSI at different stages. Study revealed that at one stage (silking), CWSI was much lower (0.42–0.48) than that of recommended CWSI (0.60) for irrigation scheduling. Therefore, more research is required to further optimize the phenology-based irrigation scheduling of winter maize in the region. This method is being used now by local producers. The intercepted photosynthetically active radiation and normalized difference vegetation index over the canopy of the crop were also measured and were found to correlate better with leaf area index.