Irrigated Wheat Crops Research Articles

Environmental efficiency of rainfed and irrigated wheat crops in Spain. A stochastic DEA metafrontier approach

Environmental efficiency of rainfed and irrigated wheat crops in Spain. A stochastic DEA metafrontier approach

Development of growth-stage specific crop coefficient for drip irrigated wheat crop grown in climatic conditions of Jalandhar, Punjab

The crop coefficient (Kc) values given in FAO-56 report need to corrected for local conditions due to differences in climate, soil types, and water management practices. Therefore, present study was undertaken to develop growth-stage-specific Kc values of wheat grown under drip irrigated conditions for two years (2022-23 and 2023-24) at Jalandhar, Punjab. The developed Kc values are 0.36, 0.77, 1.05, 0.69, and 0.25 during initial, development, mid, late, and end growth stages, respectively. These average Kc values can be effectively utilized to schedule irrigation for drip-irrigated wheat crops in the Jalandhar region of Punjab. Irrigating wheat crop under drip irrigation with developed Kc values not only enhances grain yield by 36% but also improves IWUE by three times and saves 61% use of irrigation water as compared to conventional irrigation practices (flood irrigation).

Assessing the Influence of Nano Urea on the Growth and Yield of Irrigated Wheat (Triticum aestivum L.) Crop

Wheat (Triticum aestivum L.) is one of the world's most essential cereal crops, serving as a staple food for a significant portion of the global population. In the pursuit of achieving higher yields in contemporary agriculture, the use of chemical fertilizers poses an increased environmental risk. However, the application of Nano urea offers a potential solution to mitigate this risk to a certain extent. To address this objective, a field experiment was conducted during the Rabi seasons of 2022-2023 at the A trial was executed in the rural area of Kanpur district of Mandhana, located 10 km from Kanpur in Uttar Pradesh, during the Rabi season of 2022-23. The experimental design involved two main factors: Factor-1 Nitrogen (at 50%, 75%, and 100% levels) and Factor-2 Foliar Spray (at one time Nano urea and two time Nano urea, with 4 ml/l). A control group was included, and the experiment was laid out in a Randomized Block Design (RBD) with 13 treatments in three replications. The results indicated that the combination of 100% nitrogen along with a foliar spray of 4 ml/L Nano urea had a significant positive impact on growth, yield, and various yield parameters. Treatment 6 demonstrated the highest values for plant height (95.66 cm), Dry matter accumulation (1014.09 g m-2), number of tillers m-2 (417.44), Leaf area index at 90 DAS (4.85), effective ear head per (m-2) (282.66), grains per ear head (65.75), test weight (48.52 g), grain yield (46.15 quintals/ha), and straw yield (57.92 quintals/ha). The study's results demonstrated a generally positive effect of combined Nano urea with traditional NPK nutrient supply on the growth and yield parameters of wheat in irrigated conditions.

Bio-efficacy of metsulfuron methyl and carfentrazone ethyl against weed spectrum in wheat (Triticum aestivum L.)

A field experiment was conducted during the winter (rabi) season of 2016–17 and 2017–18 at the Chandra Shekhar Azad University of Agriculture and Technology Kanpur, Uttar Pradesh, to evaluate bio-efficacy and phytotoxicity of metsulfuron methyl 10% + carfentrazone ethyl 40% against weed flora in irrigated wheat crop (Triticum aestivum L). Major dominant weeds that infested the crop were lamb’s quarters (Chenopodium album L.), scarlet pimpernel (Anagallis arvensis L.) and white sweet clover (Melilotus albus Medik.). The lowest dry weight (g/m2) and weed-control efficacy (WCE) of test weed species were found in treatments T4 (metsulfuron methyl 10% + carfentrazone ethyl 40% @ 100 g/ha), T3 (metsulfuron methyl 10% + carfentrazone ethyl 40% @ 75 g/ha) and T2 (metsulfuron methane 10% + carfentrazone ethyl 40% @ 50 g/ha) respectively. Application of metsulfuron methyl 10% + carfentrazone ethyl 40% at all doses was found to be effective against all the 3 weeds and significantly increased the yield of the main crop. Application of weedicides did not show any phytotoxicity symptoms on the wheat crop in both the seasons and also on the succeeding crop of rice (Oryza sativa L.).

Evaluation of nickel toxicity and potential health implications of agriculturally diversely irrigated wheat crop varieties

Nickel (Ni) is essential for plant metabolism but is dangerous to most plants and other organisms when present in large concentrations. In this study, nickel (Ni) was chosen as an important environmental pollutant and toxic substance due to its widespread availability, and high persistence, causing soil pollution and serious environmental problems. The main aim of the study is to determine the Ni content in various wheat varieties and soil grown in various water regimes (sewage water, groundwater and industrial water) in Punjab, Pakistan. The Ni concentrations were determined via the ecological environment (water, soils) and below (roots) and above-ground plant organs (shoots and wheat grains) and phytostabilization potential assessment using various pollution indices. The results showed that the mean Ni concentration in different wheat varieties varied from 1.35 to 2.45 mg/kg, 1.17 to 2.42 mg/kg, 1.09 to 2.10 mg/kg and 0.99 to 1.54 mg/kg in soil, root, shoot, and grains, respectively. Research findings also revealed that the nickel concentration in soil and grains is within the safe limits and all the indices for Ni are less than 1. As a result, the studied wheat cultivars appear to be safe for consumption. However, it can be said that the continuous use of wastewater for irrigation may pose health risks for living things in the food chain.

Establishment of Crop Water Stress Index for Sustainable Wheat Production under Climate Change in a Semi-Arid Region of Pakistan

The Crop Water Stress Index (CWSI) is a useful tool for evaluating irrigation scheduling and achieving water conservation and crop yield goals. This study examined the CWSI under different water stress conditions for the scheduling of wheat crop irrigation and developed indices using the leaf canopy temperature in Faisalabad, Pakistan. The experiments were conducted using a randomized, complete block design and four irrigation treatments with deficit levels of D0%, D20%, and D40% from the field capacity (FC) and D100% (100% deficit level). The CWSI was determined at pre-heading and post-heading stages through the lower baseline (fully watered crop) and upper limit (maximum stress). These baselines were computed using the air temperature and canopy temperature of plant leaves and the vapor pressure deficit (VPD). The CWSI for each irrigation treatment was calculated and the average seasonal CWSI value for the whole season was used to develop the empirical relationships for scheduling irrigation. The relationships between the air canopy temperatures and the VPD resulted in slope (x) = −0.735 and interception (c) = −0.8731 as well as x = −0.5143 and c = −1.273 at the pre- and post-heading stages, respectively. The values of the CWSI for the treatment at deficit levels of D0%, D20%, D40%, and D100% were found to be 0.08, 0.61, 0.20, and 0.64, respectively. The CWSI values developed in this study can be effectively used to promote better the monitoring of irrigated wheat crops in the region.

“Use of a GIS-Based Multicriteria Decision-Making Approach, to Increase Accuracy in Determining Soil Suitability”, Iran

ABSTRACT Land suitability analysis and land use mapping are one of the most practical applications of Geographic Information Systems in land resource management. In the present study, the qualitative assessment of land suitability was investigated using fuzzy and parametric hierarchical analysis process models for the irrigated wheat crop. Soil characteristics, climatic conditions, topography, and accessibility were selected based on the Food and Agriculture Organization framework and expert opinions. The interpolation function was used to plot values to points in terms of quality/terrain characteristics for the type of operation and the evaluation was performed based on parametric and fuzzy analytical hierarchy process models. According to the parametric model, the values of land indices vary from 50% in some places to 78% in the study area, which classifies the plain from suitable classes (S2) to upper classes (S1). Preferred values fuzzy analytical hierarchy process for wheat cultivation in the study area are from 0.25 to 0.73, which is classified as medium to very high for wheat production. Kappa Cohen coefficient between parametric land indices and preferential values fuzzy analytical hierarchy process with observed wheat yield varies between 0.03 and 0.237, respectively, which confirms the validity of both models in estimating land suitability for irrigated wheat production in the study area. The results of the present study show that fuzzy analytical hierarchy process is an effective strategy to increase the weight accuracy of the criteria affecting the analysis of land suitability.

A Calibration/Disaggregation Coupling Scheme for Retrieving Soil Moisture at High Spatio-Temporal Resolution: Synergy between SMAP Passive Microwave, MODIS/Landsat Optical/Thermal and Sentinel-1 Radar Data.

Soil moisture (SM) data are required at high spatio-temporal resolution—typically the crop field scale every 3–6 days—for agricultural and hydrological purposes. To provide such high-resolution SM data, many remote sensing methods have been developed from passive microwave, active microwave and thermal data. Despite the pros and cons of each technique in terms of spatio-temporal resolution and their sensitivity to perturbing factors such as vegetation cover, soil roughness and meteorological conditions, there is currently no synergistic approach that takes advantage of all relevant (passive, active microwave and thermal) remote sensing data. In this context, the objective of the paper is to develop a new algorithm that combines SMAP L-band passive microwave, MODIS/Landsat optical/thermal and Sentinel-1 C-band radar data to provide SM data at the field scale at the observation frequency of Sentinel-1. In practice, it is a three-step procedure in which: (1) the 36 km resolution SMAP SM data are disaggregated at 100 m resolution using MODIS/Landsat optical/thermal data on clear sky days, (2) the 100 m resolution disaggregated SM data set is used to calibrate a radar-based SM retrieval model and (3) the so-calibrated radar model is run at field scale on each Sentinel-1 overpass. The calibration approach also uses a vegetation descriptor as ancillary data that is derived either from optical (Sentinel-2) or radar (Sentinel-1) data. Two radar models (an empirical linear regression model and a non-linear semi-empirical formulation derived from the water cloud model) are tested using three vegetation descriptors (NDVI, polarization ratio (PR) and radar coherence (CO)) separately. Both models are applied over three experimental irrigated and rainfed wheat crop sites in central Morocco. The field-scale temporal correlation between predicted and in situ SM is in the range of 0.66–0.81 depending on the retrieval configuration. Based on this data set, the linear radar model using PR as a vegetation descriptor offers a relatively good compromise between precision and robustness all throughout the agricultural season with only three parameters to set. The proposed synergistical approach combining multi-resolution/multi-sensor SM-relevant data offers the advantage of not requiring in situ measurements for calibration.

Gaseous nitrogen losses from pig slurry fertilisation: can they be reduced with additives in a wheat crop?

Aim of the study: The use of pig slurry as fertiliser is associated with gaseous nitrogen (N) losses, especially ammonia (NH3) and nitrous oxide (N2O), leading to environmental problems and a reduction of its fertiliser value. This study evaluates, in an irrigated wheat crop, the effect of different additives mixed with pig slurry to decrease NH3 and N2O losses.Area of study: Middle Ebro valley, SpainMaterials and methods: The treatments were: i) non-N-fertilised control, ii) pig slurry (PS), iii) pig slurry with the urease inhibitor monocarbamide dihydrogen sulphate (PS-UI), iv) pig slurry with a microbial activator in development (PS-A), and v) pig slurry with the nitrification inhibitor 3,4-dimethylpyrazole phosphate (PS-NI). Pig slurry was applied at a target rate of 120 kg NH4+-N ha-1. Ammonia volatilisation was measured using semi-opened static chambers after treatments application at presowing 2016 and side-dressing 2017. Nitrous oxide emissions were measured using static closed chambers after treatments application at the 2017 and 2018 side-dressing.Main results: Ammonia volatilisation was estimated to be 7-9% and 19-23% of NH4+-N applied after presowing and side-dressing applications, respectively. Additives were not able to reduce NH3 emissions in any application moment. PS-NI was the only treatment being effective in reducing N2O emissions, 70% respect to those in PS treatment. Crop yield parameters were not affected by the application of the additives because of the no effect of additives controlling NH3 losses and the low contribution of N2O losses to the N balance (<1 kg N2O-N ha-1).Research highlights: The use of 3,4-dimethylpyrazole phosphate would be recommended from an environmental perspective, although without grain yield benefits.

Dual crop coefficients and performance of evapotranspiration methods in irrigated wheat

Water availability, fertilizer management and crop rotation are fundamental to the sustainability of agriculture and food security. Thus, the objective of this study was the determination of crops coefficients, verification and comparison of methods of estimation and determination of the evapotranspiration of irrigated wheat. The experiment was carried out during two consecutive years, in which BRS 254 varieties were cultivated in 2016 and BRS 394 in the year 2017. The evapotranspiration was estimated and determined using the dual kc methodology, FAO-56, with plants grown in 12 lysimeters filled with soil monoliths, and the loss of water by evaporation measured by weighing small-lysimeters. Evapotranspiration was also determined by the water balance method. The results measured in the lysimeters (standard method) were compared with the data simulated by the dual kc method and determined by method of soil water balance, in order to determine the accuracy and efficiency of the methods used. The coefficients used to determine the efficiency of the methods were the RMSE, the RSR and the confidence index "c". The total evapotranspiration of the crop in both years of cultivation was 360 mm, with mean values of 3.87 mm d-1 for cultivar BRS 254 and 4.10 mm d-1 for cultivar BRS 394. The basal crops coefficients in the emergence, tillering, flowering, maturation and harvest stages were 0.42, 0.78, 0.94, 0.74 and 0.47 for cultivar BRS 254 and 0.28, 0.27, 0.65, 0.98 and 0.66 for cultivar BRS 394. The soil water evaporation coefficients at the respective stages are 0.72, 0.52, 0.39, 0.58 and 0.13 for cultivar BRS 254 and 1.04, 0.96, 0.65, 0.34 and 0.51 for cultivar BRS 394. Ke represents on average about 47% of the evapotranspiration of the irrigated wheat crop. Between methods tested, lysimeter is the best to wheat transpiration followed by FAO method and soil water balance. The use of any methods should consider the objectives and resources availability.

Saline Water Irrigation Through Drip for Groundnut-Wheat Cropping Sequence in Hyper Arid-Region of Rajasthan

A field experiment was conducted to assess the suitability of saline water for irrigation, and to know the irrigation water requirement of groundnut-wheat cropping sequence in hyper-arid region of Rajasthan. In this split-plot experiment, the main plots had four levels of irrigation water salinity (ECiw0.25 (Best available water, BAW), 4, 8 and 12dS.m-1); and the sub-plots had combinations of two treatments on drip lateral spacing of 0.60 m and 0.90 m with 0.30 m emitter spacing, and three levels of irrigation water application (0.6, 0.8 and 1.0 times of pan evaporation (PE)). The highest biological yield (grain + straw) of groundnut and wheat recorded in BAW was statistically at par with irrigation water salinity level of 4 dS.m-1. Higher irrigation water salinity levels (8 and 12 dS.m-1) and placement of laterals at 0.90 m led to significant reduction in biological yield. In monetary terms, use of BAW resulted in highest B:C ratio of 1.73 for groundnut-wheat cropping sequence, while ECiw 4 dS.m-1 showed B:C ratio of 1.70. Highest crop yields, gross return and B:C ratio were observed under 0.60 m lateral spacing and irrigation application at 1.0 PE. Interaction effect of salinity of irrigation water and lateral spacing on yield and yield attributes was significant for both crops. Study demonstrated that the salinity limit of 4 dS.m-1 can be considered as threshold irrigation water salinity for drip irrigated groundnut and wheat crops in hyper-arid region of Rajasthan.

Canopy spectral reflectance for crop water stress assessment in wheat (Triticum aestivum, L.)*

AbstractSpectral reflectance in the near‐infrared (NIR) and short‐wave–infrared (SWIR) regions shows decreasing water absorption troughs upon crop water stress. In this study, decreasing water absorption troughs were identified from reflectance of irrigated wheat crop. The crop was grown under two different irrigation methods, sprinkler and flood irrigation. Crop reflectance was measured using an ASD FieldSpec 3 (350–2,500 nm) hand‐held spectroradiometer at 1 week before the critical growth stages. Among different growth stages, wheat crop was found to be under stress in crown root initiation, jointing, and flowering. Results based on crop yield, and raw and first derivative spectral analysis indicated that flood‐irrigated wheat had more stress compared with sprinkler‐irrigated wheat. Five water stress‐sensitive wavelengths (974; 1,195; 1,455; 1,791; and 1,935 nm) were identified from flood‐irrigated wheat. Among them, two wavelengths (974 and 1,195 nm) were found to be highly water sensitive and good indicators for water stress. Detecting crop water stress prior to the critical growth stages of wheat helps in proper irrigation scheduling.

Evapotranspiration and crop coefficients in two irrigated wheat cultivars

ABSTRACT In the state of Mato Grosso, Brazil, wheat is an alternative to the current production system, mainly in irrigated crops, with new cultivars improved for this environment and system. The objective was to determine the evapotranspiration of the irrigated wheat crop and the dual coefficients of cultivars for the Brazilian Midwest. The experiment was conducted in the field using 12 weighing lysimeters and mini-lysimeters, filled by soil monoliths. The wheat cultivars BRS-254 and BRS-394 were used in the first and second years, respectively. Reference evapotranspiration was obtained by the Penman-Monteith equation and crop evapotranspiration by the mass difference in the lysimeters. Basal crop coefficient and soil water evaporation coefficient were determined according to the crop development stages in both years of cultivation. The mean ETc and ETo values were 3.87, 3.49 mm d-1 and 4.10 and 3.23 mm d-1, respectively, in the first and second cultivation cycles, with higher values of ETc recorded in the reproductive stages of the crop, flowering and grain filling. The basal crop coefficients and soil water evaporation coefficients estimated by weighing lysimeters composed of soil monoliths are: Kcb - 0.42, 0.78, 0.94, 0.74 and 0.47 and Ke - 0.72, 0.52, 0.39, 0.58 and 0.13 for the cultivar BRS-254, and Kcb - 0.28, 0.27, 0.65, 0.98 and 0.66 and Ke - 1.04, 0.96, 0.65, 0.34 and 0.51 for the cultivar BRS-394, at the stages of emergence, tillering, flowering, maturation and harvest, respectively.

Advancing a farmer decision support tool for agronomic decisions on rainfed and irrigated wheat cropping in Tasmania

Well-designed agricultural decision support tools (DS) equip farmers with a rapid, easy way to compare multiple scenarios as well as the influence of different management strategies on crop production. One such tool, CropARM (http://www.armonline.com.au) assists users in establishing a framework of risk, with simulations incorporating climate scenarios and management actions, such as fertiliser rates, sowing time, row spacing, and irrigation regimes. When used in conjunction with soil and climate characteristics, biophysical model-based DS tools provide information that complements farmer experience and helps establish a framework for risk management given local climate characteristics. In this study, we used the APSIM model to provide the simulation data necessary to expand CropARM for new management conditions and environments in southern Australia. Prior to this work being undertaken, no CropARM data was available for Tasmania and no sites in CropARM allowed users to compare rainfed and irrigated wheat crops. This study collated data from 27 plots across ten sites in Tasmania, from the period 1981 to 2011, under both rainfed and irrigated conditions. APSIM was parameterised with these field observations and the subsequent scenario simulations were used to populate CropARM. Wheat cultivars used in the parameterisation of APSIM include Brennan, Isis, Mackeller, Revenue, Tennant (winter types) and Kellalac (spring type). The validation showed reliable model parameterisation, with an r2 value of close to 1, which is considered satisfactory. 670,680 simulations were undertaken and incorporated within the CropARM database for wheat cropping systems across Tasmania. With regularly updated climate streams, the free online framework provided by CropARM gives users the ability to assess downside risks associated with several different crop management alternatives, and by simultaneously comparing multiple scenarios, users can select management options that are likely to adhere most closely with their desired management objectives.

Modified Penman–Monteith equation for monitoring evapotranspiration of wheat crop: Relationship between the surface resistance and remotely sensed stress index

Evapotranspiration (ET) plays an essential role for detecting plant water status, estimating crop water needs and optimising irrigation management. Accurate estimates of ET at field scale are therefore critical. The present paper investigates a remote sensing and modelling coupled approach for monitoring actual ET of irrigated wheat crops in the semi-arid region of Tensift Al Haouz (Morocco). The ET modelling is based on a modified Penman–Monteith equation obtained by introducing a simple empirical relationship between surface resistance (rc) and a stress index (SI). SI is estimated from Landsat-derived land surface temperature (LST) combined with the LST endmembers (in wet and dry conditions) simulated by a surface energy balance model driven by meteorological forcing and Landsat-derived fractional vegetation cover. The proposed model is first calibrated using eddy covariance measurements of ET during one growing season (2015–2016) over an experimental flood-irrigated wheat field located within the irrigated perimeter named R3. It is then validated during the same growing season over another drip-irrigated wheat field located in the same perimeter. Next, the proposed ET model is implemented over a 10 × 10 km2 area in R3 using a time series of Landsat-7/8 reflectance and LST data. The comparison between modelled and measured ET fluxes indicates that the model works well. The Root Mean Square Error (RMSE) values over drip and flood sites were 13 and 12 W m−2, respectively. The proposed approach has a great potential for detecting crop water stress and estimating crop water requirements over large areas along the agricultural season.

Identification of ecogeographical gaps in the Spanish Aegilops collections with potential tolerance to drought and salinity.

Drought, one of the most important abiotic stress factors limiting biomass, significantly reduces crop productivity. Salinization also affects the productivity of both irrigated and rain-fed wheat crops. Species of genus Aegilops can be considered crop wild relatives (CWR) of wheat and have been widely used as gene sources in wheat breeding, especially in providing resistance to pests and diseases. Five species (Ae. biuncialis, Ae. geniculata, Ae. neglecta, Ae. triuncialis and Ae. ventricosa) are included in the Spanish National Inventory of CWRs. This study aimed to identify ecogeographic gaps in the Spanish Network on Plant Genetic Resources for Food and Agriculture (PGRFA) with potential tolerance to drought and salinity. Data on the Spanish populations of the target species collected and conserved in genebanks of the Spanish Network on PGRFA and data on other population occurrences in Spain were compiled and assessed for their geo-referencing quality. The records with the best geo-referencing quality values were used to identify the ecogeographical variables that might be important for Aegilops distribution in Spain. These variables were then used to produce ecogeographic land characterization maps for each species, allowing us to identify populations from low and non-represented ecogeographical categories in ex situ collections. Predictive characterization strategy was used to identify 45 Aegilops populations in these ecogeographical gaps with potential tolerance to drought and salinity conditions. Further efforts are being made to collect and evaluate these populations.

AN ECONOMIC STUDY OF THE MOST IMPORTANT RAIN-FED PLANT MATROUH GOVERNORATE

The present study was conducted at Matrouh Governorate, where the area exlends along the coastal plain southward depth 2.5 km (at El Alamien) and disappears in other places, i.e. Fuka and Ras El-Hekma. Due south the coastel phin the plateau rises gradually until Siwa Oasis, where the altitude falls down to around 27 m below sea level. The study aims at evaluating the agricultural resources availability of irrigation water resoures, arable land, the current status of the rainfed agricultural system adopted, in addition to productive and economic efficiency assessment. The study indicited that the net yield of irrigated wheat crops was 2210 pounds/acre, while the net return of the opportunity cost of about 492.8 pounds/acre, while showing that the opportunity cost of agriculture represents the best investment opportunity rain-fed wheat crop cultivated rainy system, where there has been a return of about 151.9 pounds/acre, while they cause the loss of about 460 pounds/acre. Also, data showed that the net yield of the irrigated olive crops was about 6450 pounds/acre, while the net return of the opportunity costs of about 1636.9 pounds/acre, which means productive activity preference for the cultivation of the crop olive about the opportunity cost of this activity represents a better investment opportunity. This study has led to some recommendations, including the need to develop a specific time-plan for the establishment of infrastructures helping in rain water harvesting and provisim. Altmioalah sources needed to identify dams and reservoirs needed for the absorption and maintenance and rainwater.

Modeling land suitability evaluation for wheat production by parametric and TOPSIS approaches using GIS, northeast of Iran

Land evaluation is the process of predicting land use potential on the basis of its attributes. In the present study, the qualitative land suitability evaluation by parametric and TOPSIS models was investigated for irrigated wheat crop based on FAO land evaluation frameworks (FAO 1976a, b, 1983, 1985) and the proposed methods by Sys et al. (1991b) and Hwang and Yoon (1981) in Joveyn plain, Northeast of Iran. Some 26 land units were studied at the study area by a precise soil survey and their morphological and physicochemical properties. The climatic and land qualities/characteristics for wheat crop were determined using the tables of soil and crop requirements developed by Sys et al. (1993). An interpolation function was used to map values to scores in terms of land qualities/characteristics for the land utilization type and the evaluation was carried out according to parametric and TOPSIS models. Our results indicated that the most limiting factor for wheat cultivation in the study area was soil fertility properties. The values of land indexes by parametric model ranged from 62.71 in some parts in east and west to 87.24 in the middle parts of the study area, which categorized the plain from moderate (S2) to high (S1) suitable classes. The TOPSIS preference values for wheat cultivation in the study area varied between 0.438 and 0.916 which categorized from moderate to very high classes for wheat production. The coefficient of determination between the parametric land index values and the corresponding TOPSIS preference values revealed a high correlation (R 2 = 0.961) between two models. The correlation coefficient (R 2) between the parametric land indexes and TOPSIS preference values with the observed wheat yield varied between 0.943 and 0.861, respectively, which verify the validation of both models in estimating land suitability for irrigated wheat production in the study area.

Identification of terminal heat tolerant bread wheat genotypes

Late sown irrigated wheat crop under Maharashtra condition always adversely affected by terminal heat during flowering and grain filling stage which results in reduced grain yield. A study was undertaken to identify terminal heat tolerant bread wheat genotypes on the basis of different stress indices. Material under study comprised of newly developed nineteen bread wheat genotypes and three recommended varieties as check. Two separate experiments were conducted at Niphad under timely and late sown conditions during rabi 2013-14. Yield trait was recorded and per cent yield reduction under late sown condition as compared to timely sown condition was estimated. On the basis of yield trait different stress susceptibility and tolerance indices were estimated. Among the new genotypes studied, NIAW 2972 had highest yield potential under both, timely (48.66 q/ha) and late sown condition (46.99 q/ha) with minimum yield reduction (3.43 %) under late sown condition except the check variety NIAW 34 (1.75 % yield reduction). On the basis of combined analysis of performance of wheat genotypes under both the sowing conditions, per cent yield reduction under late sown condition and estimates of different stress indices, variety NIAW 34 was found to be most terminal heat tolerant which was closely followed by the genotype NIAW 2972. NIAW 34 (SSI=0.17) possessed highest level of terminal heat tolerance followed by NIAW 2972 (SSI=0.34) and HI 977 (SSI=0.39). Correlation analysis indicated that yield under stress environment had significant (p<0.05) positive (r=0.95) association with that of non stress environment. Yield under both sowing condition had significant positive correlation with MP, GMP and HTI while negative significant correlation with SSI and TOL. First two factors of Principal component analysis explained 99% variation to which 93% and 6% was contributed by first and second factor respectively while maximum contribution to first component was from YLS followed by HTI, GMP and MP. The Genotype NIAW 2972 and two check varieties viz ., NIAW 34 and HI 977 were identified as terminal heat tolerant and can be used directly as well as in the crossing programme for developing terminal heat tolerant variety or line.

Impact of Sowing Date on Yield and Water Use Efficiency of Wheat Analyzed through Spatial Modeling and FORMOSAT-2 Images

Regional analysis of water use efficiency (WUE) is a relevant method for diagnosing the performance of irrigation systems in water-limited environments. In this study, we investigated the potential of FORMOSAT-2 images to provide spatial estimates of WUE over irrigated wheat crops cultivated within the semi-arid Yaqui Valley, in the northwest of Mexico. FORMOSAT-2 provided us with a unique dataset of 36 images at a high resolution (8 m) encompassing the wheat growing season from November 2007 to May 2008. Time series of green leaf area index were derived from these satellite images and used to calibrate a simple crop/water balance model. The method was applied over an 8 × 8 km2 irrigated area on up to 530 wheat fields. It allowed us to accurately reproduce the time courses of Leaf Area Index and dry aboveground biomass, as well as evapotranspiration and soil moisture. In a second step, we analyzed the variations of WUE as the ratio of accumulated dry aboveground biomass to seasonal evapotranspiration. Despite the study area being rather small and homogeneous (soil, climate), we observed a large range in wheat biomass production, from 5 to 15 t·ha−1, which was primarily related to the timing of plant emergence. In contrast, the seasonal evapotranspiration only varied from 350 to 450 mm, with no evident link with sowing practices. A significant gain in crop water productivity was found for the fields sown the earliest (maximal WUE around 3.5 kg·m−3) compared to those sown the latest (minimal WUE around 1.5 kg·m−3). These results demonstrated the value of the FORMOSAT-2 images to provide spatial estimates of crop production and water consumption. The detailed information provided by such high space and time resolution imaging systems is highly valuable to identify agricultural practices that could enlarge crop water productivity.