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Water and nitrogen (N) limitations in soil usually restrict plant growth hence reducing water and nitrogen productivity. Precise irrigation application is vital in water scarce areas of the world, such as Pakistan. Water and N are generally the most important factors in high yielding of crops. This interaction between irrigation levels and N can be analyzed through field experiments in concert with crop simulation models and decision support systems. Recently the use of crop growth models in crop husbandry has become more common to provide the decision support for farmers. The proposed study was conducted at Agronomic Research Area, University of Agriculture Faisalabad, Pakistan during the years 2012 and 2013 to evaluate OILCROP-SUN model under decision support system for agro-technology transfer (DSSAT) for simulating growth, development and achene yield of sunflower hybrid Hysun-33. The experiment was laid out using split plot design with four irrigation levels (control, 45, 60 and 75 mm potential soil moisture deficit) in main plots and three N rates (90, 120 and 150 kg ha −1 ) in sub plots. The model was first calibrated with control irrigation plus 150 kg N ha −1 treatment (I 1 N 3 ), then evaluated (2012) and validated (2013) by utilizing experimental data. The evaluation and validation exhibited that the model simulated anthesis date, maturity date, maximum leaf area index (LAI), total dry matter (TDM), achene yield and oil contents very well with an error of 0–6.15%, 0–3.96%, −25.14 to 6%, −0.37 to 17.75%, −4.58 to 17.12% and −15.04 to 12.15%, respectively. Similarly, root mean square error (RMSE) values for soil water and leaf N contents were ranged from 0.03 to 0.05 cm 3 cm −3 and 0.16% to 0.71%, respectively. While RMSE for crop evapotranspiration (ET) was 29.87 mm in 2012 and 32.56 mm in 2013. The highest achene yield and oil contents were achieved with the control irrigation in combination of 150 kg N ha −1 application. However saving of water (110 mm in 2012 and 120 mm in 2013) with 45 mm potential soil moisture deficit (PSMD) treatment (without significant reduction in sunflower productivity) recognized it as most suitable irrigation scheduling technique under water scarce areas of the world. The results disclosed that OILCROP-SUN model can be efficaciously used for simulation of spring sown sunflower under semi-arid conditions of Pakistan. [ABSTRACT FROM AUTHOR]

Appropriate nitrogen application and optimum plant population ensure economic crop yield. For assessing the response of sunflower hybridHysun-33 to different plant populations, i.e. 83,333, 66,666 and 55,555 plants ha-1at different N rates of 90, 120 and 150 kg ha-1, a field experiment was undertaken using RCBD in split plot arrangement with three replications at Agronomic Research Area, University of Agriculture, Faisalabad. Results demonstrated that each successive N dose increased the crop biomass, yield and its components although sunflower oil contents were negatively affected. Maximum plant growth and achene yield (3115.4 kg ha-1) were observed at 83, 333 plants ha-1. Conflictingly days to flowering (64.5), achene formation (73.73), physiological maturity (95.98), head diameter (19.16 cm), thousand achene weight (43.53 g) and number of achenes per head (1138.8) were maximum in 55,555 plants ha-1. Application of 150 kg N ha-1 in 83,333 plants ha-1 plant population was found to be best treatment to attain maximum achene yield. [ABSTRACT FROM AUTHOR]

Crop models are particularly valuable for understanding research across varying disciplines, crop system managements and policy analysis. The proposed study was carried out to evaluate the performance of CROPGRO-legume model under Chickpea in irrigated conditions of Faisalabad. The collected data against outstanding treatment in the field was used to calibrate the model and rest of data was used for model evaluation. Model simulated flowering and maturity dates well for all cultivars of chickpea. Comparison of simulated and observed data showed that model simulated TDM and grain yield with RMSE 248 and 34 kg ha-1, respectively. Punjab Masoor-2009, NIAB Masoor-2002 and NIAB Masoor-2006 were simulated accurately by model with the values of R2 96%, 95% and 94% for TDM, respectively. Agreement of statistics (d index) for TDM in all cultivars was 0.90. Generally model simulated well under non stressed condition. However error was higher in simulation at lesser level of nitrogen in all crop parameters. There is dire need to quantify growth and yield under varying climatic conditions to assess the accuracy of model simulations. [ABSTRACT FROM AUTHOR]

An experiment was laid out in the Department of Agronomy, University of Agriculture, Faisalabad, Pakistan during the year 2012 under semi-arid climate conditions. Layout system was RCBD with split arrangement to quantify the effects of different irrigation and nitrogen levels on growth and yield of sunflower. Data on achene yield, total dry matter (TDM), leaf area index (LAI), leaf area duration (LAD), fraction of intercepted radiation (Fi) and radiation use efficiency (RUE) were taken. TDM pattern showed sigmoid growth curve for both irrigation and nitrogen levels and showed strong relationship (R2 = 0.96) with LAD. Mean value of fraction of incident PAR (Fi) remained maximum (73%) at 80 days after sowing DAS due to maximum crop canopy development. Five irrigations at different crop growth stages produced 0.47 g/m of TDM for each MJ (mega joule) of accumulated PAR and nitrogen at 150 kg/ha statistically proved to be better in converting radiation into dry matter production. [ABSTRACT FROM AUTHOR]