Growth, development, and economic yield of agricultural crops rely on moisture, temperature, light, and carbon dioxide concentration. However, the amount of these parameters is varying with time due to climate change. Climate change is factual and ongoing so, first principle of agronomy should be to identify climate change potential impacts and adaptation measures to manage the susceptibilities of agricultural sector. Crop models have ability to predict the crop’s yield under changing climatic conditions. We used OILCROP-SUN model to simulate the influence of elevated temperature and CO2 on crop growth duration, maximum leaf area index (LAI), total dry matter (TDM), and achene yield of sunflower under semi-arid conditions of Pakistan (Faisalabad, Punjab). The model was calibrated and validated with the experimental data of 2012 and 2013, respectively. The simulation results showed that phenological events of sunflower were not changed at higher concentration of CO2 (430 and 550 ppm). However LAI, achene yield, and TDM increased by 0.24, 2.41, and 4.67% at 430 ppm and by 0.48, 3.09, and 9.87% at 550 ppm, respectively. Increased temperature (1 and 2 °C) reduced the sunflower duration to remain green that finally led to less LAI, achene yield, and TDM as compared to present conditions. However, the drastic effects of increased temperature on sunflower were reduced to some extent at 550 ppm CO2 concentration. Evaluation of different adaptation options revealed that 21 days earlier (as compared to current sowing date) planting of sunflower crop with increased plant population (83,333 plants ha−1) could reduce the yield losses due to climate change. Flowering is the most critical stage of sunflower to water scarcity. We recommended skipping second irrigation or 10% (337.5 mm) less irrigation water application to conserve moisture under possible water scarce conditions of 2025 and 2050.

The combination of nitrogen and plant population expresses the spatial distribution of crop plants. The spatial distribution influences canopy structure and development, radiation capture, accumulated intercepted radiation (Sa), radiation use efficiency (RUE), and subsequently dry matter production. We hypothesized that the sunflower crop at higher plant populations and nitrogen (N) rates would achieve early canopy cover, capture more radiant energy, utilize radiation energy more efficiently, and ultimately increase economic yield. To investigate the above hypothesis, we examined the influences of leaf area index (LAI) at different plant populations (83,333, 66,666, and 55,555 plants ha−1) and N rates (90, 120, and 150 kg ha−1) on radiation interception (Fi), photosynthetically active radiation (PAR) accumulation (Sa), total dry matter (TDM), achene yield (AY), and RUE of sunflower. The experimental work was conducted during 2012 and 2013 on sandy loam soil in Punjab, Pakistan. The sunflower crop captured more than 96% of incident radiant energy (mean of all treatments), 98% with a higher plant population (83,333 plants ha−1), and 97% with higher N application (150 kg ha−1) at the fifth harvest (60 days after sowing) during both study years. The plant population of 83,333 plants ha−1 with 150 kg N ha−1 ominously promoted crop, RUE, and finally productivity of sunflower (AY and TDM). Sunflower canopy (LAI) showed a very close and strong association with Fi (R 2 = 0.99 in both years), PAR (R 2 = 0.74 and 0.79 in 2012 and 2013, respectively), TDM (R 2 = 0.97 in 2012 and 0.91 in 2013), AY (R 2 = 0.95 in both years), RUE for TDM (RUETDM) (R 2 = 0.63 and 0.71 in 2012 and 2013, respectively), and RUE for AY (RUEAY) (R 2 = 0.88 and 0.87 in 2012 and 2013, respectively). Similarly, AY (R 2 = 0.73 in 2012 and 0.79 in 2013) and TDM (R 2 = 0.75 in 2012 and 0.84 in 2013) indicated significant dependence on PAR accumulation of sunflower. High temperature during the flowering stage in 2013 shortened the crop maturity duration, which reduced the LAI, leaf area duration (LAD), crop growth rate (CGR), TDM, AY, Fi, Sa, and RUE of sunflower. Our results clearly revealed that RUE was enhanced as plant population and N application rates were increased and biomass assimilation in semi-arid environments varied with radiation capture capacity of sunflower.

Appropriate nitrogen and optimum irrigation scheduling ensure economic yield. To access the behavior of development, growth and yield of wheat in response to nitrogen rates (80, 120 and 160 kg ha(-1)) and irrigation scheduling, an experiment was conducted at Agronomy Research Area, University of Agriculture, Faisalabad using Randomized Complete Block Design in split plot arrangement. It was observed that accumulated thermal time and photo-thermal time derive the crop phenology. Calendar time of growth stages may vary depending upon the prevailing climatic conditions particularly minimum and maximum temperatures. Application of 120 kg ha(-1) nitrogen (F-2) resulted in maximum LAI (4.21 & 4.73), mean crop growth rate (9.38 & 9.14 g m(-2) d(-1)), and grain yield (3100 & 3265 kg ha(-1)). Full irrigation performed better in terms of maximum LAI (4.97 & 5.46), mean CGR (10.89 & 12.66 g m(-2) d(-1)) and grain yield (3735 & 4603 kg ha(-1)). Application of 120 kg Nitrogen ha(-1) and full irrigation were found to be the best management practices for better growth and to attain maximum grain yield.

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 (Ii N3), 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 kgN 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. (C) 2017 Elsevier B.V. All rights reserved.

Wheat is a staple food of Pakistan and its productivity is linked with water supply. Potential soil moisture deficit (PSMD) is an approach to save water. PSMD technique was utilized to grow early and late sowing wheat (Triticum aestivum L.) for optimum yield. The experiment was conducted at the agronomic research area, University of Agriculture, Faisalabad during 2010. 2011 and 2011. 2012. The experimental design was randomized complete block design in a split plot arrangement with three replications. The main plot was sowing dates (15th November and 15th December) and the sub-plots were levels of irrigation based on PSMD (full irrigation, 45 mm, 60 mm and 75 mm). The row spacing as set 20 cm and the seed rate was 125 kg ha(-1) using cv. Sahar-2006. Fertilizer was applied at 120: 90 kg ha(-1) of nitrogen and phosphorus, respectively. Data were recorded for yield and yield components at maturity. Irrigation at 45 mm PSMD for crop sown on November 15 produced maximum grain yield. During both years, maximum plant height, number of grains per spike, thousand grain weight, productive of tillers (m(-2)), grain yield and WUE were recorded with full irrigation and irrigation at 45 mm PSMD respectively. Results revealed that deficit irrigation at 45 mm PSMD was water saving as compared to farmer conventional practice of full irrigation. (C) 2016 Friends Science Publishers

Plant population exerts a strong influence on growth and seed yield because of its competitive effect both on the vegetative and reproductive development. For evaluating the effect of different plant populations (83,333, 66,666 and 55,555 plants ha(-1)) and N rates (90, 120 and 150 kg N ha(-1)) on sunflower hybrid (Hysun-33) a field experiment was conducted during spring seasons of 2012 and 2013 using split plot design with three replications at Agronomic Research Area, University of Agriculture, Faisalabad. Results revealed that each N increment enhances the total dry matter, achene yield and its components while oil contents were undesirably affected. During both years, total dry matter, achene yield and harvest index were detected from 83, 333 plants hi(-1). Contradictorily, yield components (head diameter, number of achenes per head and 1000-achene weight) were highest in 55,555 plants ha(-1) treatment. Application of 150 kg N ha(-1) in 83,333 plants ha(-1) plant population was best treatment to attain maximum achene yield.

Field experiment was conducted to evaluate the effect of different sowing dates on yield and yield components of the direct sown coarse rice during the Kharif season of 2008, at Agronomic Research Area, University of Agriculture, Faisalabad. Experiment comprised of six sowing dates i.e. 31(st) May, 10(th) June, 20(th) June, 30(th) June, 10(th) July and 20(th) July. Data on agronomic parameters and economics of coarse rice were recorded. Results revealed that direct seeded rice sown on 20(th) June proved to be the best for obtaining maximum grain yield and net return. 20(th) June sowing also gave maximum number of productive (panicle bearing) tillers, number of kernels per panicle, 1000-grain weight and benefit-cost ratio.