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Crop production is highly sensitive to climate. It is affected by long-term trends in average rainfall and temperature, inter-annual climate variability, shocks during specific phenological stages and extreme weather events. As climate changes, crop production strategies must change too. Field trials were conducted at Nuclear Institute for Agriculture and Biology, Faisalabad-Pakistan, on wheat to assess nutrient and water productivity in irrigated semiarid conditions of Faisalabad. The treatments were six dates of sowing (DOS) (20th October, 30th October, 10th November, 20th November, 30th November and 10th December) with five nitrogen levels (N-levels), i.e., (0, 60, 120, 180 and 240 kg ha−1). CSM-CERES wheat model under the umbrella of DSSAT (4.6) was used to assess the impact of changing climate on wheat production. Model was then evaluated on the basis of data collected during field experiments. Model’s performance was evaluated by computing different statistical variables (d, R2). Intergovernmental Panel on Climate Change’s (IPCC), Representative Concentration Pathways (RCPs) were used to assess the climatic changes in the near, the middle and at the last of the century (2030, 2050 and 2090). Data collected during field experiment showed that biological and grain yields were increased up to 10th November DOS and then a decreasing trend was started up to 10th December DOS. A statistically significant (p ≤ 0.05) interaction was observed between DOS and N-levels. DOS and N-levels interactive affect showed significantly higher biological and grain yields at 180 and 240 kg N ha−1, respectively, when crop was sown on 10th November, while significantly lower yield at 0 kg N ha−1 with sowing date 20th October. The model results indicated that N-levels have not much significant effect on wheat yield under changing climate scenarios RCPs. But the changes in DOS showed significant results under these RCPs in irrigated conditions. The DOS 30th November with 180 kg N ha−1 will performs better in 2030, 2050 and 2090 than other DOS as predicted by the model. Model predicts the lowest yields in the early date of sowing, i.e., 30th October, 10th November, etc. But in later DOS model showed significantly higher yields for 2030, 2050 and 2090. more...

Simulation models are widely used for making decision support especially under sub-optimal climatic conditions for yield improvement. The impact of uncertain weather conditions on cotton production can be explored with the aid of such models. Cotton, being the queen of fibers, enjoys itself a predominant position amongst all other cash crops and has the potential to narrow the gap between production and consumption of fiber and edible oil. The goal of the study was to evaluate the performance of Cropping System Model CROPGRO-Cotton for examining temporal variation in cultivars and to determine the potential impact of planting dates. The model was calibrated using a diverse range of field observation for phenology, growth and seed cotton yield (SCY) and its components of 20-April planting date, genetic coefficients were estimated using Generalized Likelihood Uncertainty Estimation (GLUE) and sensitivity analysis sub modules in CSM-DSSAT. Calibrated and evaluated results were reasonably good for phenology, growth, boll weight, SCY and yield attributes with good statistics. Simulation and observed data revealed the decreasing trend with delayed planting for all cultivars. Phenological phases were predicted well with high d-index (>0.94 and >0.85), and the dynamics of time series for LAI and biomass were predicted also well (d > 0.96 and >0.98), respectively during model evaluation for all planting dates and cultivars. Seed cotton yield was simulated with lower RMSE (137–382) at final picking, while dynamics of time series for SCY were predicted reasonably well with high values of d-index (0.95–0.99) for all cultivars during model evaluation. Planting date analyses of the years (1980–2013) agreed with observed SCY trend, showed decrease of 27% for delayed planting from 20-April to 21-June while first too early planting (10-March) had also faced 8% reduction for all cultivars. Cultivars [MNH-886, NIAB-9811 (NIAB-Kiran) and NIAB-112] outperformed with higher SCY predominantly due to longer appropriate growing season by utilizing optimal weather conditions, attained optimum growth at all key phenological phases. Cultivar NIAB-112 performed well being a short duration and attained high SCY for late planting (1-June) as well during the growing years. Cotton cultivars planting during 1-April–10-May can be suggested for the farmer’s field to avoid weather stress and to improve utilization of resources for sustainable cotton production in the region. Result demonstrated the model potential for decision support for cotton management practices in the region, including identifying optimum planting dates for cotton production. more...

Wheat production under rainfed conditions is restrained by water scarcity, elevated temperatures, and lower nutrient uptake due to possible drought. The complex genotype, management, and environment (G × M × E) interactions can obstruct the selection of suitable high yielding wheat cultivars and nitrogen (N) management practices prerequisite to ensure food security and environmental sustainability in arid regions. The agronomic traits, water use efficiency (WUE), and N use efficiencies were evaluated under favorable and unfavorable weather conditions to explore the impacts of G × M × E on wheat growth and productivity. The multi-N rate (0, 70, 140, 210, and 280 kg N ha−1) field experiment was conducted under two weather conditions (favorable and unfavorable) using three wheat cultivars (AUR-809, CHK-50, and FSD-2008) in the Pothowar region of Pakistan. The experiments were laid out in randomized complete block design (RCBD), with split plot arrangements having cultivars in the main plot and N levels in the subplot. The results revealed a significant decrease in aboveground biomass, grain yield, crop N-uptake, WUE, and N use efficiency (NUE) by 15%, 22%, 21%, 18%, and 8%, respectively in the unfavorable growing season (2014–2015) as compared to favorable growing season (2013–2014) as a consequence of less rainfall and heat stress during the vegetative and reproductive growth phases, respectively. FSD-2008 showed a significantly higher aboveground biomass, grain yield, crop N-uptake, WUE, and NUE as compared to other wheat cultivars in both years. Besides, N140 appeared as the most suitable dose for wheat cultivars during the favorable growing season. However, any further increase in N application rates beyond N140 showed a non-significant effect on yield and yield components. Conversely, the wheat yield increased significantly up to 74% from N0 to N70 during the unfavorable growing season, and there was no substantial difference between N70–N280. The findings provide opportunities for maximizing yield while avoiding excessive N loss by selecting suitable cultivars and N application rates for rainfed areas of Pothowar Plateau by using meteorological forecasting, amount of summer rainfall, and initial soil moisture content. more...

Soil management through the cultivation of salt-tolerant plants is a practical approach to combat soil salinization. In this study, salt tolerance of 35 barley (Hordeum vulgare L.) genotype...

In the Indo-Gangetic plains of south Asia, conventional tillage (CT) and removal of crop residues have been the major cause of declining soil fertility. While zero tillage (ZT) farming combined with retention of crop residues as surface mulch are well known to improve soil quality and crop productivity in different climatic zones, only limited knowledge exists on the performance ZT technology in the Indo-Gangetic plains. A field study was conducted under subtropical arid climate to elucidate short-term effects of different tillage, residue mulch and N fertilizer regimes on the productivity of irrigated maize grown for five cropping seasons. Treatments included CT and ZT; each with mulch (M + ) or without mulch (M − ), and with N (N + ) or without N (N − ). Fate of the fertilizer-N applied to the 5th maize crop was also investigated using 15 N tracer. After five cropping seasons, soil organic C (SOC) in the arable soil layer was higher under ZT compared to CT (29% increase), under M + compared to M − (16% increase) and under N + compared to N − (13% increase). Highest SOC was recorded under ZT-M + -N + treatment (19.1 Mg ha −1 ) and the lowest under CT-M − -N − (10.7 Mg ha −1 ). Nitrogen application increased the grain yield; the increase was higher under ZT than under CT in three cropping seasons. Mulch application reduced the grain yield in four cropping seasons. During all growing seasons, the grain as well as total biomass yields were highest under ZT-M − -N + . Recovery of the fertilizer-N in soil (0–100 cm depth) ranged from 28 to 39% of the applied with lowest recorded under ZT-M − . The fertilizer-N recovery in plant was highest (40%) under ZT-M − , whereas the total fertilizer N recovery in the soil-plant system was not influenced by tillage or mulch regimes. Plant-N derived from soil (Ndfs) was higher under ZT compared to CT (47% increase), and under M + compared to M − (15% increase); the highest Ndfs was recorded under ZT-M − (31–68% increase). While mulch had no effect on the added-nitrogen-interaction, the latter was significantly higher under CT compared to ZT (65% increase). Results suggested that as compared to other tillage/mulch regimes, ZT without mulch produced similar or higher grain yield and showed highest fertilizer-N use efficiency in continuous maize cropping system under subtropical conditions prevailing in the Central Punjab, Pakistan. more...

Cadmium (Cd) contamination of farmland soils is a widespread problem around the globe, and rice (Oryza sativa L.) tends to accumulate more Cd and is considered as one of the major sources of Cd intake in humans, especially consuming rice-derived products. The current study investigated the effects of foliar applied aspartic acid (Asp) on growth parameters, biomass, chlorophyll concentration, gas exchange characteristics, Cd uptake, and antioxidative capacity in the shoots and roots of rice seedlings exposed to Cd stress. For this, 30-day-old rice nursery was transferred in the soil with aged Cd contamination (2.86 mg kg−1). After 2 weeks of growth, different concentrations (0, 10, 15, and 20 mg L−1) of Asp were foliar applied four times with a 7-day interval, and the crop was harvested after 10 weeks of transplanting. Foliar applied Asp increased the plant height, shoot and root dry weight, chlorophyll concentration, and gas exchange parameters, while it reduced the Cd concentrations in both shoots and roots as well as shoot to root Cd translocation factor compared to the control. Foliar application of Asp reduced the malondialdehyde content and electrolyte leakage in rice parts compared to the control in a dose-additive manner. The activities of key antioxidant enzymes increased while peroxidase activity decreased by exogenous Asp. The increase in plant weight and photosynthesis might be due to lower Cd concentrations in plants which may reduce the oxidative stress and also help the plants to minimize direct damage caused by Cd to the photosynthetic organs. more...

Sowing methods and harvesting times are the important management considerations for getting the optimum yield and quality of fodder crops. This study, investigated the influence of sowing methods and harvesting times on the growth, yield and quality of sweet sorghum. Chinese sweet sorghum was grown by broadcast method, 30 cm apart lines and 45 cm apart lines and harvested after 60, 75 and 90 days after sowing, respectively. All the tested sowing patterns and harvesting times considerably affected the growth, yield and quality of sweet sorghum. However, sowing in 30 cm apart rows produced maximum leaves per plant (13.09), fresh forage yield (38.1 t ha-1), dry matter yield (4.85 t ha-1), crude proteins (8.9%), ash contents (11%) and sugar contents (12.8%), respectively. Similarly, harvesting after 90 days of sowing gave highest leaves per plant (14.72), fresh forage yield (45.1 t ha-1), dry matter yield (5.60 t ha-1), ash contents (12.2%) and sugar contents (14.1%), respectively. These results suggested that sowing in 30 cm apart lines and harvesting after 90 days of sowing improved the growth, yield and quality of sweet sorghum under the semiarid region of Faisalabad. more...

Contamination of soils with heavy metals (HMs) is an important issue due to the contamination of agricultural crops, which are further transferred into the food chain. Phytoremediation is an emerging method of remediating metal-contaminated soils. Sunflower has been widely adopted for phytomanagement of HM-contaminated soils owing to its high biomass production and capacity for metal accumulation. Sunflowers can tolerate the toxic effects of certain HMs through different mechanisms, such as enhancements in antioxidant enzyme activities, deposition in nonactive parts of the plant, and stimulation of osmolytes. Stress caused by HMs affected negatively the seed germination, nutritional status, photosynthesis, and growth of sunflower. However, the responses of sunflowers to this stress vary with cultivar/variety, soil type, metal type, dose, and duration of metal exposure. This review critically summarizes the effects of HMs in sunflowers and examines field-relevant approaches to improve the phytoextr... more...

A crop modeling approach can be used to assess various crop management options and water productivity to improve crop production for different environments. The goal of this study was to determine optimum planting dates and nitrogen management options using a systems analysis approach based on the Cropping System Model (CSM) CERES-Wheat of DSSAT v 4.6. Wheat experiments were conducted from 2007 to 2013 under semi-arid conditions at the experimental fields of the Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad, Pakistan. The CSM-CERES-Wheat model was calibrated for wheat (Triticum aestivum L.) cultivar Sehar-2006 from a 3-year field experiment data on flowering day, maturity day, canopy cover, grain yield, biomass, grain nitrogen content, and nitrogen harvest index. After calibration, the CSM-CERES-Wheat model produced satisfactory simulations for wheat phenology and crop growth parameters. The model was then evaluated using six years of independent datasets for both irrigated and rainfed conditions. The evaluation showed that the model performed well as indicated by the accurate simulation of wheat phenology [the normalized root mean square error (NRMSE) = 3%] and crop growth parameters such as crop cover (NRMSE = 7%–13%), biomass (NRMSE = 17%), and grain yield (NRMSE = 9%) against measured data. The model's performance was less satisfactory for biomass production under high soil moisture or rainfed conditions. Focusing on differences in temperature and rainfall patterns during the potential growing season, the model was used to estimate the optimum planting dates and in-season nitrogen management options using 39 years (1974–2013) of historical weather data for short-term adaptation against climate variability. The scenario simulations for planting dates showed that growing wheat under rainfed conditions at the study region is not a viable option. However, based on the simulation results, we concluded that early planting from November 1st to 10th for irrigated conditions with applications of 150 kg N ha−1 in three equal splits with the first at sowing and the rest two splits during vegetative growth phase could result in higher crop yield and water use efficiency. This study showed that the model can be a promising tool for providing crop management recommendations under high-temperature conditions found in the semi-arid conditions. more...

Summer maize (Zea mays L.) is a widely cultivated crop in the arid and semi-arid Guanzhong region of China. However, due to the spatial and temporal variation in rainfall, the seasonal maize yield varies substantially and occasionally is not economical for poor farmers to produce. Recent water-saving agricultural practices were developed by the government to make it possible to apply supplementary irrigation at optimum sowing dates to maximize maize production under limited rainfall in the region. CERES (Crop Estimation through Resource and Environment Synthesis)-maize model was used to identify the appropriate irrigation strategies, crop growth stages and sowing dates for sustainable maize production. Model calibration process were carried out for full irrigation treatments of four growing seasons, (2012&ndash, 2015). The data used for calibration included: Crop phenology, grain yield, aboveground biomass and leaf area index. The calibration phase model showed good agreement between simulated and observed values, with normalized root mean square error (nRMSE) ranging from 4.51% to 14.5%. The performance of the calibrated model was evaluated using the field data of grain yield, aboveground biomass, leaf area index and water use efficiency. The performance of the model during evaluation was satisfactory with acceptable nRMSE error ranging from 7% to 10%. Soil moisture content was evaluated for full irrigation treatments for both 2012 and 2013 seasons. With results showing that soil moisture content below 35 cm layer was well simulated with nRMSE, 0.57 to 0.86 respectively. Appropriate simulated sowing dates for higher production and water productivity were from 14 to 24 June. The proper amount and timing of irrigation water application was 100 mm at the flowering stage, and 100 mm at the grain filling stage respectively. Summer maize yield can be improved by adjusting the sowing date and applying supplementary irrigation when precipitation cannot meet the crop water demand in the Guanzhong Plain. more...

Cotton (Gossypium hirsutum L.) is a well-known and economically most beneficial crop worldwide while nickel (Ni) toxicity is a widespread problem in crops grown on Ni-contaminated soils. We investigated the response of silicon (Si) in cotton under Ni stress with respect to growth, biomass, gas exchange attributes, enzymatic activities, and Ni uptake and accumulation. For this, plants were grown in hydroponics for 12 weeks with three levels of Ni (0, 50, and 100 µM) in the presence or absence of 1 mM Si. Results showed that Ni significantly reduced the plant growth, biomass, gas exchange attributes, and pigment contents while Si application mitigated these adverse effects under Ni stress. Nickel stress significantly decreased antioxidant enzymes’ activities while increased malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolyte leakage (EC) in leaves and roots. The application of Si enhanced the activities of antioxidant enzymes and reduced MDA, H2O2, and EC in plants. Nickel application significa... more...

Heavy metals are among the major environmental pollutants and the accumulation of these metals in soils is of great concern in agricultural production due to the toxic effects on crop growth and food quality. Phytoremediation is a promising technique which is being considered as an alternative and low-cost technology for the remediation of metal-contaminated soils. Solanum nigrum is widely studied for the remediation of heavy metal-contaminated soils owing to its ability for metal uptake and tolerance. S. nigrum can tolerate excess amount of certain metals through different mechanism including enhancing the activities of antioxidant enzymes and metal deposition in non-active parts of the plant. An overview of heavy metal uptake and tolerance in S. nigrum is given. Both endophytic and soil microorganisms can play a role in enhancing metal tolerance in S. nigrum. Additionally, optimization of soil management practices and exogenous application of amendments can also be used to enhance metal uptake and tolerance in this plant. The main objective of the present review is to highlight and discuss the recent progresses in using S. nigrum for remediation of metal contaminated soils. more...

Using an alkaline calcareous soil, experiments were conducted to elucidate the effects of nitrification inhibitor dicyandiamide (DCD) on the fate of 15N-labelled urea applied to cotton, maize, and wheat under greenhouse conditions. Combined effects of DCD and two levels of wheat straw (applied to cotton) and of fertilizer application method (conventional broadcast vs. point injection in maize and wheat) on the recovery of the fertilizer N were also studied. High soil temperatures prevailed under cotton and maize, whereas the soil temperature was relatively moderate during the wheat growing season. The fertilizer N loss under cotton was lowest (44% of the applied) when urea was applied alone; the loss increased due to DCD (54%) or wheat straw (50–54%) and was highest (63–64%) when DCD and wheat straw were applied together. Under maize also, DCD increased the loss of the fertilizer N applied by the conventional method (51% without DCD vs. 66% with DCD) or by point injection (26% without DCD vs. 42% with DCD). With the conventional method under wheat, DCD had no effect on the fertilizer N loss (34–37% of the applied). The fertilizer N loss under wheat was least (16%) when urea solution was point-injected but increased (24–26%) due to DCD or/and when pH of the urea solution was reduced to 2. Besides, DCD significantly reduced the fertilizer N uptake and increased the fertilizer N immobilization in soil under cotton and maize. However, DCD applied in combination with a higher level of wheat straw significantly increased the cotton dry matter and N yields due to increased N availability from sources other than the fertilizer. The results suggested that the use of DCD may not be beneficial in alkaline calcareous soils and that point injection of urea solution without any amendment is more effective in conserving the fertilizer N as compared to the conventional broadcast method. more...

Silicon (Si) is as an important fertilizer element, which has been found effective in enhancing plant tolerance to variety of biotic and a-biotic stresses. This study investigates the Si potential to alleviate zinc (Zn) toxicity stress in cotton (Gossypium hirsutum L.). Cotton plants were grown in hydroponics and exposed to different Zn concentration, 0, 25, and 50 μM, alone and/or in combination with 1 mM Si. Incremental Zn concentration in growth media instigated the cellular oxidative damage that was evident from elevated levels of hydrogen peroxide (H2O2), electrolyte leakage, and malondialdehyde (MDA) and consequently inhibited cotton growth, biomass, chlorophyll pigments, and photosynthetic process. Application of Si significantly suppressed Zn accumulation in various plant parts, i.e., roots, stems, and leaves and thus promoted biomass, photosynthetic, growth parameters, and antioxidant enzymes activity of Zn-stressed as well unstressed plants. In addition, Si reduced the MDA and H2O2 production and electrolyte leakage suggesting its role in protecting cotton plants from Zn toxicity-induced oxidative damage. Thus, the study indicated that exogenous Si application could improve growth and development of cotton crop experiencing Zn toxicity stress by limiting Zn bioavailability and oxidative damage. more...