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, (2012–2015). 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.

| Delayed wheat sowing is the main factor responsible for the lower yield of wheat owing to low temperature during emergence and early growth. Seed size has an appreciable potential to improve stand establishment, growth, and yield under late sowing conditions. Therefore, the present study was performed to assess the impact of diverse seed sizes (SS) on the growth and yield of wheat crop under late sowing conditions. The study was comprised of different sowing dates (SD), SD 1 : 15 th December, SD 2 : and 30 th December and different seed size classes i.e. bold (having a diameter of > 2.7 mm), medium (having a diameter of > 2.3 mm to 2.7 mm), small (having a diameter of ≤ 2.3 mm) and mixed seeds. The results indicated that different sowing dates and seed size classes had a significant effect on germination, growth, and yield of wheat crop. The crop sown on 15 th December took less time to start emergence (7.8 days) and resulted in maximum plant height (81 cm), grains per spike (44.5), productive tillers (321.5), spike length (10.2 cm), 1000 grain weight (37.2 g), and grain yield (3.83 t ha -1 ) and maximum time to start emergence (11 days) and minimum plant height (60 cm), grains per spike (35.7), productive tillers (273), spike length (8.6 cm), 1000 grain weight (32 g), and grain yield (2.7 t ha -1 ) was recorded in the crop sown on 30 th December. In the case of seed size classes, bold seed performed appreciably well and took less time to start emergence (8.5 days) and had more plant height (74.7 cm), productive tillers (326), spike length (10.1 cm), grains per spike (45), 1000 grain weight (37 g), and grain yield (3.67 t ha -1 ) compared to other seed size classes. In conclusion, bold seed size can significantly improve the wheat production under late sown conditions due to better stand establishment, vigorous germination, and increase in yield related traits.

The number of spray deposits plays an important role in effective and efficient spraying. The spraying equipment is one of the most significant factors that affect the number of spray deposits. Therefore, the study was focused on the parameter optimization of a newly developed self-propelled variable height crop sprayer. Response surface methodology (RSM) along with Box–Behnken design (BBD) was used to study the effect of the independent variables (forward speed, spray height, and spray pressure) on response variables such as droplet density, coverage per-centage, and Volume Median Diameter (VMD). The experiment was conducted in the cotton field. Additionally, the RSM model was validated in this research. The results revealed that the coefficient of determination (R2) values was good for all response variables in the quadratic polynomial model. The optimized parameters were 6.5 km/h, 60 cm, 4 bar for fungicide application, and 8 km/h, 70 cm, 3 bar for insecticide and herbicide application. The predicted response variable values at the optimal conditions were 60.4 droplet/cm², 27%, 230 µm for fungicides and 37.8 droplet/cm², 19.1%, 225.4 µm for insecticide and herbicides application. The model validation is confirmed by the mean of actual response variable values at the optimal condition for insecticide and herbicides application, which was 41.35 ± 3.67 droplet/cm², 21.10 ± 1.72%, 227.43 ± 1.22 µm, and the prediction error was 8.46%, 9.2%, and 0.9% for droplet density, coverage percentage, and VMD, respectively. This study can provide support for further optimizing the parameters of the sprayer.

Plants undergo a wide range of morphological, cellular, anatomical, and physiological changes in response to salinity stress. However, plants produce some signaling molecules, usually known as phytohormones, to combat stress conditions. Salinity tolerance is a complex mechanism, whereas phytohormones have a central role in it. Phytohormone-mediated plant responses improve nutrient uptake, the source-sink relationship, and plant growth and development. Phytohormones triggers the specific gene expressions which are responsible for the modification of various plant mechanisms under salinity stress. This review summarized the most recent research findings about plant responses to salinity stress at physiological and molecular levels and discussed the probable function of several (abscisic acid, indole acetic acid, cytokinins, gibberellic acid, salicylic acid, brassinosteroids, ethylene, and triazoles) phytohormones and their interaction in modulating salinity stress. Further, the understanding of specific genes involved in phytohormonal regulation toward salinity tolerance is a key to developing breeding and transgenic approaches for meeting food demand under sustainable crop production.