No abstract

Investigating the effects of optimized fertilizer and irrigation levels on water use efficiency and productivity of wheat crop at small farms is of great importance for precise and sustainable agriculture in Pakistan's irrigated areas. However, traditional farmer practices for wheat production are inefficient and unsustainable. This study aimed to investigate the effects of deficit irrigation and nitrophos fertilizer levels on bread wheat grain yield, yield parameters, nutrient use and water use efficiencies in bed planting wheat compared to traditional farmers' practices in the flat sowing method. The two-year field experiment followed a randomized complete block design of three replications, taking three irrigation treatments according to the requirement of crop estimated by CROPWAT model (100% of ETC), deficit irrigation (80% of ETC), and deficit irrigation 60% of ETC and three nitrophos fertilizer treatments (farmer practice 120 kg N ha-1, optimized 96 kg N ha-1, and 84 kg N ha-1) at different growth stages. Crop ETC was calculated using the FAO CROPWAT 8.0 model from the last ten years (2003-2013) average climate data of the experimental station. The traditional farmer practice treatment was included as a control treatment with a flat sowing method compared with other sown-by-bed planter treatments. All treatments were provided with an equivalent amount of fertilizer at the basal dose. Before the first and second irrigation, top-dressing fertilizer was used in traditional farmers' treatment at the third leaf and tillering stages. It was applied in optimized treatments before the first, second, and third irrigation at the third leaf, tillering and shooting stages, respectively, under the bed planting method. The deficit level of irrigation (80% of ETc) and optimized fertilizer (96 kg N ha-1) showed the optimum grain yield, nutrient use, and water use efficiencies, with 20% reduced irrigation water and fertilizer levels than traditional farming practice. The results suggest that bread wheat should be irrigated with 80% of ETC and applied 96 kg N ha-1 nitrophos fertilizer at the third leaf, tillering, and shooting stages to achieve higher grain yield and water and nutrient use efficiencies under bed planting.

Delayed sowing of wheat is a common problem in Punjab that exacerbates serious yield loss. However, individual or combined applications of seed rate and slow-release nitrogen fertilizer significantly impacted their efficacy in improving crop growth and productivity. In this regard, the present study explored the potential of slow-release nitrogen fertilizers (control (CK), simple urea (SU), neem-coated urea (NCU), and sulfur-coated urea (SCU)) to improve the growth, yield, and physiological and biochemical attributes of delayed sown wheat with three seed rate [(100 kg ha−1 (S1), 125 kg ha−1 (S2), and 150 kg ha−1 (S3)]. The study was carried out at the Postgraduate Agricultural Research Station of the University of Agriculture Faisalabad in 2018–19 and 2019–20. The study findings revealed that the sulfur-coated urea performed better under S3 seed rate. Combining SCU with S3 significantly increased leaf area index by 0.99 cm2 and plant height by 8.24% compared to simple urea, maximum spikelets, and spike length by 3.9 and 3.8 cm, respectively. The SCU with S3 treatment also increased the biological yield by 43% and 41% and the grain yield by 46% in 2018–2019 and 2019–2020, respectively, compared to CK. Similarly, higher N contents in straw and grain were recorded in the interaction of SCU with S3 treatment. Likewise, the SCU with S3 treatment enhanced the physiological attributes, i.e., chlorophyll contents and transpiration rate, by 18% and 25%, respectively, and decreased internal CO2 by 25.5%, compared to CK. In conclusion, applying sulfur-coated urea with a seed rate of 150 kg ha−1 could be considered a potential strategy for improving the growth and productivity of delayed sown wheat.

The dry-hot wind climate is one of the major agro-meteorological disasters associated with high temperature, low humidity, and specific wind forces, which seriously affects the yield of wheat in the North China Plain. A field experiment was conducted to investigate the field microclimate, net photosynthetic rate, chlorophyll content of flag leaves, grain filling rate, and wheat yield after sprinkler misting under the condition of a dry-hot wind climate in the 2018 and 2019 seasons. Two travel speeds, full and half speed, and the corresponding irrigation amounts of 2.5 and 5 mm were used by a center pivot irrigation system during dry-hot wind conditions. A treatment without irrigation was applied as a control. The results showed that the air temperature and relative air humidity were greatly improved within 60 min after irrigation, especially in the upper part of the canopy. The net photosynthetic rate of flag leaves under 5 mm irrigation was higher than that under 2.5 mm irrigation during the middle and late grain filling periods. The adverse effects of dry-hot wind on the chlorophyll content of the flag leaves were mainly concentrated in the late grain filling stage. In the two years of the experiment, the average 1000-grain weights of 5 and 2.5 mm of irrigation treatments were 4.3 and 2.8% higher, and the grain yields were 5.8 and 3.3% higher, respectively, than those of the non-irrigated yields. Overall, applying a small amount of water between 12:00–14:00 with a center pivot before the occurrence of dry-hot wind is an effective means to regulate the field microclimate and produce more yield in the North China Plain.