Wide space sowing achieved high productivity and effective nitrogen use of irrigated wheat in South Shanxi, China

Abstract

Wheat (Triticum aestivum L.) is a staple crop worldwide, and its yield has improved since the green revolution, which was attributed to chemical nitrogen (N) fertilizer application. However, regular N application decreases N use efficiency (NUE, the ratio of grain dry matter yield to N supply from soil and fertilizer). Various practices have been implemented to maintain high crop yield and improve NUE. Nowadays, the enhanced sowing method, i.e., wide space sowing (WS), has improved the productivity of wheat crops. However, how the sowing method and N application rate affect N use and yield productivity has not been fully elucidated. Field experiments with treatments using two sowing methods (WS, and drill sowing, DS) and four N application rates (0, 180, 240, and 300 kg ha−1, represented as N0, N180, N240, and N300, respectively) were conducted from 2017 to 2019. The results showed that grain yield under WS was 13.57–16.38% higher than that under DS. The yield advantage under WS was attributed to an increased ear number. Both the higher stem and productive stem percentage accounted for the increased ear number under WS. Higher total N quantity and larger leaf area index at anthesis under WS contributed to higher dry matter production, resulting in higher grain yield. Higher dry matter production was due to pre-anthesis dry weight and post-anthesis dry weight. The wheat crop under WS had a 12.44–15.00% higher NUE than that under DS. The increased NUE under WS was attributed to higher N uptake efficiency (the ratio of total N quantity at maturity to N supply from soil and fertilizer), which was the result of greater total N quantity. The higher total N quantity under WS was due to both higher pre-anthesis N uptake and post-anthesis N uptake. Remarkably, compared to DS with 240 kg N ha−1, WS with 180 kg N ha−1 had almost equal grain yield, dry matter, and total N quantity. Therefore, wheat crops under WS could achieve both high NUE and grain yield simultaneously with only moderate N fertilizer in South Shanxi, China.

Optimizing sowing patterns in winter wheat can reduce N2O emissions and improve grain yield and NUE by enhancing N uptake

“…This benefitted the growth of tillers and roots and resulted in an efficient N absorption capacity during the whole wheat growing season (Lv et al, 2020). In the present study, WB markedly improved grain yield and NUE at N168, N240, and N312, due to the improved plant N uptake, in line with Wang et al (2022) and Zheng et al (2023). This may be related to the improved activity of N assimilation enzymes in WB sowing, because higher activities of N assimilation enzymes, such as nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, are beneficial for crop N assimilation and absorption (Chandna et al, 2012;Agnihotri and Seth, 2016;Gupta and Seth, 2019).…”

“…This benefitted the growth of tillers and roots and resulted in an efficient N absorption capacity during the whole wheat growing season ( Lv et al., 2020 ). In the present study, WB markedly improved grain yield and NUE at N168, N240, and N312, due to the improved plant N uptake, in line with Wang et al. (2022) and Zheng et al.…”

“…Compared to conventional drilling sowing (CD), wide belt sowing (WB) is an optimized sowing pattern that increases the belt of wheat seedlings from 2–3 to 8–10 cm by altering the width of the furrow opener moldboard without increasing other costs. This improves spatial uniformity and reduces intraspecific competition within seedling belts ( Liu et al., 2020 ; Lv et al., 2020 ), and results in enhanced water, N, radiation use efficiency, and grain yield of winter wheat ( Li et al., 2015 ; Liu et al., 2020 ; Wang et al., 2022 ; Zheng et al., 2023 ). In particular, the enhanced ability to absorb N offers the possibility of reducing nitrous oxide emissions.…”

Higher Seed Rates Enlarge Effects of Wide-Belt Sowing on Canopy Radiation Capture, Distribution, and Use Efficiency in Winter Wheat

“…Thus, increasing the seed rate is applied to adapt wide-belt precision planting to compensate for the negative impacts of suboptimal land preparation and low soil fertility on the emergence rate and tillering capacity. For example, after this technique was introduced in Shanxi Province, China, the local farmers applied seed rates of 300-700 m −2 or even higher, and the yields increased by more than 10% [13]. Due to the higher seed rate, especially with suboptimal soil preparation, this sowing technique is referred to as wide-belt sowing (WBS).…”

“…Due to the higher seed rate, especially with suboptimal soil preparation, this sowing technique is referred to as wide-belt sowing (WBS). Previous studies have demonstrated that the yield increases under WBS are due to increases in the tillering capacity, ears number, and leaf area index (LAI), and thus biomass production [13][14][15].…”