Increasing basal nitrogen fertilizer rate improves grain yield, quality and 2-acetyl-1-pyrroline in rice under wheat straw returning

Abstract

Straw returning plays an essential role in crop yields and the sustainable development of agriculture. However, the effects and mechanisms of nitrogen (N) fertilizer management on grain yield, quality and aroma substance 2-acetyl-1-pyrroline (2-AP) content under wheat straw returning are still unclear. In this field experiment, two japonica rice cultivars were used as materials, wheat straw non-returning (NS) and wheat straw full returning (WS) were designed coupled with two N application ratios, namely basal fertilizer: tiller fertilizer: panicle fertilizer =5:1:4 (local farmers’ fertilizer practice, LFP) and 7:1:2 (increasing basal fertilizer rate, IBF) under the total N application rate of 270 kg ha-1. The effects of the four treatment combinations (NS-LFP, NS-IBF, WS-LFP, WS-IBF) on yield, cooking and eating quality, and 2-AP content in rice were investigated. The two-year (2020, 2021) results showed that: 1) WS-IBF significantly increased the number of panicles and grains per panicle, leading to the increase in grain yield by 6.67%–12.21%, when compared with NS-LFP, NS-IBF and WS-LFP. 2) WS-IBF enhanced the taste value, peak viscosity, breakdown value, the ratio of amylopectin to amylose, and the ratio of glutelin to prolamin while reducing the setback value and amylose content of rice flour. 3) Compared with NS, WS increased the activities of proline dehydrogenase and ornithine transaminase, the synthetic precursors of 2-AP, and finally increased 2-AP content in rice grains. WS-IBF slightly decreased 2-AP content, but there was no significant difference with WS-LFP. The above results indicated that adjusting the N regime and increasing basal N fertilizer rate under wheat straw returning is conducive to improving grain yield, cooking and eating quality, and 2-AP content in rice.

Impact of Rice–Wheat Straw Incorporation and Varying Nitrogen Fertilizer Rates on Soil Physicochemical Properties and Wheat Grain Yield

“…Our study revealed that SR application boosted accessibility of nitrogen (N), phosphorous (P), nitrates (NO 3 − ), and ammonium (NH 4 + ) within 20 cm soil depth (Figures 3-5). This is consistent with earlier reports by Zhang et al [50] and Wang et al [27]. The study revealed a significant decrease in soil phosphorus (P) availability in the SR treatment as compared to the CK treatment, specifically at depths ranging from 20 to 30 cm.…”

“…Additionally, the presence of organic matter in crop straw contributes to improved physicochemical and biological properties of the soil, resulting in increased wheat grain productivity (Figures 6 and 7). However, earlier studies have indicated that SR had no significant effect [16,25,27] or resulted in a decline in crop productivity [15,16]. This was largely ascribed to SR-induced nitrogen immobilization, resulting in decreased crop yields [16,16,27].…”

“…Hence, it is imperative to study the fluctuations in the reservoir of soil organic carbon to uphold the sustainability of the global agroecosystem. The impact of straw return on soil has been extensively studied in terms of various environmental factors, such as soil water potential [15], temperature [3,15,27], enzyme activities [16,20], fractions of soil organic matter [7,9,22], soil quality and crop productivity [16][17][18], emissions of greenhouse gases from soil [20,28,29], soil physicochemical properties [19,30], and soil microbial communities [7,18,31,32]. Several studies have suggested that the practice of straw return has the potential to enhance the ecological environment of soils [4,11,17,29,33,34].…”

RGB Imaging as a Tool for Remote Sensing of Characteristics of Terrestrial Plants: A Review

“…The sensitivity of color indices to the grain yield is mainly based on the dependence of this yield on the nitrogen content [3,4,38,107,109], which plays a key role in the grain formation and is strongly related to color parameters (see Section 4.1 and Table 2). Additionally, the nitrogen content influences the grain quality and nutritional value [144,145], i.e., these characteristics can also be related to color parameters. Vollmann et al [53] showed that R and G are moderately and negatively related to protein and oil content in soybean seeds (R 2 is about 0.45-0.65); in contrast, B is positively correlated with these characteristics (R 2 is about 0.45-0.62) (see Table 2 for details).…”

Effects of Nitrogen Application Rate on Dry Matter Weight and Yield of Direct-Seeded Rice under Straw Return

“…China is a country with high agricultural production and is rich in agricultural straw resources. The annual output of crop straw is approximately 800 million tons, accounting for 30% of the total global output [1]. However, a complete and effective institutional mechanism for the comprehensive utilization of straw in our country has not yet been established, and the utilization efficiency of crop straw remains relatively low.…”