Effects of straw returning and nitrogen addition on soil quality of a coastal saline soil: A field study of four consecutive wheat‐maize cycles

Abstract

The effects of different straw returning and nitrogen addition levels on soil quality are important for proper coastal saline soil remediation. However, relatively little is understood concerning the remediation effects, especially, on long‐term effects and mineral composition and microstructures of coastal saline soil. Two maize/wheat straw returning levels [1.0 × 104 kg ha−1 (2S) and 5.0 × 103 kg ha−1 (S)] and three inorganic nitrogen addition levels [300 kg ha−1 (N2), 150 kg ha−1 (N) and 75 kg ha−1 (N1/2)]—were studied, with 150 kg ha−1 inorganic nitrogen and without straw addition treatment as the control (CK), to elucidate the response of soil physical and chemical properties to the two factors. After four consecutive wheat‐maize cycles, different straw and N fertilizer treatments obviously decreased the salinity contents, increased the total nutrient contents, and optimized the soil structure of the saline soil. The saline soil reclamation effects showed significant distinctions among the different straw and N fertilizer treatments. The 2SN2 treatment displayed the greatest effects in regard to reducing salinity, increasing the total soil nutrient contents and optimizing the soil structure, which resulted in the best remediation effect. Straw returning plays a major role in decreasing soil salinity and enhancing saline soil aggregate formation. N fertilizer addition supplies rich nutrients for straw decomposition, and promotes soil microbial growth and reproduction, which brought about C sequestration in coastal saline soil. During the coastal saline soil remediation process in the Yellow River Delta, it is suggested to prioritize straw returning and moderate N fertilizer addition, and live together with moderate P fertilizer application.

Responses of soil aggregation and aggregate‐associated nitrogen to straw return in China: Evidence from a meta‐analysis and a pot experiment

“…The recovery rate of soybean straw-derived nitrogen was significantly greater than that of corn straw-derivednitrogen (Figure 11) (p < 0.05), and the recovery rate under low straw application was significantly greater than that under high straw application. Conversely, the rates of undecomposed and loss of soybean straw were significantly lower than those of corn straw Straw return effectively promoted the formation of macro-aggregates, which was consistent with the results of previous research (Yang et al, 2022). This is mainly attributed to the release of organic matter upon straw degradation (Yuan et al, 2023).…”

“…Soybean and corn straw have different chemical characteristics (e.g., nutrient content and C/N ratio), which affect the decomposition rate of the straws and the uptake and utilization rate of nitrogen from the straw by subsequent wheat crops due to differences in the nutrients available for microbial growth. Relevant studies have focused on the impact of straw return on the distribution of soil aggregates and the relative change in aggregate‐associated nitrogen content (Xie et al, 2019; Yang et al, 2022). There are few comprehensive studies on the retention of straw‐derived nitrogen by different soil aggregates and the utilization characteristics of straw‐derived nitrogen in subsequent crops via isotope tracing technology, and the straw types mostly include the three major grain crops.…”

The Fate and Challenges of the Main Nutrients in Returned Straw: A Basic Review

“…Returned straw decomposition is a complex and lengthy process, involving a combination of physical, chemical, and microbial activities [43,44]. Due to its inherent biochemical stability, the steps of straw decomposition are characterized by several stages.…”

Research Progress and Application Analysis of the Returning Straw Decomposition Process Based on CiteSpace

“…A soil column experiment conducted by Liao et al [49] showed that treatment with desulfurized gypsum and decomposed straw could significantly reduce the soil salinity of sodic saline soil after leaching. The simultaneous application of straw returning and nitrogen fertilizer improved the properties of the Shandong coastal saline soil and reduced the soil salinity by 27.08% [50]. Straw returning can also optimize the root growth environment by changing water and salt migration, soil porosity, and aggregate size distribution in the soil layer [51,52].…”