The combination of different nitrogen fertilizer types could promote rice growth by alleviating the inhibition of straw decomposition

Abstract

Straw return plays an important role in the improvement of farmland ecological environments, increasing soil fertility, crop quality, and yield. However, in the early growth of rice (Oryza sativa L.), straw decomposition and rice growth may be inhibited by suboptimal carbon/nitrogen (C/N) ratios. We, therefore, explored methods that could alleviate the inhibition of straw decomposition using different combinations of ammonium bicarbonate and compound fertilizer. No fertilizer (CK) and compound fertilizer (S0) were used as the control. The ratios of added ammonium bicarbonate were 10% (S1), 20% (S2), 30% (S3), and 40% (S4), respectively. Compared with the S0 treatment, the S2 treatment accelerated straw decomposition, promoted the early growth of tillers and roots, and improved the leaf area index, dry matter accumulation, and N use efficiency (apparent N utilization, agronomic N utilization, and partial factor productivity increased by 4.05‒19.48% in two years). Moreover, panicle number, filled‐grain percentage, and 1000‐grain weight were significantly higher in the S2 treatment than other treatments. The grain yield of S2 treatment was significantly higher than that of S0 treatment by 4.06% (2019) and 5.66% (2020). Regression analysis revealed that the optimal ratios of ammonium bicarbonate for increasing straw decomposition and grain yield were relatively close, 16.27% and 14.60%, respectively. These results suggest that compared with conventional fertilization method (S0), the 20% treatment is a more effective fertilization method that prevents inhibition of straw decomposition, promoting rice growth and yield, and improving nitrogen (N) use efficiency.

Improvement of straw decomposition and rice growth through co-application of straw-decomposing inoculants and ammonium nitrogen fertilizer

“…It was suggested that compared with the application of compound fertilizer alone, application of Ammonium N fertilizers can supply available N faster for the purpose of straw decomposition [ 21 ]. In this study, we showed that ammonium bicarbonate-substituted compound fertilizer (A2 treatment) significantly improved straw decomposition rate, consistent with previous observations [ 22 , 23 ]. However, we also observed no increase in the straw decomposition rates of A3 and IA4 compared with A0, indicating that an excessive increase in the proportion of ammonium bicarbonate alone in basal fertilizer did not provide a long-term N source for straw decomposition.…”

“…At maturity, the representative plants were randomly collected to determine the N content of the rice using the ECS 4024 CHNS-O Classic Analyzer (Costech, Italy). Apparent nitrogen use efficiency (ANUE, %), agronomic nitrogen use efficiency (AE, kg/kg), physiological nitrogen use efficiency (PNUE, kg/kg), and partial factor productivity of nitrogen (PFP N , kg/kg) were calculated according to the following equations [ 23 ]:…”

“…Thus, ammonium N fertilizer can supply available N nutrient faster than amide N fertilizers, which suggests that N demand for rapid straw decomposition and faster crop growth early in the growing season could be quickly met if ammonium N fertilizer is used as basal fertilizer. It was reported that the competition for N between straw-decomposing microbes and crop growth was alleviated in earlier plant growth by substituting compound fertilizer with ammonium N [ 22 , 23 ]. However, due to rapid nutrient loss, the use of ammonium N fertilizer as basal fertilizer carries the risk of nutrient deficiency in the subsequent growth stage, which results in yield decline.…”

Effects of fertilizer reduction coupled with straw returning on soil fertility, wheat root endophytic bacteria, and the occurrence of wheat crown rot

“…This means that, when the soil has reached high fertility through fertilization, the improvement of fertilization in soil nutrients was lower than that at low fertility (Fippin, 1937;Chen et al, 2021) and (2) poor microbial activity under excess fertilization. The process of straw decomposition by soil microorganisms to release nutrients is influenced by several factors, such as temperature, humidity, soil physical and chemical properties, fertilization, and pesticides (Li et al, 2017;Tang et al, 2021). Excess fertilization can cause soil compaction and acidification, which influence soil microbial community composition and ecological function (Zhao et al, 2019).…”

New approach combining food value with nutrient budgeting provides insights into the value of alternative farming systems

“…Field trial‐based European studies have also found that integrating fertilisation with organic amendment applications led to consistently higher agronomic performance than crops treated with only one or the other (Macholdt et al, 2019; Sihvonen et al, 2021). This approach has also been applied to farming systems in the developing world (Abid et al, 2020; Qazi & Khan, 2020), particularly in the cultivation of rice in which substantial improvements to crop performance and quality have been obtained through combining synthetic N additions with K inputs (Ye et al, 2021), retention and reincorporation of residues (Tang et al, 2021). An important next step is to connect findings from the efficiency index to soil quality.…”