Dataset Information

Nitrogen fertilizer reduction in combination with Azolla cover for reducing ammonia volatilization and improving nitrogen use efficiency of rice.

ABSTRACT:

Background

Excessive nitrogen (N) application rate with low N use efficiency (NUE) caused a considerable amount of N losses, especially ammonia volatilization (AV). Proper N fertilizer reduction (RN) could significantly reduce AV. However, continuous RN led to a nutrient deficiency in the soil and therefore negatively impacted the NUE and rice yield. Paddy Azolla, a good green manure, is considered as a promising measure to decrease AV and improve NUE and grain yield of rice. However, there is limited information on the integrated effects of RN and Azolla cover on the AV, NUE, and rice yield, especially in the highly fertilized rice-growing systems.

Methods

The experiment was conducted including eight treatments: the control (without N fertilizer and Azolla cover), Azolla cover without N fertilizer (A), farmer's N application rate (FN), FN + Azolla cover (FNA), 15% RN from FN (RN₁₅), RN₁₅ + Azolla cover (RN₁₅A). 30% RN from FN (RN₃₀), RN₃₀ + Azolla cover (RN₃₀A). The integrated effects of N fertilizer reduction and Azolla cover on AV, NUE, and rice grain was evaluated.

Results

RN₁₅A and RN₃₀A substantially reduced total AV by 50.3 and 66.9% compared with FN, respectively, primarily due to the lower surface water ammonia concentrations and pH. RN improved the efficiency of Azolla cover on reducing AV, with 4.1-9.9% higher than for FN. Compared with the FN, RN₁₅A and RN₃₀A enhanced apparent N recovery efficiency (ANRE) by 46.5 and 39.1%, which might be responsible for the lower NH₃ emission and the increased total N uptake / total chemical N applied. Furthermore, RN₁₅A and RN₃₀A reduced yield-scaled volatilization by 52.3 and 64.3% than for FN, respectively. Thus, combining 15-30% RN with Azolla cover may be a way to reduce AV and improve ANRE without decreasing rice grain yield.

SUBMITTER: Yang G

PROVIDER: S-EPMC7986579 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Excessive reliance on chemical fertilizer (CF) in conventional farming is a serious concern owing to its negative effects on soil health, the environment, and crop productivity. Organic manure is an alternative source of fertilizer to reduce the amount of CF usage in agriculture, decrease environmental pollution, and ensure sustainable crop production. This study assessed the integrated effect of poultry manure (PM) and cattle manure (CM) with CF on soil properties, plant physiology, and rice grain yield. Additionally, the difference in pre-and post-anthesis dry matter (DM) and nitrogen (N) accumulation and their relationship with grain yield was also determined. Pot experiments were performed in the early and late growing season at the experimental station of Guangxi University, China, in 2018. A total of six treatments, i.e., T1-CF0; T2-100% CF; T3-60% CM + 40% CF; T4-30% CM + 70% CF; T5-60% PM + 40% CF, and T6-30% PM + 70% CF were used in this pot experiment. Results showed that T6 enhanced leaf photosynthetic efficiency by 11% and 16%, chlorophyll content by 8% and 11%, panicle number by 12% and 16%, and grain yield by 11% and 15% in the early and late seasons, respectively, compared to T2. Similarly1, post-anthesis N and DM accumulation, N uptake, and soil properties (i.e., soil organic carbon, total N, and bulk density) were improved with integrated CF and manure treatments over the sole CF treatments. Interestingly, increases in post-anthesis N uptake and DM production were further supported by enhanced N-metabolizing enzyme activities (i.e., nitrate reductase, glutamine synthetase, and glutamate oxoglutarate aminotransferase during the grain-filling period in combined treatments. In-addition, the linear regression analysis showed that post-anthesis DM (R2 = 0.95) and N (R2 = 0.96) accumulation were highly associated with grain yield of rice. Thus, the combination of 30% N from PM or CM with 70% N from CF (i.e., urea) is a promising option for improvement of soil quality and rice grain yield. Furthermore, our study provides a sustainable nutrient management plan to increase rice yield with high N use efficiency.