ABSTRACT
We carried out a 3-year field experiment with three treatments: 1) no fertilizer application (CK), 2) chemical fertilizer application (F), and 3) combined organic and chemical fertilizer (FM) in which the total nitrogen inputs were equal with F (organic fertilizer applied in the early rice season). We evaluated the variations of crop yield, CH4 and N2O emission, and soil nutrient. The results showed that fertilizer application could increase rice yield in both early and late rice seasons. Compared with F treatment, FM treatment increased rice yield by 5.6% and 7.2% for early and late rice, respectively. The enhancement of yield was positively correlated with years. Compared with F treatment, CH4 emission in early rice season, late rice season and whole year in the field in FM treatment was increased by 8.2%, 4.8% and 6.7%, respectively, while the N2O emission was deceased by 31.4%, 5.0% and 18.8%, respectively. Organic fertilizer application reduced the greenhouse gas intensity (GHGI) by 6.8% and 8.5%, but there was no significant differences in global warming potential (GWP) across treatments in 2018 and 2019. Compared with F treatment, the content of organic matter, total nitrogen, available phosphorus and available potassium were increased by 9.7%, 4.1%, 30.9% and 2.5%, respectively. Overall, our results suggested FM application in early rice season is an effective measure to increase crop yield, improve soil nutrient, and reduce GHGI.
Subject(s)
Greenhouse Gases , Oryza , Agriculture , China , Fertilizers/analysis , Greenhouse Gases/analysis , Methane/analysis , Nitrogen , Nitrous Oxide/analysis , Nutrients , SoilABSTRACT
Winter wheat is an important crop in Anhui Province. Rational use of fertilizers is crucial for the achievement of successful yield. It is urgently needed to reveal the status of fertilizer application and existing problems in winter wheat planting in Anhui for better fertilization. We conducted a survey on 1591 farmers in the main winter wheat producing areas of Anhui Province. The contents of survey included fertilizer type, fertilizer dosage, fertilization method, planting area and yield level. Based on the survey results, we analyzed the current fertilization status of winter wheat growing areas in Anhui Province. Referred to the average wheat yield and fertilizer usage in Anhui, the relationship between wheat yield and fertilizers, including nitrogen (N), phosphorus (P2O5) and potassium (K2O), was evaluated by Cate-Nelson method (cross-over method) to explore the ways to increase yield and fertilizer utilization efficiency of winter wheat. The results showed that the average yield of winter wheat in Anhui Province was 5185 kg·hm-2, and the average application rates of N, P2O and K2O fertilizers were 206, 80 and 78 kg·hm-2, respectively. Compared with wheat following rice, the N, P2O and K2O fertilization rates of dry stubble wheat was higher by 14, 16 and 3 kg·hm-2, respectively. Overall, the average amount of chemical fertilizer in winter wheat cultivation in Anhui Province was rational, but there were still some problems in fertilization methods, nutrient management and fertilizer types. The results of Cate-Nelson method showed that 23.8%, 21.2% and 25.7% (for N, P2O5 and K2O fertilizers respectively) of winter wheat were below the average level that achieved high yield, reaching highest partial productivity of N, P2O5 and K2O fertilizers. There were 26.3%, 19.3% and 22.5% (for N, P2O5 and K2O fertilizers respectively) of winter wheat were below the average use level which did not achieve high yield. There were 26.2%, 29.6% and 25.0% (for N, P2O5 and K2O fertilizers respectively) of winter wheat realized high yield, but the fertilization rate was high and the partial productivity of N, P2O and K2O fertilizers was relatively low. Our results suggest that the yield and efficiency of winter wheat in Anhui Pro-vince should be improved. The percentage of mechanical fertilization in winter wheat was 62.7% for base fertilizer and 10.0% for topdressing fertilizer, respectively. Though nitrogen fertilizer was applied at different stages, the proportion of base fertilizer that accounted for 69.0% of the total should be decreased appropriately. It's a problem that farmers preferred to use chemical fertilizers but not organic substitution.
