Characteristics of soil ammonia volatilization and the absorption and utilization of nitrogen, phosphorus and potassium of pepper under slow-release fertilizer application

Laboratory diffusion simulation experiment was conducted to investigate the characteristics of soil ammonia volatilization under the application of large particle urea (PUR), special compound fertilizer (LCCF), special slow-release compound fertilizer (LSRF), with no fertilization as the control. The pot experiment was meantime carried out to investigate yield, and uptake and utilization of nitrogen (N), phosphorus (P) and potassium (K) of 'Gailiangzaofeng' and 'Yujiao5' peppers under the application of LSRF, LCCF, common compound fertilizer (OCCF) and commercially non-coated slow-release compound fertilizer (MSRF). Changes in soil organic matter content and soil enzyme activity were also analyzed. The results showed that the order of the soil ammonia volatilization rate in the first 28 days of laboratory diffusion simulation experiment was as follows: PUR > LCCF > LSRF > no fertilizer (CK). Then soil ammonia volatilization rate of LSRF after 28 days of the experiment was higher than those of PUR and LCCF. Cumulative soil ammonia volatilization from PUR, LSRF and LCCF at 70 days were 71.87 mg·kg^-1, 54.29 mg·kg^-1 and 63.49 mg·kg^-1 respectively under laboratory diffusion simulation experiment. Cumulative ammonia volatilization from LSRF respectively dropped by 24.5% and 11.7% compared with PUR and LCCF under the same dose of N fertilizer. For the pot experiment, yield of 'Yujiao5' and 'Gailiangzaofeng' under LSRF respectively increased by 64.7% and 33.8% compared with OCCF, While the content of soil organic matter and activities of urease, invertase and catalase increased, plant uptake and utilization of N, P and K were enhanced under LSRF treatment. Apparent N fertilizer utilization rates of 'Yujiao5' and 'Gailiangzaofeng' respectively increased by 62.5% and 123.1% compared with that of OCCF. Apparent P and K fertilizer utilization rates of 'Gailiangzaofeng' under LSRF treatment respectively enhanced by 14.0 times and 28.7% compared with OCCF. Also apparent P and K fertilizer utilization rates of 'Yujiao5' under LSRF treatment respectively increased by 3.2 times and 120.9% compared with OCCF treatment.