Effect of N-Loaded Clinoptilolite on Soil Available Nutrients and Yield Under Water-Saving Irrigation

Abstract

Highlights Clinoptilolite was used to adsorb ammonia from agricultural wastewater and as a nutrient carrier to cultivate crops. Nitrogen-loaded clinoptilolite (NZ) prolonged the N supply time, which met the N demand for plant growth. NZ under water-saving irrigation purified wastewater, saved irrigation water and increased grain yield.Abstract. The extensive application of nitrogen (N) fertilizer causes soil acidification and increases the risk of water eutrophication, especially in irrigated areas. To reduce the eutrophication level of the water body and improve the soil fertility, clinoptilolite (Z) was used to adsorb N in simulated eutrophic water bodies, and then as a nutrient carrier to supplement the soil N source and promote the reuse of N. The results show that the NH4+-N loading process caused ion bonds to break inside the Z, which increased the contact area for ion adsorption. Z successfully reduced the NH4+-N concentration by 36.25% in the simulated N-rich water. The soil NH4+-N and NO3--N contents of N-loaded clinoptilolite (NZ) under alternate wet-dry irrigation (AWD) were higher during the critical growth period, which enhanced the soil N pool and replenished N in time. The NZ as a slow-release fertilizer prolonged the N supply time under AWD, which increased rice tillers by 13.68% and yield by 11.24% compared with control (without NZ amendment). In conclusion, the approach of NZ combined with AWD is beneficial to the rice growth and improvement of the soil-water environment in irrigated areas. Keywords: Ammonium Adsorption, Clinoptilolite, Nitrogen Releaser, Paddy Soil, Water-saving Irrigation.