Water-saving and Fertilizer-reducing Effect of Clinoptilolite in Water-saving Irrigated Paddy Fields in Semiarid Areas of Western Liaoning

The low water and fertility retention capacity of paddy soils in the semiarid area of Western Liaoning is one of the important obstacles restricting water conservation and high yield in this area. In order to study the water-saving and fertilizer-reducing effects of clinoptilolite in water-saving irrigated paddy fields and clarify the relationship between the process parameters of nitrogen accumulation and rice yields, field experiments were conducted in semiarid areas of Western Liaoning in 2019 and 2020. Conventional flooding irrigation treatment was taken as control, and alternate wet-dry irrigation with application of clinoptilolite, alternate wet-dry irrigation with application of clinoptilolite and 1/4 less nitrogen treatment, alternate wet-dry irrigation with application of clinoptilolite and 1/4 less phosphorus treatment, alternate wet-dry irrigation with application of clinoptilolite and local organic fertilizer instead of quick-acting fertilizer treatment, were designed to monitor rice water consumption, dry matter, nitrogen uptake, etc. Results showed that compared with conventional flooding irrigation, clinoptilolite coupled with alternate wet-dry irrigation significantly saved irrigation water by 4.8% to 11.4%, increased water productivity by 6.2% to 15.5%, reduced phosphate fertilizer by 25%, and increased rice grain yield up to 9.7%. The rice water consumption presented that it was firstly increased and then decreased, and the plant nitrogen requirement conformed to the Richards's growth function. The principal component analysis showed that the three important parameters affecting the highrice yield were the nitrogen accumulation amount, nitrogen accumulation duration and stablity of nitrogen accumulation process. The significant increase in rice yield for "alternate wet-dry irrigation with application of clinoptilolite and 1/4 less phosphorus" treatment, and "alternate wet-dry irrigation with application of clinoptilolite" treatment was due to the increased nitrogen accumulation in leaves, and then increased the dry matter accumulation and the nitrogen accumulation in rice panicles. In summary, alternate wet-dry irrigation with application of clinoptilolite and 1/4 less phosphorus treatment, and alternate wet-dry irrigation with application of clinoptilolite treatment had characters of both high nitrogen accumulation amount and duration, and stable nitrogen accumulation process, which became the important ways to save irrigation water and increase production efficiency in apaddy field of the semi-arid area of Western Liaoning. © 2021, Chinese Society of Agricultural Machinery. All right reserved.