Relationship between Crop Yield and Soil Properties and Its Application for Optimizing Irrigation and Fertilization in Hetao Irrigation District

Abstract

【Objective】 Crop yield is inherently influenced by soil properties. This paper analyzes the spatial distribution of soil properties in Hetao Irrigation District (HID) and its relationship with crop yields, from which we propose how to optimize irrigation and fertilization to improve soil quality and crop yield in the district. 【Method】 The analysis was based on experimental data. The spatial distribution of soil physicochemical properties and crop yields in the district were analyzed using the classical statistics and geostatistics. Their correlations were used to help improve irrigation and fertilization. 【Result】 ①We found prominent issues such as high salinization, increased soil bulk density, and reduced crop yields, in the district. Notably, organic matter and nitrogen levels are relatively low, while available phosphorus is adequate and available potassium is abundant. Soil salinity showed considerable spatial variability, whereas organic matter, total nitrogen, available phosphorus, potassium, and crop yield coefficients showed moderate spatial fluctuations. Bulk density and soil pH, on the other hand, demonstrated only minor spatial variation. Bulk density and soil pH showed weak spatial variation. ②Spatially, soil salinity was pronounced in the central region, decreasing towards the periphery. Crop yield coefficients declined from the Southwest to the Northeast. Organic matter content increased from the West to the East. Soil bulk density, pH, total nitrogen and available phosphorus were the highest in the central region and the least in the East and the West. Low available potassium content was in the Southeast corner, with other areas featuring medium to high levels. ③Soil salinity was the main constraint to crop yields. ④Nitrogen and organic fertilization should be increased to improve soil fertility and crop yields. Specially, we recommend applying 225 kg/hm2 of urea and 3 393.7 kg/hm2 of organic fertilizer for heavily salinized and saline regions, 295.4 kg/hm2 of urea and 3 332.8 kg/hm2 of organic fertilizer for moderately salinized regions, and 365.1 kg/hm2 of urea and 1 280.9 kg/hm2 of organic fertilizer for slightly salinized and non-saline regions. In addition, drainage systems in the Northwest, South, and Southeast of the district should be improved to facilitate salt leaching. 【Conclusion】 The findings outlined in this paper establish a fundamental reference for enhancing soil salinity control and drainage management, as well as optimizing fertilization and irrigation to maintain and bolster crop yields in the Hetao Irrigation District.

Keywords

• hetao irrigation district
• soil properties
• crop yield
• spatial distribution
• soil salinization
• water and fertilizer management