Maize Straw Return and Nitrogen Rate Effects on Potato (Solanum tuberosum L.) Performance and Soil Physicochemical Characteristics in Northwest China

Abstract

The average yield of fresh potato tubers per hectare is relatively low in China, partly due to poor nutrient management. Chronic inorganic N enrichment leads to soil acidification, which deteriorates soil fertility. Straw residues are removed from the field or burnt during land preparation, resulting in nutrient depletion and air pollution. However, these residues can be returned to the soil to improve its fertility. Therefore, a two–year experiment was conducted in an existing field with five years of different inorganic nitrogen (N) rate to determine the effects of straw return and N rate on potato growth, tuber yield, and quality, profit margin, and soil physicochemical properties. The experiment consisted of four N rates: 0 (control, CK), 75 (low N rate, LN), 150 (medium N rate, MN), and 300 (high N rate, HN) kg N ha−1 with and without straw (9 t ha−1) return. The results showed that straw with N enrichment improved soil fertility, which increased tuber yield and quality. Compared to the control, MN + straw treatment stimulated economic tuber yield (34.73% and 38.34%), profit margin (55.51% and 63.03%), and protein content (20.04% and 25.46%) in 2018 and 2019, respectively. Nitrogen enrichment after straw return is a sustainable practice for stimulating potato tuber yield, profit margin, and improving soil fertility to promote sustainable agriculture development.