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Acta Prataculturae Sinica ›› 2025, Vol. 34 ›› Issue (3): 56-70.DOI: 10.11686/cyxb2024165

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Effects of straw and milk vetch mulching on the ecological stoichiometric characteristics of soil-microbe-sweet potato plants

Shao-xing LI(), Wen-feng SONG(), Yu-ling ZHOU, Li-xia SONG, Ke REN, Qun MA, Long-chang WANG()   

  1. College of Agronomy and Biotechnology,Southwest University,Engineering Research Center of South Upland Agriculture,Ministry of Education,Chongqing 400715,China
  • Received:2024-05-07 Revised:2024-06-24 Online:2025-03-20 Published:2025-01-02
  • Contact: Long-chang WANG

Abstract:

There is an urgent need to explore sustainable agricultural cultivation measures and alleviate nutrient limitations as a response to the problems of soil erosion and low quality of cultivated land in the dry-farming areas of southwest China. This study focused on sweet potato plantings within a “fava bean (Vicia faba)/corn (Zea mays)/sweet potato (Ipomoea batatas)” rain-fed three-crop rotation pattern in southwest China. Four treatments were set up: no mulching (CK), straw mulching (S), straw and milk vetch (Astragalus sinicus) mulching (S+M) and milk vetch mulching (M). By studying the content of carbon, nitrogen and phosphorus, ecological stoichiometric characteristics and the homeostasis index of the soil-microbe-sweet potato plant stoichiometric data, the effects of straw and milk vetch mulching cover on soil nutrient restriction and ecological stoichiometric characteristics were explored. It was found that: 1) The straw and milk vetch mulching treatments significantly increased soil organic carbon and total nitrogen content, and from changes in the soil stoichiometric ratio, it was deduced that the mulching treatments effectively alleviated soil nutrient restriction. 2) The straw and milk vetch mulching treatments significantly increased the content of soil microbial biomass carbon, nitrogen and phosphorus, and showed differences in the C-N-P stoichiometric ratios of microorganisms at different crop growth stages, with large fluctuations in the early growth period, and relatively stable values in the middle and late growth period. In terms of homoeostasis characteristics, except for the CK treatment, the microbial and soil stoichiometric ratios showed strong homoeostasis. 3) The nitrogen content of sweet potato organs was significantly increased by straw and milk vetch mulching treatments, and the best effect was achieved in the S+M mulching treatment. The yields of sweet potato were ranked S+M>S>M>CK. In terms of stoichiometric ratio, S+M treatment was superior. This treatment prolonged the growth time of sweet potato, and effectively alleviated the nutrient restriction. The stoichiometric ratio of various organs of sweet potato plants showed strong homoeostasis during the whole crop growth period. In summary, in the dry-farming areas of southwest China, crop mulching with straw and milk vetch improved the yield of sweet potato, regulated soil nutrient limitations and resulted in a stable homoeostasis in the stoichiometric ratios of soil and microorganisms.

Key words: straw mulching, milk vetch mulching, sweet potato, stoichiometric characteristics, homoeostasis