Improvement of soil acidification and ammonium nitrogen content in tea plantation by long-term use of organic fertilizer.

Abstract

Soil acidification was common in Chinese tea plantations, which seriously affected the growth of tea trees, and it was of great significance to explore soil remediation in acidified tea plantations for the sustainable development of tea industry. We sought to determine how different fertilizers improve acidified soil and their nitrogen transformation in tea plantation. Different fertilizers were used to treat acidified soils in tea plantations for 4 consecutive years from 2017 to 2021, and the changes in soil pH, indexes related to soil nitrogen transformation and tea yield were analyzed to construct interaction networks of the above indexes and obtain the indexes with the greatest influence on the fertilization effect. Long-term use of sheep manure fertilizer in tea plantation improved soil acidification, increased the soil pH value, enhanced the number and intensity of nitrogen-fixing bacteria and ammonifying bacteria, urease, protease, asparaginase and N-acetamide glucose ribosidase activities, nifH gene expression, reduced the number and intensity of soil nitrifying bacteria and denitrifying bacteria, nitrate reductase and nitrite reductase activities, and the expressions of amoA-AOA, nirK, nirS, narG and nosZ genes, which in turn increased ammonium nitrogen content of the soil, reduced nitrate nitrogen content, and enhanced tea yield. Topsis index weight analysis showed that ammonium nitrogen content in soil had the greatest impact on the fertilization effect. Long-term use of sheep manure fertilizer was beneficial to restore the balance of micro-ecosystem of acidified soil. This study provided an important practical basis for soil remediation and fertilizer management in acidified tea plantation soils.