Effects of biochar on the physicochemical property of irrigated silt soil and the quality of Brassica campestris

LI Baiyun; LI Hui; XU Zehua; GUO Xinnian; ZHOU Tao; XING Rundong; LI Yongxiang

doi:10.16861/j.cnki.zggc.2025.0324

Abstract：This study was conducted at a vegetable supply base for Hong kong in Qingtongxia city through filed plot ex-periments to investigate the effects of different biochar application rates(CK,0 t·hm-2;T1,7.5 t·hm-2;T2,15 t·hm-2;T3,22.5 t·hm-2;T4,30 t·hm-2)on the physicochemical properties and enzyme activity of irrigated silt soil,as well as the yield and quality of Brassica campestris.The aim was to provide a scientific basis for the promotion and application of biochar in agricultural production.The results showed that soil fertility and soil enzyme activity generally exhibited a trend of first increasing and then decreasing with the increase of biochar application rate.Two years after applying biochar,all applica-tion rate treatments significantly increased soil organic matter,available potassium,available phosphorus,microbial bio-mass carbon,and soil moisture content in the vegetable field.Compared to the control,soil available phosphorus,avail-able potassium,and soil moisture content increased by 1.9%-6.9%,2.3%-7.4%,and 6.9%-12.9%,respectively.The activi-ty of soil urease,phosphatase,and sucrase increased by 73.5%-175.4%,50.9%-136.1%,and 20.3%-55.5%,respectively.Among the four treatments,the order of activity for urease and invertase enzymes was T2>T4>T3>T1>CK.Soil ammoni-um nitrogen and nitrate nitrogen content increased by 56.4%-126.9%,and 75.4%-166.9%,respectively,with the order for ammonium nitrogen content being was T2>T4>T3>T1>CK,and for nitrate nitrogen content being T3>T4>T2>T1>CK.Compared to the control,biochar application significantly increased the vitamin C and total nitrogen content of Brassica campestris leaves,with increases ranging from 33.1%-146.2%,and 9.3%-103.2%,respectively.The vitamin C content across treatments followed the order T3˃T4˃T2˃T1˃CK,while the total nitrogen content followed T2˃T3˃T4˃T1˃CK.Regarding total phosphorus content in leaves,the T2 and T3 treatments significantly increased by 6.6%and 7.4%,respec-tively.For the total potassium content,the T1 and T4 treatments significantly increased by 14.5%and 3.9%,respectively.Principal component analysis results showed that treatment T2 had the highest score,followed by treatment T3.Consider-ing all indicators comprehensively,the application of 15 t·hm-2 biochar(treatment T2)had the best overall effect on,im-proving vegetable soil quality and enhancing the quality of Brassica campestris.