减肥条件下生物炭施用方式对土壤肥力及酶活性的影响

Effect of biochar application pattern on soil fertility and enzyme activity under limited fertilization conditions

为研究生物炭逐年施加和一次性施入4年后对土壤肥力和酶活性的影响,采用定位试验设置100%(F1)、80%(F2)和60%(F3)推荐施肥量的三种施肥水平×四种施炭量(CK:0 t·hm^-2,B1:2.6 t·hm^-2·a-1,B2:13 t·hm^-2,B3:26 t·hm^-2)共12个处理,分析土壤氮磷钾养分含量和酶活性指标的变化,其中B1处理逐年施加,B2和B3处理一次性施加。结果表明生物炭对土壤氮素提高效果显著,其中全氮含量较对照处理提高23.08%~52.25%,硝态氮含量是对照的1.80~2.46倍,并随施炭量提高而增加,提升效果优于铵态氮。60%推荐施肥条件下,施加13 t·hm^-2和26 t·hm^-2生物炭土壤速效磷含量分别高于不施炭对照84.99%和159.23%。土壤全钾含量未因生物炭加入发生显著变化,但是速效钾含量较对照提高了18.99%~61.24%。土壤酶活性主要受生物炭施加方式的影响:逐年施加生物炭(B1)显著提高了酸性磷酸酶活性,但降低了土壤脲酶和过氧化氢酶活性,而一次性施炭可提高土壤脲酶活性。研究表明,生物炭对土壤氮磷肥力和速效钾肥力均有一定的提升效果,其中对氮素的提高效果最理想,可弥补减肥40%引起的土壤氮素降低。逐年施炭对土壤酶活性影响显著,新鲜生物炭中所含物质是影响酶活性的主要因素。

The aim of this study was to determine the effect of biochar application on soil fertility and enzyme activity.The soil nitrogen(N),phosphorus(P),and potassium(K)contents and enzyme activity were measured in 12 treatments,including 3 fertilizer application rates:100%,80%and 60%of full recommended fertilization,marked as F1,F2,F3,and 4 biochar application rates:CK:0 t·hm^-2,B1:2.6 t·hm^-2·a-1,B2:13 t·hm^-2,B3:26 t·hm^-2.The results showed that biochar amendment compensated soil N decline by reducing 40%of N fertilizer inputs.In detail,biochar caused 23.08%~52.25%increase of soil total N content and 39.39%~85.76%increase of soil ammonium(NH+4-N)concentration when compared with control soil.Meanwhile,soil nitrate(NO-3-N)concentration was 1.80~2.46 times of control.The soil P availability was elevated by biochar addition at F3 fertilization rate,e.g.,the available P content in B2×F3,B3×F3 were 84.98%and 159.23%higher than their corresponding control.Furthermore,although soil total K content was not affected by biochar,the soil avail⁃able K content was 18.99%~61.24%higher than in the control.Soil enzyme activity was mainly affected by biochar application pattern:One-time biochar application(B2 and B3)improved soil urease activity,and when biochar was applied annually(B1),it enhanced acid phosphatase activity,but soil urease and catalase activity was inhibited,implying that labile fraction in fresh biochar was the main substanc⁃es affecting soil enzyme activity.Our results indicated that biochar application is an effective measure for soil fertility improvement and its application pattern has a great influence on soil enzyme activity.