有机肥对桃园土壤硝态氮分布的影响

Effects of organic manure on the profile distribution of soil nitrate-N in a peach orchard

于2004—2005年在北京市平谷区有机桃园设置不同有机肥处理:2年连续施有机肥,年均67500kg.hm-2(T1);第一年不施肥,第二年施有机肥135000kg.hm-2(T2);第一年不施肥,第二年施有机肥67500kg.hm-2(T3);不施肥对照(CK),并于2006年对0～120cm土层土壤进行取样分析,研究施用有机肥对土壤硝态氮分布和淋失的影响.结果表明:对照土壤中硝态氮分布较均匀,T1和T3在0～120cm土层硝态氮浓度变化呈单峰曲线,其中60cm以上较高,在60～120cm逐渐降低;而T2土壤硝态氮浓度由浅到深逐渐增加,峰值出现在100～120cm土层,其在60cm以下土层的硝态氮浓度在所有处理中最高,说明过量施用有机肥易导致硝态氮的淋失.相关分析表明,土壤硝态氮的浓度和分布与多年施氮总量、最近一年施氮量和检测点与树的距离呈显著相关关系,并据此建立了有机肥施用与土壤剖面硝态氮浓度之间的相关模型.

In 2004 and 2005,a field experiment was conducted in a peach orchard in Pinggu District of Beijing to study the effects of organic manure on the profile distribution of nitrate-N in soil.Four treatments were installed,i.e.,applying 6.75×10^4 kg·hm^-2 of organic manure both in 2004 and in 2005（T1）,no fertilization in 2004 but applying 13.5×10^4 kg·hm^-2 of organic manure in 2005（T2）,no fertilization in 2004 but applying 6.75×10^4 kg·hm^-2 of organic manure in 2005（CK）,and no fertilization both in 2004 and in 2005（CK）.In 2006,soil samples at the depth of 0-120 cm were collected from the treatments and analyzed.The results showed that soil nitrate-N had a relatively uniform distribution in the profile in CK,accumulated more at the depth of 0-60 cm and decreased gradually at 60-120 cm in T1 and T3,and increased with increasing depth,with the peak at the depth of 100-120 cm in T2.The soil nitrate-N content below 60 cm in T2 was the highest among all the treatments,indicating that applying excessive amount of or ganic manure could induce nitrate-N leaching.The profile distribution of soil nitrate-N had significant correlations with the total amount of applied organic manure,the amount of organic manure applied in the nearest year,and the distance of sampling sites from peach tree.A correlation model of organic manure treatments and soil nitrate-N distribution was established.