长期施用家畜废弃物堆肥对土壤剖面^(15)N自然丰度的影响

NATURAL ^(15)N ABUNDANCE IN SOIL AFFECTED BY LONG-TERM APPLICATION OF ANIMAL WASTES

通过对两个长期田间试验的研究 ,分析了日本火山灰土 (Andisols)及其溶液中15N自然丰度(δ15N)在土壤剖面的分布 ,其目的是为了评价δ15N值能否作为预测家畜废弃物氮在迁移转化过程中形成的NO3 N污染的指标。在日本中央农业综合研究中心 (NARC)进行了 6年的试验处理包括 :猪场废弃物堆肥 (猪粪堆肥 ) ,缓释尿素 (缓释肥 ) ,普通铵态氮肥 (普通化肥 ) ,及不施肥 (对照 ) ;而在日本农业研究所(NARI)进行了 1 2年的试验则包括三个施用量的牛场废弃物堆肥 (牛粪堆肥 ) ,以该地长期不施肥的森林土壤 (森林 )作为对照。研究结果表明在NARC长期施用猪粪堆肥显著改变了δ15N值在土壤剖面的分布模式 ,猪粪堆肥小区 0～ 2 0cm的δ15N值最高 ,然后按对照≥普通化肥 >缓释肥排列 ,原因主要为猪粪堆肥本身的δ15N值较高及其随后在土壤中的转化等反应 ;缓释肥处理后的土壤δ15N值最低 ,表明缓释肥施入土壤后的循环速率较慢或相对于施肥量其损失较低。在NARI,土壤δ15N值随着施肥量的增加而升高。同样不施肥条件下 ,NARI的森林土壤剖面的δ15N值比相对应的NARC的对照土壤剖面值高 1～ 2个δ单位。NARC土壤剖面 1 0 0cm收集的土壤溶液的δ15N值的大小排列为 :猪粪堆肥 >普通化肥≥对照 >缓释肥 ;并且普通化肥小区土壤溶?

Two field experiments were conducted on Andisols in Japan to evaluate changes in natural 15N abundance in the soil profile and to estimate whether the values of δ 15N can be used as an indicator of fertilizer sources or fertilizer fate. The 6-year experiment at the National Agricultural Research Center (NARC) consisted of the following treatments: swine compost (COMPOST), slow-release nitrogen fertilizer (SRNF), readily available nitrogen fertilizer (RANF), and no fertilization (CONTROL). Experimental plots at the Nippon Agricultural Research Institute (NARI) received cattle compost at different rates for 12 years; a forest soil at this site was sampled for comparison. Swine compost greatly changed δ 15N distribution pattern in the soil profile, with the highest δ 15N values occurring in the top 20-cm layer of the COMPOST plot, decreasing in the sequence of CONTROL≥RANF>SRNF, mainly due to relatively high δ 15N value of swine compost and its subsequent decomposition. In contrast, SRNF resulted in the lowest δ 15N values in soil, indicating small nitrogen losses relative to input and low nitrogen release rates. Values of δ 15N increased with compost application rates at NARI, and, for the unfertilized soil, the values of the FOREST plot at NARI were 1～2 δ units larger than the CONTROL plot at NARC. In leachate collected at 100 cm depth, δ 15N values decreased in the sequence of COMPOST>RANF≥CONTROL>SRNF. The lowest δ 15N values of leachate of RANF plot was observed in the depth of 200～250 cm. These results indicated that δ 15N values in upper soil or leachate may help us infer pollution sources of organic or inorganic nitrogen qualitatively in Andisols.