有机物料输入对关中土碳氮影响的后效作用

土壤有机碳氮是土壤肥力的关键因素，有机物料施用是提高土壤有机碳氮的有效措施。研究和比较了不同有机物料输入对土耕层（0—20 cm）土壤有机碳、全氮、可溶性有碳氮及0—200 cm剖面土壤硝态氮和含水量分布变化的后效作用。结果表明，停止施入有机物料两年后，与对照（CK）相比，秸秆与氮磷肥配施（SNP）和生物炭与氮磷肥配施（BNP）的表层（0—20 cm）土壤有机碳（SOC）分别提高了29.5%和29.8%（p<0.05）；氮磷肥（NP）、有机肥与氮磷肥配施（MNP）、秸秆与氮磷肥配施（SNP）和生物炭与氮磷肥配施（BNP）的表层土壤全氮含量较CK分别提高了22.0%，14.3%，24.2%和26.4%（p<0.05）。BNP处理的土壤可溶性有机碳（DOC）显著高于其他处理（p<0.05），分别比CK，NP，MNP和SNP提高了23.4%，10.9%，21.3%，20.5%；所有施肥处理的土壤可溶性有机氮（DON）均显著高于CK（p<0.05），分别提高了39.3%，29.3%，34.5%和52.3%。与CK相比，各施肥处理显著提高了表层土壤硝态氮含量（p<0.05），增加了0—100 cm土层的硝态氮累积量。与NP处理相比，MNP和SNP显著提高了0—200 cm土层的硝态氮累积量（p<0.05），而BNP则差异不显著。相比CK，施肥处理（NP，MNP，SNP，BNP）可显著提高0—20 cm土层的含水量，增加0—40 cm土层的储水量，且BNP处理显著高于SNP和MNP。总体而言，生物炭在提高和维持表层土壤肥力以及降低剖面硝态氮淋溶风险等方面的后效作用显著优于秸秆和有机肥，是陕西关中地区旱地土上一种较好的有机物料施用方式。

Post-Effects of Organic Material Input on Soil Carbon and Nitrogen on Anthropogenic Loess Soil in Guanzhong Area

Soil organic carbon and nitrogen are the key factors of soil fertility, and organic material application is an effective measure to improve soil organic carbon and nitrogen. We studied and compared the post-effects of inputs of different organic materials on soil organic carbon, total nitrogen, dissolved organic carbon and nitrogen in the top layer (0—20 cm) and the distribution of soil nitrate and water in 0—200 cm depth. The results showed that compared with CK (p<0.05), the soil organic carbon (SOC) under the treatments of straw together with nitrogen and phosphorus fertilizers (SNP), and biochar together with nitrogen and phosphorus fertilizers (BNP) increased by 29.5% and 29.8%, respectively after 2 years of the application of organic materials. The soil total nitrogen contents under the treatments of nitrogen and phosphorus fertilizer(NP), Organic fertilizer together with nitrogen and phosphorus fertilizer (MNP), straw together with nitrogen and phosphorus fertilizers(SNP) and biochar together with nitrogen and phosphorus fertilizers(BNP) increased by 22.0%, 14.3%, 24.2% and 26.4%, respectively (p<0.05). The soil dissolved organic carbon (DOC) of BNP was 23.4%, 10.9%, 21.3% and 20.5% higher than that of other treatments (CK, NP, MNP and SNP), respectively (p<0.05). The soil dissolved organic nitrogen (DON) of all fertilization treatments were 39.3%, 29.3%, 34.5% and 52.3% higher than that of CK, respectively (p<0.05). Compared with CK, the fertilization treatment significantly improved the nitrate content in the surface soil and increased the nitrate accumulation in the 0—100 cm soil layer (p<0.05). Compared with NP treatment, MNP and SNP significantly increased nitrate accumulation in 0—200 cm soil layer (p<0.05), while it was not significantly different from BNP. Compared with CK, NP, MNP, SNP and BNP could significantly increase the soil water content in 0—20 cm soil layer and the water storage in 0—40 cm soil layer and BNP treatment was Significantly higher than treatments of SNP and MNP (p<0.05). In general, the post-effects of biochar on the improvement and maintenance of the soil fertility and the reduction of the risk of nitrate leaching in the profile were more significant than that of straw and organic fertilizer. Therefore, application biochar was a much better way to apply organic material to the anthropogenic soil of dry land area in Guanzhong Area of Shaanxi.