有机物料对红壤几种形态碳氮及酸度的影响

摘要

[目的]为合理施用有机物料调节土壤碳.氮以阻控土壤酸化,对有机物料施入红壤后土壤几种形态碳、氮及酸度变化进行了研究,并分析了相关关系.[方法]通过室内恒温培养试验研究了添加3种有机物料(稻草、紫云英和猪粪)后红壤中铵态氮(NH_4~+-N),硝态氮(NO_3~--N)、可溶性有机氮(WSON)、可溶性有机碳(WSOC)、微生物量碳(SMBC)、微生物量氮(SMBN)和土壤pH动态变化.[结果]与对照相比,添加有机物料均提高了土壤WSOC、SMBC和pH,且有机物料添加量越大,增幅越大.猪粪处理中土壤NH_4~+-N、NO_3~--N和WSON含量显著增加;而稻草和紫云英处理中土壤NO_3~--N和WSON含量下降,NH_4~+-N含量没有显著变化.施用稻草和紫云英7～14 d左右,土壤pH达到最大值,随后逐渐下降趋于平衡;而施用猪粪后土壤pH立即升高,随后逐渐下降趋于平衡.84 d培养试验结束时,与对照相比,猪粪、稻草和紫云荚处理的土壤pH分别平均增加了0.26、0.23和0.09.几种有机物料处理中,土壤pH与SMBC和WSOC均存在显著的正相关关系.稻草和紫云英处理中,土壤pH与WSON和NO_3~--N之间存在显著负相关性,而猪粪处理中pH与WSON和NO_3~--N相关性不显著.[结论]施用有机物料能够显著提高红壤WSOC、SMBC和pH,其中酸度改良效果猪粪>稻草>紫云英;土壤碳、氮动态与土壤pH变化紧密相关,且相关性与有机物料的性质有关.%[Objective] In order to prevent soil acidification by regulating soil carbon and nitrogen, the change of several forms of soil carbon, nitrogen and soil pH, and the con'relations among them were studied after the application of several organic materials. [Method] Incubation experiments were conducted at the temperature of (25±1)℃. The dynamics of NH_4~+-N, NO_3~--N, water-extracted soluble organic carbon (WSOC), water-extracted soluble organic nitrogen (WSON), soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN) and pH after application of several organic materials (rice straw, Chinese milk vetch and pig manure) were measured. [Result] Compared with the control treatment, soil pH, SMBC and WSOC increased after application of organic materials, and increased with the application rates. ARer application of pig manure, NH_4~+-N, NO_3~--N and WSON in soil increased significantly. WSON and NO_3~--N in soil decreased after application of rice straw and Chinese milk vetch, and decreased with the application rates, while application of rice straw and Chinese milk vetch had no significant effect on NH_4~+-N. Soil pH reached its maximum between the 7th and 14th day of incubation after application of rice straw and Chinese milk vetch, while increased immediately after application of pig manure, decreased thereafter, and tended to be stable. Compared with the control treatment, soil pH increased by 0.26, 0.23 and 0.09 on average in the treatments of pig manure, rice straw and Chinese milk vetch at the end of incubation for 84 d. Soil pH was positively correlated with SMBC and WSOC in the treatments of organic materials, while soil pH was negatively correlated with WSON and NO_3~--N after application of rice straw and Chinese milk vetch, and insignificantly correlated with WSON and NO_3~--N in the treatments of pig manure. [Conclusion] Application of several organic materials could significantly increase WSOC, SMBC and pH of the soil, with the pH increasing is in the order of pig manure > rice straw > Chinese milk vetch. Dynamics of soil carbon and nitrogen are important in relation to the change of soil acidity after application of organic materials, and the relativity is related to the properties of organic materials.