有机物料对喀斯特地区石灰土有效N、Fe、Zn含量的影响

为研究不同有机物料对喀斯特石灰土元素有效性的影响，采用40 d的室内培养实验，比较了单独添加不同比例（1%、3%、5%）的生物质炭、鸡粪肥、羊粪肥对喀斯特石灰土有效N、Fe、Zn含量的影响。结果表明：添加生物质炭提高了喀斯特石灰土的pH值，而添加鸡粪肥和羊粪肥降低了喀斯特石灰土的pH值；添加3种有机物料均增加了喀斯特石灰土的有机质含量，大小关系为：生物质炭 > 鸡粪肥 > 羊粪肥，但添加鸡粪肥和羊粪肥土壤有机质的化学活性和微生物活性更高。受pH、有机质活性、碳氮比等因素的影响，添加鸡粪肥和羊粪肥能增加土壤有效N含量，但两种有机肥对土壤有效N的提高效果相差不大，而添加生物质炭反而降低了土壤有效N的含量；3种有机物料均能提高土壤的有效Fe和有效Zn含量，其中鸡粪肥效果最佳，其次为羊粪肥和生物质炭。当3种有机物料的添加比例为5%时，生物质炭处理土壤的有效N、Fe、Zn含量分别是对照处理的0.92、1.13、1.21倍；鸡粪肥处理土壤的有效N、Fe、Zn含量分别是对照处理的1.22、1.63和3.39倍；羊粪肥处理土壤的有效N、Fe、Zn含量分别是对照处理的1.27、1.34和2.59倍。所以，相对于生物质炭，有机粪肥对喀斯特地区的石灰土有更好的改良效果。

Effect of organic materials on the content of available N, Fe and Zn in karst calcareous soil

The effect of organic materials on the availability of nutrient elements in karst calcareous soil was investigated by a 40-day soil incubation experiment. Biochar, chicken manure and sheep manure were incorporated separately with 1%, 3%, and 5% amount for comparing their impact on soil available N, Fe, and Zn. Our results indicated that chicken manure and sheep manure amendment decreased soil pH, while the opposite was true for biochar. Soil organic matter was enhanced by addition of these organic materials with the order:biochar > chicken manure > sheep manure, but the chemical and microbial activity of organic matter in soil ascribed to biochar application was the lowest. Due to pH, organic matter activity, C/N ratio, and other factors, there was no significant difference between the increment of available N in soil by chicken manure and sheep manure addition with the same amount. Whereas, 5% biochar amendment reduced soil available N significantly. The increment of available Fe and available Zn in soil was optimum by the application of chicken manure, followed by sheep manure and biochar. With 5% addition amount, the contents of available N, available Fe, and available Zn in the soil with biochar were 0.92, 1.13 and 1.21 times as much as that in control respectively, 1.22, 1.63 and 3.39 times respectively for chicken manure treatment, and 1.27, 1.34 and 2.59 times respectively for sheep manure treatment. Hence, compared with biochar, the additions of organic manure were a better choice for the improvement of calcareous soil in karst areas.