Existing Versus Added Soil Organic Matter in Relation to Phosphorus Availability on Lateritic Soils
Existing Versus Added Soil Organic Matter in Relation to Phosphorus Availability on Lateritic Soils
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现有土壤有机质与添加土壤有机质与红土土壤磷有效性的关系
DOI：
10.5400/jts.2008.v13i1.23-34
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
F. Yusran
中科院分区：
文献类型：
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作者：
F. Yusran
由于粘土的类型，红土土壤（腐土和氧化土）通常具有高磷酸盐吸附能力，并且铝 (Al) 和铁 (Fe) 氧化物含量高。 添加新鲜有机物（OM）可能有助于这些土壤的管理，通过有机磷（OP）转化释放更多的碳酸氢盐可提取磷（BP），或者通过配体交换解吸磷酸盐的OM添加物的可溶性成分。 然而，尚不清楚 BP 是否仅由添加新的 OM（通过矿化或解吸）产生，还是由土壤中固有的或预先存在的转化产生。 我们认为，去除现有的土壤 OM 并用等量的新 OM 替换它可能有助于解决这个问题，特别是在添加 OM 后的 P 转化方面。 使用西澳大利亚的三种红土土壤（包括具有非常低的固有土壤有机质（SOM）的深层风化层材料），并将三种土壤的子样品燃烧（450°C）以获得有效不含现有有机质的土壤。 土壤的另一个子样本没有燃烧。 两个土壤组均从泥炭、小麦秸秆 (Triticum aestivum L.) 和苜蓿干草 (Medicago sativa L.) 接收相同量的有机碳（OC，来自 80 吨 ha -1 生物量 + 土壤 OM 或等于土壤 OM 的生物量），培养九个月。 由于新的 OM 施用，土壤碳酸氢盐可提取 P 以及不可提取 P（NP，以总磷 (TP)-BP 测量）增加，顺序为苜蓿干草 > 泥炭 > 麦秆。 随着时间的推移，BP 与土壤有机碳 (SOC) 之间的相关性变得更加正相关。 微生物量磷（MBP）与NP含量的增加没有很好的相关性，磷酸酶与BP的增加无关。 总体而言，与现有的 OM 处理相比，新施用的（新的）OM 不仅有助于提高 P 水平。
Lateritic soils (Ultisols and Oxisols) are commonly characterised by high phosphate sorbing capacity due to the type of clay and present high content of aluminium (Al) and iron (Fe) oxides. Addition of fresh organic matter (OM) may contribute to management of these soils by releasing more bicarbonate-extractable phosphorus (BP) through organic phosphorus (OP) transformation, or by the soluble component of OM additions desorbing phosphate by ligand exchange. It is not known, however, whether BP results solely from addition of new OM (by either mineralisation or desorption) or from transformation of inherent or pre-existing in soil. We considered that removing the existing soil OM and replacing it with an equivalent amount of new OM may help to resolve this issue, especially with respect to P transformation after OM additions. Three lateritic soils of Western Australia (including a deep regolith material with very low inherent soil OM (SOM)) were used, and sub-samples of the three soils were combusted (450° C) to obtain soils effectively free from existing OM. A further sub-sample of the soils was not combusted. Both soil groups, receiving the same amount of organic carbon (OC, from 80 ton ha -1 biomass + soil OM or biomass equal to soil OM) from peat, wheat straw ( Triticum aestivum L . ) and lucerne hay ( Medicago sativa L . ), were incubated for nine months. Soil bicarbonate-extractable P as well as non-extractable P (NP, measured as Total-P (TP)-BP) increased due to new OM application in the order lucerne hay>peat>wheat straw. The correlation between BP with soil organic carbon (SOC) became more positive over time. Microbial biomass phosphorus (MBP) was not well correlated with the increase of NP content and phosphatase was not related to the increase in BP. Overall, freshly applied (new) OM not only contributed to the increased level of P compared with the existing OM treatment.