ABSTRACT

Phosphorus availability and acid pH are major limiting factors for grass and crop production in the Andisols of Southern Chile. Sustainable management requires both the efficient use of fertilizers and the recycling of agricultural waste. The aim of this study was to investigate the effect of citrus waste, alone or in combination with beef cattle manure (CM), on phosphorus availability. Controlled laboratory incubations were carried out for up to six weeks. Lemon (L) and mandarin (M) fruit wastes were added to an Andisol, amended or not with dried CM. Fruit parts (Peel, Juice or whole fruit), and for whole fruit the size of the fruit pieces added to soil, were compared. Water-extractable (WE) P, phosphatase activity (P-ase), and pH were monitored. In general, the size and distribution of the citrus fruit wastes gave similar trends in WE-P, P-ase, and pH. Lemon induced larger effects on WE-P and pH than did mandarin. CM caused sustained soil alkalization, increased soil WE-P and P-ase. Citrus addition produced a short-lived acidification followed by net alkalization and immediate increases in WE-P and P-ase. The combined amendment with citrus wastes enhanced the positive effect of CM on soil WE-P and alkalization, with only a small effect on P-ase. These findings indicate that citrus wastes would intensify the beneficial effects of CM amendment on soil P availability and additionally the liming effect on acid soils.

摘要

磷的有效性和酸性 pH 值是智利南部安迪索地区草和作物生产的主要限制因素。可持续管理既需要高效使用化肥，也需​​要回收农业废弃物。本研究的目的是调查柑橘废物单独或与肉牛粪便 (CM) 结合对磷的有效性的影响。受控实验室孵化进行了长达六周。将柠檬 (L) 和柑橘 (M) 水果废料添加到 Andisol 中，无论是否用干燥的 CM 进行修正。比较水果部分（果皮、果汁或整个水果）以及加入土壤中的水果块的大小。水可萃取 (WE) P, 磷酸酶活性 ( P-ase)，并监测 pH 值。一般来说，柑橘类水果废弃物的大小和分布在 WE-P、P - ase 和 pH 值方面具有相似的趋势。柠檬对 WE-P 和 pH 的影响比普通话大。CM 导致土壤持续碱化，增加土壤 WE-P 和P - ase。添加柑橘会产生短暂的酸化，然后是净碱化和 WE-P 和P - ase 的立即增加。柑橘废弃物联合改良剂增强了CM对土壤WE-P和碱化的积极作用，对P- ase的影响很小。这些发现表明柑橘类废弃物会加强 CM 改良剂对土壤磷有效性的有益作用，以及对酸性土壤的石灰作用。