增進土壤生產力策略下之磷循環探討

Studies on the Phosphorus Cycling in Soils under the Strategy of Improving Soil Productivity

陳仁炫(Jen-Hshuan Chen) ； 吳振記(Jenn-Jih Wu)

《土壤與環境》 1卷2期 (1998/06) Pp. 99-114

https://doi.org/10.30058/SE.199806.0002

摘要

有機質的施用及水旱輪作制度為改善本省土壤生產力的重要對策，唯土壤中原本平衡的磷循環將因而遭受劇烈的改變，因而影響磷在土壞中的行為和磷有效性，此即為本研究的主要探討的目的所在。設在台灣省農業試驗所之試驗田經分別添加不同分解程度之有機質肥料〔豬糞堆肥、豆科綠肥（田菁，或埃及三葉草）和泥炭〕及化學肥料，於水旱輪作制度（玉米－水稻－玉米）下，探討有機質肥料的施用配合在水旱輪作制度下，對土壤磷行為及磷有效性的影響，並與傳統化學肥料的處理比較之。結果顯示，三種供試有機質肥料的添加可以降低土壤磷吸附能力，其中以磷含量較高且較易分解的豬糞堆肥的效果最顯著。一般而言，三種供試有機質肥料均可提昇土壤全磷，有機磷，溶液磷，不穩定（Labile）磷，活性（Active）磷，及穩定性（Stable）磷量，以及玉米和水稻的磷吸收量，唯除豬糞堆肥外，綠肥和泥炭的增進效應與化學肥料差異不大。水田與旱田狀況對磷行為的影響效應不一；在水田狀況下，因處於還原狀態，有機質分解速率較慢及土壤對磷吸附能力的增強，因而降低土壞溶液磷，有機磷，及不穩定磷的含量，唯可增加活性磷，及穩定性之鐵，鋁結合性磷的含量；而在旱田狀況下，則呈相反的趨勢。由化學肥料及有機質肥料施用後，土壤中各型態磷的相對分配（distribution）百分率可知，有機質肥料的添加有助於不穩定磷比率的提昇及固定性磷比率的下降。在經過玉米－水稻－玉米的輪作後，三種供試有機質肥料的添加，對土壤磷有效性真有增進的效應，而增進的程度則決定於有機質肥料的分解速率和其含磷量，其中以磷含量較高的豬糞堆肥的效果最佳。

關鍵字

磷循環 ； 有機肥料 ； 輪作 ； 土壤生產力

並列摘要

Organic fertilizers application and rice-corn rotation are two important practices to improve soil productivity, however, the balanced P cycle and the behavior of P in soils will be altered and needed to be investigated.The experiment was conducted in the field of the Taiwan Agriculture Research Institute. The experimental plots were applied with three different kinds of organic fertilizers (Swine compost, green manure, and peat), and cultivated under corn-rice-corn rotation. The behavior and availability of P in each treatment was investigated.Results showed that all organic fertilizers used in this experiments would reduce the P adsorption capacity, and increase the concentrations of Total P, Organic P, Solution P, Labile P, Active P and Stable P of the soils. In general, the effects were found higher in the fields with swine compost application, however, there was no significant difference in the effects among other treatments. In addition, the behavior of P in the rice field was found to be different with that of upland soil. Generally speaking, the P adsorption capacity, the concentrations of Active P, ( AI-P+Fe-P ) were reduced and the concentrations of Solution P, Organic P , Stable P were increased in the rice field due to slower decomposition rate of organic matter under the reduced condition, however, the contrary tendency was found in the condition of upland soil.It is concluded that the application of organic fertilizers did increase the percentage of Labile P and reduce the percentage of Stable P. Results also showed that the application of three organic fertilizers used in this experiment did improve the availability of P in the soils, and the effects was determined by the rate of decomposition and the P content of the organic fertilizers.

並列關鍵字

P cycle ； organic fertilizer ； rotation ； soil productivity