长期施肥下红壤性水稻土有效磷的演变特征及对磷平衡的响应

【目的】分析长期不同施肥下土壤有效磷含量、全磷含量、土壤磷素盈亏和磷素活化效率（PAC）的动态变化，探讨不同施肥下水稻土磷素演变特征及与磷平衡的响应关系。【方法】基于1982年开始的红壤性水稻土长期不同施肥定位试验，试验包括不施肥（CK）、有机肥（牛粪，M）、氮磷钾肥（NPK）、氮磷钾肥＋有机肥（NPKM）、氮磷肥＋有机肥（NPM）、氮钾肥＋有机肥（NKM）和磷钾肥＋有机肥（PKM）共7个处理。【结果】经过30年不同施肥，土壤有效磷含量均呈上升趋势。M、NKM、NPK、NPM、NPKM和PKM处理土壤有效磷含量变化速率分别为0.18、0.20、0.83、1.35、1.46和1.62 mg·kg^-1·a^-1。M、NPK、PKM、NPM和NPKM处理土壤全磷增加速率分别约为4.3、15.4、16.0、18.3和22.9 mg·kg^-1·a^-1。所有施肥处理，土壤中磷素均有盈余，磷素盈余量与土壤有效磷增加量呈显著正相关关系（P＜0.05），土壤中每盈余100 kg P·hm^-2，M、NKM、NPM、NPKM、PKM和NPK6个处理的土壤有效磷含量分别增加0.4、0.7、1.9、2.1、2.2和3.2 mg·kg^-1。在土壤中磷素盈余量接近的情况下，单施化肥（NPK）的PAC显著高于单施有机肥（M）处理（P＜0.05）。【结论】化学磷肥和有机肥配施相比单施化肥或有机肥能够显著提高红壤性水稻土土壤有效磷、全磷含量和磷素活化效率。

Evolution Characteristics of Soil Available Phosphorus and Its Response to Soil Phosphorus Balance in Paddy Soil Derived from Red Earth Under Long-Term Fertilization

【Objective】 In order to reveal the impact of various fertilization treatments on the characteristics of paddy soil phosphorus (P) evolution, and its response to soil P balance. We analyzed the annual variation of soil available P content, total P content, soil P balance, and phosphorus activation coefficient (PAC). 【Method】 This study was based on a long-term different fertilization experiment of paddy soil in subtropical China that was established in 1982. The different fertilization treatments included non-fertilization (CK), cattle manure (M), chemical nitrogen (N), P and potassium (K) fertilizer (NPK), NPK with M (NPKM), N and P fertilizer with M (NPM), N and K fertilizer with M (NKM), and P and K fertilizer with M (PKM). The annual variation characteristics of soil available P content, total P content, soil P balance, and PAC from 1982 to 2012 were analyzed. 【Result】 Soil available P content improved efficiently through fertilizer application. The change rate of soil available P content of M, NKM, NPK, NPM, NPKM, and PKM was 0.18, 0.20, 0.83, 1.35, 1.46, and 1.62 mg·kg^-1·a^-1, respectively. The soil total P content was on the decline under non-fertilization. The change rate of the soil total P content of M, NPK, PKM, NPM, and NPKM was 4.3, 15.4, 16.0, 18.3, and 22.9 mg·kg^-1·a^-1, respectively. All the fertilizer treatments had a P surplus no matter whether applying chemical fertilizer or cattle manure. The P apparent balance was significantly correlated with the Olsen-P increment (P＜0.05). With an average surplus of 100 kg P·hm^-2, the soil Olsen-P increased by 0.4, 0.7, 1.9, 2.1, 2.2, and 3.2 mg·kg^-1, in the M, NKM, NPM, NPKM, PKM, and NPK treatments, respectively. The PAC of NPK was significantly higher than M and NKM (P<0.05), while there was no significant difference in the soil P surplus amount among these treatments. 【Conclusion】Applying chemical P fertilizer plus cattle manure can significantly improve the soil available P, total P content, and PAC, compared with the treatments that applied chemical fertilizer or cattle manure alone.