长期轮作施肥棕壤磷素对磷盈亏的响应

Response of soil phosphorus to P balance under long-term rotation and fertilization in brown soil

【目的】研究长期轮作施肥条件下棕壤磷素盈亏状况及其与土壤磷素的关系,为棕壤科学施用磷肥提供理论依据。【方法】玉米-玉米-大豆轮作长期施肥定位试验始于1979年,设不施磷肥(CK)、施氮磷肥(NP)、施氮磷钾肥(NPK)、低量有机肥配施氮磷肥(M1NP)、低量有机肥配施氮磷钾肥(M1NPK)、高量有机肥配施氮磷肥(M2NP)和高量有机肥配施氮磷钾肥(M2NPK),共7个处理。测定1979—2015年不同施肥处理土壤OlsenP和全磷含量,计算了土壤磷的盈亏状况,分析了全磷和有效磷与累积磷盈亏之间的关系。【结果】CK处理土壤磷素水平处于亏缺状态,平均土壤年亏缺磷为9.0 kg/hm^2;磷肥处理(NP和NPK)和有机肥配施磷肥处理(M1NP、M1NPK、M2NP和M2NPK)土壤磷素均处于盈余状态,且M2NP和M2NPK盈余较多。所有施肥处理的有效磷增量与土壤累积磷盈亏均呈极显著相关关系(P <0.01),CK处理土壤每亏缺磷100 kg/hm^2,Olsen-P下降0.84 mg/kg;磷肥及有机肥磷肥配施处理每盈余磷100 kg/hm^2,Olsen-P上升范围为1.97～7.23 mg/kg。除CK外,所有施肥处理土壤全磷增量与累积磷盈亏均呈极显著相关关系(P <0.01)。土壤每盈余磷素100 kg/hm^2,各施肥处理全磷增加范围为0.03～0.04 g/kg。【结论】磷肥投入是影响棕壤全磷和有效磷水平的关键因素。长期轮作不施磷肥,棕壤磷素亏缺;长期轮作施用化学磷肥(年均投入P2O5 70 kg/hm^2)和磷肥有机肥配施(年均投入P2O5 126～182 kg/hm^2),棕壤磷素有盈余,增施高量有机肥的盈余量高于增施低量有机肥,高于单施磷肥。磷肥配施有机肥提升棕壤有效磷的速率高于单施磷肥。

[ Objectives ] The study aimed to explore characteristics of P balance and response of soil phosphorus to P balance under a long-term rotation and fertilization, in attempt to provide theoretical bases for scientific application of phosphorus fertilizer in brown soil. [ Methods ] The long-term fertilization and maize- maize-soybean rotation experiment in brown soil was started since 1979, in Shenyang, Liaoning Province. The selected seven treatments included CI（ （without applying P fertilizer）, NP, NPI（, low manure plus NP （M1NP） and NPK （M1NPK）, and high manure plus NP （M2NP） and NPK （M2NPK）, In 2015, soil samples were collected to analysis the contents of Olsen-P and total P, and the relationships between soil Olsen-P, total P and P balance were studied. [ Results ] The soil P was in deficit for the CK, with annual deficit of soil P 9.0 kg/hm2. While the soil P in the phosphorus fertilizer treatments （NP and NPK） and chemical P plus manure applied （M1NP, M1NPK, M2NP and M2NPK） remained in surplus status, and M2NP and M2NPK accumulated higher soil P than others. The Olsen-P was highly and significantly correlated with P balance （P 〈 0.01）. For every mean deficit of P 100kg/hm2 in brown soil, Olsen-P of the CK would be correspondingly decreased by 0.84 mg/kg. For every mean surplus of P 100 kg/hm2 in the soil, Olsen P of the treatments would be correspondingly increased by 1.97-7.23 mg/kg. There was significant positive correlation between total P and P balance under the long-term different fertilization except for the CK treatment （P 〈 0.01）. For every mean surplus of P 100 kg/hm2 in the soil, total P of the chemical P fertilizer, and chemical P fertilizer plus manure would be correspondingly increased by 0.03-0.04 g/kg. [ Conclusions ] Input of phosphorus fertilizers affects soil total P and Olsen-P significantly. The P in brown soil is remained deficit under the long-term rotation and without P input. The P is remained surplus with the annual input of chemical P205 70 kg/hm2, and more P is surplus with the total input of chemical plus annual P2O5 126-182 kg/hm：. The combination of chemical phosphorus fertilizer and manure performs better in the increase rate of Olsen-P content than chemical P along does in brown soil.