长期轮作施肥棕壤磷素对磷盈亏的响应

【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Olsen-P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/hm2；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/hm2，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/hm2) 和磷肥有机肥配施 (年均投入P₂O₅ 126～182 kg/hm2)，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。

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

【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 CK (without applying P fertilizer), NP, NPK, 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 100 kg/hm 2 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/hm 2 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 P₂O₅ 70 kg/hm2, and more P is surplus with the total input of chemical plus annual P₂O₅ 126?182 kg/hm2. 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.