Based on long-time location experiments, the changing condition of exchangeable Ca in soil profiles of different cropping systems under the condition of 22 years' continuous application of NP chemical fertilizer in the Loess Plateau was studied. The results show that the content of exchangeable Ca is high because of research area was calcareous soil. The eluviation and accumulation of exchangeable Ca occur in soil profiles. The peak is at 140 - 180 cm soil depth with the values of 13 180, 12 597, 11 960, 11 778, 11 590 mg/kg and 11 290 mg/kg under the maize-wheat(2a) + millet rotation, pea- wheat(2a) + millet rotation, sainfoin - wheat(2a) rotation, pea - wheat(2a) + maize rotation, wheat succession and wheat(2a) + millet- maize rotation systems, respectively. The accumulation of exchangeable Ca in soil profiles (0 - 200 cm) under the maize - wheat(2a) + rniiiet rolation is 269.67 l/hm2, which is higher than those of olher treatments. However the accumulation of exchangeable Ca in soil profiles (0 - 200 cm) under the wheat succession is 218.78 t/hm2, which is lower than those of other treatments. The results suggest dial different crops and cropping systems have effects on exchangeable Ca distribution in soil profile. The results also indicate that the total accumulation amount of exchangeable Ca in soil profiles (0 ~ 200 cm) are not significantly different in various cropping systems.%以22年定位试验为基础,研究了长期施用氮磷化肥(NP)下不同种植体系土壤交换性钙在剖面上分布与累积状况.结果表明:研究区为石灰性土壤,交换性钙含量较高；不同种植体系交换性钙在土壤剖面上发生淋溶累积现象,在140～180cm土层产生累积蜂,累积峰值:玉米-小麦(2a)+糜子轮作为13180mg/kg、豌豆-小麦(2a)+糜子轮作为12597mg/kg、红豆草-小麦(2a)轮作为11960mg/kg、豌豆-小麦(2a)+玉米轮为11778mg/kg、小麦连作为11590mg/kg、小麦(2a)+糜子-玉米轮作为11290mg/kg;不同种植体系0～200cm土壤交换性钙的总累积量以玉米-小麦(2a)+糜子轮作最高,为269.67t/hm2,小麦莲作最低,为218.78t/hm2.不同种植体系交换性钙在土壤剖面上分布不同主要是由作物和种植方式不同引起,不同种植体系0～200cm土壤交换性钙的总累积量差异不显著.
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