<正>通过对江苏沿海滩涂具代表性的银杏采叶园(A)、银杏果—叶—农复合园(B)、银杏材—农复合园(C)等3种不同银杏与农作物复合系统中植物和土壤养分分布规律及生物循环效率的测定分析,研究了不同复合系统的营养动态特征。结果表明,各模式表层土壤有机质、全氮、速效磷含量(ρ)呈现出ρB>ρA>ρC的特征,而钾素含量是ρA>ρC>ρB,同时表层土壤有机质、全氮、速效磷变异系数都以B模式最大,钾素的分布较均匀。土壤养分的垂直分布基本呈现出随土层加深而逐渐减小的趋势,但各模式各层养分含量的季节变化具不同特征。养分的生物循环率以钾最高,达55.26%,但模式B、C平均养分循环效率分别为45.6%、53.59%,明显高于A。氮素在各模式的总量是ρB>ρC>ρA,磷、钾都为ρA>ρB>ρC。土壤养分总体特征为有机质含量不高,贫氮缺磷,钾素较丰,因而提高豆类间作的强度,加强秸杆还田力度,增施磷肥是维持系统养分平衡的必要措施。

In order to improve the productivity in different agroforestry systems in coast area.The nutrient dynamic characteristic in three types of typical agroforestry model,namely,the model of Ginkgo biloba leaf utilization(A),the model of Ginkgo biloba leaf and fruit utilizationcrop(B) and the model of Ginkgo biloba wood utilizationcrop(C),commonly practiced in the coast area in Jiangsu province,were studied by analysing the budget of nutrient in plant and soil,and their rates of recycling.The results were as follows:Maxium store of nutrients is estimated for each model:646.605 kg/hm2 in B,644.926 kg/hm2 in C and 278.616 kg/hm2 in A.About 86.8% to 99.5% of the annual retention in three models is contributed in annuals by crops.Soil nutrient distribution in each model is also studied.In general,the nutrient content(ρ) of organicmatter(O.M),totalnitrogen(T.N) and availablephosphorous(A.P ) is ρB>ρA>ρC,the content of K is ρA>ρC>ρB.Meanwhile,B has the highest coefficient of variation about O.M,T.N and A.P in top layer soil,which is up to 42.4%,46.5% and 74%,K is distributed evenly.The nutrient distribution in the soil profile shows slowly down from the top layer to bottom layer but each layer has different conditions in different seasons.Potassium has the highest rate of nutrient recycling which is up to55.26%,but the mean rates of nutrient recycling are 45.61% and 53.59% in B and C,which is significantly higher than A.The total store of nitrogen is highest in B and lowest in A,but phosphorus and potassium are ρA>ρB>ρC.The common characters in each model are that O.M,T.N,A.P are poor and availablepotassium(A.K) is rich in the soil.Therefore,it is necessary to strengthen entreecrop combinations and increase the amount of manure and phosphorus for nutrient equilibrium of systems.