黄河三角洲地区不同种植模式下人造白蜡林的土壤养分特征研究

为探索黄河三角洲地区白蜡人造林种植模式,提高该地区白蜡人造林管理水平,以5年生白蜡为试验材料,设置不同种植密度、林间套种不同作物等多个处理,并对不同处理种植土壤进行分层取样,分析土壤养分差异。结果如下：（1）随着土层深度增加,土壤中的有机质、碱解氮、速效磷、有效钾含量减少;（2）种植密度会影响土壤养分含量,各土层中的碱解氮以株行距1 m×1 m含量最高,速效磷以株行距为3 m×3 m含量最高;（3）套种作物能改变白蜡种植土壤养分,套种南瓜、地瓜区域的碱解氮含量较未套种区域分别下降了25.85%、19.94%,套种大豆、苜蓿区域的碱解氮含量较未套种区域分别上升4.52%、2.8%;套种南瓜、大豆、地瓜、苜蓿区域的有机质含量较未套种区域分别下降11.54%、6.82%、17.94%、3.25%;（4）同树龄的白蜡规格越大,土壤中速效磷的含量越多,碱解氮、有效钾、有机质含量基本呈递减趋势。本研究对黄河三角洲地区白蜡人造林的种植模式提供了技术支持和指导。

Soil Nutrient Characteristics of Fraxinus chinensis Plantation in Yellow River Delta Under Different Planting Patterns

To explore the planting model of Fraxinus chinensis plantation in the Yellow River Delta and improve the management level, 5-year-old Fraxinus chinensis was used as material, and the treatments were set up, including different planting densities and different intercropping crops. The stratified samplings in different planting soils were taken for the difference analysis. The results were as follows: (1) with the increase of soil depth, the contents of organic matter, alkali nitrogen, available phosphorus and available potassium in soil decreased gradually; (2) planting density had great influence on the soil nutrient contents, the highest alkali nitrogen content in each soil layer was observed in the planting spacing of 1 m×1 m, however the highest available phosphorus content was obtained in the planting spacing of 3 m×3 m; (3) intercropping could alter the soil nutrients in a Fraxinus chinensis plantation, in comparison with un-planted areas, the contents of alkaline nitrogen in the areas of intercropping pumpkin and sweet potato decreased by 25.85% and 19.94%, and increased by 4.52% and 2.8% respectively in the areas of intercropping soybean and alfalfa; the organic matter contents of intercropping pumpkin, soybean, sweet potato and alfalfa decreased by 11.54%, 6.82%, 17.94% and 3.25%, respectively; (4) the larger the specification of Fraxinus chinensis with the same age, the more the available phosphorus content in the soil, whereas the contents of alkali nitrogen, available potassium and organic matter presented a decreasing trend. This study provides technical support and guidance for the planting patterns of Fraxinus chinensis plantations in the Yellow River Delta.