广西桑园土壤养分状况及丰缺分级

【目的】对广西桑园土壤养分含量及丰缺程度进行研究，以全面掌握广西桑园土壤养分状况，为提高肥料利用率和单位面积产桑量、促进广西桑蚕业可持续发展提供依据。【方法】从广西桑树主要种植区采集有代表性的桑园耕层土壤样品，按《土壤农业化学分析方法》分析其养分含量状况，并参照前人研究成果进行丰缺分级。【结果】广西桑园土壤pH值大多在6．5以下，有机质平均含量为2．33％；速效氮、磷、钾平均含量分别为98、20．7和82mg／kg，缺乏比例分别为51．52％、53．03％、74．24％；有效钙、镁平均含量分别为3896、137．4mg／kg，其中有效钙过量比例达31．82％，有效镁缺乏比例达68．18％；有效铁、锰、铜、锌平均含量分别为32．40、32．20、1．26和1．35mg／kg。【结论】广西桑园土壤肥力总体水平不高，普遍缺乏速效氮、磷、钾、镁，其他养分也存在一定程度的缺乏或过量现象，不同种植区、同一种植区不同桑园之间土壤养分丰缺程度差异较大。实际生产中应做到因地制宜合理施肥，尤其要重视氮、磷、钾、镁肥的施用，以实现桑叶高产、优质、高效生产。

Nutritional status of mulberry plantation soils and its excess and deficiency grading

Objective]The present study is an attempt to study the soil nutrient status and its excess or deficiency in mulberry orchards of Guangxi in order to increase fertilizer efficiency and mulberry yield per unit area and provide references for the sustainable development of Guangxi mulberry industry. Method]By using stainless steel knife, top soil samples were collected from representative orchards of main mulberry-planting areas of Guangxi. The nutrient contents in soil samples were analyzed according to Agriculture Chemical Analysis Methods of Soil and their excess or deficiency in soil was classified in accordance to the previous researches. Result]Most of the mulberry soil samples showed an average pH value of 6.5 and the average organic matter content was 2.33%. The average available N, P and K contents in soils were found to be 98, 20.7 and 82 mg/kg, respectively. Data revealed that 51.52% of mulberry orchards were deficient in available N, 53.03% deficient in available P and 74.24% in available K. The average available Ca and Mg contents were 3896 and 137.4 mg/kg, respectively. Out of all the samples, 31.82% were found to have excess Ca and 68.18% were found deficient in Mg. The average available Fe, Mn, Cu and Zn contents were detected as 32.40, 32.20, 1.26 and 1.35 mg/kg. Conclusion] The overall soil fertility status of Guangxi mulberry orchards was not high and they were generally lack available N, P, K and Mg. Besides, other nutrients were also deficient or excess to some extent. The degree of deficiency and excess of nutrient contents in soils varied greatly among different mulberry-planting areas and different mulberry orchards in the same mulberry-planting area. In order to achieve highly efficient production of mulberry with high yield and good quality, fertilization should be rational and fit the local conditions and the fertilization of N, P, K and Mg fertilizers should be paid more attention.