黄土高原典型苹果园地深层土壤氮磷钾养分含量与分布特征

测定了黄土高原6个苹果生产基地县21个果园0-300 cm土层土壤氮磷钾养分含量,分析和比较了不同县区果园土壤氮磷钾养分含量差异及其土壤剖面分布特征.结果表明:(1)6个试点21个果园0-300 cm土层土壤氮磷钾全量分别为0.54、0.53和6.79 g/kg,土壤氮磷钾速效量分别为102.66、7.95和102.75 mg/kg,不同苹果产区果园土壤氮磷钾全量和速效量差异明显,除全氮含量外均以中部高塬黑垆土苹果产区氮磷钾全量和速效量最高,而以北部丘陵黄绵土苹果产区最低.(2)不同苹果产区果园0-300 cm土层土壤氮磷钾全量和速效量剖面分布特征类似,除全钾和速效氮外其余养分全量和速效量剖面分布具有明显“表层积聚效应”.(3)6个试点果园土壤全氮含量呈现缺或较缺,土壤速效氮含量丰富或中等或缺,土壤速效磷含量中等或缺,土壤速效钾含量丰富或较丰富,应该增施有机肥,氮磷肥配合,适当增施钾肥.

Distribution of soil NPK nutrient content in deep soil profile of typical apple orchards on the Loess Plateau

0-300 cm soil nitrogen, phosphorous and potassium contents of 21 apple orchards of 6 apple production counties of the Loess Plateau as apple production bases were measured and compared, and accordingly their nitrogen, phosphorous and potassium profile characteristics were examined. It was revealed that (1) Of the orchards of the Counties, the average nitrogen, phosphorous and potassium contents were 0.54 g/kg, 0.53 g/kg and 6.79 g/kg, the average available nitrogen, phosphorous and potassium contents were 102.66 mg/kg, 7.95 mg/kg and 102.75 mg/kg, respectively. Among the orchards of the counties, the nitrogen, phosphorous and potassium contents significantly differed. The phosphorus totals of the apple orchards of Fengxiang County were not at an adequate level. The phosphorus and potassium totals of the apple orchards of Baishui County were not at an adequate level. The nitrogen, phosphorous and potassium contents of the apple orchards of Changwu County and Xifeng District were at an adequate or high level. The nitrogen, phosphorous and potassium contents of the apple orchards of Yan'an were at a deficient level. The nitrogen totals of the apple orchards of Jingning County were at a deficient level. Among all the soil nutrient parameters, the nitrogen, phosphorous and potassium totals of the apple orchards varied less than their available nitrogen, phosphorous and potassium contents. The nitrogen, phosphorous and potassium contents of the orchards lying in Heilu soil covered central Loess Plateau (e.g. Changwu County and Xifeng District) were the highest, and the nitrogen, phosphorous and potassium contents of the orchards lying in loess covered northern hilly Loess Plateau (e.g. Yan'an and Jingning County) were the lowest. (2) The soil nutrient parameters of the orchards of the counties presented similar profile distributions. All the nutrient totals and available nutrient contents but the potassium totals and available nitrogen contents of all the orchards of the counties presented the obvious effect of "surface enriching". The nitrogen, phosphorous and potassium contents of the orchards were higher in top soil than in soil beneath topsoil. (3) Of the orchards of the apple production counties, the nitrogen total stood at a deficient or slightly deficient level, the available nitrogen contents stood at an adequate, moderate or deficient level, the available phosphorus contents were at a moderate or deficient level, and the available potassium contents were at a sufficient level or an adequate level. The soil phosphorus contents of the orchards lying in the southern part of the Plateau with terrace lands and brown soil (e.g. Fengxiang County and Baishui County) and so in this part, the orchards should increase Phosphate fertilizer rates and fertilization depths. The orchards standing in the highland and Heilu soil-covered central part of the Plateau (e.g. Changwu County and Xifeng District) suffered soil nitrogen deficiency and thus in the part, the orchards should increased the uses of organic and nitrogen, phosphorous and potassium fertilizers in a formulated manner. The orchards located in the hilly loess part of the loess Plateau (e.g. Yan'an and Jingning County) suffered phosphorous and potassium deficiencies. It was proposed that the orchards concerned greatly increase organic fertilizer uses, properly increased potassium fertilizer uses, and apply Nitrogen and phosphorous fertilizers in a formulated manner.