陕西省苹果主产区土壤有机质、氮磷钾养分含量与分布特征

【目的】研究陕西省苹果主产区土壤养分状况，为陕西省苹果主产区施肥策略的合理制定及土壤养分管理提供科学依据。【方法】自2012～2016年，在陕西省延安、铜川、渭南、咸阳和宝鸡5个苹果主要生产地区选取典型果园，样点数依次为17208、2634、8589、14723和303个，采集0—40 cm土层土壤样品，测定土壤有机质、碱解氮、有效磷和速效钾含量，并利用现有果园土壤养分分级标准，比较分析各地区土壤养分分布状况。【结果】目前，陕西省苹果主产区土壤有机质、碱解氮、有效磷和速效钾含量平均值分别为11.5 g/kg、57.1 mg/kg、13.0 mg/kg和160.4 mg/kg，较低和低等水平所占比例分别为33.3%、61.8%、85.0% 和50.4%。不同地区土壤养分存在一定差异，从全区来看，基本呈西、南高，东、北低的分布特征，即宝鸡是果园土壤养分含量最高的地区，咸阳、渭南和铜川次之，延安果园土壤养分含量最低。延安地区果园土壤平均有机质含量9.5 g/kg、碱解氮49.4 mg/kg、有效磷9.0 mg/kg和速效钾140.0 mg/kg，处于较低和低等养分水平的果园百分比分别为61.6%、77.7%、99.3%和67.5%。铜川地区果园土壤有机质平均含量为14.2 g/kg，有机质达中等及以上水平果园占88.9%；碱解氮含量均值为62.0 mg/kg，46.4%的果园处于较低和低等水平；有效磷含量均值为13.9 mg/kg，75.3%的果园处于较低和低等水平；速效钾含量均值为181.6 mg/kg，处于中等及以上水平的果园所占比例为67.2%。渭南地区果园土壤有机质含量均值为13.1 g/kg，有机质达中等及以上水平果园占83.2%；碱解氮含量均值为61.6 mg/kg，54.6%的果园处于较低和低等水平；有效磷含量均值为13.7 mg/kg，81.0%的果园处于较低和低等水平；速效钾含量均值为170.1 mg/kg，42.6%的果园处于较低和低等水平。咸阳地区果园土壤有机质含量均值为12.3 g/kg，有机质达中等及以上水平的果园占85.7%；碱解氮含量均值为62.7 mg/kg，49.4%的果园处于较低和低等水平；有效磷含量均值为16.7 mg/kg，74.2%的果园处于较低和低等水平；速效钾含量均值为173.2 mg/kg，处于中等及以上水平果园所占比例为60.9%。宝鸡地区果园土壤有机质含量均值为17.5 g/kg，有机质达中等及以上水平果园占97.4%；碱解氮含量均值为78.3 mg/kg，21.7%的果园在较低和低等水平；有效磷含量均值为23.4 mg/kg，64.9%的果园在中等及以上水平；速效钾含量均值为179.2 mg/kg，处于中等及以上水平果园所占比例为70.0%。【结论】陕西省苹果主产区土壤养分含量总体较低，不同地区苹果园土壤有机质和氮磷钾有效养分含量差异较大，需因地制宜确定合理的施肥方案。

Contents and distribution of soil organic matter and nitrogen,phosphate,potassium in the main apple production regions of Shaanxi Province

Objectives]Soil nutrients status in the main apple production regions of Shaanxi Province was studied to provide a scientific support for formulating a suitable fertilization strategy and soil nutrients management.Methods]From 2012 to 2016, soil samples in 0-40 cm depth were collected from apple orchards in the main production regions located in Yan'an, Tongchuan, Weinan, Xianyang and Baoji cities of Shannxi Province, China, and the numbers of sampling sites were 17208, 2634, 8589, 14723 and 303, respectively. Soil organic matter, available N, available P and K were determined and were further analyzed by classification standards of the soil nutrients status in apple orchards.Results]The mean contents of soil organic matter, available N, P and K were 11.5 g/kg, 57.1 mg/kg, 13.0 mg/kg and 160.4 mg/kg, respectively, which occupied 33.3%, 61.8%, 85.0% and 50.4% of the orchards in the low and lower levels. The soil nutrient contents were different in different regions, basically higher in the west and south and lower in the east and north, and with the highest in Baoji City and lowest in Yan'an City. In Yan'an, the average soil organic matter, available N, available P and K contents were 9.5 g/kg, 49.4 mg/kg, 9.0 mg/kg and 140.0 mg/kg, respectively, their proportion in the low and lower levels accounted for 61.6%, 77.7%, 99.3%, 67.5%, respectively. In Tongchuan City, the average soil organic matter, available N, P and K contents were 14.2 g/kg, 62.0 mg/kg, 13.9 mg/kg and 181.6 mg/kg, and the percentages of the orchards in the medium level and above was 88.9%, 53.6%, 24.7% and 67.2%, respectively. Soil organic matter, available N, available P and K in Weinan orchards were 13.1 g/kg, 61.6 mg/kg, 13.7 mg/kg and 170.1 mg/kg on average, and those in Xianyang were 12.3 g/kg, 62.7 mg/kg, 16.7 mg/kg and 173.2 mg/kg. In Weinan, the soil organic matter content was in the medium level and above in 83.2% of the orchards, while that in Xianyang was 85.7%. In terms of soil available N, 54.6% of the orchards of Weinan and 49.4% of the orchards of Xianyang were in the low and lower levels. What's more, the percentages of soil available P in the low level and below in Tongchuan and Xianyang were higher than 70%. For the soil available K, 57.4% of the orchards in Weinan and 60.9% of the orchards in Xianyang were in middle and upper level. The average contents of soil organic matter, available P and K of Baoji were 17.5 g/kg, 23.4 mg/kg and 179.2 mg/kg respectively, which made up 97.4%, 64.9% and 70.0% of the orchards separately in the medium and above levels. Meanwhile the mean available N was 78.3 mg/kg, and only 21.7% of the orchards were in the low and lower levels.Conclusions]Soil nutrients in the main apple production regions of Shaanxi Province were relatively low, and varied among the apple orchards in different areas, so specific fertilization plans should be made according to local soil nutrient conditions.