陕西省商洛核桃产区施肥现状评价

Evaluation of current fertilization status in walnut orchards of Shangluo District, Shaanxi Province

【目的】了解商洛核桃园施肥情况,诊断评价商洛核桃产区施肥状况,提出合理施肥量和养分管理建议。【方法】2014、2016两年调查511个果园的生产和养分管理现状,分析187个果园土壤养分状况,结合该区域核桃施肥文献、土壤养分测定结果对施肥现状进行综合评价。【结果】商洛地区核桃园果农户均面积0.28hm^2,产量1245.4 kg/hm^2;2014、2016年果农施用有机肥的养分量占总养分投入量的21.6%和20.0%,未施用有机肥农户分别占总调查农户的34.5%和12.7%;2014年化肥N、P_2O_5、K^2O投入量依次为(189.1±111.1)kg/hm^2、(114.8±61.1)kg/hm^2、(56.9±72.5)kg/hm^2;2016年相应提高为(222.4±115.1)kg/hm^2、(153.7±80.8)kg/hm^2、(77.4±91.1)kg/hm^2。随着施肥量的增加,调查区土壤速效氮、速效磷由2014年的(19.02±3.72)mg/kg、(16.42±4.50)mg/kg显著提高到2016年的(24.78±5.12)mg/kg、(22.16±4.40)mg/kg;2014、2016年调查区化肥氮投入量合理比例分别为15.0%、22.6%,不足比例为74.5%、59.5%;P_2O_5投入合理的比例为39.4%、33.9%,不足比例为44.0%、27.3%,过量比例为16.6%、38.4%;K^2O投入合理的比例为8.3%、13.5%,不足比例高达86.2%、74.5%;有机肥合理比例为38.7%、39.2%,不足比例为61.3%、60.8%。调查区基肥以有机肥为主,追肥以尿素为主;商洛地区核桃园盛果期化肥投入最佳量应为N 220~270 kg/hm^2、P_2O_5 110~140 kg/hm^2、K^2O 150~190 kg/hm^2,有机肥投入氮最佳量应大于77 kg/hm^2。【结论】调查区核桃园应适时追施氮肥,钾肥投入严重不足,磷肥呈现过量化趋势;农户忽视追肥,施肥结构不合理。今后该区域果园养分管理中,应大力改善氮、钾养分比例,合理引导磷肥的科学施用,减少养分损失带来的面源污染;最后还应该重视追肥次数和微量元素投入。

[Objectives] For improving nutrient management, determining the optimum baselines of nutrient input in walnut production, the authors have thoroughly evaluated the fertilization behaviors of producers in Shangluo District, one of the walnut main production areas based on a complete survey and field investigation.[Methods] More than 511 walnut orchards were investigated and clarified in 2014 and 2016, simultaneously soil samples at 0-20 cm depth were collected in 187 of the 511 orchards. The basic data were used to improve the current fertilizer management and to evaluate the soil fertility in Qinba Mountainous area, Shaanxi Province.[Results] The average area of walnut orchard was 0.28 hm2 per farmer and the annual total walnut yield was 1245.4 kg/hm2 in the area. The N, P2O5 and K2O inputs were （189.1 ±111.1） kg/hm2, （114.8 ±61.1） kg/hm2 and （56.9 ±72.5） kg/hm2 respectively in 2014, and （222.4 ±115.1） kg/hm2, （153.7 ±80.8） kg/hm2, （77.4 ±91.1） kg/hm2 in 2016. Most of the orchards were lack of organic fertilizer input. The soil available N, P and K contents increased as the chemical nutrient input. The soil available P was increased significantly from （16.42 ±4.50） mg/kg in 2014 to （22.16 ±4.40） mg/kg in 2016. For the walnut orchard established more than 8 years, the rectified recommended N, P2O5 and K2O input should be （220-270） kg/hm2, （110-140） kg/hm2 and （150-190） kg/hm2 respectively, with the N：P2O5：K2O ratio of 1：0.5：0. 7 and the organic N input 〉 77 kg/hm2. In 2014 and 2016, there were 15.0% and 22.6% of the orchards in which the N input were reasonable, and 74.5% and 59.5% did not input enough; 39.4% and 33.9% of the orchards were reasonable for P2O5 inputs, and 44.0% and 27.3% were not enough, and 16.6% and 38.4% were over applied; there were 8.3% and 13.5% of the orchards whose K2O inputs were proportional, and as high as 86.2% and 74.5% were not enough; there were 38.7% and 39.2% of the orchards whose organic fertilizer inputs were appropriate, and 61.3% and 60.8% were not enough. Demonstration for nutrient management should be strengthened in this district such as for basal fertilizers, adequate organic manure, while for topdressing, supplementary N in the right time.[Conclusions] In general, nitrogen fertilizer should be topdressed in right time in walnut orchards, and potassium fertilizer was heavily inadequate; while phosphorus nutrient was abused recently, and that indicating an environmental risk; compost or manure should be more and wildly used in walnut orchards. Moreover, altering the ammonium bicarbonate into urea or other long-releasing N-fertilizer for basal fertilizer, and more topdressing application as well as some trace nutrients should also be used in the right time.