集约化果园钾肥施用现状及钾素表观平衡状况研究——以福建省平和县琯溪蜜柚为例

Current potassium fertilizer management practice and potassium apparent balance status of intensive orchards——A case study in Guanxi honey pomelo in Pinghe County,Fujian Province

【目的】明确福建省平和县集约化蜜柚果园钾肥施用现状及钾素表观平衡状况,为指导蜜柚园科学施用钾肥提供参考。【方法】2016—2018年,以农户调研和土壤调查的方式,获取福建省平和县363个琯溪蜜柚果园的钾肥施用现状数据及29个蜜柚园的土壤剖面样品,对蜜柚园钾肥施用现状、钾素表观平衡状况及土壤钾素状况进行分析。【结果】福建省平和县蜜柚园钾肥(以K2O计,下同)平均施用量为955 kg/ha,96%果农钾肥年投入量超过400 kg/ha,复合肥是主要钾素来源。相关性分析结果表明,钾肥投入量与蜜柚产量无明显相关性,与钾素表观平衡具有极显著的线性相关(P<0.01),全县钾素表观平衡高达874 kg/ha,各乡(镇)间钾肥投入量与土壤钾素平衡状况变异较大。73%蜜柚果园土壤速效钾含量超过120 mg/kg,处于过量水平。0～20、20～40和40～60 cm土层的土壤速效钾含量随土层深度增加而下降,但各层土壤速效钾含量均处于丰富水平,分别为192.15、144.44和138.88 mg/kg,表层与亚表层间、亚表层与下层间土壤速效钾含量存在较好的线性关系。【结论】福建省平和县蜜柚园钾肥施用过量和钾素盈余严重等问题较突出,过量的钾素盈余导致蜜柚园土壤速效钾含量在表层富集并向深层迁移。今后应合理控制钾肥用量,减少钾素盈余和淋溶,提高蜜柚果园钾肥利用率。

【Objective】The current potassium(K)management and its apparent balance status in honey pomelo orchards of Pinghe,Fujian were studied to provide reference for scientific application of potassium fertilizer in honey pomelo orchards.【Method】K fertilizer application data of 363 Guanxi honey pomelo orchards and 29 soil profile samples in Fujian were collected through farmers’survey and soil investigation during 2016-2018.K fertilizer application status,K apparent balance and soil K of honey pomelo orchards were analyzed.【Result】The average K fertilizer application rate(calculated by K2O,the same below)in honey pomelo orchards in pinghe,Fujina was 955 kg/ha,and 96% farmers exceeded K2O 400 kg/ha annually.Compound fertilizer was the main source of K fertilizer.Correlation analysis indicated that no obvious correlation between K application input and and honey pomelo yield was observed,but there was extremely linear correlation between K application input and K balance(P<0.01).The K apparent balance of the whole county reached 874 kg/ha and there was a huge variation of K fertilizer application and soil K balance in different townships.The soil available K of nearly 73% of orchards exceeded 120 mg/kg,which was excessive.And the available K in 0-20,20-40 and 40-60 cm of pomelo orchard soil layers showed a decreased trend with the increasing of soil vertical depth,although overall in a sufficient status and presented as 192.15,144.44 and 138.88 mg/kg,respectively.There was linear relation between surface layer and subsurface layer,and between subsurface layer and lower level soil available K.【Conclusion】High surplus K input and high K accumulation in Pinghe honey pomelo orchards in Fujian are major problems,and excessive K accumulation leads to leaching of soil available K to the deep soil in orchards.It is suggested to rationally manage the K application,reduce K surplus and leaching,and improve the K fertilizer utilization rate of honey pomelo orchards.