西瓜钾营养诊断的叶片含量法分析  

Evaluation of Potassium Nutrition by Potassium Content in Watermelon Leaf

作　　者：王硕[1] 吴萍[1] 董亚[1] 董彩霞[1] 任丽轩[1,2] 沈其荣[1] 

机构地区：[1]南京农业大学资源与环境科学学院/农业部长江中下游植物营养与肥料重点实验室/江苏省有机固体废弃物资源化协同创新中心,南京210095 [2]土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所),南京210008

出　　处：《土壤》2015年第6期1040-1048,共9页Soils

基　　金：国家公益性行业(农业)科研专项经费项目(201203013);土壤与农业可持续发展国家重点实验室项目(Y412201438)资助

摘　　要：采用不同土壤钾水平的多点田间试验,研究了施用钾肥对西瓜植株钾含量以及产量、品质的影响,探讨了西瓜植株各叶位钾含量与西瓜产量之间的相关性,分析了叶片钾含量诊断西瓜钾营养的临界指标。结果表明:西瓜新叶钾含量与西瓜产量达极显著相关关系,相关系数为0.600 8(P_(0.01)=0.575)。90%相对产量下新叶钾含量为32.6 g/kg时,西瓜产量可达91.39 t/hm^2。在极低钾含量(50 mg/kg和70 mg/kg)的土壤上,施用钾肥显著提高西瓜产量、开花期西瓜植株新叶和老叶钾含量;显著提高开花期、坐果期和膨大期西瓜植株茎和根中的钾含量。在低钾含量(84 mg/kg和85 mg/kg)的土壤上,施用钾肥显著提高西瓜产量,提高西瓜果实中的可溶性糖和可溶性固形物的含量而降低可滴定酸含量。随着钾肥施用水平的提高,新叶钾含量有提高趋势,老叶和挂果叶中的钾含量逐渐升高;施用钾肥显著提高坐果期和膨大期西瓜植株茎中钾含量。在中钾含量(170 mg/kg)和高钾含量(260 mg/kg)的土壤上,西瓜开花期新叶钾含量的最大值和最高产量相关联。总之,推荐开花期西瓜新叶钾含量32.61 g/kg为营养诊断临界值。Six field experiments were carried out to investigate the effects of potassium fertilizer management on watermelon yield and quality in the fields with very low, low, middle and high potassium concentration. The relationships between the leaf potassium concentration and yield and quality of watermelon were studied. The threshold potassium concentration in leaf was recommended to evaluate potassium nutrition in watermelon. Potassium concentration in watermelon young leaves was significantly positive correlated to watermelon yield （R2=0.600 8, P〈0.01）. Potassium content was 32.6 g/kg in watermelon young leaves when watermelon yield （91.39 t/hm2） was up to 90% of the highest yield. In soils with very low potassium levels （50 mg/kg and 70 mg/kg）, K fertilization significantly enhanced watermelon yield. K content in young and old leaves at flowering stage, as well as increased K content in stem and root at flowering stage, fruit forming stage and fruit expanding stage. In soils with low potassium levels （84 mg/kg and 85 mg/kg）, K fertilization significantly improved watermelon yields, concentrations of soluble sugar and soluble solid substance in fruits, while decreased titratable acid concentration in fruits. K concentration in young leaves, old leaves and leaves close to fruits was increased with the increase of K fertilizer quantity. Potassium concentration was increased in stems at fruit forming stage and fruit expanding stage. In soil with middle and high potassium levels （170 mg/kg and 260 mg/kg）, the significant correlation was observed between the maximum watermelon yield and the highest K concentration in young leaves. K content of 32.61 g/kg was recommended as threshold in young leaves at flowering stage.

关 键 词：西瓜 钾含量 新叶 营养诊断 

分 类 号：S651[农业科学—果树学]