水稻土肥际微域铵对钾形态转化与迁移的影响  

Transformation and Movement of Potassium in Ferti-sphere of Paddy Soil as Affected by Co-application of Ammonium

作　　者：苏同庆[1,2] 王火焰[1] 周健民[1] 陈小琴[1] 杜昌文[1] 

机构地区：[1]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 [2]中国科学院研究生院,北京100049

出　　处：《土壤》2011年第3期367-373,共7页Soils

基　　金：国家重点基础研究发展计划项目(2007CB109301);国家自然科学基金项目(40971176)和IPI项目资助

摘　　要：通过室内土柱培养试验,研究了水稻土肥际微域铵对钾形态转化与迁移的影响。结果表明,钾自肥际向非肥际的扩散距离随钾肥用量增加而增加,施同等铵态氮条件下,施钾量增加2.4倍,导致肥际钾含量最高区域水溶态钾含量提高了2.1倍,交换态钾和非交换态钾则分别提高了1.7和0.3倍,而钾的迁移距离提高了16.4%(12 mm),说明肥际钾的固定能力有限,钾肥量增加导致更多的钾以有效性较高的形态存在。同等钾量条件下,施用铵态氮肥显著提高了水稻土肥际钾含量最高区域水溶态钾含量,使钾的迁移距离较未施铵时增加了23.2%(16 mm);铵钾共施还显著提高了肥际到普通土壤过渡区域中交换态钾含量,降低了所有土样中的非交换态钾含量。铵钾共施显著抑制了肥际微域中肥料钾向非交换态的转化,这种抑制作用随距肥际距离的增加而减弱。利用不同回归方程拟合由肥际到非肥际钾的分布曲线,无论是水溶态钾还是交换态钾,反S型曲线y=a/[1+b exp(c×x)]可以很好地拟合由肥际到非肥际K+的分布。A soil column incubation experiment was conducted in this study to investigate the effect ofNH4＋ on transformation and movement of K＊ in ferti-sphere of paddy soil. The results showed that movement of K＋ increased with K dose. In presence of same amount of NH4＋, as K dose increased by 2.4 times, the water-extractable K （WE-K）, Exchangeable K （E-K） and non-exchangeable K （NE-K） in the nearest part of ferti-sphere significantly increased by 2.1, 1.7 and 0.3 times, respectively. While the K diffusion distance increased by 16.4% （12 mm） as K dose increased. The results indicated that fixation of K in ferti-sphere is somewhat limited; more portion of K remained in labile form as K dose.increased. Co-application ofNH4＋ and K significantly increased both WE-K in the nearest part of ferti-sphere and the K diffusion distance as compared with K solely applied treatment. Co-application of NH4＋significantly increased E-K in the transition area from fcrti-sphere to bulk soil and reduced NE-K in all the soil samples that NH4＋ possibly reached. Co-application of NH4＋ significantly restrained transformation of added K into NE-K in ferti-sphere, and the effect declined as the distance from ferti-sphere increased. Different models were compared to describe the change of K concentration from ferti-sphere to bulk soil, for both WE-K and E-K, the anti-S-shape curvey = a / [1 ＋ b exp （e x x）] can be well fitted.

关 键 词：铵 钾 水稻土 肥际 转化 迁移 

分 类 号：S153.3[农业科学—土壤学]