水氮耦合对三倍体毛白杨无性系BT17叶片养分的影响

Effects of water-nitrogen coupling on leaf nutrient contents of triploid Populus tomentosa clone BT17

以2年生三倍体毛白杨无性系BT17为试验材料,采用随机区组设计于2007—2009年在河北省威县苗圃布设了氮肥4水平、水分3水平的大田试验,研究水氮耦合效应对毛白杨叶片养分含量的影响,并确定了最佳水氮用量组合.结果表明:季节对毛白杨叶片N、P、K含量的影响均达到显著水平,且3种元素的季节变化均为春季>夏季>秋季;不同处理间的叶片N、P、K含量均达到显著差异,当土壤含水量为田间持水量的75%,施氮量为每株160g时,叶片N、P、K含量最高;水与氮肥耦合对叶片N、P、K含量均有较好的促进作用,对毛白杨的管理应注重水分与养分耦合的正效应;叶片各养分元素对水分和氮肥的响应不同,叶片N、K含量受水分的影响更大,P含量受氮肥的影响更大.

To understand the coupling effect of water and nitrogen on the leaf nutrient contents of Populus tomentosa and to search for an optimal combination of water and nitrogen for P. tomentosa, a field experiment with randomized block design （3 levels of irrigation water and 4 levels of fertilizer nitrogen） was conducted in a two-year-old P. tomentosa clone BT17 plantation in the nursery of Weixian County, Hebei Province of North China from 2007 to 2009. The N, P and K contents in BT17 leaves differed significantly among seasons, with the order of spring 〉 summer 〉 autumn, and had significant differences among the 12 treatments, being the highest in the treatment 75% of field capacity and 160 g per plant of N application rate. The coupling of water and nitrogen had positive effects on the leaf N, P, and K contents, and thus, more attention should be paid to this coupling effect in the management of P. tomentosa. The leaf nutrient contents had different responses to wa- ter and nitrogen. The leaf N and K contents were more affected by soil water content, while the leaf P content was more affected by N application rate.