水施磷肥对长白落叶松苗木生长和磷吸收的影响

Growth and P-uptake for Larix olgensis seedlings with phosphorus top-dressed using fertigation

以长白落叶松Larix olgensis 2年生移栽苗为试验材料,在底施磷肥的基础上,进行生长期水施追肥。按照水施追肥占总磷肥量的多少设置不同水平,即水施比例。试验采用裂区设计,主区为磷肥量(163,326,489 kg·hm-2),副区为水施比例(0,25.0%,33.3%,50.0%,100%)。结果表明:苗木生长指标在各磷肥处理间差异不显著,但苗高、地茎、I级侧根数(D>1.0 mm)和生物量随磷肥增大而增大。由于在163 kg·hm-2处理下,苗高和地径就能能达到国家标准,因此最经济施肥量应为163 kg·hm-2;茎磷质量分数,根、茎、整株含磷量、磷肥利用率在各水施比例间差异显著,并且在33.3%水施比例达到最大,其中全磷量为0.405 g·株-1,磷肥利用率高达11.4%。所以,33.3%为最佳水施比例,即在163 kg·hm-2磷肥量下,将磷肥总量的1/3用于水施追肥是长白落叶松移栽苗最佳施肥方式。

With the aim to improving the phosphorus efficiency and finding the best phosphorus applying method,two types of phosphorus（P） fertilizer application to Larix olgensis transplanted seedlings were undertaken：1） into the soil as a basal fertilizer before transplanting and 2） by fertigation as a topdressing three times during the growing season.A split-plot experimental design with P（163,326,and 489 kg·hm-2） as main treatments and fertigation ratios（0,25.0%,33.3%,50.0%,and 100%） as sub treatments was established.There were three replications,and the rapidly-available phosphorus content in the soil is 37.11 mg·kg-1.Results showed that P application did not significantly affect seedling growth or P content,however,seedling height,diameter,first-order lateral root in diameter at a junction ≥ 1 mm,and biomass increased with increasing P.With a top-dressing of 163 kg·hm-2 P,seedling height and diameter reached the national seedling standard（the seedling height35 cm,the seedling dimater5 mm）.Also,with the 33.3% fertigation ratio,P concentration in the stem;P content in the root,stem,as well as the entire seedling;and P use efficiency were maximum with the total P content of 0.405 g and P use efficiency of 11.4%.Therefore,163 kg·hm-2 P with 33.3% of it to be applied as a top-dressed fertigation during the growing season was the best P application for L.olgensis transplanted seedlings.