马尾松人工中龄林细根生长对施肥的响应

Response of fine root growth of Pinus massoniana middle-aged forest to fertilization

对12年生马尾松林进行施肥试验,采用尼龙网袋法研究单位体积土壤中的细根生物量、根长、根体积、根表面积及根尖数对不同营养元素的响应,从而实现人为调控根系的生长发育。结果表明:施用N肥时,除总根长随施肥量的增加生长量降低外,其他指标的生长量都随施肥量的增加而增加;施P肥对所有指标生长都有促进作用,并且促进作用随施肥量的增加而增加;施K肥时,细根生物量、表面积及根尖数随施肥量的增加而减少,总根长却随之增加而增加,根体积随施肥量的增加呈现先增加后减少的趋势;NPK以不同的方式混合施用时,对细根的生长都有一定的促进作用,其中N1P2K1效果最好。此外,施肥还能改变细根的生长时间,使其生长峰值推迟出现,施P、K3肥能使总根长的推迟,施P2、P3能使体积的推迟,而施N2、N3及NPK混合肥能使表面积的推迟。

The fertilization experiments on 12-year-old Pinus massoniana were conducted to study the response of fine root biomass,root length,root volume,root surface area and number of root tips to different nutrients per unit soil by using nylon bags method.The results show that the application of nitrogen fertilizer,except from root length,all other growth indexes increased with the increasing the amount of fertilization;the application of phosphate fertilizer raised all growth indexes and the effects enhanced with the increasing the amount of fertilization;the application of potassium fertilizer reduced fine root biomass,root surface area and number of root tips with the increasing the amount of fertilization,the total root length increased with the increasing the amount of fertilization,the root volume first raised then reduced with the increasing the amount of fertilization;the mixed fertilizer of NPK had certain promoter action on the fine root growth,the N1P2K1’s effect was the best.Besides,fertilization can prolong the growth duration of P.massoniana fine root,delay the appearance of growth peak.When applying P,K3 fertilizer can delay the total root growth,applying P2,P3 can delay the volume growth,applying N2、N3 and NPK mixed can delay fine root surface area growth.