氮磷钾肥对木薯‘桂热4号’生物量动态的影响

Dynamic Effect of N, P and K Fertilizers on Biomass Accumulation of the Cassava Variety GR4

为了了解氮磷钾肥对木薯品种‘桂热4号’生物量动态的影响,为其生产管理和推广奠定基础,开展了本试验。试验分5个处理:CK(不施肥)、NK、NP、PK、NPK。每月采集木薯全株样品,分为叶片、叶柄、茎秆、种茎、块根、细根等6个部分,测定生物量(干重),并收集用于测定凋落物干重,收获测产。结果表明:木薯‘桂热4号’叶片干物质呈顶峰型抛物线生长曲线,在8月下旬后,以快速-缓慢交替模式凋落。木薯茎秆、块根、地上部和地下部呈S型增长。根冠比前期出现单峰型波折,169 d后逐渐提高。块根干物质率表现出升高-降低-稳定-升高-稳定的模式。鲜薯产量与132 d之后的茎秆生物量和132~194 d的叶片生物量极显著相关。施氮处理增加了鼎盛期的叶片、茎秆生物量,还能促进169 d之后的块根生长,施氮处理的鲜薯产量和淀粉产量比不施氮处理高。

A field fertilizer experiment was carried out to analyze the dynamic effect of N,P and K fertilizers on biomass accumulation of the cassava variety GR4. Five treatments, i.e. NK, NP, PK, NPK and CK （without fertilizer） were arranged in the experiment. Whole cassava plants treated were collected every month, and then divided into 6 portions, i.e., leaf blade, leaf petiole, seed stem, stalk, tuberous roots and thin fibrous roots. The biomass of each portion and litters collected were measured in dry weight. Yield of tuberous roots were determined after harvest. The results showed the cassava leaves had a parabolic growth curve in dry matter content with a peak, and dropped in an alternative pattern of fast and slow after late August. The cassava stalk, tuberous roots, and aboveground and underground parts of the plant showed a sigmoid pattern of growth. The curve of root shoot ratio showed a unimodal pattern at the early stage, and then rose gradually after 169d. The dry matter content of the tuberous roots showed a high-low-stable-high-stable pattern. The fresh root yield at harvest had a highly significant correlation with the stalk weight after 169d and the leaf weight from 132d to 169d. The N treatments increased the leaf and stalk biomass at the peak stage and promoted the root growth after 169 d. The N treatments produced significantly higher root yield and starch yield than the treatment without N. The whole plant of the cassava variety GR4 produced biomass in a sigmoid curve, and the dry matter content of the tuberous roots showed a pattern of two platforms. N fertilizer enhanced the growth of leaves and stalks of the cassava variety GR4 as well as the root and starch yield.