滴灌施肥生育期比例分配对榆林市马铃薯生长和水分利用的影响

以当地主栽品种“紫花白”为研究材料,按前期(苗期+块茎形成期,ES)少、后期(块茎膨大期+淀粉积累期,LS)多的施肥比例,基于马铃薯苗期、块茎形成期、块茎膨大期、淀粉积累期占全生育期总施肥量的比例设置了8个处理(T1-T8),研究了同一滴灌施肥水平下,生育期内施肥比例分配对马铃薯的生长、产量和水分利用的影响.结果表明:马铃薯LAI和干物质值均表现为苗期和块茎形成期,ES_0.4~0.5处理大于ES_0.2~0.3,在块茎膨大期时,处理ES_0.2大于ES_0.3~0.5;淀粉积累期和成熟期,处理T7的LAI和干物质下降明显.而块茎形成期开始施肥的处理T1,T2在块茎膨大期、淀粉积累期和收获时都获得了较高的LAI和干物质.对于干物质转运而言,开花后块茎积累量表现为ES_0.2>ES_0.3~0.5,块茎干物质累积主要是在花后同化作用下建立的.产量变化规律为ES_0.2>ES_0.5(处理T7除外)>ES_0.4(处理T5除外)>ES_0.3(处理T2除外).各处理马铃薯单株商品薯质量变化规律与产量一致,而平均单薯质量、单个商品薯质量和单株结薯数间没有统一的变化规律.施肥处理水分利用和肥料偏生产力变化趋势与产量类似,各处理耗水量差异不具有统计学意义.综上,从产量和节水角度考虑,试验条件下滴灌施肥马铃薯生育期内比例分配最优方案为苗期和块茎形成期总施肥比例20%(苗期不施肥,形成期20%),块茎膨大期占施肥总量的55%和淀粉积累期占施肥总量25%.

Effects of fertilizer application rate of drip irrigation fertilization in various growing stages on growth and water use efficiency of potato in Yulin City

In order to explore effects of fertilizer application rate on growth, yield and water use efficiency of potato in drip irrigation fertilization, a local cultivar-′Zihuabai′ potato in Yulin was targeted and a series of pot cultivating experiments were conducted at various fertilizer levels in different growth stages. Eight treatments(T1_{(0-0.2-0.55-0.25)}, T2_{(0-0.3-0.5-0.2)}, T3_{(0.1-0.2-0.5-0.2)}, T4_{(0.1-0.2-0.45-0.25)}, T5_{(0.1-0.3-0.4-0.2)}, T6_{(0.2-0.2-0.4-0.2)}, T7_{(0.2-0.3-0.4-0.1)}, and T8_{(0.2-0.3-0.3-0.2)})were established based on the principle such as a less fertilizer application rate(20%, 30%, 40% and 50%)in the early stages(seedling and tuber formation stages, ES), a higher rate(80%, 70%, 60% and 50%)in the later stages(tuber enlargement and starch accumulation stages, LS). The results show that the LAI(leaf area index)and dry mass value are all presented with treatments ES_0.4-0.5>ES_0.2-0.3 in seeding and tuber forming stages, treatments ES_0.2 is better than ES_0.3-0.5 in tuber enlargement and starch accumulation stages, but the LAI and dry mass decreases significantly in T7 treatment in starch accumulation maturation stage for treatments T1 and T2, fertilization starts at tuber formation stage, a higher LAI and a more dry mass are obtained in tuber enlargement, starch accumulation and harvesting periods. For dry mass transport, the performance of dry mass accumulation of tuber after flowering is ES_0.2>ES_0.3-0.5, and the tuber dry mass accumulation is mainly caused by the assimilation after flowering. The variation of yield is ES_0.2>ES_0.5(except T7)>ES_0.4(except T5)>ES_0.3( except T2). The variation of the weight of commercial potato per plant is consistent with that of the yield; however, there isn′t a general correlation among averaged single tuber weight, single commodity weight and number of tubers per plant. The trend of water use efficiency and partial fertilizer productivity are similar to that of yield, and there is no statistical significance in water consumption among various treatments. In summary, from the yield and water utilization efficiency point of view, the optimum fertilizer application rates should be 20% in seedling and tuber formation periods(no fertilization at seedling stage), 55% in tuber expansion period and 25% in starch accumulation period, respectively, under our experimental conditions.