水肥空间组合对冬小麦生物学性状及生物量的影响

 【目的】研究水肥空间组合对冬小麦形态指标及生物量的影响，对指导旱地施肥具有一定理论和实践意义。【方法】以肥熟土垫旱耕人为土为供试土壤，在全生育期遮雨和人工控制土壤水分条件下，采用分层隔水土柱试验法研究与田间土层分布相同土柱不同土层水分、氮、磷组合对冬小麦叶面积、株高、分蘖数、生物量、根冠比和收获指数等指标的影响。【结果】与整体湿润水分处理相比，上干下湿水分处理（0～30 cm土层干旱胁迫，30～90 cm土层湿润）下，抽穗期小麦旗叶面积、株高分别降低7.03%和3.77%；小麦地上部和根系生物量及收获指数也不同程度降低，但根冠比增加。从肥料处理看，单施磷和氮磷配施处理，小麦叶面积、株高、有效分蘖数和总生物量均极显著高于单施氮和CK，这与供试土壤各土层严重缺磷，而氮素供应相对丰富有关。从不同土层施肥看，在两种水分处理下，单施氮时，以均匀施入0～90 cm土层小麦叶面积、株高、有效分蘖数、地上部生物量和根系生物量最高，施入0～30 cm土层最低；单施磷和氮磷配施时，0～90 cm与0～30 cm土层施肥间总叶面积、旗叶面积、株高、有效分蘖数以及总生物量差异不显著，但均显著高于30～60 cm和60～90 cm土层相应施肥处理。【结论】由于土壤供氮充分，将氮肥集中施于0～30 cm土层对生物量形成具有一定抑制作用，而均匀施入0～90 cm土层有明显促进作用；在上层干旱胁迫时，这种趋势更加明显。两种水分处理下氮磷配施，特别是在上干下湿水分处理下，保证0～30 cm土层较充分的养分供应对改善形态指标和增加生物量仍具有重要作用。因此，对旱地养分和水分应同层供应较好的观点，应予以重新认识和评价。

Effects of Water and Fertilizer Spatial Coupling on Biological Characteristics and Biomass of Winter Wheat

A column experiment was conducted with Eum-Orthic Anthrosols (Cinnamon soils) to study the effects of spatial coupling of water, nitrogen and phosphorus on leaf area, plant height, tillers, biomass, R/S and harvest index (HI) of winter wheat. The column consist of three layers (each soil layer is 30cm thick) with a 2cm layer of coarse sand between them for obstructing water and nutrients exchanging. The results showed that compared with 0-90cm soil-moisture (W), the effect of the water condition of 0-30cm soil-dry and 30-90cm soil-moisture (D) on total leaf area of jointing stage was ruleless, but leaf area and plant height of tassel stage reduced 7.03% and 3.77% separately. Comparing the treatment of fertilizer at the same layer, that the effective tillers reduced 2.6(n/plant) of P treatment(applying phosphorus) than NP treatment (mixing nitrogen and phosphorus); that the difference of the leaf area and plant height was not significant between P treatment and NP treatment; that leaf area, plant height and effective tillers of N treatment (applying nitrogen) and CK were lower markedly to P treatment and NP treatment, which is related to P lacking badly and N providing enough. Comparing the treatment of layer with the same fertilizer, that leaf area, plant height and effective tillers of P and NP applying layer of 0-90cm and 0-30cm were higher markedly than of 30-60cm and 60-90cm; but the rule was not obvious at the treatment of N applying in different layer. The above-ground biomass, root biomass and HI were lower inconsistently, but R/S higher under the water condition of D than W. Under each water treatment, that above-ground biomass of NP treatment was maximal, followed by P treatment, then was N treatment, but root biomass and R/S were maximal at the treatment of P. Comparing the treatment of layer with the same fertilizer, that above-ground biomass and root biomass of N applying layer of 0-90cm was maximal, of 0-30cm was lowest; that above-ground biomass, root biomass and R/S of P applying layer of 0-90cm and 0-30cm were higher markedly than of 30-60cm and 60-90cm; that above-ground biomass and root biomass of NP applying layer of 0-90cm was maximal, followed by 0-30cm, 30-60cm and 60-90cm orderly. Because the soil was full of nitrogen, applying N in layer of 0-30cm was inhibitory to biomass，but of 0-90cm was stimulative, which is more obvious under the condition of D. The biomass of crop will be higher mixing nitrogen and phosphorus in layer of 0-30cm, regardless of the condition of D and W.