木薯间作玉米共生期间的作物生长及根系互作

Growth and root interaction during symbiotic period when intercropping cassava with maize

  • 摘要: 【目的】探究不同间作模式对木薯和玉米共生期间的农艺性状、根系分布、土壤理化性状和根系养分含量的影响,为优化木薯间作玉米高产高效栽培技术提供理论依据。【方法】以华南9号食用木薯和特早熟糯玉808鲜食玉米为试验材料,设等行距、宽窄行单作木薯及木薯等行距间作1行玉米、宽窄行间作2行玉米共4个处理,对比分析二者共生期间的农艺性状、三维立体根系分布以及不同土层的土壤理化性状和根系养分含量。【结果】宽窄行的木薯和玉米地上部长势均优于等行距。宽窄行间作比等行距增产玉米21.1%。单株的玉米、木薯根系均以植株为中心水平对称,由里向外呈由密至疏分布;单株玉米根系呈上密下疏、上窄下宽分布,68.7%~77.3%根重、46.2%~49.4%根长、52.7%~59.3%根表面积聚集在玉米行两侧各宽10 cm、深10 cm土带内;单株木薯根系呈上密下疏、上宽下窄分布,细根的50.8%~61.4%根长、47.7%~57.2%根表面积聚集在木薯种茎基端线两侧各宽20 cm、深10 cm土带内,而粗根的35.7%~42.0%根长、39.3%~48.8%根表面积和35.9%~46.3%总根重聚集在木薯种茎基端线两侧各宽20 cm、种茎中线两侧各宽30 cm、深10 cm土块内。土壤碱解氮、速效磷钾及作物根系磷钾含量基本呈表层(0~10 cm) > 中层(10~20 cm) > 深层(20~30 cm)的分布规律,而作物根系氮含量则表现相反规律;土壤和木薯、玉米根系的氮磷钾含量基本呈间作 > 单作,其中,宽窄行间作玉米的绝大部分养分指标为最高。【结论】玉米和木薯根系虽穿插生长,但其密集生长带(块)互不重叠,为弱竞争关系,以宽窄行为优,且宽窄行木薯间作玉米有利于提高两者的根系养分、土壤养分含量和玉米产量,故生产中推荐宽窄行木薯间作玉米模式。

     

    Abstract: 【Objective】The purpose of this research was to explore the effects on the agronomic traits, root distribution, soil physicochemical characteristics and root nutrients contents during their symbiotic period within different intercropping models, to provide theoretical basis to improve high-yield and high-efficient cultivation techniques of cassava in-tercropping maize.【Method】Using South China No. 9 edible cassava variety and Fresh Edible Glutinous Maize No. 808 of extra-early mature variety as materials, a total of 4 treatments were set up with equidistant row sole cassava(CK1), wide-narrow row sole cassava(CK2), equidistant row cassava intercropping 1 row of maize(T1), wide-narrow row cassava intercropping 2 rows of maize(T2). Then comparative analysis of the agronomic traits, three-dimensional root distribution, soil physical and chemical properties, root nutrients contents in the different soil layers between cassava and maize during the symbiosis period was conducted.【Result】The growth potential of cassava and maize in wide-narrow row was better than equal row spacing. T2 increased maize yield by 21.1% compared with T1. The root systems were distributed horizontally and symmetrically from dense to sparse where from the center towards the surround around the individual plant of maize or cassava. The root system of single maize was distributed with dense top and bottom sparse, narrow top and wide bottom, and their 68.7%-77.3% root weight(RW), 46.2%-49.4% root length(RL), and 52.7% -59.3% root surface area(RSA) were gathered in the soil belt, where was 10 cm deep and 10 cm wide on the two sides along maize planting line. The root system of single cassava was distributed with top dense and sparse bottom, wide top and narrow bottom, and their 50.8% -61.4% RL and 47.7% -57.2% RSA of fine roots were gathered in the soil belt, where was 10 cm deep and 20 cm wide on the two sides along the base terminal line of cassava stem, meanwhile, 35.7% -42.0% RL and 39.3% -48.8% RSA of rough roots and 35.9%-46.3% RW of total root weight were gathered in the soil block within the range of 10 cm deep, 20 cm wide on the two sides along the base terminal line of cassava stem, 30 cm wide on the two sides along the central line of cassava stem. Alkali-hydrolyzable nitrogen(N), available phosphorus(P) and potassium(K) of soil and PK content in the crop roots were basically showed the order of surface layer(0-10 cm) > middle layer(10-20 cm) > deep layer(20-30 cm), while their nitrogen(N) content was opposite. Available NPK of soil and NPK content of the crop roots were basically showed the order of intercropping > single cropping, and the most nutrient indexes of T2 were the highest.【Conclusion】There is weave growth among the root systems between cassava and maize, and their dense growth belts or blocks do not overlap each other, therefore the roots interaction between cassava and maize is weak competition, particularly, T2 is the weakest competition in the two intercropping models, meanwhile, T2 is beneficial to increase root nutrients, soil nutrient content and maize yield, so the T2 intercropping model is recommend in production.

     

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