施肥方式对春玉米||蔬菜条带间作边行效应的影响

Effects of fertilization methods on border effect of cereal-vegetable strip intercropping system

粮菜条带间作系统中作物的种间相互作用主要集中在条带的边行区域,加强粮菜条带间作系统的中间行与边行区域的作物地上部、地下部生长差异的研究,对深化条带间作的认识及构建可持续的条带间作系统具有重要的意义。通过在粮菜条带间作体系的蔬菜条带中设置单施化肥和有机无机配施两种施肥方式,对春玉米||(矮生菜豆?秋白菜)的条带间作系统中边行、次边行和中间行的作物产量、干物质累积和分配、根层土壤速效氮、磷、钾养分含量以及根系空间分布的测定,研究了粮菜条带间作系统中作物生长的边行竞争效应及施肥方式对边行效应的影响。结果表明:单施化肥和有机无机配施方式下,边行春玉米的产量、地上部干物质量均显著高于中间行,产量分别比中间行提高58.7%、40.8%;边行蔬菜植株的生长均受到抑制。两种施肥条件下边行、次边行矮生菜豆的生长均受到抑制,其中单施化肥下的边行、次边行矮生菜豆的产量显著低于中间行,分别比中间行降低49.7%和45.6%。春玉米吐丝期时,边行春玉米的根系下扎深度比中间行深,且呈现偏向蔬菜条带一侧的"偏态"生长。有机无机配施菜田春玉米条带边行区域表层土壤的根长密度、根系质量密度比单施化肥分别提高104.3%、77.5%,边行矮生菜豆根长密度显著降低,且有机无机配施的边行矮生菜豆根系生长受到的抑制最为严重。结合春玉米和蔬菜作物的地上部生长情况分析可以发现,蔬菜条带的有机无机配施加剧了边行春玉米植株与边行蔬菜的竞争程度。边行春玉米的养分吸收优势使得边行区域根区土壤的速效氮、磷、钾养分含量显著降低。

Inter-specific interactions in cereal-vegetable strip intercropping system mainly occur at border-row areas. It is meaningful to know more about the differences in the growths of belowground（root） and aboveground（shoot） of crop systems between border-row and middle-row crops for establishment of a sustainable strip intercropping system. Two fertilization methods — chemical fertilization（CF） and combined application of organic materials and chemical fertilizers（OMFC）, were used in a cereal-vegetable strip intercropping system（spring maize intercropped first with dwarf bean then with autumn Chinese cabbage, expressed as spring maize｜｜bush bean →autumn Chinese cabbage） and then yield, biomass, root and soil available NPK of border row, sub-border row and middle row of crops tested in relation to border effects on crops. The results showed that compared with middle row, aboveground biomass and yield of maize in border row increased significantly by58.7% and 40.8% under the CF and OMCF fertilization methods, respectively. In contrast, vegetable growth in the border row was suppressed. However, aboveground biomass and yield of border row and sub-border row of bush bean under differentfertilization conditions were less than those of middle row. Specifically, border row and sub-border row bush bean yields decreased by 49.7% and 45.6% under CF treatment, respectively. At silking stage of spring maize, the depth of maize root in border row was deeper than that in middle row, and growth direction of all the roots was partial to vegetable strip. Compared with CF treatment, maize root length and weight in the 0-15 cm soil layer in border row under OMCF treatment increased by104.3% and 77.5%, respectively, while bush bean root length in the border row significantly decreased. Conversely, the roots of border row bush bean were inhibited when compared with middle row bush bean, which was much more severe under OMCF treatment. OMCF treatment strengthened intra-specific competition between spring maize and vegetable crops. In addition, the competitive advantage in nutrient absorption of border rows of spring maize significantly decreased soil available NPK contents in border row areas.