不同装土量对玉米植株·根系·籽粒养分浓度及化学计量比的影响

Effects of Different Soil Amounts on Nutrients Concentration and Stoichiometry of Maize Plant,Root and Seed

[目的]研究不同装土量对苗期、抽雄期和成熟期玉米植株、根系和籽粒中氮、磷含量以及氮磷比的影响。[方法]采用室外盆栽模拟试验。[结果]玉米植株:从苗期到成熟期,氮、磷浓度呈下降趋势;苗期磷浓度有随装土量增加而增加的趋势;无论施肥与否,同一时期基本呈现随装土量增加,氮∶磷比值呈下降的趋势,氮供应相对不足。玉米根系:从苗期到成熟期,氮浓度呈下降趋势,而且随着装土量的增加氮浓度呈下降趋势;苗期磷浓度较高,装土量不同磷浓度相差不大,抽雄期和成熟期磷浓度均为轻度或重度缺磷;苗期氮∶磷比值皆下降,而抽雄期有上升的趋势。玉米籽粒:施肥玉米随装土量增加氮浓度呈下降趋势;磷浓度差别不大,基本呈现随装土量增加,籽粒磷浓度呈下降的趋势;装土量不同,玉米籽粒中氮∶磷比值也有差异。[结论]松辽平原玉米带黑土区现行耕作制度下产生的2种不同的剖面构型"波浪型"和"平面型"导致有效土量差异,是导致黑土肥力退化的主要原因之一。

[ Objective ] The paper aimed to study the effects of different soil amounts on the nitrogen concentration, phosphorus concentration and N： P stoiehiometry of Maize Plant, root and seed in weeding stage, heading stage and maturity stage. [ Method] Outdoor pot simulation ex- periment was adopted. [ Result] From seedling stage to maturity, nitrogen and phosphorus concentrations of Maize plants display a downward trend; phosphorus concentrations have increased with increment of packing soil amounts in weeding stage; regardless of fertilization or not, N： P show downward trend with increment of packing soil amounts at the same period, nitrogen takes on the relative shortage. From seedling to maturity, nitrogen concentration of Maize roots takes on a downward trend, nitrogen concentration decreases with increment of packing soil amounts ; phosphorus concentration of seedling stage is higher than that of heading stage and maturity stage, phosphorus concentrations is mild or severe deficiency; N! P ratio is decreased in seedling stage, while there is an upward trend in heading stage. Nitrogen concentration of Maize grain is higher in seedling stage ; nitrogen concentration and phosphorus concentration of Maize grain after fertilization take on downward trend with increment of packing soil amounts; N： P ratio is different under different packing soil amounts. [ Conclusion] Different effective soil amount resulting from ＂wave type＂ and ＂fiat type＂ under the current cultivation system is one of the main reasons that causes fertility degradation of the black soil in Song-liao Plain maize belt.