施磷量对小麦物质生产及吸磷特性的影响

在低磷土壤条件下,以中筋小麦扬麦12号和弱筋小麦扬麦9号为材料,研究了施磷量对小麦物质生产和吸磷特性的影响。结果表明,在施磷量(P2O5)0～180.kg/hm2范围内,植株对磷的吸收量、吸收速率和磷的积累量随施磷量增加而上升;以施磷量108.kg/h2处理的叶面积指数(LAI)、植株茎蘖数、茎蘖成穗率、干物质积累量、花后干物质积累量和子粒产量最高。当施磷量超过108.kg/hm2时,相关物质生产指标则呈下降趋势,说明即使在缺磷土壤上,施磷量有其适宜值。小麦一生对磷的吸收存在两个高峰,出苗至越冬始期为第一个吸收高峰,拔节至孕穗期为第二个吸收高峰。植株磷素积累量的70%～75%是在拔节后吸收,表明拔节期施磷对满足小麦第二个吸磷高峰和磷的最大积累期需磷有重要意义。

Effects of phosphorus application on dry matter production and phosphorus uptake in wheat (Triticum aestivum L.)

Phosphorus(P) is one of the essential nutrient elements to maintain wheat growth.Phosphorus deficiency in the soils is constraint to the yield and quality of wheat.So increasing phosphorus application under phosphorus-deficient soils has biological and economic benefits.This experiment is to examine the effects of phosphorus application on dry matter production and phosphorus uptake in wheat in low phosphorus soils.It would be useful for improving wheat yield and quality under phosphorus-deficient conditions.The wheat cultivars tested were Yangmai 9(YM9)with weak-gluten and Yangmai 12(YM12) with medium-gluten.Phosphorus application was applied at six levels(P₂O₅ 0,36,72,108,144 and 180 kg/ha,respectively) on a sandy loam soil(4.95(mg/kg) available phosphorus).A randomized complete block design with three replicates was adapted in this study.Dry matter production and phosphorus uptake were determined.The results showed that phosphorus uptake,uptake rate and accumulation increased with increasing of P application rate within the range of P₂O₅ 0—180 kg/ha.Leaf area index,number of main stems and tillers per plant,rate of harvested spikes,accumulation of dry matter,dry matter accumulation after anthesis and grian yield reached their climax when phosphorus application was P₂O₅ 108 kg/ha while those declined when phosphorus application was more than P₂O₅108 kg/ha, indicating that there existed an optimistic phosphorus application rate even in low-phosphorus soil.The results in this experiment also suggested that there existed two phosphorus uptake peaks during wheat growth.The first peak occurred from emerging to wintering,the second appeared from jointing to booting.About 70%—75% phosphorus uptake occurred after the jointing,which suggested that phosphorus application at jointing stage was critical for the growth of winter wheat.