高粱光合产物及养分吸收规律的研究

REGULATION OF PHOTOSYTHETIC SUBSTANCE AND NUTRIENT OF SORGHUM IN GUIZHOU

为制订贵州高粱优质高产的合理施肥技术，研究了贵州杂交高粱对氮、磷、钾养分的吸收规律。结果表明：高粱在出苗后８０天干物质积累最快，日积累量达高峰；高粱对氮、磷、钾的积累表现为，出苗后６０天，积累量占总积累量的比率氮素达７７％，磷素４０％，钾素６０％，随后氮、磷持续积累到成熟，钾在出苗１００天积累达最大值后不再增加；高粱对氮和钾吸收速度基本相同，在出苗后６０天达到高峰，此时每天的单株吸收量分别为氮３５．４６ｍｇ和钾３８．２１ｍｇ，磷在出苗后８０天达最大速度，单株日吸收磷为１６．３６ｍｇ。因此贵州杂交高粱施肥应以氮、钾重基肥，早追肥，磷作基肥深施为基本原则来确定合理的施肥时期及方法，以保证高粱养分积累的重要时期和养分吸收速度的峰值期，土壤中有足够的有效养分供高粱吸收、积累。在试验条件下，杂交高粱生产１００ｋｇ籽粒需要吸收Ｎ１．９ｋｇ，Ｐ＿２Ｏ＿５１．１８ｋｇ，Ｋ＿２Ｏ２．２８ｋｇ。Ｎ：Ｐ＿２Ｏ＿５：Ｋ＿２Ｏ＝１：０．６２：１．２。可以将此作为贵州高粱栽培的合理施肥用量的参考。

The experiment was carried out to study the regulation of photosythetic substance and nutrient ofsorghum(hybrid strain)in Guizhou. The results showed as follows.The dry matters accumulated mostquickly in 80 days after seedling, The accumulation of nitrogen,phosphorous and potassium teached to 77%,40%and 60%of total amount respectively in 60 days after seedling. The accumulation of potassium wasmaximum at the milky stage(100 days after seedling).The absorptivity of nitrogen and potassium was maxi- mum in 60 days after seedling but phosphorous in 80 days. When sorghum was grown in centre areas ofGuizhou,it proved that 1.9 kg nitrogen,1.8 kg P2O5 and 2.28 kg K2O with the ratio of N:P2O5:K2O=1:0.62:1.2,should be required for yielding 100 kg sorghum seeds.