河西干旱区蒙古黄芪干物质积累及养分吸收规律研究

Study on the Rules of Dry Matter Accumulation and Nutrient Absorption of Astragalus membranaceus var.mongholicus in Hexi Arid Area

目的:为了解河西干旱区蒙古黄芪干物质积累及养分吸收特性。方法:通过田间试验研究不同生育时期蒙古黄芪干物质积累特征及氮、磷、钾含量的变化特性,并运用Logistic方程进行拟合分析。结果:蒙古黄芪全株干物质积累量随生育期变化而逐渐增加,在出苗104~142天是蒙古黄芪干物质积累最快的时期,占总积累量的83.38%;蒙古黄芪地上部氮、磷含量随生育期推进整体呈现下降趋势,钾含量呈现先增后减的变化趋势,根部氮、磷含量在整个生育期有2个增长高峰,分别出现在出苗后第104天与收获期,钾含量变化在整个生育期相对平稳;不同生育期蒙古黄芪氮、钾含量总体上表现为地上部>根部,磷含量在生育后期表现为根部>地上部;蒙古黄芪地上部和根部氮、磷、钾素积累量分别在出苗后第104天和182天达到最高;Logistic方程回归分析结果表明出苗后100~120天是全株氮、磷、钾养分积累量最迅速的时期;蒙古黄芪出苗100天左右是氮、磷、钾营养临界期,对氮的积累强度最大,钾次之、磷最小,氮、磷、钾积累量地上部分在生育前期积累强度大,根部在收获期均达到最大。结论:蒙古黄芪出苗后的100~130天是干物质积累与养分积累量最关键的时期,应合理追施氮肥。

Objective:To understand the characteristics of dry matter accumulation and nutrient absorption of Astragalus membranaceus var.mongholicus in Hexi arid area.Methods:The characteristics of dry matter accumulation and the variation of nitrogen,phosphorus and potassium contents in Astragalus membranaceus var.mongholicus with different growth stages were studied by field experiments,Logistic equation was used for fitting analysis.Results:The dry matter accumulation of the whole plant of Astragalus membranaceus var.mongholicus increased gradually with the changes of growth stages.The dry matter accumulation of Astragalus membranaceus var.mongholicus was the fastest from the 104 th to 142 th day after seedling emergence,accounting for 83.38%of the total accumulation.The contents of nitrogen and phosphorus in the aboveground parts of Astragalus membranaceus var.mongholicus presented an overall downward trend along with the advance of the growth stages,while the content of potassium first increased and then decreased.In the whole growth stages,there were two increasing peaks of nitrogen and phosphorus contents,which appeared on the 104 th day after seedling emergence and the harvest period,respectively.The change of potassium content was relatively stable during the whole growth stages.The nitrogen and potassium contents of Astragalus membranaceus var.mongholicus in different growth stages were generally shown as aboveground>root,while the phosphorus content was shown as root>aboveground in the late growth stage.The accumulation of nitrogen,phosphorus and potassium in the aboveground and root parts of Astragalus membranaceus var.mongholicus reached the highest level on the 104 th and 182 th day after emergence,respectively.The results of Logistic equation regression analysis showed that the nitrogen,phosphorus and potassium nutrient accumulation of the whole plant was the most rapid period from 100 th to 120 th day after seedling emergence,about 100 th day after emergence of Astragalus membranaceus var.mongholicus was the critical period of nitrogen,phosphorus and potassium nutrition,the accumulation intensity of nitrogen was the highest,followed by potassium and phosphorus.The accumulation of nitrogen,phosphorus and potassium was high in the aboveground in the early growth stages,and the root reached the maximum in the harvest stage.Conclusion:The 100 th to 130 th day after the sprout of Astragalus membranaceus var.mongholicus is the most critical period for dry matter accumulation and nutrient accumulation,so nitrogen application should be reasonable.