原位提取法与Olsen-P法比较石灰性土壤磷的有效性

The Response of Corn P uptake to Olsen-P and Available P of Soil Solution in Situ Determination in Drip Irrigation

【目的】精准有效简便的测定土壤磷有效性,为土壤磷素养分诊断与磷肥推荐奠定基础。【方法】通过设置不施磷(CK)、固体磷酸二铵60%基施+40%追施(DAP60-40)、液体磷酸60%基施+40%追施(PA60-40)3个施肥处理的田间小区试验,分别利用Olsen法、土壤水溶性磷浸提法和土壤原位提取法对土壤有效磷的含量及土壤供磷能力进行比较,并对玉米磷素吸收进行相关分析。【结果】3种方法均反映出土壤磷的有效性和作物磷素吸收能力,以抽雄期为例,利用土壤原位浸提法测定土壤有效磷,PA60-40较DAP60-40提高了14.6%,相比其他2种方法效果更加明显。Olsen-P、Water-P、土壤原位提取磷与植株吸磷量之间存在显著的相关性,相关决定系数R2分别为0.639 7、0.468 7、0.793 9。说明土壤原位提取磷浸提法对石灰性土壤磷有效性响应更为敏感,是诊断土壤磷素营养的有效手段。【结论】土壤原位提取法是一种准确的测定土壤有效磷的方法,利用土壤原位提取法能够方便、快速研究土壤对植物的供磷状况。

[ Objective] An accurate,effective and simple method tor measunng the etIecuveness ot sou r is the basis for soil phosphorus fertility diagnosis and P fertilizer recommendation in drip irrigated calcareous soil. [ Method ] In this study, a filed plot experiment was set up to compare the difference of three method soil available measurements of Olsen - P, distilled water extraction and the soil in situ extraction P on evaluation soil P bioavailability. Three treatments included （i） no P fertilizer （CK）, and （ii） 81 kg P2Os/hm^2 diammonium phosphate （DAP） fertilizer applied at planting plus 54 kg P2O5/hm^2 DAP as a topdressing （DAP60 - 40） , （iii） 81 kg P2O5/hm^2 liquid phosphoric acid （PA） fertilizer applied at planting plus 54 kg P2O5/hm^2 liquid PA as a topdressing （PA60 -40）. [ Result] The methods above are all able to reflect the soil P availability and crop P absorption capacity. The available P content which was measured by the method of in situ extraction in treatment PA60 -40 was 14. 6% higher than in treatment DAP60 -40 at tasseling stage. Compared with the other two methods, soil in situ extracted P was a more accurate method on evaluating liquid P and diammonium P fertilizer. There was a significant correlation between plant P uptake and the concentrate Olsen - P, Water - P, soil concentrate extraction P, the relevant determination coefficient （R2） were 0. 639 7, 0. 468 7,0. 793 9, respectively. [ Coclusion ] The method of soil in situ extraction was a more accurate approach to diagnose soil phosphorus level.