The alteration of plant nutrient absorptive coefficient of soil after the soil suspension treated with the usual absorptive method

[Author abstract]The study had carried on the dissolubilities of phosphate and ammonium ions which absorpted with usual plant nutrient absorptive coefficient method(neutral 2.5% ammonium phosphate solution added to the soil with soil: solution ratio are 1;2. and soil suspensions keeped a day. The components of phosphate and ammonium were determined in the filtrates. The coefficients were expressed in P_2Osmg or N mg per lOOg soil from decrease of the components.) The purpose of the experiment are to define the coefficients concerned to the ions solubilities in filtrate. The resultes are summarized as follows. 1. The absorptive coefficients had the larger effect on original solubilities of suspension than after diluted with same volume distiled water, but, the treatments of water dilution had the considerable effect on each chemical potential. 2. Since the ionicspecies of phosphate had been controled of the pH of filtrate, thire each concentrations did not corresponded to phosphorus absorptive coefficient, but corresponded to nitrogen. 3. The ionic strengths of the filtrate were opposed to absorbe the ions by soil particles, but thire alternation with diluted treatment influenced not only on the diluted effect, but on the dissolusion of absorpted ions. 4. A resemblance of phosphate and ammonium ions dissolubility with water dilution asumed that the absorption of phosphate by soil is correlated to dissolution of ammonium. 5. The phosphate potentials toward the ammonium (pH_2PO_4 +pNH_4) were equivalented to the both coefficient, and suggested the power of component absorption by soil.[著者抄録]本報は中性2.5%リン酸アンモニウム溶液(常法)による土壌の養分吸収係数測定法で吸収したリン酸およびアンモニウムの希釈による溶出性について溶液化学的方法で検討を行なった。そして、土壌の養分吸収係数の実体を明らかにすることが目的である。吸収成分の溶出性については常法による成分吸収後に水による倍量希釈を行なっており、濾別液中の主要イオン成分の溶存性、化学ポテンシャルの変化などを考察し、以下の結果を得た。1.土壌の養分吸収係数は当初の成分溶存性により強く影響を受け、水希釈の影響は大きくなかった。しかし、水希釈操作は各ポテンシャルの変化に影響を及ぼした。2.リン酸の各イオン濃度は外液のpHにそれらのイオンの配分が支配され、リン酸吸収係数に対応しない場合が多い。3.外液のイオン強度は成分の吸収によって影響を受けるが、水希釈によるそれらの変化は希釈による効果だけでなく、吸収成分の溶出による影響も受けた。4.リン酸とアンモニウムの水希釈による行動の類似はリン酸の吸収に起因するアンモニウムの溶存性が推察される。5.アンモニウムイオンを対象としたphosphate potentialは土壌の養分吸収係数とよい対応を示し、養分の土壌による吸収力を示唆するものと考えられる