The Absorption Of Nitrogen(N), Phosphorus(P) And Potassium(K) And Fertilizing Technology Research Of Castor (Ricinus Communis L.) In Red Soil Districts Of Yunnan Province

This paper aims to find out the nutrition characteristics and fertilizer absorption rule of Castor in arid red soil districts under the subtropical climate of Yunnan province, and establish a corresponding fertilizing technology under the condition. It choose the variety TCO-202 of Castor (Ricinus communis L. ) as test material to observe and record the dry matter accumulation of each organ as root, stem, foliage and inflorescence, which are in the five critical growth stages as seedling stage, bud stage, blooming stage, filling stage, maturation stage of Castor {Ricinus communis L.) respectively, and measure out the fertilizer absorption amount of nitrogen(N), phosphorus(P) and potassium(K). Then have a test on contrasting the two dispositions that taking ordinary superphosphate and decayed farm manure as basal manures respectively without fertilizing any basic manure before, and treating urea as complementary fertilizer in three fertilizing quotas, to analyze the two-year yields comprehensively through the result of testing to the two-factor random group. The results indicate that the accumulation speed of dry matter keep ascending from emerging to grain filling until hit its maximum in filling stage and keep descending after that time. And the dry matter accumulation arranged in order of amount in each stage is: Blooming stage to Filling stage>Seedling stage to Bud stage>Filling stage to Maturation stage>Bud stage to Blooming stage>Seedling stage. The absorption amount of nitrogen (N), phosphorus (P) and potassium (K) of Castor (Ricinus communis L.) in the whole growth duration comply with the law of "slow-fast-slow-fast-slow", and the function curve of absorption speed present a type of hump with two pinnacles of fertilizer absorption speed appeared in the stage of bud and filling. The Castor (Ricinus communis L.) under the condition of red soil cultivation of Yuunan province needs 7.71kg nitrogen(N), 1.26kg phosphorus(P) and 4.42kg potassiurn(K) respectively to produce each 100kg seed with the proportion of fertilizer absorption as 1: 0.16: 0.57. TCO-202 will hit its best yield and maximum seedling yield both in annual and perennial under the condition of red soil cultivation with taking 15000kg/hm organic manure as basic manure and 450kg/hm urea as complementary fertilizer.