Interaction of Lime Levels and Zinc in Castor Beans Plants: Chemical Attributes of Soil and Nutrients Accumulation On Seeds Produced.

The castor bean crop has little information about its behavior at different levels of soil fertility, climate, soil management, etc. But we know that is a plant of nutrient demanding, with high concentration of oil and protein in seed, which leads to a high need for essential elements. In order to evaluate the effects of lime levels and zinc, and the interaction of these on chemical attributes of soil and in nutrients accumulation on castor beans seeds, the experiment was carried out under greenhouse conditions without control of temperature, in pots with 17 dm³ of “RED LATOSOIL dystrophic”, medium texture, in São Paulo - Brazil. The statistical design was of randomized blocks, factorial 3 x 5, with four replicates. The treatments consisted of liming to reach three basis saturation of 40, 60 and 80%, combined with five zinc levels (0,5; 1,0; 2,0; 4,0 e 8,0 mg dm^-3). Eight castor bean seeds (cv Al Guarani 2002) were sown per pot, roughed-hew for two seedlings ten days after the emergence. Of this, one plant has grown until 79 days after emergence (beginning of flowering) and the other plant has grown until 174 days after emergence (first raceme mature), when were evaluated the soil chemical attributes and nutrients accumulation on produced seeds. Higher lime levels resulted in higher values of pH, levels of Ca, Mg and Mn, sum of bases and saturation for bases in soil; and increased accumulation of P, Mg, B and Cu in grains. On the other hand, it resulted in lower values of H + Al and levels of K, B and Fe in soil. Higher zinc levels applied to the soil increased the average content of zinc in soil and resulted higher accumulation of Zn in grains. There was interaction of lime and zinc only in the accumulation of Ca in the grains. The accumulation of macronutrients and micronutrients in grains occurred in the following order: N>K>P>Ca>Mg>S and Zn>Fe>Mn>B>Cu, respectively.