Rubens Fey

Initial growth of physic nut as a function of sources and doses of organic fertilizers

Organic fertilization provides low cost, supplemental nutrition for plant production. This study aimed to determine the best source and dose of organic fertilizer on the growth of physic nut (Jatropha curcas L.), a potential biodiesel producer. Physic nut seedlings were transplanted to 18 dm3 black plastic pots filled with soil mixed with four sources of organic fertilizer (chicken, fish, cattle manure or urban waste compost) at four dose levels (50, 100, 200 or 400 L m-3). Fertilized and control (no fertilization) plants were grown under shadehouse conditions and morphological plant features were assessed at 30, 60, 90 and 120 days after transplanting. Doses higher than 100 L m-3 of poultry manure mixed with claysoil should be avoided. The use of other sources such as cattle manure, fish manure and composting may be used and result in increase in height, leaf area, SPAD index up to doses of 200 L m-3 manure mixed in clay soil.

Response of wheat to foliar application of zinc

Wheat is grown in Brazil, mostly in no-till, a system in which the zinc can become potentially deficient, due to excessive application of acidity corrective and phosphate fertilizers in surface and, or at shallow depths. This study aimed to evaluate the effect of foliar application of zinc in agronomic characteristics and yield of wheat. The experimental design was randomized blocks with five replications. Treatments consisted of four doses of zinc (0, 54, 108 and 216g ha-1 Zn), divided into two foliar applications, the first at tillering (18 days after plant emergence) and the second at the boot stage (65 days after emergence). Foliar application of zinc increased the number of fertile tillers and yield of wheat, however, have little effect on the agronomic characteristics of no-tilled crop with high nutrient content in soil.

Phosphorus and potassium fertilization in culture of soybean plants in the Oxisol

It is recommended to use phosphorus and potassium fertilization on soybean; however it has been common to verify the absence of effect on crop productivity, especially in no-tillage system. Thus, the study aimed to evaluate the effect of doses of superphosphate and potassium chloride in the leaf tissue nutrient content and yield of soybean growing in Oxisol. The experiment was installed in October 2011 in a randomized block design in split-bands with two factors (4x4), with four replications, totaling 64 plots, being Factor 1 with doses of superphosphate (0, 136, 331 and 700 kg ha-1) at sowing and Factor 2 with doses of potassium chloride (0, 160, 320 and 800 kg ha-1) released with cultivar Vmax RR (SYN 7059RR). In the experiment, the variables evaluated were Ca, Mg, K, P, S, Cu, Zn, Mn and Fe in leaf tissue and grain yield. The fertilization with superphosphate and potassium chloride do not interfere in leaf nutrient content and yield of soybean cultivar Vmax RR (SYN 7059RR) grown on an Oxisol of clayey with levels of P and K classified as high. In these cases, it is advisable to keep only the maintenance fertilization according to the values ​​of P and K exported by grain. Key words: Chemical fertilizer, tillage systems, organic mineral fertilizer, superphosphate, potassium chloride.