The authors evaluated the effects of doses of organic compost on the production and accumulation of macronutrients in endive plants in two areas with different fertility levels. The experiments were carried out at Fazenda Experimental São Manuel, located in the municipality of São Manuel, São Paulo State, Brazil. The study was carried out in a completely randomized design with seven treatments, six doses of organic compost (0, 35, 70, 105, 140 and 175 t/ha) and one additional treatment with inorganic fertilizer (N-P-K 4-14-8) and four replicates. In both areas, when the dose of organic compost was increased, the authors noticed a linear increase in fresh matter weight, number of leaves and plant height. In high-fertility area, compared to control (dose 0), using the highest dose (175 t/ha), the authors observed an increase of 280, 58 and 101% in fresh matter weight, number of leaves and plant height, respectively. For dry weight, we observed a linear increase in low fertility area and quadratic effect in high fertility area, with maximum estimated dry matter of 22.26 g applying 144 t/ha of organic compost. The nutrient accumulation was proportional to dry matter, with a linear increase in low fertility area and quadratic effect in high fertility area. The decreasing order of accumulated nutrients was K>N>Ca>P>S>Mg, with the highest values, in high fertility area, of 1,269, 471, 185, 91, 53 and 35 mg/plant, respectively, for doses varying from 121 to 158 t/ha.

Fertilizers supply in the appropriate period and dose is important to obtain satisfactory production. In this research we studied the effect of different split applications and doses of nitrogen in top dressing on the production of the carrot and the physicochemical characteristics of the roots. Nine treatments, resulting from a factorial of 4x2+1 (control without nitrogen fertilization), were evaluated in the randomized blocks experimental design, with four replications. The first factor were four nitrogen (N) doses in top dressing (60, 90, 120 and 150 kg ha-1) and the second were two forms of splitting [three equal applications (1/3+1/3+1/3 of the dose) and one with increasing proportions (1/6+2/6+3/6 of the dose) applied 15, 30 and 50 days after emergence]. We evaluated shoot height, fresh and dry shoot weight, fresh and dry root weight, root diameter and length, yield and some physicochemical characteristics of roots (soluble solids, titratable acidity, maturation index, pH, carotenoid content and reducing sugars). For most of the studied characteristics were observed quadratic effects for N dose, with an estimated maximum yield of 117.7 t ha-1 for the dose of 138 kg N ha-1. The splitting 1/6+2/6+3/6 resulted in higher values for fresh weight of shoot and root, root diameter, yield and carotenoid content, compared to the splitting 1/3+1/3+1/3.

Phosphorus is a finite natural resource and the use of gradual-release phosphate sources, associated with an organic compound may favor a more rational use of this nutrient, since organic matter protects P from soil fixation. The aim of this study was to evaluate the effect of phosphorus sources application, associated with organic compound at planting, on single inflorescence type broccoli production and soil chemical properties at the end of the cycle. Eight treatments were evaluated, in a 4 x 2 factorial scheme, using four phosphorus sources [thermophosphate (TM), natural phosphate (NP), reactive natural phosphate (RNP) and triple superphosphate (TSP)]; in the presence (55 t ha-1) and absence of organic compound Visafértil® at planting. The experimental design was randomized blocks, with four replicates. TSP source presented higher P contents. TM source showed, in the absence of organic compound, higher pH and contents of organic matter, Ca, Mg, SB and V%. In the presence of organic compound, NP source provided higher contents of organic matter and K. The addition of organic compound increased pH and resulted in higher contents of P, K, Ca, SB, CEC and V%. The presence of organic compound favored higher productivity for the sources TM, NP and TSP. Among these sources, TSP provided the highest production both in the presence or absence of organic compound, considering that NP source was the only one which did not differ from TSP for inflorescence fresh weight and productivity, both in the presence and in the absence of organic compound. We concluded that TSP and NP are the best P sources, associated with the application of organic compound.

ABSTRACT Although there exist researches about fertilization in top dressing in the production of cabbage, these are usually made with inorganic fertilizers, being rare the researches with organic fertilization in top dressing in the production of most vegetables. The objective was to evaluate the effect of different splitting of two organic fertilizers in top dressing in the production of cabbage. Six treatments were evaluated, with four replications in randomized block design. The six treatments were the result of the factorial 3x2, with three types of splitting (1/3+1/3+1/3; 4/6+1/6+1/6; 1/6+4/6+1/6 of the total dose in each application) and two organic fertilizers (castor bean cake and organic compost). The total dose of each fertilizer was calculated to apply 120 kg ha-1 N. The evaluated characteristics were number of external leaves, fresh weight of external leaves (g), fresh and dry head weight (g), head diameter (cm) and length (cm), yield and crop cycle (days after transplanting). Fertilization with castor bean cake resulted in greater yield, producing heads with higher weight, diameter and length in relation to the organic compost, besides reducing the cycle. The 4/6+1/6+1/6 splitting was better than the 1/6+4/6+1/6 splitting using castor bean cake.