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Ros A.B.,Agencia Paulista de Tecnologia dos Agronegocios APTA | Tavares Filho J.,State University Londrina | Barbosa G.M.C.,Instituto Agronomico do Parara IAPAR

Studies about reduced tillage in soil cultivated with roots and tubers are rare and controversial. This study aimed to assess and compare the sweet potato tuberous roots yield in an alfisol type soil managed with conventional tillage (plowing followed by leveling and making mounds) and reduced tillage with straw on the soil surface (cultivated only along the rows). The experimental design was in randomized blocks in split-plot scheme. The principal plots corresponded to conventional tillage (with mounds) and reduced tillage, and the subplots to four collect periods: 90, 120, 150 and 180 days after planting. The characteristics evaluated were: total and commercial yields, numbers of total and commercial tuberous roots, and commercial tuberous roots individual fresh mass. Sweet potato crop had total and commercial tuberous roots yields around 68 and 75% higher in conventional tillage, respectively, than in reduced tillage. This response was caused by the high numbers of total and commercial roots in soil under conventional tillage. There was no difference between the soil management on tuberous roots individual fresh mass. As conclusion, the conventional tillage is better to the sweet potato crop. Source

Korndorfer P.H.,University of Florida | Da Silva G.C.,Federal University of Goais | Teixeira I.R.,State University of Goias | Da Silva A.G.,University of Rio Verde | De Freitas R.S.,Agencia Paulista de Tecnologia dos Agronegocios APTA
Pesquisa Agropecuaria Tropical

This research assessed the effect of calcium silicate application to soil surface on dry matter production and Si concentration on grass shoots, as well as chemical characteristics of a soil under degraded forage grass pasture. The experiment was carried out in a greenhouse, using a completely randomized design, in a 5×2 factorial arrangement, with four replicates. Treatments consisted of five calcium silicate doses (0 kg ha-1; 500 kg ha -1; 1,000 kg ha-1; 1,500 kg ha-1; and 2,000 kg ha-1) and two forage grasses (Brachiaria brizantha cv. Marandu and Panicum maximum cv. Mombaça). Shoot cuttings were performed at 45 and 95 days after sowing. Shoot dry mass accumulation and absorbed Si foliar concentrations were quantified, besides soil pH, Ca, P, Al, and V values, after grass harvesting. Calcium silicate application induced higher absorption of Si in Marandu, as well as in Mombaça. Marandu cultivar dry mass accumulation did not differ from Mombaça. Calcium silicate application increased pH and soil base saturation decreased the aluminum level. Source

Vidal A.A.,Agencia Paulista de Tecnologia dos Agronegocios APTA | Prado R.M.,Sao Paulo State University
Pesquisa Agropecuaria Tropical

Slag is a calcium silicate and silicon source, whose corrective action on soil is similar to the limestone one. Despite its corrective and fertilizing potential, there is little information about its effects on soil chemical attributes. The study evaluated the effects of the slag, limestone, and urea application on the chemical attributes of a Brazilian Oxisol cultivated with rice. The treatments consisted of two corrective agents sources (limestone and slag), with three doses (1.3 g dm-3, 2.6 g dm-3, and 5,2 g dm-3); three N doses (80 mg dm-3, 160 mg dm-3, and 320 mg dm-3), applied as urea; and a control, arranged in randomized blocks, in a factorial scheme, with four replications. Ninety days after the soil incubation and 120 days after planting, soil samples were collected for chemical analysis. The slag was efficient in correcting soil acidity, and nitrogen fertilization contributed to increment acidity in the soil cultivated with rice, decreasing base saturation, as well as the Ca and Mg content. The slag application improved silicon availability, however, when associate to the nitrogen fertilization, the silicon content in the soil did not change. Source

Lima J.D.,Paulista University | Moraes W.S.,Agencia Paulista de Tecnologia dos Agronegocios APTA | Modenese-Gorla da Silva S.H.,Paulista University
Revista Brasileira de Plantas Medicinais

The experiments were carried out to evaluate the effect of medium acidic and aluminum, as well as determine the most suitable concentration of indolebutyric acid (IBA) for rooting cuttings of different genotypes of Camellia sinensis L (tea plant). Such, stems were collected from mother plants in Pariquera-Açu, São Paulo state, Brazil, in winter 2012 and prepared semi-hardwood cuttings, with one bud and one leaf, which were kept in a nursery with 70% of shading. Irrigation substrate was taken with water and solutions containing phosphoric acid and aluminum sulfate at pH 5.5, 4.5; 3,5. In the first experiment, the experimental design was completely randomized in a factorial scheme 3×7, three genotypes (F 15, IAC 259 and Comum) and seven different conditions of rooting (vermiculite at pH 6.5, acidified with phosphoric acid or aluminum sulfate vermiculite at pH 3.5, 4.5 and 5.5). In the second experiment, the treatment that promoted the highest rooting in the first experiment (vermiculite acidified with aluminum sulfate at pH 3.5) was combined with treatment with IBA The experimental design was completely randomized in a factorial scheme 3×6, three genotypes and six concentrations of IBA (0, 2.000, 4.000, 6.000, 8.000 and 10.000 mg L-1). Vermiculite acidified with aluminum sulphate to pH 3.5, combined application of 10.000 mg L-1 IBA for 30 seconds was the most appropriate treatment for cutting propagation of genotypes F15, IAC 259 and Comum. Vermiculite acidified with aluminum sulfate at pH 3.5, combined treatment with 10,000 mg L-1 IBA for 30 seconds, was the most suitable conditions for the rooting of cuttings Camellia sinensis L. © 2016, Instituto de Biociencias. All rights reserved. Source

de Camargo M.S.,Agencia Paulista de Tecnologia dos Agronegocios APTA | Korndorfer G.H.,Federal University of Uberlandia | Wyler P.,University of Sao Paulo
Field Crops Research

Although the benefits of silicon (Si) fertilization for sugarcane yields have already been demonstrated, few studies have examined the effects of silicate fertilization applied at less than 200kgha-1 Si in the furrow at planting on the soluble Si concentration in the soils, plant uptake in sugarcane (a Si-accumulating crop) and damage caused by the stalk borer (Diatraea saccharalis) under field conditions. The objective of this study was to evaluate the effects of a Ca-Mg silicate that was applied in the furrow at planting on the available Si in the soil, sugarcane yields and stalk borer damage of two sugarcane cultivars under field conditions. Two experiments were conducted on two soil types with a low silicon content (a Typic Quartzipsamment-Q and a Rhodic Hapludox-RH) using a completely randomized factorial scheme design with four replicates, four Si application rates (0, 55, 110 and 165kgha-1 Si) and two cultivars (IAC 86-3396 and SP 89 1115). Ca-Mg silicate was applied during furrow planting such that all plots received the same quantity of Ca and Mg. On both of the soil types, silicate fertilization increased the Si concentrations in the soil and the leaves of the plants at 8 months for both the plant cane and the first ratoon, thereby showing residual effects. Additionally, the potential for silicon fertilization applied in the furrow at planting to reduce stalk borer (D. saccharalis) damage was confirmed for stalk Si concentrations that were greater than 3gkg-1 Si as shown in the RH soil experiment. Therefore, the practice of silicate placement at low rates (<200kgha-1 Si) in the furrow at planting should be considered an alternative method of nutritional management for sugarcane in sandy and loam sandy soils with additional benefits of increased soluble Si in the soil, Si uptake and sugarcane yield and may help reduce the stalk borer damage of D. saccharalis. © 2014 Elsevier B.V. Source

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