Características agronômicas e demanda energética de cultivares de soja sob efeito dos sistemas de preparo do solo

The aim of this study was to evaluate the influence of preparation: intermediate grade, minimum tillage and no-till on the agronomic characteristics and energy demand of transgenic soybean cultivars and non-GMO soybeans. Soil preparation aims at improving physical, chemical and biological conditions, aiming at good emergence and plant development. The different types of tillage may interfere with the agronomic characteristics and productivity of plants, and in energy use which can cause variation in production costs. Genetically modified plants can be one of the alternatives for reduction of production costs in crops by reducing pesticide applications, enabling higher productivity with less environmental impact. The test was conducted in 2010/2011 at the agricultural Experimental Farm Lageado, belonging to the Faculty of Agronomic Sciences – UNESP, located in the city of Botucatu, SP in an area using no-till systems for the past 12 years. The experiment was carried out in a 3 x 2 factorial, randomized treatments were comprised of three soil preparation systems, minimum cultivation, intermediate grade preparation and no-till, with two cultivars of soybeans: MGBR-46 Conquest (conventional), Valuable RR (Transgenic). The data obtained was submitted to variance analysis using Tukey test at a 5% probability. With the results analyzed it might be observed that there was no significant difference between treatments, in the variables, the percentage of soil cover, final soybean plant population, grain yield and plant height. The results obtained show that the no-till system resulted in higher productivity than conventional tillage and minimum cultivation. The higher specific energy use per area was observed in minimum cultivation with a chisel plough, when compared to the preparation across the grid. The greatest fuel consumption was to treat minimum cultivation with chisel plough. The highest values were found in the skating system of minimum cultivation, being greater in conventional tillage system. It is more satisfactory for the producer to sow transgenic soy using a no-till system, because productivity retrieved from that system compensates for fuel expenditure.

Atividade da enzima nitrato redutase em cultivares de arroz de terras altas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sistema radicular de cultivares de painço em resposta à calagem

The root growth is genetically controlled. There is variability among cultivars and soil factors such as toxicant Al and low contents of Ca and Mg can harm it. The objective of this study was to evaluate the root growth and the shoot growth of millet cultivars in response to liming. The experiment was carried out in pots with 13 dm3 of soil, in greenhouse conditions until 62 days after the emergence of the plants. The used experimental design was completely randomized, in a 2x4 factorial scheme, that is to say,two painço cultivars (AL Mogi e AL Tibagi), and four level of calcareous (0,0; 0,83, 1,67 e 3,34 g dm-3 ), with four replications. Liming promotes increase of the root system and of the aerial parts of the cultivars. The AL Tibagi cultivar presents a root system more tolerant to the low saturation by bases in comparison to the AL Mogi, however, the maximum root growth was occurred in saturations at around 64%. Millet cultivars in high acidity conditions reduce root diameter at the expense of the growth in length.

Comprimento radicular e nutrição de cultivares de painço em resposta à calagem

Information on improved cultivars of fall panicum and cultural practices concerning its cultivation is scarce in Brazil. So, the objectives of this research work were to evaluate root length and the mineral nutrition of fall panicum plants as influenced by liming in an acidic soil. The experiment was conducted in vases containing 13 dm3 of soil under greenhouse conditions up to 44 days after seedling emergence. The experimental units were distributed inside the green house according to a completely random design in a 2 X 4 factorial scheme, that is, two fall panicum cultivars (‘AL Mogi’ and ‘AL Tibagi’) and four doses (0.0, 1.67, 2.91, and 4.15 t ha-1 ). The experimental units were replicated 4 times. ‘AL Tibagi’ plants root system showed more tolerance to soil conditions of low base saturation. That cultivar also absorbed more efficiently P, N, Ca, Mg, and K from the acidic soil. Liming brought about increments of P, N, Ca, Mg, and S absorption by the fall panicum cultivars.

Desempenho agronômico e produtivo de cultivares de soja em diferentes ciclos e safras

With the objective of gathering technical data about soybean cultivars performance in Botucatu, state of São Paulo, Brazil, an experiment was conducted to evaluate seventeen genotypes. The experiment was conducted during the Summer seasons of 2002/03, 2003/04, and 2004/05. The experiment was set in the field according to a complete block design with four repetitions. The soybean cultivars were ‘Embrapa 48’, ‘BRS 132’. ‘BRS 183’, ‘BRS 212’, ‘IAC 22’, and ‘IAC 23’ (early cycled varieties), ‘BRS 133’, ‘BRS 154’, ‘BRS 156’, ‘BRS 184’, ‘BRS 214’, ‘IAC 18’, and ‘IAC 24’ ( semi early varieties), and ‘BRS 134’, ‘BRS 215’, ‘IAC 8.2’, and ‘IAC 19’ (medium cycled varieties ). All the varieties, during the three cropping years, showed adequate plant height and first pod height of insertion for mechanical harvest. Among the production components, mass of 100 grains showed the highest variability. Cultivar ‘BRS 154’ (medium cycle) showed the highest variation in mass of 100 grains and was also the highest yielding variety in the cropping year of 2004/05. The majority of the cultivars yielded above 3,000 kg ha -1 during the cropping years of 2002/03 and 2004/05. The best yielding performance during the three cropping years were displayed by cultivars ‘IAC 22’ (early cycle), ‘BRS 133’ and ‘BRS 156’ ( both semi early cycled varieties).