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Sugarcane production has increased in recent years mainly because of the demand for ethanol. Soil preparation in areas where sugarcane has not been planted yet can increase productivity by improving physical and chemical characteristics. The objective of this study was to evaluate the effect of soil tillage on agronomic traits and productivity of sugarcane. The experiment was conducted in the municipality of Goianésia (GO) on a Red-Yellow Latosol of medium texture using the CTC-2 variety. The experimental design was randomized blocks with six treatments and four replications. The treatments were: T1) desiccation + moldboard plow + harrow, T2) moldboard plow + harrow, T3) harrow + moldboard plow + harrow, T4) no-till, T5) subsoiler, and T6) harrow + disc plow + harrow. The number, diameter, height and productivity of stalks were evaluated. The treatment which resulted in the highest number of stalks was harrow + moldboard plow + harrow; however, this treatment was differed only from the treatment with moldboard plow + harrow. The seedbed preparation with desiccation + moldboard plow + harrow and also harrow + disk plow + harrow provided the highest yield of sugarcane stalks. The no-till treatment proved to be a viable alternative, since it did not differ in productivity from treatments that provided the highest yields. It is a more economical form of cultivation when compared to the other treatments studied in this work.

The confinement of pigs stands out as a great generator of swine wastewater (SW). The final destination of waste generated is currently a concern of society, since if handled improperly, it can cause serious impacts to the environment. One of the alternatives is the use of SW as a source of nutrients, which are made available to the plants, after the mineralization of organic matter. The objective of this work was to compare soil chemical attributes under two planting arrangements, in single and double lines of Corymbia citriodora. Two experiments were carried out at the Bonsucesso farm, in Uberlândia-MG, the first with C. citriodora in simple lines, with five plants per plot, spacing two meters between plants and 15 meters between rows. The second experiment was with C. citriodora in double lines, with two meters between plants in the line, three meters between lines in the plot and 15 meters between the double lines of C. citriodora. The statistical design was in randomized blocks. The treatments used were five doses of SW (0; 200; 400; 600 and 800 m³ ha-1) with five replicates. The application of SW rates was divided in the dry season, in the months of June, July and August. The chemical characteristics of the soil were evaluated in the 0-20 cm depth layer. Planting on double lines of C. citriodora provided higher soil nutrient contents. The application of swine wastewater raised the levels of potassium and heavy metals such as copper and zinc. The dose of 200 m3 ha-1 provided adequate levels for most nutrients present in the soil.

ABSTRACT:The cowpea is an important food crop in the North and Northeast regions of Brazil, where the beans are consumed either green or ripe. Yet, considering its socio-economic importance and its tropical origin, cowpea yields are low in those regions, due to inadequate cultivation practices and incorrect soil management. Therefore, the objective of this study was to study the development of cowpea crop inoculated and fertilized with two different nitrogen (N) sources. The experiment was conducted in the municipality of Rorainópolis (RR). The experimental design was randomized blocks with four treatments and five replications. The plant material was 'BRS Guariba' cowpea cultivar, and the treatments were: (i) control (no nitrogen fertilization), (ii) seeds inoculated with Bradyrhizobium elkanii, (iii) urea as N source (60 kg N ha -1 ), and (iv) ammonium sulphate as N source (60 kg N ha -1 ). The following crop traits were evaluated: foliar macronutrients (N, P, K, Ca, Mg and S), green and dry weight of shoots, dry beans per plant, pod yield and bean yield. Urea and ammonium sulphate promoted high accumulation of nutrients in leaves. Ammonium sulphate also stood out regarding productivity traits, thus proving to be a viable N source for cowpea in the Amazon region. The nodulation with Bradyrhizobium elkanii wasn't efficient to replace the fertilization with nitrogen fertilizers for cowpea BRS Guariba.

The objective of this study was to evaluate the effect of different sources and doses of N combined with marine algae on the development of corn plants. Field experiments were conducted from December 2010 to February 2012 in Uberlândia, Minas Gerais. The experimental plots were laid out in a randomized block design with sub-subdivided plots. Different nitrogen sources in the form of immediate-release and controlled-release urea were evaluated on plots; rates of 0 (control), 60, 100 and 120 kg of N ha-1 were evaluated on subplots; and applications with or without marine algae were evaluated on sub-subplots. The dose of marine algae corresponded to 20% of the dose of urea. The study concluded that the application of marine algae in corn did not influence the efficiency of the different nitrogen sources. However, increasing nitrogen doses resulted in higher content of foliar N, thousand-grain weight and crop yield.