Nutrient content in aboveground biomass of Brazilian peanut cultivars in conservation tillage on sugarcane straw and pasture area.

Fields studies were conducted in 2004/2005 in order to evaluate the effects of tillage on nutrient content in aboveground biomass of two peanut cultivars, cultivated in rotation after mechanical harvested sugarcane and pastures. These trials were carried out in two types of soils; Oxisol and Ultisol, respectively in Ribeir?ao Preto and Mirassol, S?ao Paulo State, Brazil. The experimental design was split-plot with four replications. Tillage treatments (conventional, minimum and no-tillage) were main plots while sub-plots were peanut genotypes IAC-Tatu ST (Valencia market-type, erect growth habit, red seed coat, maturity range around 100 days after planting) and IAC-Caiap´o (Runner market-type, prostate growth habit, pink testa, maturity range more than 135 days). From 15 to 90 days after emergence, samples of leaves and stems were harvested, dried, weighted and ground to determine macro and micronutrient concentration. At 75 days after sowing, the cultivar IAC-Caiap´o showed higher contents of N, P, K, Cu, and Zn while IAC-Tatu presented higher concentrations of Ca, Mg, and S. Zn content was higher in conservation tillage than in conventional, mainly in Oxisoil for both of cultivars.

Soil chemical attributes and leaf nutrients of Pacovan banana under two cover crops.

Banana is one of the most consumed fruits in the world, which is grown in most tropical countries. The objective of this work was to evaluate the main attributes of soil fertility in a banana crop under two cover crops and two root development locations. The work was conducted in Curaçá, BA, Brazil, between October 2011 and May 2013, using a randomized block design in split plot with five repetitions. Two cover crops were assessed in the plots, the cover 1 consisting of Pueraria phaseoloid es, and the cover 2 consisting of a crop mix with Sorghum bicolor, Ricinus commun is L., Canavalia ensiform is, Mucuna aterrima and Zea mays, and two soil sampling locations in the subplots, between plants in the banana rows (location 1) and between the banana rows (location 2). There were significant and independent effects for the cover crop and sampling location factors for the variables organic matter, Ca and P, and significant effects for the interaction between cover crops and sampling locations for the variables potassium, magnesium and total exchangeable bases. The cover crop mix and the between-row location presented the highest organic matter content. Potassium was the nutrient with the highest negative variation from the initial content and its leaf content was below the reference value, however not reducing the crop yield. The banana crop associated with crop cover using the crop mix provided greater availability of nutrients in the soil compared to the coverage with tropical kudzu.

Nitrate in soil solution with use of plant cocktails as green manure in diferent tillage systems in the brazilian semi-arid

Tillage systems strongly affect nutrient transformations and plant availability. The objective of this study was to assess the nitrate dynamic in soil solution in different tillage systems with use of plant cocktail as green manure in fertilized melon (Cucumis melon) in Brazilian semi-arid. The treatments were arranged in four blocks in a split-plot design and included three types of cover crops and two tillage systems, conventional tillage (CT) and no-till (NT). The data showed no strong effect of plant cocktails composition on NO3-N dynamic in the soil. Mean concentration of NO3-N ranged from 19.45 mg L-1 at 15 cm to 60.16 mg L-1 at 50 cm soil depth, indicating high leachability. No significant differences were observed between NT and CT treatments for 15 cm depth. The high soil moisture content at ~ 30 cm depth concentrated high NO3-N in all treatments, mean of 54.27 mg L-1 to NT and 54.62 mg L-1 to CT. The highest NO3-N concentration was observed at 50 cm depth in TC (60.16 mg L-1). High concentration of NO3-N in CT may be attributed to increase in decomposition of soil organic matter and crop residues incorporated into the soil.

Adubação de capim-elefante com composto orgânico produzido com resíduos animais.

Resumo: A utilização do composto orgânico proveniente de resíduos da criação e abate de pequenos ruminantes pode elevar a produção de matéria seca do capim-elefante, tendo em vista o teor de nutrientes contidos nesse fertilizante orgânico, diminuindo os impactos da produção animal sobre o ambiente e reduzindo os custos de produção na área de capineira de capim-elefante. Dada à escassez de informações na literatura e a importância do manejo adequado da adubação orgânica na agropecuária, objetivou-se avaliar os atributos químicos e físicos do solo, o estado nutricional e a produção do capim-elefante submetido à aplicação de doses do composto orgânico proveniente de resíduos da produção e abate de pequenos ruminantes. O delineamento experimental adotado foi em parcelas subdivididas, com medidas repetidas no tempo, sendo as parcelas as doses (0; 13,3; 26,6; 39,9; 52,3; 79,8 t ha-1 ) de composto orgânico e um tratamento adicional com adubos minerais e as subparcelas os ciclos (1, 2, 3 e 4) com 4 blocos, totalizando 28 parcelas. As variáveis mensuradas foram atributos físicos e químicos do solo, a diagnose foliar e a produtividade de capim-elefante. Para o fator ciclo, a adubação orgânica incrementou a umidade gravimétrica e umidade volumétrica e ainda houve diminuição da densidade de partículas em função dos ciclos. Com as doses do fertilizante orgânico houve aumento nas concentrações da matéria orgânica, amônio, nitrato, amônio + nitrato, fósforo e saturação por base; houve redução do valor da acidez potencial, além da elevação dos teores de nitrogênio e fósforo nas plantas. As doses de composto orgânico aumentaram a biomassa de forragem total de capim elefante. A adubação mineral proporcionou maior incremento da produção do capim em relação à adubação orgânica no decorrer dos ciclos. Abstract: The use of organic compost from residues of production and slaughter of small ruminants can increase dry matter production of elephant grass, in due function of quantity nutrients in this compost, thus reducing the animal production impacts in the environment and production costs in elephant grass fields. Due to the Lack of information in literature and the importance regarding organic fertilization in agriculture, the aim of this work was evaluate chemical and physical soil attributes, nutritional status in plants and production of elephant grass in function of doses of organic compound of residues of production and slaughter of small ruminants. The experimental design was in split-plot, with the main treatment the doses (0; 13,3; 26,6; 39,9; 52,3; 79,8 t ha-1 ) of organic compost and one additional treatment with mineral fertilization and secondary treatments was the cycles (1, 2, 3 and 4) with 4 blocks, and 28 plots. The measured variables were physical and chemical attributes in the soil, nutritional diagnosis in plants and production of elephant grass. For cycle factor the organic fertilization increased gravimetric and volumetric humidity, yet, occurred decrease of density in function of cycles. With the doses of organic compost increased organic matter, ammonium, nitrate, ammonium + nitrate, phosphor and base saturation; and decreased the value of potential acidity; and increased content of N and P in plants. The doses of organic compost increased the elephant grass production. The mineral fertilization increased the elephant grass production in relation of organic fertilization over the cycles.

Nitrate and potassium concentration in fertigated soil cultivated with wine vines.

In the semiarid region of Brazil the use of irrigation systems for applying fertilizers in horticulture is the primary means for incorporating nutrients in the soil. However, this technique still requires its use in wine vines to be assessed. In view of this, this study aimed to assess nitrate and potassium concentrations in soil fertigated with nitrogen and potassium fertilizers in 3 wine grape growing cycles. A field experiment was conducted with ?Syrah? wine grapes, in Petrolina, Pernambuco, Brazil; it assessed five nitrogen doses (0, 15, 30, 60 and 120 kg ha-1) and five K2O doses (0, 15, 30, 60 and 120 kg ha-1) applied by drip irrigation system with two emitters per plant, with a flow rate of 4 L h-1. The experimental design used was the factorial split-plot, making up 13 combinations arranged in 4 randomized blocks. Soil solution samples were collected weekly with the aid of porous cup extractors for all treatments and at depths of 0.4 and 0.6 m by determining nitrate and potassium concentrations and electrical conductivity. Increased levels of both nutrients in the irrigation water increased the availability of nitrate and potassium in the soil solution. The highest nitrate and potassium concentrations were found in the second growing cycle at both depths studied.

Planting times and spacing of carrot crops in the São Francisco Valley, Pernambuco state, Brazil.

Climate variations over the year and plant density tend to strongly affect the agronomic performance of carrot crops. Thus, the objective of this work was to evaluate the performance of the cultivar Brasilia in crops under mild (winter) and high (summer) temperatures. An experiment was conducted from May 2011 to February 2012, using a randomized block design and treatments arranged in split plot, with three replications. The plots consisted of planting seasons (winter and summer) and the subplots of plant spacing (4, 6, 8 and 10 cm). The height of plants presented a linear decrease, from 53.4 to 51.0 cm, with an increase in spacing in summer planting, while in winter the greatest height (50.7 cm) was obtained with spacing of 8.0 cm between plants. The lowest commercial yields were found in summer crops and with the widest spacing between plants. The smallest spacing between plants (4 cm) had yields of 45.9 Mg ha -1in summer and of 63.1 Mg ha-1 in winter crops. The winter planting had higher fresh root weight (89.9 g root - 1 ) compared to the summer (81.4 g root - 1 ), reaching higher weight with increasing plant spacing. Higher yields are achieved with plant spacing of 4 cm during winter. The carrot can be grown throughout the year in the Submiddle of the São Francisco Valley.

Soil management systems for sustainable melon cropping in the Submedian of the São Francisco Valley.

Changes in soils management systems, including the application of green manure, are able to increase crop productivity. The aim of this study was to propose a soil management system with the use of green manure to improve the nutritional status and melon productivity in the submedian of the São Francisco Valley. The experiment was installed in Typic Plinthustalf and conducted in split plot. There were two soil tillage systems, tillage (T) and no tillage (NT), and three types of green manure (two vegetal cocktails: VC1- 75% legumes (L) + 25% non-legumes (NL); VC2- 25% L+ 75% NL and spontaneous vegetation (SV)). The experimental design was a randomised block with four replications. Fourteen species of legumes, grasses and oilseeds were used for the composition of the plant cocktails. We evaluated production of the dry shoot and root biomass and carbon and nutrient accumulation by green manures and melon plant. Data were subjected to analysis of variance and the treatment means were compared by Tukey´s test (P<0.05). Shoot biomass production and carbon and nutrient accumulation were higher in plant mixtures compared to spontaneous vegetation. The root system of the plant cocktails added larger quantities of biomass and nutrients to the soil to a depth of 0.60 m when compared to the spontaneous vegetation. The cultivation of plant cocktails with soil tillage, regardless of their composition, is a viable alternative for adding biomass and nutrients to the soil in melon crops in semi-arid conditions, providing productivity increases.

Flowering synchronization in hybrid rice parental lines.

The cultivation of hybrid rice is a technology that allows for an increase in grain yield of 30% relative to the grain yield of conventional cultivars. However, the main challenge for this technology is related to seed production, which has high production costs and low seed yields. Therefore, agronomic techniques that could enhance flowering synchrony of parental lines in the field are essential for an efficient production system of hybrid rice seeds. The objective of this work was to study the effects of sowing depth, plant density and fertilization with nitrogen or phosphorus as potential techniques to increase the pollen availability in the field and, consequently, the flowering synchrony between parental lines in the production of hybrid rice seeds. The experiments were conducted during two growing seasons in the Central Region of Brazil. All of the experiments were conducted as a randomized complete block in a split plot scheme; however, the experiment with P fertilization had a factorial design. Our research allow inferring that nitrogen fertilization technique applied to the soil or foliar at the time of panicle differentiation does not affect the time of onset of flowering of rice varieties INTA Puitá CL and L106R, which are potential R lines for the production of hybrid rice. Agronomic techniques of variation in sowing depth, seeding rate and the phosphate fertilization affect the time of onset of flowering from 10 to 19 degree-days, which could represent two days in the crop cycle, for the line L106R. Such techniques constitute potential alternatives for use in hybrid rice seed production systems and could be applied in alternated blocks of R lines in the field to obtain longer periods of pollen availability in the field.

Adubação de capim-elefante com composto orgânico produzido com resíduos animais.

A utilização do composto orgânico proveniente de resíduos da criação e abate de pequenos ruminantes pode elevar a produção de matéria seca do capim-elefante, tendo em vista o teor de nutrientes contidos nesse fertilizante orgânico, diminuindo os impactos da produção animal sobre o ambiente e reduzindo os custos de produção na área de capineira de capim-elefante. Dada à escassez de informações na literatura e a importância do manejo adequado da adubação orgânica na agropecuária, objetivou-se avaliar os atributos químicos e físicos do solo, o estado nutricional e a produção do capim-elefante submetido à aplicação de doses do composto orgânico proveniente de resíduos da produção e abate de pequenos ruminantes. O delineamento experimental adotado foi em parcelas subdivididas, com medidas repetidas no tempo, sendo as parcelas as doses (0; 13,3; 26,6; 39,9; 52,3; 79,8 t ha-1) de composto orgânico e um tratamento adicional com adubos minerais e as subparcelas os ciclos (1, 2, 3 e 4) com 4 blocos, totalizando 28 parcelas. As variáveis mensuradas foram atributos físicos e químicos do solo, a diagnose foliar e a produtividade de capim-elefante. Para o fator ciclo, a adubação orgânica incrementou a umidade gravimétrica e umidade volumétrica e ainda houve diminuição da densidade de partículas em função dos ciclos. Com as doses do fertilizante orgânico houve aumento nas concentrações da matéria orgânica, amônio, nitrato, amônio + nitrato, fósforo e saturação por base; houve redução do valor da acidez potencial, além da elevação dos teores de nitrogênio e fósforo nas plantas. As doses de composto orgânico aumentaram a biomassa de forragem total de capimelefante. A adubação mineral proporcionou maior incremento da produção do capim em relação à adubação orgânica no decorrer dos ciclos. Abstract: The use of organic compost from residues of production and slaughter of small ruminants can increase dry matter production of elephant grass, in due function of quantity nutrients in this compost, thus reducing the animal production impacts in the environment and production costs in elephant grass fields. Due to the Lack of information in literature and the importance regarding organic fertilization in agriculture, the aim of this work was evaluate chemical and physical soil attributes, nutritional status in plants and production of elephant grass in function of doses of organic compound of residues of production and slaughter of small ruminants. The experimental design was in split-plot, with the main treatment the doses (0; 13,3; 26,6; 39,9; 52,3; 79,8 t ha-1 ) of organic compost and one additional treatment with mineral fertilization and secondary treatments was the cycles (1, 2, 3 and 4) with 4 blocks, and 28 plots. The measured variables were physical and chemical attributes in the soil, nutritional diagnosis in plants and production of elephant grass. For cycle factor the organic fertilization increased gravimetric and volumetric humidity, yet, occurred decrease of density in function of cycles. With the doses of organic compost increased organic matter, ammonium, nitrate, ammonium + nitrate, phosphor and base saturation; and decreased the value of potential acidity; and increased content of N and P in plants. The doses of organic compost increased the elephant grass production. The mineral fertilization increased the elephant grass production in relation of organic fertilization over the cycles.

Straw and early nitrogen fertilization affect soil properties and upland rice yield.

The presence of cover crop straw and early application of total N at sowing may provide significant changes in the microbial population, reflecting on the N dynamics in the soil and in upland rice plants. This study aimed at determining the effect of the early application of nitrogen doses as mineral N and microbial biomass carbon in the soil, as well as in the activity of nitrate reductase, and grain yield of upland rice plants cultivated under notillage system (NTS). A randomized blocks design, in a split-plot scheme, with four replications, was used. The treatments consisted of N doses (0 kg ha-1, 40 kg ha-1, 80 kg ha-1 and 120 kg ha-1) and the presence or absence of U. brizantha cover straw. Maintaining the straw on the soil surface reduces the ammonium levels and increases the microbial biomass carbon content of the soil. The application of increasing doses of N in the soil provides increases in the levels of nitrate and ammonium in the soil up to 28 days after emergence. The activity of the nitrate reductase enzyme in the plants increases and the contents of ammonium and nitrate in the soil decrease with the crop development. The number of panicles and grain yield of upland rice increase with the increase of the nitrogen fertilization, but decrease in the presence of U. brizantha straw. Thus, it is recommend the use of early N fertilization in upland rice crop.