Arranjo espacial de plantas de milho em sistema plantio direto

The interaction of management practices that increases plant density and reduces row spacing by spatial arrangement, if well planned, can be an excellent opportunity for the producers to increase their profitability. The objective of this study was to evaluate the variation effects of plant spatial distribution in two maize hybrids cultivated in a no-tillage system on the production components. The study was conducted in the CECA/UFAL. The treatments consisted of the cultivation of two hybrids of maize, FORT and AGN 30A00, in row spacings of 0.80 and 0.40 m and with plant densities of 60,000 and 70,000 plants ha -1. The statistical design was randomized blocks in a 2 x 2 x 2 factorial scheme, with three replications. From the results obtained, it may be concluded that neither the row spacing reduction nor plant density increase, as isolated practices, do not increase grain yield in the tested cultivars. The association of the reduction in row spacing and increase in plant population resulted in significant gain in grain productivity for the hybrid FORT.

Compactação do solo e intervalo hídrico ótimo no crescimento da parte aérea e produtividade da cultura do milho

The aim of this work was to evaluate the effect of soil compaction caused by tractor wheel traffic on the limiting water range (LLWR), shoot growth and levels of compaction and four replications in a completely randomized experimental design. Soil samples with preserved structure were collected in the layers: 0.02-0.05; 0.08-0.11; 0.15-0.18 and 0.22-0.25m to determine macroporosity, microporosity, total porosity, bulk density, resistance to penetration and LLWR. The evaluated corn parameters were: plant and first spike height, steam diameter, number of spikes per plant, plant dry matter, dry matter of 1000 seeds and seed productivity. The soil compaction restricted all corn parameters except the number of spikes per plant and dry matter of 1000 seeds. The LLWR was reduced by the soil resistance to penetration, even in the tilled soil with bulk density of 1.12 Mg m-3. Only the treatment with 11 Mg tractor, repeated four times on the area, demonstrated bulk density above critical bulk density in the LLWR that was 1.37 Mg m-3, where the seed productivity was significantly smaller.

Atributos químicos e físicos de um solo tratado com biossólido industrial e cultivado com milho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Parcelamento da adubação nitrogenada na cultura do milho irrigado em sistema plantio direto

The purpose of this study was to evaluate the best time for application of N for an irrigated corn crop in a no-tillage system in the State of Alagoas. Three corn hybrids were used (TORK, FORT and BRS-3003) with four application times (days after sowing - DAS) for fertilizing with nitrogen as top dressing, consisting of the following treatments: 1) 120 kg ha-1 at 15 DAS, 2) 60 kg ha-1 at 15 DAS and 60 kg ha-1 at 30 DAS, 3) 120 kg ha-1 at 30 DAS, 4) 60 kg ha-1 at 30 DAS and 60 kg ha -1 at 45 DAS and 5) control treatment without N fertilization. The experimental design was in randomized blocks with four replications in a subdivided plot scheme. The components of the production studied were: final population of plants ha-1, numbers of corn ears ha-1 length of corn ears and number of rows of grains of corn and mass of 1000 grains. The productivities of grains obtained did not present significant differences among the treatments that received fertilization with nitrogen, independent of the time of application and number of split applications. It is concluded that in the notillage system in Alagoas spliting the manuring with nitrogen (top dressing) is not necessary.

Produção de Brachiaria brizantha e Panicum maximum com milho e adubação nitrogenada

In places characterized with high temperatures and rain occurrence in great intensity in the summer, but with dry winter, the major limitations for the sustainability of no tillage systems are low production of straw during fall-spring period and the fast decomposition during the rain season. To try to solve the problem, intercropped cultures of grains with forage species has presented reliable results; because offer vegetal covering to the next sowing, giving sustainability to the no tillage system. However, being a recent technology, its needed further studies in different areas involved for this system of production. Thus, this study had the objective 1) to evaluate the production of corn grain at different periods of intercropping with Brachiaria brizantha and Panicum maximum in no tillage system, and 2) aimed to evaluate the performance of forage at different periods of intercropping and the responses to nitrogen fertilization after the harvest of the corn, assessing mass productivity and quality. The experiment was carried out at the Lageado experimental farm, School of Agricultural Sciences, Botucatu campus belonged to São Paulo State University (UNESP) in structuralized Red Nitosol (Afisol). The experimental design was randomized blocks with four replications. The treatments were composed for four systems of no tillage involving corn: 1) single corn; 2) corn with Brachiaria brizantha cv. Marandu intercropped in the sowing; 3) corn with Brachiaria brizantha cv. Marandu intercropped with the fertilization of covering; 4) corn with Panicum maximum cv. Mombaça intercropped in the sowing and 5) corn with Panicum maximum cv. Mombaça intercropped with the fertilization of covering. After the harvest of the corn, it was applied, in equivalent quantities of nitrogen, ammonium nitrate in covering in doses of 0, 30, 60 and 120 kg ha-1, determining the forage mass productivity and quality. The simultaneous tillage of corn with P. maximum cv. Mombaça in the sowing compromises the grain productivity. When sowed in intercropping, B. brizantha presents a fiber concentration reduction and greater TDN concentration during the fall-spring period. Regarding benefits of intercropped cultures seeking to use in systems of production like agriculture-pasture integration, the best intercropping to be utilized is corn sown simultaneously with B. brizantha cv. Marandu.

Custos e rentabilidade do milho em função do manejo do solo e da adubação nitrogenada

Agronomic practices that help farmers to raise yield and reduce costs must be studied to ensure agricultural sustainability. Thus, the objective of this study was to analyze economically the effect of soil management and nitrogen fertilization in maize crops. Treatments consisted of a combination of 3 soil management techniques (plow harrows + floating harrows, chisel + floating harrows, and no-tillage), 5 periods of nitrogen fertilization (control - 0 kg ha -1 N; 120 kg ha -1 after sowing (S); 120 kg ha -1 in the V 6 stage; 30 kg ha -1 (S) + 90 kg ha -1 in V 6; 30 kg ha -1 (S) + 45 kg ha -1 in V 4 + 45 kg ha -1 in V 8 The total operating cost (TOC), gross revenue (GR), operating profit (OP), profitability index (PI), break-even yield, and break-even price were estimated. It was concluded that the no-tillage system, after 11 years of management, associated with nitrogen fertilization promotes positive PI and OP, being useful to farmers.

Custo de produção e indicadores de rentabilidade da cultura do milho safrinha

The objective of this study was to evaluate the production cost and profitability of the second season corn crop in the Medio Paranapanema region, São Paulo State Brazil, under two technological levels (middle and high technology), crop 2008/2009, and compare the results with the 2006/2007 agricultural year. Effective and total operational cost as well as five profitability indicators were used. It was concluded that the high technology production cost for corn crop (direct seedling, sowing during the recommended period, use of simple hybrid seed, application of side-dressing fertilization, and treatment of seeds with different insecticides) was superior to the middle technology production cost (direct seedling, sowing after the recommended time, use of double hybrid seed, and no side-dressing fertilization). However, the average cost was inferior (US$ 8.5), due to a higher yield (4 t). The high technology corn crop was profitable (gross income and profitability index of 14% and 12%, respectively). For the middle technology crop, profitability indexes pointed out that the cropping system needs to be reevaluated by technicians and research institutions, regarding the adequate technical recommendations. Profitability indexes decreased considerably in both cropping systems. It was verified that, in relation to the 2006/2007 harvest period, the total operational cost increased for both technologies, mainly because of the increase of supplies prices.

Estrutura do capim-braquiária durante o diferimento da pastagem

This experiment was performed aiming to evaluate tiller population density, forage mass and its morphological components on pastures of Brachiaria decumbens cv. Basilisk. during deferment. The treatments encompassed four deferred grazing periods (18, 46, 74 and 121 days). A randomized block design with two replications was used. The numbers of vegetative tillers (VT), reproductive tillers (RT) and dead tillers (DT) in the pasture were determined. The masses of green leaf blade (GLBM), dead stem (DSM) and dead forage (DFM) were also determined. There was a reduction in the number of VT (from 1, 491 to 944 tiller m-2) during the deferment period. RT and DT numbers were not influenced by the deferment periods. Their averages were 211 and 456 tiller m-2, respectively. Longer deferring periods resulted in an increase in GSM (from 2, 965 to 4, 877 kg ha-1 of dry mass) and DFM (from 2, 324 to 4, 823 kg ha-1 of dry mass), but it did not influence GLBM (average of 2, 047 kg ha-1 of dry mass). In Viçosa, Minas Gerais State Brazil, Brachiaria decumbens cv. Basilisk pasture fertilized and deferred in the beginning of March must be kept deferred for about 70 days in order to conciliate both quality and quantity forage production.

Massa seca e composição bromatológica de quatro espécies de braquiárias semeadas na linha ou a lanço, em consórcio com milho no sistema plantio direto na palha

The objective of this research was to evaluate the dry mass yield and chemical composition of four Brachiaria species in different options for sowing, exclusively or in intercrop with corn crop, under a no-tillage system. The experiment was carried out during the growing seasons of 2006 at FEPE (FE/Unesp, Ilha Solteira Campus) located in Selvíria, Mato Grosso do Sul State, Brazil. The soil of the experimental area was classified as distroferric Red Latosol (Oxisol). The experimental design was in randomized blocks, in a factorial scheme (4 × 4), with five replications. The treatments consisted of four Brachiaria species (Brachiaria brizantha cv. Marandu, Brachiaria decumbens, Brachiaria ruziziensis and Mulato II grass) grown in rows and spread on total area, exclusively or intercropped simultaneously with corn crop sowing. The study evaluated the dry mass yield and total digestible nutrients, crude protein, ash, neutral detergent fiber, acid detergent fiber, hemicelluloses, cellulose and lignin content of forage. The spread on total area intercrop of forages with corn crop proved to be viable by presenting similar dry mass yield to exclusive sowing arrangements, conversely to what happened with intercrop in row of corn crop, which decreased such yield. Brachiaria ruziziensis showed superior chemical composition and the intercrops increased energy and crude protein contents, and decreased cell wall components.

Desempenho de semeadora-adubadora em função do prepa ro de solo e espa çamento da cultura do milho

The performance of machines and agricultural implements are of fundamental importance, especially when subjected to different types of soil tillage, and have to adapt to these conditions, in order to promote good operational performance. The objective of this study was to analyze the operational performance of a Marchesan Supreme Cop grain drill, equipped with four rows, spaced 0.90 m, according to three types of tillage: conventional tillage (plowing and two harrowing series), reduced tillage (scarification with a roller), and no-tillage, in areas previously seeded with maize (Zea mays L.), at two spacing measures (0.90 m and 0.45 m). The results indicate that the demand for power, tensile stress, and motor rotation, in the sowing operation, were not influenced by tillage and maize crop. The tractor wheel slip showed different results, being lower in no-tillage and higher in conventional and reduced tillage.

Fontes e parcelamento do nitrogênio em cobertura, na cultura do milho sob plantio direto

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Número de perfilhos do capim-braquiária em regime de lotação contínua

The study was conducted to identify, through assessments of tillering, appropriate management strategies for Brachiaria decumbens cv. Basilisk under continuous stocking with cattle. Two management strategies were studied: pasture with 25 cm throughout the experimental period, and pasture with 15 cm in winter and 25 cm in spring and summer. A split-plot and randomized block design with four replications were adopted. The management strategies represented the primary factor, and the seasons (winter, spring and summer) were the secondary factor. The lowest balance between rates of appearance (TAR) and mortality (TMR) of tillers and the lowest number of vegetative tillers occurred in winter. In spring and summer, the balance and number of vegetative tillers were higher and did not differ. The lowering of pasture in winter resulted in greater balance between TAR and TMR and higher number of tillers in relation to management on sward fixed at 25 cm. There were greater numbers of reproductive and dead tillers in summer and winter, respectively. The pastures with fixed height of 25 cm contained a higher number of dead tiller. Under continuous stocking, the lowering of B. decumbens pasture in winter and its increase to 25 cm in spring and summer optimizes turnover of tillers.

Taxa de semeadura de Brachiaria brizantha consorciada com milho na incidência de plantas daninhas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Produção, composição bromatológica e índice de clorofila de braquiárias após o consórcio com milho

We evaluated the effect of fertilization with 0, 50, 100 and 200 kg/ha of N, applied in each four growth intervals in the winter/spring season on dry matter yield in 30 days (DMY), leaf chlorophyll index (LCI) and total digestible nutrients (TDN), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin contents, and correlation equations of LCI with DMY and CP content in the marandu and ruziziensis grasses after intercrop arrangements with corn in Red Latosol (Oxisol) under irrigation. The major DMY occurred with photoperiod increasing, however, there were different responses to this attribute over of growth intervals, between and among the grasses with the N fertilization. In irrigated croplivestock integration under savannah soil is technicality viable the cultivation of marandu and ruziziensis grasses, established by intercrop with corn at sowing or at the N fertilization. As even, in the N fertilization absence, produced satisfactory amounts of forage, with 1733 kg/ha (DMY), at the time of greatest scarcity of roughage to animals (winter/spring season). However, after the corn harvest, the N fertilization increase the DMY and improves the chemical composition, increasing the LCI, and CP and TDN contents, and decreasing NDF and ADF contents in the winter/spring season.The best correlation equations in function of LCI were logatithmica for DMY and potential for CP of the marandu grass and potential for both attributes of the ruziziensis grass.

Efeito da antecipação da adubação nitrogenada na cultura do milho em sistema plantio direto

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)