Salatiér Buzetti

Alterações nas propriedades físicas de um latossolo vermelho-escuro sob diferentes culturas

The present work had the objective to analyze the alterations of the physical properties of a dark-red Latosol (typic acrustox), under different use systems. In 1996, samples of soils were collected, under corn crop, pinus, eucalyptus, pasture, ciliary forest (after 10 years of cultivation), and native cerrado vegetation, in three depths (0,00-0,10; 0,10-0,20, and 0,20-0,40 m), in the experimental station from Faculdade de Engenharia de Ilha Solteira - UNESP, located in Selviria county (MS). The experimental design was the totally randomized, with 18 treatments and 10 replications. In the different treatments the macroporosity, microporosity, total porosity, bulky density, texture, and resistance to penetration were determined. By the results we may conclude that alterations of the physical properties of the soil occurred in the different areas, compared to natural condition; the area with ciliary forest and pinus are closer to the natural conditions, presenting an accommodation of the superficial layer; the other areas of the soil; the areas presented greatest alterations in depths of the 0,00-0,10 m, except for the area with annual crop.

Resposta de cultivares de arroz a doses de nitrogênio e do regulador de crescimento cloreto de clormequat

The objective of this work was to evaluate N rates (0, 50, 100 and 150 kg ha-1) and the growth regulator chlormequat chloride effect (0, 1 e 2 L ha-1) on some agronomic characteristics of rice cultivars IAC 201 and IAC 202. The experimental design was a randomized block with four replicates. Nitrogen was applied as side-dressing at flower differentiation and the growth regulator was split in two times and applied at 20 and 30 days after seedlings emergency (tillering). In the harvests of 2001/2002, there was no significant effect of N rates on plant height, panicle length, spikelet per panicle, 100-grain mass and grain yield. The growth regulator rates were significant for panicle length and spikelet per panicle. IAC 202 presented higher grain yield. In the harvest of 2002/2003 there was no effect of N rates on plant height, spikelet fertility, 100-grain mass and grain yield. The growth regulator rates had no effect on tested characteristics, and IAC 202 cultivar presented higher grain yield.

Produtividade e composição bromatológica do capim-marandu a fontes e doses de nitrogênio

Objetivou-se, no trabalho, avaliar o efeito de doses e fontes de nitrogenio nas caracteristicas produtivas e qualitativas da Brachiaria brizantha cv. Marandu. O delineamento experimental utilizado foi o de blocos ao acaso, em esquema fatorial 5x3x3 (5 doses de N, 3 fontes de nitrogenio e 3 cortes), com 4 repeticoes. As doses de N foram: 0, 50, 100, 150, 200 kg/ha/corte, com as fontes: Entec - sulfonitrato de amonio + inibidor de nitrificacao (dimetilpirazolfosfato), Sulfato de Amonio e Ureia, sendo os cortes realizados em novembro/2006, dezembro/2006 e janeiro/2007. As coletas foram realizadas com intervalos entre corte de 30, 30 e 34 dias onde se determinou a produtividade de massa seca, teor de proteina bruta (PB), fibra em detergente neutro (FDN), fibra em detergente acido (FDA), nutrientes digestiveis totais (NDT) e teor de clorofila. As leituras no clorofilometro foram lineares crescentes quando se utilizaram o Entec e a Ureia, ate 200 kg/ha de N e, ate 174 kg/ha de N, com a utilizacao do Sulfato de amonio; apresentando correlacao significativa com os teores de N na planta. Independente da fonte nitrogenada, a aplicacao de doses crescentes de ate 200 kg de N/ha/aplicacao na forrageira Brachiaria brizantha cv. Marandu proporcionou incremento na producao de massa seca, melhorando a composicao bromatologica por aumentar os teores de PB e NDT e, diminuicao dos teores de FDN e FDA.

Doses, fontes e épocas de aplicação de nitrogênio em trigo irrigado em plantio direto

The objective of this work was to evaluate the effects of different doses and sources of nitrogen, applied at sowing or at side-dressing, on the yied components and grain yield of irrigated wheat, under no-tillage. Nitrogen sources with or without the nitrification inhibitor (Entec) were used for applications at sowing or at side-dressing periods. Wheat was cultivated in Selviria, state of Mato Grosso do Sul, Brazil in a low-altitude Cerrado region. A randomized block design was used in the factorial arrangement 5x3x2, with four replicates. Treatments consisted of the combination of: five N doses, 0, 50, 100, 150 and 200 kg ha-1; three sources, Entec, ammonium sulfate, and urea; and two application times, at sowing, near of the lines, or at side-dressing. The different N sources had similar influence on plants height and grain yield of irrigated wheat. Nitrogen applications, totally at sowing and in the traditional way, at sowing and at side-dressing, are both equally viable. The increment of the N doses up to 121.5 kg ha-1 increases the grain yield, independently of application time and N source.

Aproveitamento do nitrogênio (15N) da crotalária e do milheto pelo milho sob plantio direto em Latossolo Vermelho de Cerrado

The cultivation of green manure in the fallow ground alter the dynamics and the recovery of the nitrogen by corn in the soil-plant system. The objective of this work was to evaluate the utilization of nitrogen (15N) from sun hemp and millet by corn grown under different N rates in no-tillage in Red Latosol of Cerrado. The research was carried in the Experimental Farm of Faculty of Engineering, Sao Paulo State University (UNESP), Ilha Solteira, located in Selviria-MS, Brazil, during the 2001/02 and 2002/03 growing season. The experimental design was randomized complete blocks, with 15 treatments and four replications in a factorial 5 x 3, constituted by the combination of five N rates (0, 30, 80, 130 and 180kg ha-1), as urea, applied at four leaf stage; and three preceding cover crops: sun hemp, millet and fallow ground. The inorganic N promoted a synergic effect on the amount of absorbed N and utilization of sun hemp and millet N by the corn crop. The sun hemp, in average for two growing season, provided in the corn cultivated without the application of N an equivalent effect of the application of 56.0 and 73.0kg ha-1 as urea, compared to the corn grown in fallow soil and in succession to millet, respectively. The grain yield increased in a quadratic way in function of the N rates, in the two growing season.

Straw decomposition of nitrogen-fertilized grasses intercropped with irrigated maize in an integrated crop-livestock system

The greatest limitation to the sustainability of no-till systems in Cerrado environments is the low quantity and rapid decomposition of straw left on the soil surface between fall and spring, due to water deficit and high temperatures. In the 2008/2009 growing season, in an area under center pivot irrigation in Selviria, State of Mato Grosso do Sul, Brazil, this study evaluated the lignin/total N ratio of grass dry matter , and N, P and K deposition on the soil surface and decomposition of straw of Panicum maximum cv. Tanzânia, P. maximum cv. Mombaca, Brachiaria. brizantha cv. Marandu and B. ruziziensis, and the influence of N fertilization in winter/spring grown intercropped with maize, on a dystroferric Red Latosol (Oxisol). The experiment was arranged in a randomized block design in split-plots; the plots were represented by eight maize intercropping systems with grasses (sown together with maize or at the time of N side dressing). Subplots consisted of N rates (0, 200, 400 and 800 kg ha-1 year-1) sidedressed as urea (rates split in four applications at harvests in winter/spring), as well as evaluation of the straw decomposition time by the litter bag method (15, 30, 60, 90, 120, and 180 days after straw chopping). Nitrogen fertilization in winter/spring of P. maximum cv. Tanzânia, P. maximum cv. Mombaca, B. brizantha cv. Marandu and B. ruziziensis after intercropping with irrigated maize in an integrated crop-livestock system under no-tillage proved to be a technically feasible alternative to increase the input of straw and N, P and K left on the soil surface, required for the sustainability of the system, since the low lignin/N ratio of straw combined with high temperatures accelerated straw decomposition, reaching approximately 30 % of the initial amount, 90 days after straw chopping.

Doses e épocas de aplicação de nitrogênio no feijoeiro irrigado cultivado em plantio direto

O nitrogenio e o nutriente exigido em maiores quantidades pela cultura do feijao. A resposta a sua aplicacao depende da dose aplicada e da epoca de sua aplicacao. O objetivo deste trabalho foi avaliar os componentes de producao, produtividade de graos e a qualidade fisiologica de sementes de feijao, decorrentes de diferentes doses de N (ureia) aplicadas em cobertura em tres estadios da cultura. O experimento foi conduzido no sistema plantio direto. Os tratamentos foram constituidos por 0, 40, 80, 120,160, 200 e 240 kg ha -1 de N aplicados em cobertura nos estadios V 4-5 , R 5 e R 6 , correspondendo, respectivamente, a 21, 32 e 38 dias apos a emergencia das plantas. A qualidade fisiologica de sementes foi avaliada por meio do teste de germinacao e testes de vigor. O N aplicado nas diferentes fases da cultura nao interferiu nos componentes de producao. A maxima produtividade de graos foi obtida com 164 kg ha -1 de N em cobertura, independentemente do estadio de desenvolvimento. A qualidade fisiologica das sementes nao foi influenciada pelos tratamentos.

Estirpes de Rhizobium tropici na inoculação do feijoeiro

To evaluate five Rhizobium tropici strains and N fertilization on the productivity components of the common bean (Phaseolus vulgaris L.) crop, an experimental design of randomized blocks was used. The eight treatments consisted of five Rhizobium tropici strains (CIAT899; F35; F54; F81, and CM255), two controls without inoculation (30 kg ha-1 N with PK at sowing plus 30 kg ha-1 N as top dressing, and other without fertilization NPK) with the IAC Carioca cultivar and one non-nodulating cultivar (NORH54). Number of nodules per plant, shoot dry mass, leaf N content, number of pods per plant, number of grains per plant, number of grains per pod, 100 grain weight, and grain yield, were evaluated. The nodulating cultivar with inoculation or in soil with efficient native population can eliminate the N top dressing with no decrease in yield.

Efeito da rotação de culturas, adubação verde e nitrogenada sobre o rendimento do feijão

O presente trabalho foi conduzido na regiao de Selviria, MS, e teve como objetivo avaliar o efeito da incorporacao de mucuna-preta, lab-lab e restos culturais de milho no desenvolvimento e producao do feijao (Phaseolus vulgaris L.) de inverno. O delineamento experimental foi o de blocos ao acaso; os tratamentos foram constituidos pela combinacao do efeito da incorporacao de restos culturais do milho, mucuna-preta e lab-lab no desenvolvimento do feijoeiro, na presenca e ausencia de adubacao nitrogenada em cobertura. Pelos resultados obtidos nas condicoes experimentais, pode-se concluir que a incorporacao de mucuna-preta praticamente dobrou a producao de graos de feijao em relacao ao tratamento com incorporacao apenas de palhada de milho; as maiores produtividades foram obtidas nos tratamentos com incorporacao de mucuna-preta, lab-lab e milho + mucuna-preta semeada 100 dias apos a semeadura do milho, e a aplicacao de 45 kg ha-1 de N aumentou em 17,8% a produtividade do feijoeiro.

Utilização do nitrogênio da palha de milho e de adubos verdes pela cultura do milho

The quality of commercial crop residues and green manure influences the N mineralization-immobilization rate and the respective use by subsequent crops. With the objective of evaluating N utilization by corn of N from the shoot and root system of sunnhemp (Crotolaria juncea) and millet (Pennicetum americanum) and corn straw, labeled with 15N, a green house experiment was carried out at the Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, S. Paulo, Brazil, in 5 kg pots with dystroferric Red Latosol in a completely randomized design, with four replications and the following six treatments: T1 = 15N labeled corn straw (above ground part, except grains) (80 mg kg-1 N in soil); T2 = 15N labeled millet root (30 mg kg-1 in soil); T3 = 15N labeled millet shoot (80 mg kg-1 N in soil); T4 = 15N labeled sunnhemp root (30 mg kg-1 N in soil); T5 = 15N labeled sunnhemp shoot (80 mg kg-1 N in soil) and T6 = treatment without addition of organic N source. In the treatments with 15N labeled root application, unlabeled shoot at the same amount added as in those where labeled shoot was applied, and vice-versa. The roots were incorporated into the soil and shoots left on the surface. To evaluate N absorption from 15N corn straw (7.35 Mg ha-1, equivalent to 56 kg ha-1 N) by corn crop, a field experiment was carried out, in the same area where the soil for the green house experiment had been collected. The amount of corn N derived from sunnhemp (111.80 mg pot-1 N) was higher than from millet (30.98 mg pot-1 N), which in turn higher was than from corn plant residues (11.80 mg pot-1 N). Sunnhemp resulted in highest nitrogen absorption and dry matter weight of the corn crop. The corn utilized more N from sunnhemp shoot than from roots, but there was no difference in N derived from millet. The N absorption of corn from corn straw was 4.1 % of the initial amount in the field experiment.