Antonio Luiz Fancelli

Comportamento de espécies de adubos verdes em diferentes épocas de semeadura e espaçamentos na região dos Cerrados

RESUMO - Com o objetivo de avaliar o crescimento e desenvolvimento de leguminosas utilizadas como adubos verdes, instalaram-se tres ensaios, em tres epocas de semeadura e dois espacamentos na regiao dos Cerrados, durante o ano agricola de 1991/1992, na area experimental da Embrapa-Centro Nacional de Pesquisa do Solo (CNPS), em Senador Canedo, GO. As especies avaliadas foram Crotalaria juncea L., mucuna-preta (Mucuna aterrima (Piper & Tracy) Merr.), guandu cv. Kaki (Cajanus cajan (L.) Millsp.) e Crotalaria ochroleuca G. Don. O delineamento experimental utilizado, dentro de cada epoca, foi o de blocos ao acaso com parcelas subdivididas, com tres repeticoes. Os resultados indicaram que C. juncea e C. cajan apresentaram as maiores producoes de fitomassa seca. O atraso da semeadura, em relacao ao inicio da estacao chuvosa, reduziu os rendimentos de fitomassas verde e seca produzidos pelas leguminosas, exceto pela mucuna-preta. Os espacamentos de 0,5 m e 0,4 m nao influenciaram o periodo para o florescimento e as producoes de fitomassas verde e seca. Termos para indexacao: Mucuna aterrima, Crotalaria juncea, Crotalaria ochroleuca, Cajanus cajan , adubacao verde. EVALUATION OF GREEN MANURES IN DIFFERENT SOWING DATES AND ROW-SPACINGS IN THE CERRADOS REGIONIn 1991/1992 growing season, three field experiments were carried out to evaluate the growth and development of sunn ( Crotalaria juncea), Crotalaria ochroleuca, black velvet bean ( Mucuna aterrima), pigeon pea cv. Kaki ( Cajanus cajan) as green manures at three sowing dates and two row spacings at Embrapa-Centro Nacional de Pesquisa de Solos (CNPS), Senador Canedo, GO, Brazil. The experimental design used was a complete randomized block with split-plot and three replicates . Highest yields of dry matter were obtained with C. juncea and C. cajan. The delay in sowing dates to the beginning of the rainy season, reduced yield of fresh and dry matter of all legume species, except black velvet bean. Row-spacings of 0,5 and 0,4 cm did not influence the time for flowering and the yield of fresh and dry matter.

Manejo do solo e o rendimento de soja, milho, feijão e arroz em plantio direto

O sistema de plantio direto tem sido adotado expressivamente por agricultores do cerrado brasileiro. Contudo, seu uso continuado em regioes tropicais, com insuficiencia de cobertura do solo e sucessivas adubacoes superficiais, pode resultar em alteracoes nos parâmetros do solo, como compactacao e acumulo de nutrientes na superficie, e na baixa expressao do potencial produtivo das culturas. O presente estudo teve como objetivo principal verificar o efeito de quatro sistemas de manejo de solo (plantio direto; grade aradora; escarificacao profunda e aracao profunda) associados com tres niveis de adubacao fosfatada e potassica (sem adubacao, recomendacao oficial e equivalente a exportacao pelas colheitas) sobre o rendimento das culturas do milho, soja, feijao e arroz em area submetida a plantio direto durante oito anos. Os experimentos com soja, milho, arroz e feijao foram conduzidos em um Latossolo Roxo eutrofico no esquema de faixas e delineamento de blocos completos casualizados, com quatro repeticoes. Avaliou-se ainda o rendimento de graos. Nao houve resposta da soja aos diferentes manejos do solo nem aos niveis de adubacao. Ja a aracao profunda resultou nos maiores rendimentos de milho, arroz e feijao, sendo intermediarios os efeitos devidos a escarificacao. Exceto para o feijao, nestas culturas tambem nao se verificou efeito da adubacao.

Características químicas de solo e rendimento de fitomassa de adubos verdes e de grãos de milho, decorrente do cultivo consorciado

A adubacao verde e uma das formas de aporte de materia orgânica ao solo. O sistema de cultivo consorciado de culturas pode ser uma alternativa para aumentar a reciclagem de nutrientes e melhorar a produtividade. Para avaliar o sistema consorciado de adubos verdes com o milho, foram estudadas as caracteristicas quimicas do solo, a producao de materia seca, a composicao mineral de adubos verdes e o rendimento de graos de milho, num experimento realizado em campo, entre 1995 e 1997, em solo classificado como Nitossolo Vermelho eutrofico. O milho foi semeado no espacamento de 90xa0cm nas entrelinhas, perfazendo, aproximadamente, 50.000xa0plantas por hectare. Os tratamentos constaram de quatro especies de adubos verdes: mucuna ana [Mucuna deeringiana (Bort.) Merr], guandu anao (Cajanus cajan L.), crotalaria (Crotalaria spectabilis Roth) e feijao-de-porco (Canavalia ensiformis L.) e um tratamento-testemunha, sem cultivo consorciado. Essas especies foram semeadas sem adubacao, no meio da entrelinha, em duas epocas: simultânea ao milho e 30xa0dias apos. O delineamento experimental foi o de blocos ao acaso em parcelas subdivididas, com quatro repeticoes. O feijao-de-porco apresentou maior producao de fitomassa e acumulo de N, P, K, Ca, Mg e S. No primeiro ano de cultivo, o rendimento de graos de milho nao foi influenciado pelo cultivo consorciado com adubos verdes; no entanto, no segundo, a producao foi beneficiada pelo consorcio com feijao-de-porco.

Produtividade do Panicum maximum cv. Mombaça irrigado, sob pastejo rotacionado

Irrigation of tropical grasses is a reality based on the empirical knowledge of farmers, having no scientific evidence. This field experiment was carried out to evaluate the productivity of the Mombaca grass (Panicum maximum Jacq.cv. Mombaca) under rotational grazing and center pivot irrigation, and the main weather attributes responsible for increases of the Mombaca dry mass yield. The experiment was carried out from July to December 1998, in the Central Brazilian Savannah region (Typic Haplustox), Sao Desiderio, Bahia, Brazil. The Mombaca forage mass was measured at 30 days of growth and before each grazing. Mathematical models were developed to relate the forage productivity to weather attributes. The dry mass yield and the rate of growth, during the winter season, were not statistically different. Even though, both of them increased during the spring season, with the higher dry mass yield at the end of the experimental evaluation period. The lower growth rates, during the spring season, were observed in the initial period, corresponding to lower air temperatures during the pasture rest period. With the increase of the minimum air temperature, the dry mass yield also increased. The forage yield was higher during the spring season as compared to the winter season, because of the higher minimum air temperature during the rest period, and of the initial leaf area. At the Savannah region, the main attributes responsible for increasing the Mombaca dry mass yield were minimum air temperature and soil water availability.

PROPRIEDADES DO SOLO E SISTEMA RADICULAR DO FEIJOEIRO IRRIGADO EM ROTAÇÃO DE CULTURAS

Root system growth of the common bean, variety IAC-Carioca, under center pivot irrigation in rotation with fallow; corn; black oat; sunn hemp (Crotalaria juncea L.); pigeon pea [Cajanus cajan (L.) Millsp.] and velvet bean (Mucuna aterrima) was evaluated during a non-conventional (Autumn - Winter) cultivation period, from 1993 to 1995, on a typic Haplorthox soil, at an experimental area of the Instituto Agronomico, in Ribeirao Preto, Sao Paulo, Brazil. The crop sequences of common bean with corn and green manure reduced the soil resistance to penetration into the ploughed layer; maintained the normal contents of the soil organic matter; reduced acidity and increased the base saturation index in depth, in relation to the initial content. The basic infiltration rate was increased with the inclusion of velvet bean, sunn hemp and corn in the crop sequence. Effective root depth (80% of the total) was around 0.35 to 0.40 m.

INFLUENCE OF INTERCROPPED COMMON VETCH (VICIA SATIVA L.) AND NAKED OAT (AVENA STRIGOSA) ON BIOMASS PRODUCTION AND NITROGEN ADDITION

The effect of intercropping common vetch (Vicia sativa L.) with naked oat (Avena strigosa Schieb.) at different seed proportions was evaluated. The trial was set up on a Red Yellow Podzolic soil of Santa Maria, RS, Brazil. The treatments were the following: 1- 100% E (common vetch); 2- 90% E + 10% A (naked oat); 3- 75% E + 25% A; 4- 50% E + 50% A; 5- 25% E + 75% A; 6- 100% A; 7- fall tillage organized in four randomized blocks. Biomass production was evaluated at the flowering stage in an area of 0.8 m2 per plot. Data show that both species can be intercropped which is beneficial to biomass production and nitrogen accumulation.

RENDIMENTO DO FEIJOEIRO IRRIGADO EM ROTAÇÃO COM CULTURAS GRANÍFERAS E ADUBOS VERDES

An experiment was carried out from May 1992 to January 1996 to study the residual effect of grain and green manure crops on the grain yield of irrigated common bean, variety IAC-Carioca. The experiment was installed at the Experimental Station of Instituto Agronomico, at Ribeirao Preto, Sao Paulo State, Brazil, in a typic Haplorthox soil. The experimental design was a randomized complete block with six treatments and six replications. The rotation schemes consisted of irrigated common bean from July to December, followed by an early variety of corn, from December to April and by fallow, corn, oats (Avena strigosa), sunnhemp (Crotalaria juncea L.), pigeonpea [Cajanus cajan (L.) Millsp.] and velvet beans (Mucuna aterrima), from March to August. The soil nutrient contents at 0-20 cm depth, were reduced during the three year period, being normal for organic matter and medium for phosphorus, potassium, calcium and magnesium. The medium to high acidity level did not restrict the grain yield of common beans. The inclusion of velvet bean, sunnhemp and corn in rotation with common bean and corn is feasible. These crops produced the greatest amounts of green matter. The basic infiltration rate of the soil was also increased. There was an effect of the rotations during the years with the inclusion of velvet bean, in the non-conventional Autumn-Winter season, which increased the grain yield of irrigated common beans in relation to the fallow treatment.

Produção e estado nutricional do milho em cultivo intercalar com adubos verdes

The use of green manure to establish diversity and equilibrium of a crop system is one of the paragons in modern agriculture.Soil samples and green manure species intercropped with maize were evaluated in a field experiment, from 1995 to 1997, carried out in an Aleudalf Soil, located in Piracicaba (SP)Maize seeds were planted at 0.90 meter spacing within lines totaling 50,000 plants per hectare.The treatments were performed with four green manure species: dwarf mucuna (Mucuna deeringiana (Bort.) Merr), dwarf pigean pea (Cajanus cajan (L.) Millisp), crotalaria (Crotalaria spectabilis Roth), jack beans (Canavalia ensiformis (L.) DC.), and a control treatment without green manure.Seeds of green manure species were planted between maize lines at 45: cm distance without fertilization simultaneously with maize and 30 days after maize planting.In the first year, the soil was prepared under a conventional system; in the second year, cultivation was seedling under no tillage system, using randomized blocks in a split plot design with four replicates.The nutritional status and grain production of maize showed the best results in the system intercropped with jack beans.The positive effects of this species on maize productivity were more evident in the second year of the intercropped system, with seedling under no tillage system.The simultaneous planting of maize and green manure species is the most recommended management practice, because maize growth is not affected by any other planting activities.

EFEITO DE ÉPOCAS DE SEMEADURA NA FISIOLOGIA E PRODUÇÃO DE FITOMASSA DE LEGUMINOSAS NOS CERRADOS DA REGIÃO DO MATOGROSSO DE GOIÁS

The use of green manure is not a common conservation practice in cerrado regions. In order to investigate the phenological characteristics and mineral composition of leguminous plants used as green manure at different sowing times, three experiments were conducted during the 1991/92 growing seasons at the Soils National Research Center/West Center Coordination - EMBRAPA, in EMGOPAs Experimental Station, Senador Canedo, GO. Four species, Crotalaria juncea L., Mucuna aterrima (Piper & Tracy) Merr., Cajanus cajan (L.) Millsp. and Canavalia brasiliensis, were tested for three sowing dates. A randomized block design was used, with three replications. The results obtained allow the following conclusions: 1) In all sowing dates Crotalaria juncea e o Cajanus cajan showed the highest dry matter yield; 2) The sowing delay in relation to the begining of the rainy season accelerates flowering of the leguminous plants and decreased the dry matter yield of C. juncea and C. cajan.

Absorção de N, P e K por espécies de adubos verdes cultivadas em diferentes épocas e densidades num latossolo vermelho-escuro argiloso sob cerrados

Planting spacings and sowing dates may influence nutrient absorption. Therefore, a field experiment was carried out from 1991 to 1992, at the experimental station of Embrapa/Soil Research National Center, located in Senador Canedo, Goias, Brazil, to determine the N, P and K uptake levels in the aerial part of sunhemp (Crotalaria juncea), Crotalaria ochroleuca, black velvet bean (Mucuna aterrima) and pigeonpea cv. Kaki (Cajanus cajan), under three sowing times (beginning, middle and end of the growing season) and two spacings between the planting rows. The experiment was arranged in a randomized split plot design, with three replications, with the sowing dates in the main plots and the planting spacings in the split plots. The results indicated that there the levels of N, P and K uptake varied among the species. N, P and K uptake levels in the legume shoot dry matter were influenced by the sowing times, and the species x sowing time interaction was significant for N and P. Nevertheless, N, P and K uptake levels were not influenced by the spacings between the planting rows.