Cícero Monti Teixeira

Adubação verde na produção orgânica de alface americana e repolho

The exclusive use of organic compost in the production of organic vegetables has been found to be a costly practice due to the high volume of compost demanded to obtain commercial productions. Thus, one of the alternatives for complementary fertilization of vegetables is the use of green manure. The objective of this work was to evaluate three green manure species, used to complement the fertilization with organic compost, in relation to the nutrient contents in their biomass, and to productivity and agronomic traits of crisphead lettuce and cabbage. The experiment was carried out at the Olericulture Sector of the Federal University of Lavras (UFLA), in Lavras, Minas Gerais State, Brazil, from December 2001 to August 2002, in a soil classified as Udox. The experiment was arranged in a randomized block design in a factorial scheme (4x2) with three repetitions. The first factor was constituted by the green manure species: black-velvet bean (Stizolobium aterrimum), jack bean (Canavalia ensiformis), and sunnhep (Crotalaria juncea), plus a control treatment (weed and mineral fertilizers); and the second factor was constituted by the vegetable crops: crisphead lettuce and cabbage. Among the tested green manure species, sunnhep presented the best potential for extraction of N, P, K, Mg, B, Mn and Zn. In addition, sunnhep was more efficient than jack bean or black velvet bean in increasing the commercial weight of cabbage head. In relation to productivity, as for lettuce, green manuring plus organic compost did not differ from the control; while for the cabbage, these treatments had a performance statistically inferior. The use of green manure plus organic compost allowed to obtain commercial crisphead lettuce and cabbage heads with satisfactory weight for the market.

Produção de biomassa e teor de macronutrientes do milheto, feijão-de-porco e guandu-anão em cultivo solteiro e consorciado

Objetivou-se determinar a producao de biomassa e o teor de macronutrientes do milheto (Pennisetum typhoides (Burm.) Stapf), feijao-de-porco (Canavalia ensiformes (L.) DC.) e guandu-anao (Cajanus cajan (L.) Millsp.) em cultivo solteiro e nos consorcios da graminea com as leguminosas, visando a producao de palha no sistema plantio direto. O trabalho foi conduzido no campo experimental do Departamento de Agricultura da Universidade Federal de Lavras (Lavras, MG, Brasil). O delineamento foi o de blocos casualizados, com cinco tratamentos e quatro repeticoes. Apenas o guandu-anao solteiro apresentou menor producao de fitomassa fresca e seca, sendo que os demais tratamentos nao diferiram entre si, pelo teste de Tukey a 5% de probabilidade. De forma geral, as leguminosas apresentaram maiores teores de N e Ca e o milheto maiores teores de S. Apenas o feijao-de-porco solteiro apresentou menor teor de P. Os maiores teores de K foram apresentados pelo milheto solteiro e consorciado com as leguminosas e pelo feijao-de-porco em consorcio com milheto. Os menores teores de Mg foram verificados para o guandu-anao.

Liberação de macronutrientes das palhadas de milheto solteiro e consorciado com feijão-de-porco sob cultivo de feijão

Nutrients recycle is related to the absorption capacity by different cover crop species. Already speeds of decomposition and of nutrient release of straws produced is mostly related with C/N ratio, with a marked difference between grasses and leguminous. In this sense, the objective of this study was to evaluate the biomass production and macronutrient contents and accumulation, decomposition, and nutrient release from straw of millet (Pennisetum typhoides (Burm.) Stapf) and millet - jack - bean (Canavalia ensiformes (L.) DC.) intercropping, under field conditions, under common bean, sown in August (winter/spring). Decomposition and nutrient release was determined in nylon bags (0.2 x 0.2 m, 1 mm mesh) filled with straw quantities according to the area of the bag. The experimental design was randomized blocks with four replications in split plot arrangement. The straws represented the plots and the subplots evaluation periods (0, 8, 16, 24, 40, 56, and 72 days). The residues were dried to constant weight in a forced-air oven at 65 oC to determine the remaining dry matter, then ground and sent to a laboratory to analyze macronutrient contents. Based on the contents and remaining dry matter amounts, the remaining nutrient amounts were determined, expressed in relation to the initial amount. Non-linear models were fit to the values, choosing the best adjustment in each case. Biomass quantity, N and Ca contents and cycling of nutrient quantities was greatest in the intercropping straw. The decomposition and nutrient release speeds were also highest in millet - jack - bean intercropping straw.

Potencial alelopático de plantas de cobertura no controle de picão-preto (Bidens pilosa L.)

Extratos aquosos da parte aerea de mucuna-preta (Stilozobium aterrimum Piper & Tracy), mucuna rajada (Stilozobium sp.), Crotalaria juncea L., Crotalaria spectabilis Roth, guandu e guandu anao (Cajanus cajan (L.) Druce) foram preparados com o objetivo de se determinar a potencialidade alelopatica dessas especies, largamente utilizadas como plantas de cobertura, sobre sementes de alface (planta-teste) e aquenios de picao-preto (Bidens pilosa L.). Os experimentos foram conduzidos no Laboratorio de Analise de Sementes da Universidade Federal de Lavras, durante o mes de abril de 2003. Foram avaliados o indice de velocidade de germinacao (IVG) e a germinacao final. No experimento com alface, houve reducao significativa da germinacao apenas para o extrato aquoso de crotalaria juncea. Para as outras especies, houve uma tendencia de reducao na germinacao, porem, nao diferindo da testemunha com agua destilada. O IVG apresentou reducao significativa nos tratamentos com extratos aquosos de crotalaria juncea, guandu comum, mucuna-rajada e mucuna-preta. As outras especies tiveram uma tendencia em reduzir o IVG, porem, nao diferindo da testemunha. No experimento com picao-preto, a germinacao apresentou comportamento semelhante ao experimento com alface, com reducao significativa apenas para o tratamento com crotalaria juncea, porem, para o IVG, houve reducao significativa apenas para a mucuna-preta, com uma tendencia de reducao para os tratamentos com as outras especies, mas nao diferindo da testemunha.

Fitomassa, teor e acúmulo de micronutrientes do milheto, feijão-de-porco e guandu-anão, em cultivo solteiro e consorciado

Intercropping leguminous with gramineous crops for straw production in no-tillage systems aims to conciliate soil protection (through greater durability of gramineous crops) with nitrogen fixation and faster micronutrient availability (through leguminous decomposition). Therefore, an experiment was conducted with the intention of evaluating phytomass production as well as micronutrient levels and accumulation in millet (Pennisetum typhoides (Burm.) Stapf), jack bean (Canavalia ensiformes (L.) DC.), and pigeon pea (Cajanus cajan, dwarf cultivar), as sole crops and intercropping gramineous with leguminous crops, for straw production in a no-tillage system. The experiment was carried out in the experimental field at the Agriculture Department of the Federal University of Lavras (Lavras, Minas Gerais state, Brazil). The experimental was conducted using a randomized block design, with seven treatments for species nutrient levels under different conditions (sole crops or intercropping) and five treatments for phytomass production and micronutrient accumulation, with four replications. For phytomass production, only the pigeon pea sole crop displayed lower yield of fresh and dry phytomass, while the others produced on average 12.361 and 2.854 t ha-1 of fresh and dry phytomass yield, respectively. There were significant differences in B, Cu and Zn levels, and in accumulation of all evaluated micronutrients. The leguminous species presented the greatest B levels, with the greatest Cu and Zn levels found in millet. In general, millet plus jack bean intercropping presented the greatest micronutrient accumulation.

Micronutrient phytomass, levels and accumulation in millet, jack bean and pigeon pea, as sole crops and in intercropping

Intercropping leguminous with gramineous crops for straw production in no-tillage systems aims to conciliate soil protection (through greater durability of gramineous crops) with nitrogen fixation and faster micronutrient availability (through leguminous decomposition). Therefore, an experiment was conducted with the intention of evaluating phytomass production as well as micronutrient levels and accumulation in millet (Pennisetum typhoides (Burm.) Stapf), jack bean (Canavalia ensiformes (L.) DC.), and pigeon pea (Cajanus cajan, dwarf cultivar), as sole crops and intercropping gramineous with leguminous crops, for straw production in a no-tillage system. The experiment was carried out in the experimental field at the Agriculture Department of the Federal University of Lavras (Lavras, Minas Gerais state, Brazil). The experimental was conducted using a randomized block design, with seven treatments for species nutrient levels under different conditions (sole crops or intercropping) and five treatments for phytomass production and micronutrient accumulation, with four replications. For phytomass production, only the pigeon pea sole crop displayed lower yield of fresh and dry phytomass, while the others produced on average 12.361 and 2.854 t ha-1 of fresh and dry phytomass yield, respectively. There were significant differences in B, Cu and Zn levels, and in accumulation of all evaluated micronutrients. The leguminous species presented the greatest B levels, with the greatest Cu and Zn levels found in millet. In general, millet plus jack bean intercropping presented the greatest micronutrient accumulation.

Fitomassa, teor e acúmulo de micronutrientes do milheto, feijão-de-porco e guandu-anão, em cultivo solteiro e consorciado - DOI: 10.4025/actasciagron.v30i4.5314

Intercropping leguminous with gramineous crops for straw production in no-tillage systems aims to conciliate soil protection (through greater durability of gramineous crops) with nitrogen fixation and faster micronutrient availability (through leguminous decomposition). Therefore, an experiment was conducted with the intention of evaluating phytomass production as well as micronutrient levels and accumulation in millet (Pennisetum typhoides (Burm.) Stapf), jack bean (Canavalia ensiformes (L.) DC.), and pigeon pea (Cajanus cajan, dwarf cultivar), as sole crops and intercropping gramineous with leguminous crops, for straw production in a no-tillage system. The experiment was carried out in the experimental field at the Agriculture Department of the Federal University of Lavras (Lavras, Minas Gerais state, Brazil). The experimental was conducted using a randomized block design, with seven treatments for species nutrient levels under different conditions (sole crops or intercropping) and five treatments for phytomass production and micronutrient accumulation, with four replications. For phytomass production, only the pigeon pea sole crop displayed lower yield of fresh and dry phytomass, while the others produced on average 12.361 and 2.854 t ha-1 of fresh and dry phytomass yield, respectively. There were significant differences in B, Cu and Zn levels, and in accumulation of all evaluated micronutrients. The leguminous species presented the greatest B levels, with the greatest Cu and Zn levels found in millet. In general, millet plus jack bean intercropping presented the greatest micronutrient accumulation.

Componentes de produção do milho em diferentes épocas de adubação nitrogenada em cobertura nos sistemas de plantio convencional e direto

The objective of this work was to evaluate the maize production components in conventional and in no-till systems, under the straw of black oat (Avena strigosa Sereb), after different epochs of N fertilization in coverture. The black oat produced 6,37 t ha-1 of straw. It was not verified significant difference between the epochs of fertilization and plantation systems for the characteristics: stand, plant height, ear height, number of ears per plant, broken and fallen plants and productivity. The female flowering was faster in the conventional than in no-till system, because plant emergency is quicker than in no-till. The time of female flowering for conventional and for no-tillage system was 74 and 76 days, respectively