Micronutrient deficiency effect on the nutritional status of the castor bean cultivar IrisAbstract -The objectives of this work were to characterize the visual symptoms of micronutrient deficiencies, and their effects on nutricional status of castor beans. A greenhouse experiment with nutrient solutions was carried out from February to June, 2003. The commercial hybrid "Iris" was used. Treatments were as follows: complete, minus B, minus Cu, minus Fe, minus Mn, minus Mo, and minus Zn. Symptoms of deficiency were observed in the treatments with omission of B, Fe, and Mn. The symptoms firstly developed when either Fe or Mn was deficient, and they were followed by those deficient in boron. Dry matter yield was affected in the decreasing order: Fe>Mn>B. Both upper and lower leaves reflect the nutritional status of the castor bean with respect to B, Cu, Fe, Mn, Mo and Zn. Leaf chlorophyll, as measured in units SPAD, was influenced by the treatments.
Agronomic performance of cauliflower genotypes under climatic conditions of SinopThe productivity of cauliflower depends on the interaction between genotype and environmental conditions. To minimize this effect it is necessary to identify genotypes with good stability and wide adaptability to different environmental conditions. We evaluated the agronomic performance and adaptability of cauliflower cultivars at Sinop, Mato Grosso state, Brazil, under field conditions in the period from March 4 th to July 22 nd , 2011. The experimental design was randomized blocks with eight treatments (Verona 184; Venice, Verona 284; First Snow; Sahara; Luna F1; Piracicaba Precoce and Quatro Estações) and eleven replications. The plots consisted of 36 plants distributed on the spacing of 80x60 cm and 16 plants were evaluated. The following characteristics were evaluated: fresh weight, curd diameter, yield, cycle and inflorescence classification. The hybrid cultivars Verona 184, Verona 284, Venice, Luna F1, First Snow and Sahara showed yield of 18.90; 18.70; 16.68; 16.14; 15.65 and 15.50 t ha -1 respectively and were classified as Extra. However, the cauliflower cultivars Piracicaba Precoce and Quatro Estações showed low productivity (6.67 and 5.12 t ha -1 , respectively) beyond its classification in category III. The hybrids Verona 184, Verona 284, Veneza, Luna F1, First Snow and Sahara present adaptation to be grown under the climatic conditions of Sinop. Cultivars Piracicaba Precoce and Quatro Estações are unfit for cultivation in Sinop because of its low yield and head quality.
INTroduçãoo uso de cana-de-açúcar pelos pecuaristas tem aumentado significativamente. As principais vantagens associadas ao uso da cultura como volumoso são a facilidade de implantação e manejo, por tratar-se de uma cultura semiperene que apresenta baixo custo de manutenção, possibilidade de autoarmazenamento ou conservação a campo e rendimentos de até 120 t ha -1
Nutrients found in residues from agricultural cultures are important reserves for subsequent crops. The objective was to assess the decomposition and release of nutrients from different crop residues for subsequent soybean cultivation. The study was conducted in Mid-Northern Mato Grosso State, Brazil. The residual straw of cropping systems -maize, brachiaria and maize/brachiaria consortium -were sampled, weighted, disposed in litter bags and then distributed on the soil. The adopted experimental design followed the completely randomized arrangement with three repetitions. Treatments were determined based on harvest time, which was performed every 14 days within 140 days for maize, and within 154 days for brachiaria and for the consortium. The remaining dry matter and nutrients content, and half-time life were evaluated. Maize showed the highest straw dry matter yield (14,176 kg ha -1 ), and the consortium recorded the biggest nutrient accumulation per hectare (K=172.2; N= 141.7 and Ca=56.0 kg ha -1 ). Brachiaria straw presented the fastest decomposition rate (85%) and the highest nutrient release (K=99%; N=92%; Mg=98% and Ca=90% of total initial content). The total K released reached 150 kg ha -1 , which can fit the needs of soybean crops.Key words: crop management; integrated; mixed systems; nutrient cycling Decomposição e liberação de nutrientes de resíduos de culturas no sistema de cultivo soja-milho RESUMO: Os nutrientes contidos nos restos culturais representam uma importante reserva para culturas subsequentes. O objetivo foi avaliar a decomposição e a liberação de nutrientes de diferentes resíduos de culturas para subsequente cultivo da soja. O estudo foi realizado na região Médio Norte do estado de Mato Grosso, Brasil. A palhada residual dos sistemas de cultivo; milho, braquiária e consórcio milho/braquiária foram amostrados, pesados e acomodadas em litter bags e distribuídos sobre o solo. O design experimental foi o inteiramente casualizado com três repetições. Os tratamentos foram estabelecidos com base no tempo de colheita, realizado a cada 14 dias, em um período de 140 dias para o milho e 154 dias para a braquiária e consórcio, aonde foi avaliando a permanência da matéria seca e nutrientes e o tempo de meia vida. O milho apresentou a maior produtividade de matéria seca (14.176 kg ha -1 ), e o consórcio o maior acúmulo de nutrientes por hectare (K=172,1; N= 141,7 e Ca=56,0 kg ha -1 ). A braquiária apresentou a maior taxa de decomposição (85%) e a maior porcentagem de liberação de nutrientes (K=99%; N=92%; Mg=98% e Ca=90% do conteúdo inicial). A quantidade de K liberado pode ser de até 150 kg ha -1 o que pode corresponder às necessidades da soja.Palavras-chave: manejo de culturas; integrados; sistemas mistos; ciclagem de nutrientes Decomposition and release of nutrients from crop residues on soybean-maize cropping systems Rev. Bras.
RESUMONos últimos anos, tem-se procurado elevar os teores de C orgânico do solo e, ao mesmo tempo, aumentar a produtividade das culturas. Neste contexto, o sistema semeadura direta (SSD) tem importante participação, principalmente na região dos Cerrados. Entretanto, para se alcançar altas produtividades, as gramíneas requerem a adição de doses elevadas de adubos nitrogenados. Este trabalho teve por objetivo avaliar as alterações no solo decorrentes da aplicação de palha e de N em solo cultivado com milho por 10 anos (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001) em SSD. O experimento foi desenvolvido na Embrapa-Milho e Sorgo, em Sete Lagoas-MG, em um Latossolo Vermelho distrófico típico sob cerrado. Os tratamentos constaram da combinação de palha sobre o solo (0, 3, 6, 9 e 12Mg ha -1 de matéria seca) dispostas nas parcelas, e de cinco níveis de N aplicados em cobertura (0, 40, 80, 120 e 160kg ha -1 ), na forma de uréia, dispostos nas subparcelas. Foram realizadas duas coletas de solo (antes e após uma calagem), nas profundidades de 0-0,025; 0, 025-0,05; 0,05-0,10; 0,10-0,20; 0,20-0,40m. Análises químicas e físicas de rotina foram efetuadas usando-se métodos padrões. Os teores de C orgânico e de K foram influenciados pelas doses de palha e aumentaram à medida que se aumentou a aplicação de palha sobre o solo. A variação nas doses de N promoveu alterações no pH, nos teores de Ca, Mg e nas saturações por bases e por Al até a profundidade de 0,20m. A calagem superficial promoveu o aumento do pH do solo em profundidade e dos teores de Ca, até 0,20m, provavelmente devido à alta pluviosidade no período pós-calagem (1600mm em oito meses). Palavras-chave: calagem superficial; adubação nitrogenada;Latossolo; Cerrados. ABSTRACTAgricultural practices have been trying to increase the content of organic C in soils and at the same time to increase yields. In this context, the no-till system (NTS) has an important role to play, particularly in the Cerrado region of Brazil. However, to reach high yields, the crops demand high inputs of N fertilizers. The objective of this work was to evaluate the modifications induced in the soil after ten years (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001) of NTS, influenced by different straw and N doses. The experiment was set at the Embrapa farm in Sete Lagoas-MG, on a typic Dystrofic Red Latosol under Cerrado vegetation. The treatments consisted of five straw doses (0, 3, 6, 9 e 12Mg ha -1 of dry matter) in the plot and five doses of N (0, 40, 80, 120 e 160kg ha -1 ) as urea in the subplot. Two samplings were accomplished, before and after liming. The soil layers sampled were 0-0.025; 0.025-0.05; 0.05-0.10; 0.10-0.20; and 0.20-0.40m. Routine soil physical and chemical variables were measured according to standard procedures. The contents of organic C and K were influenced by the different straw doses and increased as the application of straw increased. The different doses of N influenced pH, Ca, Mg, Al, base and Al saturation, up to 0.20m. The surfac...
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