Decomposição e liberação de macronutrientes da palhada de milho e braquiária, sob integração lavoura-pecuária no cerrado baiano

Lange

et al. 2018

Agraria

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.

Section: /8mentioning

confidence: 94%

Section: The Accumulation and Release Of Straw Nutrientsmentioning

confidence: 95%

Section: The Accumulation and Release Of Straw Nutrientsmentioning

confidence: 99%

See 1 more Smart Citation

Decomposition and release of nutrients from crop residues on soybean-maize cropping systems

Lange

et al. 2018

Agraria

“…In the literature, half-life times were found to vary between 40 and 131 days for millet (TORRES et al, 2005;BOER et al, 2008;FERREIRA et al, 2010;PACHECO et al, 2011;TEIXEIRA et al, 2011;SORATTO et al, 2012;TEIXEIRA et al, 2012;COSTA et al, 2015), between 24 to 160 days for Urochloa ruziziensis (BELO et al, 2012;ROSSI et al, 2013;COSTA et al, 2014;SANTOS et al, 2014), and from 21 to 114 days for Cajanus cajan (TORRES et al, 2005;PEREIRA, 2008;BELO et al, 2012). These discrepancies may be related to the use of cultivars with different potential for dry matter production, different chemical compositions, greater contact between the straw and the soil, and the combination of high temperatures and rainfall that influence the decomposition process.…”

Section: Resultsmentioning

confidence: 99%

Dry Matter Decomposition of Cover Crops in a No-Tillage Cotton System

2018

-No-tillage cotton systems require soil coverage with cover crop residue for a longer time due to the late cycle of cotton. However, decomposition rates may vary between cover crops, and the adjustment of models to describe it is critical to no-tillage cotton management. Two non-linear regression models, exponential (EM) and Michaelis-Menten (MM), were adjusted to dry matter decomposition of cover crops in a cotton no-tillage system, in Brazil. Three field trials were performed in 2012 for the cover crops Urochloa ruziziensis (brachiaria), Pennisetum glaucum (pearl millet), and Cajanus cajan (pigeon pea). Samples of cover crop were collected at 20, 50, 70, 110, 140, and 170 days after sowing upland cotton to measure dry matter decomposition. MM showed better adjustment than EM for all cover crops. The estimations of half-life parameters were different between the cover crops, suggesting that each cover crop has its own rate of decomposition. For pearl millet, brachiaria, and pigeon pea, the half-life estimation by exponential model was over the MM in 9, 12, and 12 days. RESUMO -Para a semeadura direta é preciso adequada quantidade de palha sobre o solo, e devido ao longo ciclo do algodoeiro, sua persistência deve ser alta. Entretanto, como a decomposição dos resíduos vegetais ao longo do tempo pode variar entre as plantas de cobertura, o ajuste de modelos que melhor a descreva é essencial. Dois modelos de regressão não-linear, exponencial (ME) e Michaelis-Menten (MM), foram ajustados à decomposição de matéria seca de plantas de cobertura no sistema de semeadura direta do algodoeiro, em condições do Cerrado goiano. Três experimentos foram instalados no ano de 2012, cada um consistido de uma espécie de planta de cobertura, sendo Urochloa ruziziensis (braquiária ruziziensis), Pennisetum glaucum (milheto) e Cajanus cajan (guandu). Em cada ensaio, procedeu-se a amostragem da palha da planta de cobertura aos 20, 50, 70, 110, 140 e 170 dias após a semeadura do algodoeiro, para determinação da matéria seca remanescente. Para as três plantas de cobertura o modelo MM apresentou melhor ajuste que o ME. As estimativas dos tempos de meia-vida das palhadas via MM diferiram entre as plantas de cobertura, indicando que cada uma possui velocidade de decomposição específica. Para o milheto, o guandu e a braquiária, as estimativas de tempo de meia-vida pelo ME foram superiores às do MM em 9, 12 e 12 dias, respectivamente.Palavras-chave: Modelo exponencial. Michaelis-Menten. Gossypium hirsutum. Plantio direto.

“…Kliemann et al (2006) observed a relative loss of 56% by 150 days, and Santos et al (2014a) found that one half of the dry cumulative biomass had decomposed by 115 days. Compared with the other forage systems, the monocropped pearl millet showed a higher carbon/ nitrogen ratio (P<0.05) for both sowing periods at soybean planting at 30 and 90 days.…”

Section: Production and Decomposition Of Biomassmentioning

confidence: 99%

Dynamics of biomass of pearl millet and Paiaguas palisadegrass in different forage systems and sowing periods in yield of soybean

Costa¹,

Costa²,

Assis³

et al. 2016

Afr. J. Agric. Res.

There is increasing global concern with environmental food production and sustainability to maintain high carbon stocks in soil biomass. The biomass produced in crop-livestock integration system increases soil organic matter, acts in nutrient cycling, improves the physical, chemical and biological characteristics of soil and increases grain production. Moreover, this soil management system mitigates greenhouse effect and preserves the environment. However, in the Savannah of Central Brazil region, an efficient mulching production of biomass is one of the factors limit sustainability of direct seeding of soybean, mainly due to accelerated decomposition of crop residues. Thus, this study aimed to evaluate biomass dynamics of pearl millet and Paiaguas palisadegrass in different forage systems and sowing periods on soybean yield. The experiment followed a randomized block design with a 5 x 2 factorial arrangement and three replications, under five forage systems (monocropped pearl millet, monocropped Paiaguas palisadegrass, pearl millet intercropped in rows with Paiaguas palisadegrass, pearl millet intercropped between rows of Paiaguas palisadegrass and pearl millet oversown and intercropped with Paiaguas palisadegrass) at two sowing periods (February and March). The results showed that Paiaguas palisadegrass in a monocropped system generated the highest biomass production and lowest carbon/nitrogen ratio. The highest carbon/nitrogen ratio and cumulative biomass loss occurred with millet in monocropped and intercropped with oversown Paiaguas palisadegrass in which biomass production was reduced by plant competition. Paiaguas forage systems in palisadegrass monocropped and intercropping on and between rows supported higher yield of soybean. The second sowing periods resulted in higher production of remaining biomass and grain yield, in all forage systems. Intercropping in crop-livestock integration systems showed a promising cultivation technique to maintain a sustainable stock of soil carbon.