Doses crescentes de gesso agrícola, estabilidade de agregados e carbono orgânico em Latossolo do Cerrado sob Cafeicultura

Abstract

The management of perennial crops could encourage the improvement of the soil, making it more productive, provided that appropriate agronomic practices are adopted. In order to evaluate the structure of a Cerrado Latosol subjected to soil management that adopts the use of high doses of gypsum and brachiaria on the coffee plants interrow, we studied the stability of aggregates and total soil organic carbon after two years of deployment of coffee. Soil samples were collected at 5 and 15 cm of depth in the crop coffee row located in the Alto São Francisco region, Minas Gerais states. The treatments were: G-0, no gypsum on the row, G-7, 7.0 Mg ha-1 of gypsum distributed in the coffee row, G-28, 28 Mg ha-1 of gypsum distributed in the coffee row, G-56, 56 Mg ha-1 of gypsum distributed in the row, CV-0, conventional management without gypsum CV-0 conventional tillage without gypsum in the row and grasses between row Brachiaria sp. between rows of coffee plants. Chemical analyzes were performed to determine the cations K + , Ca +2 , Mg +2 , P, and Al +3 , total organic carbon and physical analysis of soil aggregate stability. It was determined the mean weight diameter and geometric mean diameter of aggregates retained on sieves with diameters ranging from 4 to 0.105 mm. All treatments were found more than 90% of aggregates with a diameter >2 mm suggesting that the management adopted a positive influence soil aggregate stability. The total organic carbon were positive and significantly correlated with aggregation. The dose of gypsum 7 t ha-1 positively altered the aggregation of soil specially in the superficial layer (15 cm). RESUMO: O manejo de culturas perenes pode favorecer a melhoria da qualidade do solo, tornando-o mais produtivo, desde que sejam adotadas práticas agronômicas adequadas. Com o objetivo de avaliar a agregação de um Latossolo da região do Cerrado Mineiro submetido a sistema inovador de manejo, que utiliza gesso agrícola e braquiária na entrelinha de lavoura cafeeira, foi estudada a estabilidade de agregados e verificado o carbono orgânico total após dois anos da implantação de cafeeiros. Foram amostradas as profundidades de 5 e 15 cm na linha do cafeeiro em área experimental localizada na região do Alto São Francisco-MG. Os tratamentos foram: sem gesso na linha; doses de 7,0; 28, e 56 t ha-1 de gesso distribuído na linha; manejo convencional, sem gesso na linha e sem Braquiaria sp. na entrelinha do cafeeiro. Foram realizadas análises químicas para determinação dos cátions K + , Ca +2 , Mg +2 , P e Al +3 , e do carbono orgânico total, além da análise física de estabilidade de agregados do solo. Determinou-se o diâmetro médio ponderado e o diâmetro médio geométrico dos agregados retidos em peneiras com diâmetro variando de 4 a 0,105 mm. Verificou-se que o carbono orgânico total do solo correlacionou positiva e significativamente com a agregação do solo, que as doses elevadas de gesso agrícola alteraram positivamente a agregação do solo na camada de 15 cm de profundidade e que a dose de gesso de 7 t ha-1...

Aggregates morphometry in a Latosol (Oxisol) under different soil management systems

“…Nevertheless, it is truly observed an influence of OM on the DF, which decreases with OM reduction (ROSA JUNIOR et al, 2006). Table 2 also shows a GMD increment that followed the sequence: NV > P > NT, corroborating Silva et al (2013Silva et al ( , 2006 results. Lack of human interference and elevated OM content in NV might be possible explanations for GMD increase (Table 3).…”

“…Therefore, knowing soil structural quality and its variation throughout the time is crucial to predict such effects (VIANA et al, 2004). This way, several researches have been carried out to draw structural quality indexes by monitoring the effects of management practices on soil physical, chemical, water and biological attributes (BERGAMIN et al, 2010;LIMA et al, 2012;OLIVEIRA et al, 2004;SEVERIANO et al, 2009); besides organic matter dynamic along its profile (COSTA JUNIOR et al, 2012;SILVA et al, 2013;TIRLONI et al, 2012).…”

Spatial variability of pores in oxidic latosol under a conservation management system with different gypsium doses

“…(Costa Júnior et al 2012), which was also observed by Silva et al (2013) at a depth of 0.15 m in G7, working in the same area of this experimental research. The formation and stability of macro-and microaggregates, which influence the distribution of space voids is strongly related primarily to the oxidic mineralogy and clay texture.…”

“…Ciênc. Agrotec., Lavras, v.38, n.5, p.445-460, set./out., 2014 These new aggregates were formed possibly by the action of biological factors (Silva et al 2013;Martin et al 2012), via the constant supply of the organic material throughout the soil profile, by both the mowing of the interrow Brachiaria sp. and the renewal of the coffee roots, that increase the soil microorganism activity (mycorrhizal fungi, preferentially).…”

Resistência Do Solo À Penetração Em Pasto De Capim-Tifton 85 Sob Irrigação E Adubação Nitrogenada

“…Dessa forma, a adubação nitrogenada pode ser adotada com a finalidade de minimizar os efeitos do pisoteio animal, uma vez que uma maior produção de matéria verde reduziria a pressão aplicada pelo peso dos animais na superfície do solo (CARASSAI et al, 2011). Essa prática pode promover, ainda, melhorias na qualidade física do solo, já que proporciona incremento do teor de matéria orgânica e favorece a descompactação do solo por meio do desenvolvimento das raízes (SILVA et al, 2013).…”