Qualidade química do solo e dinâmica de carbono sob monocultivo e consórcio de macaúba e pastagem

Abstract

RESUMONeste trabalho objetivou-se avaliar o efeito do monocultivo e do consórcio de macaúba e pastagem sobre a qualidade química e os compartimentos de carbono em Latossolo Vermelho-Amarelo no Cerrado Maranhense. Foram estudados quatro sistemas de uso do solo: macaúba, pastagem, macaúba consorciada com pastagem e vegetação nativa de cerrado. Nesses sistemas foram coletadas amostras de solo da superfície até 60 cm, para determinação dos atributos químicos e dos teores e estoques de carbono orgânico do solo. Os maiores valores de P, K, Ca e Mg foram observados nas áreas sob pastagem. Os estoques de carbono orgânico total e os teores de carbono lábil foram maiores no solo com vegetação nativa até 60 cm de profundidade, seguida pelo sistema macaúba associada com pastagem. Maiores valores de carbono da biomassa microbiana e de quociente microbiano foram observados no solo sob pastagem em todas as camadas. A presença da pastagem é importante no consórcio com macaubeiras pois aumenta os níveis de fertilidade do solo e os estoques de carbono favorecendo a melhoria da qualidade do solo nas condições do cerrado maranhense. Palavras-chave: cerrado, oleaginosas, agrofloresta, fertilidade do solo, matéria orgânica do soloChemical quality of soil and dynamics of carbon under monoculture and intercroping of acrocomia palm and pasture ABSTRACT This study aimed to evaluate the effects of the cultivation of acrocomia palm (Acrocomia aculeata) intercropped or not with pasture on the chemical quality and carbon pools of an Oxisol of the Savanna of Maranhão state. Four land use systems were studied: acrocomia, pasture, acrocomia intercropped with pasture and savanna native vegetation. Soil samples were collected up to 60 cm depth for determination of chemical attributes and soil organic carbon contents and stocks. The highest values of P, K, Ca and Mg were observed in the soil under pasture. Total organic carbon stocks and labile carbon content were higher under native vegetation up to 60 cm followed by acrocomia intercropped with pasture system. Higher values of microbial biomass carbon and microbial quotient were verified in the soil under pasture in all depths. Pasture is important to be intercropped with acrocomia since it increases the soil fertility levels and soil carbon stocks favoring the improvement of the soil quality in the Savanna of Maranhão state.

Agronomic performance of Safflower genotypes (Carthamus tinctorius L.) under different soil bulk density levels in the Oxisol of the Cerrado

“…Considering this aspect, soil compaction, among the other factors, may decrease the nutrient absorption by the plants; thus, hindering their development (Leite et al, 2013).…”

Soil organic matter pools under management systems in Quilombola Territory in Brazilian Cerrado

“…These compounds are not quantified when potassium permanganate is used as the oxidation agent (Blair et al, 1995). In addition, the lower proportion of C in the labile form probably explains the higher contents of TOC in areas under natural vegetation in the Cerrado biome obtained in other studies (Figueiredo et al, 2010;Leite et al, 2013).…”

“…The lowest value was observed in Past (1.36 g kg -1 ) (Figure 2A and B). Silva et al (2011) and Leite et al (2013) indicate that conservation systems favor the maintenance of crop residues on soil surface, promoting slow decomposition of the deposited plant material and favoring LC accumulation.…”

Carbon stocks of an Oxisol after thirty-eight years under different tillage systems

“…According to Leite et al (2013), pasture is important for intercropping, because it increases soil fertility levels and C stocks, favoring the improvement of soil quality under Cerrado conditions. Therefore, the lower the frequency of soil disturbance and the maturity of the conservational tillage, the higher is the probability of organic C storage.…”