Microbiological properties and oxidizable organic carbon fractions of an oxisol under coffee with split phosphorus applications and irrigation regimes

Abstract

SUMMARYPhosphorus fertilization and irrigation increase coffee production, but little is known about the effect of these practices on soil organic matter and soil microbiota in the Cerrado. The objective of this study was to evaluate the microbiological and oxidizable organic carbon fractions of a dystrophic Red Latossol under coffee and split phosphorus (P) applications and different irrigation regimes. The experiment was arranged in a randomized block design in a 3 x 2 factorial design with three split P applications (P1: 300 kg ha -1 P 2 O 5 , recommended for the crop year, of which two thirds were applied in September and the third part in December; P2: 600 kg ha -1 P 2 O 5 , applied at planting and then every two years, and P3: 1,800 kg ha -1 P 2 O 5 , the requirement for six years, applied at once at planting), two irrigation regimes (rainfed and year-round irrigation), with three replications. The layers 0-5 and 5-10 cm were sampled to determine microbial biomass carbon (MBC), basal respiration (BR), enzyme activity of acid phosphatase, the oxidizable organic carbon fractions (F1, F2, F3, and F4), and total organic carbon (TOC). The irrigation regimes increased the levels of MBC, microbial activity and acid phosphatase, TOC and oxidizable fractions of soil organic matter under coffee. In general, the form of dividing P had little influence on the soil microbial properties and OC. Only P3 under irrigation increased the levels of MBC and acid phosphatase activity.Index terms: P cycling, soil microbial activity, acid phosphatase, soil organic matter.( Adriana Rodolfo da Costa et al. RESUMO: ATRIBUTOS MICROBIOLÓGICOS E FRAÇÕES OXIDÁVEIS DO CARBONO ORGÂNICO DE LATOSSOLO CULTIVADO COM CAFEEIRO, SOB PARCELAMENTOS DE FÓSFORO E REGIMES HÍDRICOS

Biological P cycling is influenced by the form of P fertilizer in an Oxisol

“…Similarly, acid phosphomonoesterase suppression did not occur in Oxisols in Brazil following 6 years of cumulative P application of up to 549 kg P ha −1 (Conte et al 2002) and 797 kg P ha −1 (Costa et al 2013). In some cases, P fertilization at rates comparable or greater than in this study elevated acid phosphomonoesterase activities, which was attributed to increased SOC (Alvear et al 2005), organic P (Redel et al 2007), and microbial biomass (Costa et al 2013).…”

Organic matter fractions in soil under coffee with split applications of phosphorus and water regimes

“…This means that, considering all properties together, irrigation had a prevailing effect, forming distinct environments for the soil microbiota and for the accumulation of TOC, LC and humified SOM fractions. Similar results were obtained by Costa et al (2013), who described the water regime as determinant for the distribution of the variables Cmic, TOC and oxidizable SOM fractions. An improved water supply leads to an increased biomass generation and therefore to a higher input of carbon into the soil in the form of roots and dead plant material (Trost et al, 2013).…”

“…In the cultivation of perennial crops such as coffee, soil management, water and mineral fertilizers are essential factors for the input of organic waste and its humification (Partelli et al, 2009;Costa et al, 2013).…”

“…The microbial biomass was high in coffee production systems with high nutrient concentrations and soil water availability (Costa et al, 2013).…”

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

“…In this context, many authors (Figueiredo et al, 2010;Fontana et al, 2011;Costa et al, 2013) have demonstrated the benefits of conservation systems such as no-tillage, croplivestock integration and organic agriculture in the reduction of losses of SOM fractions and improvement of soil quality.…”