Agroforestry systems, nutrients in litter and microbial activity in soils cultivated with coffee at high altitude

Abstract

Agroforestry systems are an alternative option for sustainable production management. These systems contain trees that absorb nutrients from deeper layers of the soil and leaf litter that help improve the soil quality of the rough terrain in high altitude areas, which are areas extremely susceptible to environmental degradation. The aim of this study was to characterize the stock and nutrients in litter, soil activity and the population of microorganisms in coffee (Coffea arabica L.) plantations under high altitude agroforestry systems in the semi-arid region of the state of Pernambuco, Brazil. Samples were collected from the surface litter together with soil samples taken at two depths (0-10 and 10-20 cm) from areas each subject to one of the following four treatments: agroforestry system (AS), native forest (NF), biodynamic system (BS) and coffee control (CT).The coffee plantation had been abandoned for nearly 15 years and, although there had been no management or harvesting, still contained productive coffee plants. The accumulation of litter and mean nutrient content of the litter, the soil nutrient content, microbial biomass carbon, total carbon, total nitrogen, C/N ratio, basal respiration, microbial quotient, metabolic quotient and microbial populations (total bacteria, fl uorescent bacteria group, total fungi and Trichoderma spp.) were all analyzed. The systems that were exposed to human intervention (AS and BS) differed in their chemical attributes and contained higher levels of nutrients when compared to NF and CT. BS for coffee production at high altitude can be used as a sustainable alternative in the high altitude zones of the semi-arid region in Brazil, which is an area that is highly susceptible to environmental degradation.

Impacts of different coffee systems on soil microbial populations at different altitudes in Villavicencio (Colombia)

“…However, a similar concept of sustainability of the systems was applied. The low amount of (BP) found in the (S2) at the 0-20 cm depth (D1) (7.07 x 10 6 CFU/g) was similar when compared to data found by Notaro et al (2014) in biodynamic coffee plantations (BS) at 0-10 cm depth (8.1 x 10 6 CFU/g).…”

“…2), possibly related with the deficiency of soil nutrients through of soil profile in more simplified coffee production systems (unshaded), as demonstrated by Notaro et al (2014).…”

“…The variables analyzed were bacteria, fungi and actinomycetes population (BP, FP, AP), determined by serial dilution plate count method (Notaro et al, 2014). Soil dilution (10 -1 ) prepared by 10 g of soil sample was transferred into 90 mL sterile water and mixing the solution for few seconds.…”

“…The result of the vertical distribution of bacteria, fungi and actinomycetes in coffee systems was observed by Notaro et al (2014). The surface soils (0-30 cm) recorded higher bacteria (41.3%), actinomycetes (38.4%) and fungi (26.1%) as compared to the subsurface horizons (Srivastava et al, 2014).…”

“…Studies have revealed that the agroforestry coffee systems are more effective in promoting soil microbial population than conventional monoculture (unshaded) coffee systems (Evizal et al, 2012;Notaro et al, 2014;Bagyaraj et al, 2015).…”