M. M. Campanha

Growth and yield of coffee plants in agroforestry and monoculture systems in Minas Gerais, Brazil

This research compared coffee plants (Coffea arabica L.) grown in an agroforestry and monoculture systems. Data were collected during two years, on vegetative growth, reproductive development, nutritional status and yield of coffee, besides monitoring air temperature and the tree growth. All trees in agroforestry system increased in growth, resulting in a reduction in the magnitude of the diurnal temperature variation and also maximum temperature. Coffee plants in agroforestry system had less branch growth and leaf production, more persistent and larger leaves, and presented earlier flowering, with a smaller number of productive nodes and flower buds, leading to smaller berry yield than plants in monoculture system. In both systems, the coffee plants showed adequate leaf nutrient levels, except for P and K. The yield of 2443 kg ha-1 of coffee from the monoculture was greater than 515 kg ha-1 of coffee from the agroforestry system.

Análise comparativa das características da serrapilheira e do solo em cafezais (Coffea arabica L.) cultivados em sistema agroflorestal e em monocultura, na Zona da Mata MG

Coffee plants in agroforestry systems is an alternative to full sunlight cultivation, presenting the potential benefits of enhancing soil chemical and physical characteristics, reducing soil erosion, besides maintaining soil moisture for longer periods. This research aimed at comparing the quantity and nutrient concentration in the litter, soil fertility and soil moisture in coffee crops under full sunlight monocrop and in agroforestry systems, at the Zona da Mata, Minas Gerais, Brazil. The research was carried out between January 1999 and May 2000. The agroforestry system, contributed with 6.1 Mg ha-1 year-1 of litter dry matter while the monoculture produced 4.5 Mg ha-1 year-1, which presented higher nutrient content. The litter in monoculture presented higher nutrient content. The agroforestry system presented higher soil moisture content (20-40 cm depth) and K, Ca, Mg, Sum of Basis, Cation Exchange Capacity, Cu and Zn levels in both soil depth, besides lower aluminum saturation and Al values in deeper layer than soil of monocrop coffee. Soil under monoculture presented higher P and organic matter content than agroforestry system.

Does biomass production depend on plant community diversity

In order to ensure the sustainability of agroecosystems, biodiversity must be a priority. Agroforestry, which includes trees, is an example of such diverse systems. We evaluated plant diversity and aboveground biomass production to assess whether areas under fallow following traditional cultivation return to their initial condition. Also, plant diversity and aboveground biomass production were assessed in agroforestry systems (AFS) to determine if these were similar to unmanaged ecosystems. Another objective of the study was to observe the influence of plant diversity on aboveground biomass production in plant communities and also in the population of the dominant species, Cordia oncocalyx. Plant diversity was evaluated by assessing species richness, as well as using Shannon’s (H′) and Pielou’s (J′) indices. Aboveground plant biomass was evaluated in two AFS: agrosilvopastoral (ASP) and silvopastoral (SP), and also in a traditionally managed agricultural system (AG), areas that had been under fallow for six years (F6) and nine years (F9) and an area of unmanaged caatinga (CAT) vegetation. We observed that the ASP system had a lower diversity and number of species, especially tree species. However, it sustained the same total biomass production as CAT and fallow areas. The SP system, despite having lower H′ and J′ indices as well as lower total biomass production, had a similar number of species to CAT and cropped and fallow systems AG, F6 and F9. Plant biomass in F6 and F9 had recovered to productivity levels of unmanaged CAT vegetation; however the diversity indices were not restored to the same level. Plant diversity did not have an effect on the productivity of the agroecosystems. Likewise, annual biomass production by C. oncocalyx is not dependent upon diversity, but it is influenced by the growth stage of individuals.

CARBON SEQUESTRATION AND NUTRIENT RESERVES UNDER DIFFERENT LAND USE SYSTEMS 1

This study evaluated the contribution of agroforestry (AFS) and traditional systems to carbon sequestration and nutrient reserves in plants, litter and soil. The study was carried out in the semiarid region of Brazil in a long-term experiment on an experimental farm of the goat and sheep section of the Brazilian Agricultural Research Corporation (Embrapa). Two agroforestry systems were investigated: agrosilvopastoral (ASP) and forest-pasture areas (SP) as well as traditional agriculture management (TM), two areas left fallow after TM (six fallow years - F6 and nine fallow years - F9) and one area of preserved Caatinga vegetation (CAT). Soil, litter and plants were sampled from all areas and the contents of C, N, P, K, Ca and Mg per compartment determined. The AFS (ASP and SP) had higher nutrient stocks than the traditional and intermediate stocks compared to the preserved Caatinga. In the ASP, a relevant part of the nutrients extracted by crops is returned to the system by constant inputs of litter, weeding of herbaceous vegetation and cutting of the legume crops. After fallow periods of six and nine years, carbon and nutrient stocks in the compartments soil, litter and herbaceous plants were similar to those of the preserved Caatinga (CAT), but still lower than under natural conditions in the woody vegetation.

Levantamento florístico e fitossóciológico em área de caatinga manipulada durante o período chuvoso

Objetivou-se com este trabalho realizar o levantamento floristico do estrato herbaceo em area de Caatinga pastejada por caprinos durante o periodo chuvoso. O trabalho foi realizado na fazenda experimental Crioula, area fisica da EMBRAPA Caprinos e Ovinos, localizada na zona fisiografica do Sertao Cearense, municipio de Sobral, CE. O experimento foi realizado em uma area de 4,8 ha pastejada por um rebanho de 19 matrizes caprinas, onde foram lancadas vinte vezes a cada mes uma moldura (1,0 m x 0,25 m), para identificacao do numero de especies, familias e feita contagem do numero de individuos por especie em cada parcela. O numero de parcelas amostradas foi suficiente para refletir a fitodiversidade do local estudado. Foram identificadas 15 familias e 30 especies ao longo do periodo chuvoso. A familia que apresentou maior numero de especies foi Leguminoseae (8). As especies com maiores densidades absoluta e relativa foram a Hyptis suaveolans (L.) Poit e Blainvillea rhomboidea Cass.. A dominância de especies de pouco ou nenhum valor forrageiro indicaram elevado nivel de degradacao da pastagem e o ciclo de vida efemero de algumas especies presentes na area afetou a composicao floristica ao longo do periodo chuvoso. DOI: 10.15528/2176-4158/rcpa.v17n1p41-49

Levantamento Florístico do Estrato Herbáceo em Área de Caatinga Pastejada por Caprinos Durante o Período Chuvoso

O trabalho foi conduzido com o objetivo de conhecer a composicao floristica do estrato herbaceo de uma area de Caatinga pastejada por caprinos durante o periodo chuvoso (fevereiro a julho), realizado na fazenda experimental Crioula, CE. Numa area de 4,8 ha utilizada durante todo ano por 19 matrizes Anglo-Nubiana foram realizadas coletas mensais para identificacao das especies presentes utilizando uma moldura com dimensao de 1,0 m x 0,25 m, lancada 20 vezes em toda a area. A flora herbacea foi representada por 15 familias e 30 especies ao longo dos 6 meses de avaliacao. Leguminosae foi a familia que apresentou maior numero de especies (8) seguida das familias Asteraceae e Poaceae com 3 especies cada. As especies Bidens sp., Auxemma oncocalyx, Combretum leprosum Mart., Ipomoea sp., Hyptis suaveolans (L.) Poit, Clidemia hirta e Fleurya aestuans L. estiveram presentes em todo periodo de avaliacao. O ciclo de vida efemero de algumas especies presentes na area afetou a composicao floristica ao longo do periodo chuvoso. DOI:10.15528/2176-4158/rcpa.v14n2p161-164