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.

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Eficiência de biofertilizantes de rochas com Acidithiobacillus em melão, no Vale do São Francisco RESUMOBiofertilizantes de rochas fosfatada (RP) e potássica (RK), com enxofre inoculado com Acidithiobacillus (S+Ac) foram comparados com o superfosfato triplo (SFT) e cloreto de potássio (KCl) no melão, em um Argissolo do Vale do São Francisco. Usou-se o fatorial 3 2 +3, em blocos casualizados, com biofertilizante fosfatado (BP) e potássico (BK) nos níveis 50, 100 e 200% da recomendação para SFT e KCl. Tratamentos adicionais: a) (RP+RK+S-Ac); b) SFT+KCl, no nível recomendado, e c) controle sem P e K. Houve efeito da fertilização com P e K no peso médio de frutos, produtividade, e nutrientes nas folhas, sendo os melhores resultados com aplicação de SFT+KCl, RP+RK+S-Ac., e com biofertilizantes (BK) e (BP). Para P, K e Mg nas folhas, os melhores resultados ocorreram com BP 200 e RP+RK+S-Ac.. O SO -4 nas folhas foi mais elevado com biofertilizantes BK e mais reduzido no controle. Biomassa de folhas, brix, vitamina C, firmeza de polpa e ATT não responderam à fertilização com P e K. Os Biofertilizantes BP+BK+S+Ac., e as rochas RP+RK+S-Ac. mostraram potencial como alternativa aos fertilizantes minerais com P e K. Palavras-chave:Cucumis melo, absorção de P e K, fertilização PK, oxidação do enxofre Effectiveness of rock biofertilizers with sulfur and Acidithiobacillus on melon in the San Francisco Valley ABSTRACTBiofertilizers with phosphate rock (PR) and potash rock (KR) plus sulfur and Acidithiobacillus (S+Ac) were compared with triple superphosphate (TSP) and potassium chloride (KCl) fertilizers on melon in an Argisol of the San Francisco Valley. A factorial 3 2 +3 in randomized blocks design with phosphate biofertilizer (PB) and potassium biofertilizer (KB) applied in levels 50%, 100% and 200% based on recommendation to TSP and KCl. Additional treatments were: a) rocks (PR+KR+S-Ac), b) fertilizers (TSP+KCl) and c) control treatment (P 0 K 0 ). Response of P and K fertilization on fruit weight, fruit yield, and nutrient in leaves were observed with best results obtained applying TSP+KCl, PR+KR+S-Ac and PB and KB. Total P, K and Mg in leaves showed best results when applied P biofertilizer in PB 200 and PR+KR+S-Ac. Uptake of SO 4 -in leaves increased with BK biofertilizers and lowest results were obtained in the control treatment. No effects of PK fertilization were observed in biomass of leaves, brix, vitamin C , fruit texture and ATT. Biofertilizers BP and BK with S+Ac and P and K rocks with S-Ac may be used as alternative to P and K fertilizers.

Fertilizer application may promote significant changes in soil reaction and on the availability of important nutrients for plants. The utilization of rock biofertilizers is a practical process that reduces energy consumption and increases nutrient availability in soils. In a field experiment, the effect of biofertilizers produced with phosphate and potash rocks plus Acidithiobacillus inoculation were evaluated on the chemical attributes of an Argisoil from the São Francisco Valley, Pernambuco State, Brazil, after melon cultivation. The experiment was arranged in a factorial 3 2 +2 scheme in randomized block design, with four replicates. Two sources of P biofertilizer (PB) and K biofertilizer (KB) were applied in the same doses recommended for simple superphosphate (SS) and potassium chloride (KCl), and in doses which corresponded to two and three times the recommended ones. Additional treatments were carried out (soluble fertilizers (SS) and potassium chloride KCl), applied in the recommended dose, and control treatment with no addition of P and K (P 0 +K 0 )). Biofertilizers reduced soil pH and higher available P and K values were obtained when higher doses of biofertilizers (PB and KB) were applied. Mg content increased when KB biofertilizers were applied in higher rates, probably due to the solubilization of Mg present in the biotite. The rock biofertilizers with Acidithiobacillus may be recommended as an alternative to soluble fertilizers by the residual effect in nutrient availability, especially in sodic soils or in limed acid soils.Keywords: Cucumis melo, Acidithiobacillus, apatite, biotite, available P and K, sulfur oxidation. RESUMO Atributos químicos de um Argissolo do Vale do São Francisco após cultivo de melão com biofertilizantes de rochas fosfatada e potássicaA aplicação de fertilizantes pode promover mudanças na reação do solo e na disponibilidade de nutrientes importantes para as plantas. A produção de biofertilizantes a partir de rochas é um processo prático que reduz o consumo de energia e aumenta a disponibilidade de nutrientes no solo. Em experimento de campo foram avaliados os efeitos de biofertilizantes produzidos com rochas, além do enxofre elementar inoculado com Acidithiobacillus, em atributos químicos de um Argissolo do Vale do São Francisco após cultivo do melão, em comparação com fertilizantes minerais solúveis. Usou-se o fatorial 3 2 +2, em blocos casualizados, com biofertilizante fosfatado (PB) e potássico (KB), em quantidades correspondentes à adição de superfosfato simples (SS) e cloreto de potássio (KCl), o dobro e o triplo da recomendação. Foram usados tratamentos adicionais com SS+KCl na quantidade recomendada e o controle sem adição de P e K (P 0 K 0 ). Os biofertilizantes reduziram o pH do solo, e os teores mais elevados de P e K disponíveis foram obtidos com aplicação de PB e KB nas doses mais elevadas. Os maiores teores de Mg foram obtidos com o biofertilizante KB na dose 240 kg ha -1 , em função da liberação de Mg da biotita. Os biofertilizantes de rochas com P e K...