O manejo do solo, com técnicas que possibilitem maior sustentabilidade, visa a sustentabilidade e recuperação do solo, maiores produtividades e maior retorno econômico ao produtor. Objetivou-se com este trabalho avaliar a fertilidade do solo (fósforo, potássio, matéria orgânica e pH) em função das profundidades de amostragem e sistemas de preparo do solo e cultivo. O experimento foi instalado em um Latossolo Vermelho-Amarelo. Foi utilizado um esquema de parcela subsubdividida. Os preparos de solo foram: 1 - PRT - preparo tradicional (uma grade aradora e duas grades niveladoras), 2 - PRA - preparo alternativo (subsolagem), 3 - PDA - plantio direto com um preparo alternativo a cada quatro anos e 4 - PDC - plantio direto contínuo. O segundo fator utilizado foi a sequência de culturas, sendo estas: 1) SF: soja - feijão; 2) MF: milho - feijão; 3) SM: soja - milho; 4) MM: milho - milho. O PRT e PDC apresentaram menor fertilidade e na camada superficial do solo. O PRT apresentou menores quantidades de fósforo, potássio e matéria orgânica e o pH foi menor no PDC e no PRT.

Litterfall is an important source of soil nutrients, but its decomposition can be affected by the crop system used. The objective of this study was to evaluate litterfall decomposition and macronutrient stocks in coffee crop systems in shaded (SHCS) environments and those in full sun (FSCS). The experiment was conducted on a rural property in Cacoal, state of Rondônia, Brazil, in a 2 × 6 factorial scheme with two crop systems (SHCS and FSCS), and six litterfall decomposition evaluation times (0, 30, 60, 180, 300, and 360 days after the litterfall was returned to the soil (DAL)), with seven replicates. The constant of decomposition (k), half-life time (t1/2) at 360 DAL, and phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), and nitrogen (N) concentrations of the remaining litterfall were determined at each evaluation time. The litterfall in the SHCS had a greater weight loss and constant of decomposition and a lower half-life time at the last evaluation, and the weight loss increased as a function of decomposition time. The litterfall stocks of macronutrients N, P, K, Ca, and Mg showed a linear decrease throughout the decomposition time, and increases in sulfur stock were found at the last evaluation.

ABSTRACT The form of occupation of the state of Rondônia, Brazil, favored the extensive agriculture, which resulted in a fast deforestation. The removal of forests and inadequate soil management and use, combined with a hot and wet climate, affected the soil chemical, physical, and biological attributes. In search for less impacting and alternatives that promote greater soil conservation for coffee production in the North region of Brazil, the objective of this work was to evaluate the effects of two coffee crop systems on the soil chemical and microbiological attributes. The treatments consisted of a shaded coffee crop (SCC) and a full-sun coffee crop (FCC). A completely randomized design was used, with four clusters per treatment and seven sampling points per cluster, which constituted a replication, totaling 28 replications per treatment. The data were collected in April 2018, in a rural property in the municipality of Cacoal, state of Rondônia, Brazil (11º21’50’’S, 61º20’10’’W, and altitude of 238 m). The soil organic matter, pH, P, K, Ca, Mg, Al, H+Al, base saturation, and basal respiration were determined. The soil under SCC had higher Ca content, pH, and base saturation, and lower potential acidity (H+Al) and Al content than that under FCC. The litterfall on the soil under FCC presented higher N and Mg contents. The soil basal respiration increased in the first 5 cm depth in the treatment with SCC.