The change in land use in the Brazilian Cerrado modifies the dynamics of soil organic matter (SOM) and, consequently, carbon (C) stocks and their fractions and soil enzyme activities. This study evaluated the effect of brachiaria (Brachiaria decumbens Stapf.) intercropped with Arabica coffee (Coffea arabica L.) on the stock and fractions of soil carbon and enzyme activities. The experiment was arranged in a completely randomized block design with three replications and treatments in a factorial design. The first factor consisted of coffee with or without intercropped brachiaria, the second of Arabica coffee cultivars (‘I.P.R.103’ and ‘I.P.R.99’) and the third factor of the point of soil sampling (under the canopy (UC) and in inter-rows (I)). Soil was sampled in layers of 0–10, 10–20, 20–30, 30–40, 40–60 and 60–80 cm. Soil from the 0–10 cm layer was also used to analyze enzymatic activity. Significant effects of coffee intercropped with brachiaria were confirmed for particulate organic carbon (POC), with highest contents in the 0–10 and 20–30 cm layers (9.62 and 6.48 g kg⁻¹, respectively), and for soil enzymes (280.83 and 180.3 μg p-nitrophenol g⁻¹ for arylsulfatase and β-glucosidase, respectively).

Cover crops in no-tillage systems may alter soil mineral N and influence the N fertilizer use efficiency (NFUE) of subsequent maize. The hypothesis of this work is that no-tillage systems with cover crops affect nitrate, ammonium and maize NFUE in the Brazilian Cerrado. The objective was to evaluate the cover crop mineralization effect on soil N mineral and maize NFUE in a no-tillage system, with and without N topdressing. The experiment was arranged in a randomized block split-plot design. The plots were represented by cover crops (Cajanus cajan, Crotalaria juncea, Raphanus sativus and Mucuna aterrima). The subplots consisted of the application (WN) or non-application (NN) of N topdressing to maize. The soil was sampled in six layers (up to 60 cm) at the end (April) and at the beginning of the rainy season (November). NH₄⁺ was lower for all cover crops and WN and NN management in April. NO₃⁻ differed between seasons and cover crops in WN and NN. The lignin concentration and N uptake of M. aterrima were the highest compared to other species. The highest NFUE was on R. sativus, showing higher fertilizer dependency. In a no-tillage system with cover crops, the N topdressing fertilization needs to be improved, considering mineralization.

Coffee intercropped with Urochloa decumbens modifies nutrient uptake, and consequently the yield and quality of coffee, by the greater release of nutrients and efficient nutrient cycling. There is little information about the increasing nutrient content in Arabica coffee plants intercropped with Urochloa decumbens. The objective of this study was to evaluate the effect of Urochloa decumbens intercropped with two coffee cultivars (Coffea arabica L.) on the levels of macro- and micronutrients and coffee crop yield. The experiment was conducted at Embrapa Cerrados, Planaltina-DF, and was arranged in a completely randomized block design with three replications, in a factorial design. The first factor consists of two management systems: with (WB) and without (NB) Urochloa decumbens intercropped; the second factor is composed of Arabica coffee cultivars ‘IPR-103’ and ‘IPR-99’. There was no significant difference in yield of the coffee cultivars with and without Urochloa decumbens intercropped between the rows. The treatment with ‘IPR-99’ coffee cultivar intercropped with Urochloa decumbens achieved 400 kg ha⁻¹ (8 bags) more than the other treatments. The presence of Urochloa decumbens increased leaf nutrient contents of the macronutrients Ca and Mg and micronutrients Mn and Fe. Thus, the Arabica coffee–Urochloa decumbens intercropping system is an efficiency management strategy which improves nutrient content for the main crop with consequent yield gains.

In the context of global climate change, eucalyptus stands in the planted forest sector have become a viable alternative for reducing greenhouse gas (GHG) emissions, in addition to presenting great potential for the carbon (C) stock. Thus, the objective of this study was to quantify C stocks in different eucalyptus compartments, in addition to evaluating three mathematical models at the individual tree level. We evaluated four areas of eucalyptus stands located in the Federal District, Brazil. The data were collected from the forest inventory and rigorous cubing procedures using the following statistical models: Spurr, Schumacher–Hall, and adapted Schumacher–Hall. The highest Pearson’s linear modification coefficient, lowest root means square error percentage (RMSE%), and lowest Akaike information criterion (AIC) were used to select the best model. The C content and stock varied between the compartments and areas studied owing to age and, above all, genetic differences. Clone I224 had the highest carbon concentration per acre at 233.35 Mg ha⁻¹ and carbon difference per compartment. The adapted Schumacher–Hall was the best model. It included data on biometric factors, such as the diameter at breast height, height, and age. The contribution of eucalyptus plantations to carbon sequestration is fundamental to socioenvironmental enhancement.