-The objective of this work was to evaluate the effects of lignin, hemicellulose, and cellulose concentrations in the decomposition process of cover plant residues with potential use in no-tillage with corn, for crop-livestock integrated system, in the Cerrado region. The experiment was carried out at Embrapa Cerrados, in Planaltina, DF, Brazil in a split plot experimental design. The plots were represented by the plant species and the subplots by harvesting times, with three replicates. The cover plants Urochloa ruziziensis, Canavalia brasiliensis, Cajanus cajan, Pennisetum glaucum, Mucuna aterrima, Raphanus sativus, Sorghum bicolor were evaluated together with spontaneous plants in the fallow. Cover plants with lower lignin concentrations and, consequently, higher residue decomposition such as C. brasiliensis and U. ruziziensis promoted higher corn yield. High concentrations of lignin inhibit plant residue decomposition and this is favorable for the soil cover. Lower concentrations of lignin result in accelerated plant decomposition, more efficient nutrient cycling, and higher corn yield.

No abstract

Brazil is the largest producer of soybeans (Glycine max) in the world. In 2014/2015 only, approximately of 46.22 million tons of soybeans were exported. Asian Soybean Rust (Phakopsora pachyrhizi) is considered the main disease of soybean. This disease causes early defoliation, preventing the complete formation of grains and drastic reduction in productivity. Due to the limitation of other measures, the application of fungicide is still the main way to control this disease. Studies show that protective fungicide application is the main form of Asian rust control. One of the biggest challenges for the Brazilian soybean sector today is to optimize the decision about when to apply fungicide for protection against rust. Most soybean growers of the Federal District adopt the calendar schedule for fungicide application with an average of 3 applications per crop in mid to early cycle cultivars. The aim of this work was to study different planting seasons and different times of application of fungicides for the control of Asian rust, proposing to end, a timetable for the implementation of protective fungicide and recommendation of planting season for the region of the Federal District. Early seeding and protective fungicide application based on phenological stages of the plant resulted in lower disease severities and higher average productivity. Late plantings and the non-application of fungicide or delayed applications resulted in an increased in the severity of the disease and grain yield reduction