Cover crops affecting phosphorus dynamics in different soil management systems

Abstract

Tropical soils, due to their constitution, show a restriction on the availability of nutrients, mainly regarding the high P fixation, which can limit the development of plants. Thereby, the association of cover crops with conservation management systems emerges as a sustainable alternative to increase the availability of this nutrient in the soil. This research aims to evaluate the changes promoted by the use of cover plants and by the different soil managements on the availability of phosphorus and chemical attributes of the soil, in experiments established in the long term in the Cerrado. Four long-term experiments will be evaluated in the Brazilian Cerrado region, being two in the state of Mato Grosso (MT), one in Goiás state (GO) and another in Mato Grosso do Sul state (MS). The experimental design will be in random blocks, in subdivided plots, with three replications. The plots will consist of two management systems (conventional and direct); and the subplots by the cover plants (millet - Pennisetum glaucum L., braquiária- Brachiaria ruzizienses and e crotalária -Crotalaria juncea, ochroleuca and spectabilis) with posio as control for both management systems. Will be evaluated in the 2020/21 and 2021/22 agricultural harvests the chemical attributes of the soil (pH, H + Al, K, Ca, Mg), chemical fractionation of P, nuclear magnetic resonance to identify P species, enzymatic activity and abundance of phosphate solubilizing microorganisms (qPCR). As a result of this research, it is expected that the cover plants associated with the no-tillage system increase the availability of nutrients, the labile fractions of P and the legacy of this in the soil.