Morfofisiologia de milheto e propriedades físico-hídricas do solo em função de sistemas de produção

Abstract

In Brazil, one of the main economic activities in the semi-arid region is livestock. However, due to the irregular distribution of rain, there is no constant supply of forage throughout the year. To increase the support capacity and sustainability of the activity, strategies for living with the semi-arid environment must be applied. In view of this, the objective was to evaluate the morphophysiological characteristics of millet and changes in the physical-hydric properties of the soil with the use of mulch and a system of consortium with legumes. The trial was conducted at the Federal Rural University of Pernambuco / Academic Unit of Serra Talhada, municipality of Serra Talhada, state of Pernambuco, Northeast region of Brazil, from August 2019 to March 2020. A randomized block design was adopted, with subdivided plots and four replications. The main plot consisted of the use of mulch (with and without cover) and the subplots in the cultivation of single millet and in consortium with two legume species, namely: cowpea and pigeonpea. The stem diameter, plant height, number of live leaves were measured and the leaf area of the millet was determined. For morphogenic characterization of millet, the following were calculated: leaf appearance rate, phyllochron, leaf elongation rate, leaf senescence rate and stem elongation rate. Measurements of the leaf area index and stomatal conductance in millet were also performed. The accumulation of dry leaf, stem and panicle phytomass was determined, in addition to the total dry phytomass at the end of each cycle. The physical-hydric properties of the soil were evaluated, such as: soil density, total porosity, soil resistance to penetration, water storage in the soil, saturated hydraulic conductivity and sorbidity. The collected data were submitted to analysis of variance and Tukey's test. The consortium of millet with legumes promoted a smaller stem diameter, number of live leaves, height and plant and leaf area of the millet in the first cycle. There was no effect of treatments on the accumulation of millet phytomass in two evaluation cycles. The mulch and cultivation systems did not influence soil resistance to penetration in the 0 to 30 cm layer. However, there was a reduction in the PR from one cycle to another in the plots with coverage. There was no significant effect of treatments on soil density, saturated hydraulic conductivity, sorbidity and total porosity. The use of mulch promoted an improvement in the structural characteristics of the millet, such as plant height, and in the physical-hydric properties of the soil, increasing water retention in the soil, being, therefore, a recommended practice for semi-arid environments. The consortium systems reduced structural and morphogenic characteristics in the initial growth phase of millet. However, there were no changes in physiology, total millet phytomass and in the physical-hydric properties of the soil due to the consortia. There were no significant effects of the association between the use of mulch in the soil and the cultivation of millet in consortium with legumes in this research.