Interactions between green manure and rock phosphate on corn production in family farms

ABSTRACT The aim of this study was to analyze whether the use of green manures in association with rock phosphate rates can guarantee corn yields to family farmers. An experiment was conducted with six types of green manures: Mucuna cinereum, Crotalaria juncea, Crotalaria ochroleuca, Cajanus cajan, Pennisetum glaucum and a weedy fallow control treatment; and three rates of phosphorus (0, 50 and 100 kg P2O5 ha-1) in a complete randomized block design. The management with Crotalaria juncea achieved the highest dry mass yield (39.3 Mg ha-1) and in year 2 (2016), with the water deficit during the corn cultivation, led to an increase of the root/shoot mass ratio, as well as presented the lowest water deficit sensitivity index (Ky), indicating that it can be an alternative for managing climate change. The highest corn yield (7510 kg ha-1) was obtained in the management with the Crotalaria ochroleuca, which defines it as a technically and economically viable alternative for family farming, with corn yield exceeding the average yield of the State of Mato Grosso and production cost lower than the average production cost of corn in the State of Mato Grosso.