Phosphate Fertilization in Amaranth Culture cv. BRS Alegria in Second Harvest in the Cerrado

Vegetable species, capable of diversifying production in the second crop of the Cerrado, producing grains rich in protein and providing dry matter for off-season, are most welcome. The amaranth presents these characteristics, however its cultivation is little known in Brazil. The adequate availability of nutrients for this plant, under cerrado conditions, has not yet been defined and these soils, in turn, are of low natural fertility, deficient, mainly, in phosphorus. Before this senary, the present work was developed with the objective of evaluating agronomic and productive aspects of amaranth cv. BRS Alegria, cultivated in succession to soybean, underwent increasing doses of phosphorus. The experimental design was a randomized complete block design with five levels of phosphorus (0, 30, 60, 100 and 150 kg.ha-1 of phosphorus - triple superphosphate) applied in the sowing furrow, with four replications. Plant height was evaluated; stem diameter; panicle length; final population of plants; phosphorus content in leaf tissue; mass of dry matter of panicle, stem, leaf and total and; grain yield. The model with higher R2 in the regression analysis was selected to express the behavior of the phosphorus doses on the evaluated characteristics. The phosphorus applied in the sowing furrow increases productivity and phosphorus content in the amaranth foliar tissue in succession to the soybean crop. The highest estimated productivity of amaranth grains was obtained with 98.7 kg ha-1 of P2O5, with values close to the level of economic response to the application of the input.