Estimativa da produção da cultura do milho irrigado através de simulação com o modelo AquaCrop e determinação da lâmina ótima econômica

Abstract

One of the technologies that has been used notably in agriculture is the simulation of crop growth and productivity, as well as obtaining parameters that respond to the efficient use of irrigation water, reducing the volume of water used. Thus, the objective of this study was to evaluate the performance of the AquaCrop model for different hybrids of irrigated corn under different levels, in different edaphoclimatic scenarios, as well as to determine the optimal economic level for the region of Alegrete, RS. Data from experiments of four harvests were used: 2015/16 and 2016/17 harvests, developed in the municipality of Santiago, RS, and conducted by Ben (2019), in a randomized block design, composed of five irrigation treatments (0 , 50, 75, 100 and 125% of ETc), with four and six corn cultivars, respectively, and four replicates each; and 2017/18 and 2018/19 crops, developed in the municipality of Alegrete, RS, in a randomized block design, composed of five irrigation treatments (0, 50, 75, 100 and 125% of ETc) (2017/18 harvest) ), and 0%; 50, 75 and 100% (suppressed by 50% in the reproductive period of the culture); and, 100% of the ETc (2018/19 harvest), with three repetitions each. The hybrids used to calibrate the model were: AG 9025 (Santiago - 2015/16) and AG 8780 (Alegrete - 2017/18), while for validation were used: AG 9045, DKB 240 and Status VIP3 (2015/16 crop); AG 9025, AG 8780, DKB 177, DKB 230, DKB 290 and P1630H (2016/17 harvest); and AG 8780 (2018/19 harvest). The main results of this study demonstrated satisfactory performance of the AquaCrop model, obtaining ratings from “good” to “excellent”. Even if the model tends to overestimate or underestimate the results, in some conditions, it can be used, given its adaptability to different corn hybrids and water conditions. Corn production responds positively to supplementary irrigation in the region of Alegrete, RS, for the cultivar AG 8780, suggesting that levels greater than 81.5% of ETc should not be used, aiming at the greatest economic return.