CRESCIMENTO E PRODUTIVIDADE DE CULTIVARES DE BATATA SUBMETIDAS A DOSES DE SUBSTÂNCIAS HÚMICAS

Abstract

Nowadays, potato cultivar Agata is the most cropped in Brazil. Focusing on to decrease the Brazilian dependence on importation of planting material for multiplication, EMBRAPA, through its potato breeding and genetics program, has developed new cultivars, including the BRS-Camila, that was officially launched in 2015. Humic substances (HS) are recognized for their beneficial effects on the chemical, physical and biological properties of soils as well on growth and yield of plants. However, there are few results about its utilization, most of them controversial or inconsistent, related to the application of HS in different crops and conditions. Therefore, in order to verify the outcome of HS application in the potato crop, four doses of peat extracted HS: 0, 5.05, 10.10 and 15.15 L ha-1 were tested and applied in the furrow of Agata and BRS-Camila cultivars grown in Oxisol Distroferric with about 500 g kg-1 of clay and 35 g dm-3 of organic matter. The experimental design was a completely randomized block in a factorial design (cultivar x HS) with four replications. Phytotechnical evaluations were done on 15; 31; 47 and 63 days after emergence (DAE), and quantification of total and marketable yields at 83 DAE. At 15 DAE, there was a negative linear effect of HS on several morphological parameters, such as the length of largest stem; shoot dry weight (DW); number and DW of formed tubers; leaf area index and total plant DW, but there was no significant effect on the total and marketable yield. The BRS-Camila cultivar showed a bigger growth than Agata cultivar at 15 DAE. There was difference on marketable yield, in which Agata obtained an average of 38,283 kg ha-1, and BRS-Camila 45,296 kg ha-1, representing a difference of 18.3%. The application of SH did not result in increases on yield. The BRS-Camila cultivar proved to be a viable alternative to commercial potato crops, needing, however, additional studies to a more appropriate management.