Balanço de nutrientes em silagens de raízes de variedades de mandioca submetidas a diferentes correções do solo

Abstract

Cassava root silage can be an interesting alternative for animal feed instead of high-cost ingredients such as corn. Cultural treatments such as soil correction and plant genetics can modify the chemical composition of the roots and, consequently, of the silages obtained from this material. Thus, it is extremely important to know the balance of nutrients during the ensiling process to accurately predict the amount of food available, as well as make adjustments to the diet. Based on this, the objective of the present study was to determine the effect of soil correction and cassava variety on the nutrient balance in root silages. The test was conducted in an experimental area located in the municipality of Belém, Pará, Brazil. A randomized block design was used, with 4 blocks, in a 3 × 2 factorial arrangement, with 4 repetitions. The studied factors were three forms of soil correction (limestone, plaster or limestone + plaster) and two varieties of cassava (Caeté or Manteiguinha). The roots were harvested on the 19th; 20; January 27 and 30, 2019. The roots were separated from the aerial part, disintegrated and ensiled in PVC type silos, remaining stored for 45 days. After this period, the silos were depleted and the chemical composition of the root silages was evaluated. Likewise, the chemical composition of the roots in natura was evaluated before silage. In view of the chemical composition data, in addition to the minisil weights, the nutrient balance was calculated. The soil correction did not impact the nutrient balance of the silages. There were better results in the balance of dry matter (DM), organic matter (MO) nutrients for the Caeté variety. There was a greater reduction of these components in the Manteiguinha variety. Less losses were observed for DM, MO and non-fibrous carbohydrates (CNF) in the Caeté variety. The Caeté variety had better nutrient recovery compared to Butter.