Methods of Establishment of Pintoi Peanut into Marandu Palisadegrass Pastures in Northern Brazil.

Pintoi peanut (Arachis pintoi) is a warm-season perennial legume used as forage in tropical and subtropical regions; however, management practices to overseed pintoi peanut into warm-season grasses are not well explored. The objective of this study was to evaluated methods of establishment of ‘Amarillo’ pintoi peanut into established ‘Marandu’ (Urocloa brizantha) plots. The experiment was conducted in Araguaina, TO, Brazil from December 2014 to May 2015. Treatments were seeding pintoi peanut into 1) glyphosate treated rows followed by prepared seedbed, 2) glyphosate treated rows with no seedbed preparation, or 3) control with no pintoi peanut seeding, distributed in a randomized complete block design with four replicates. Plots were 5 x 4 m and glyphosate treated rows were 0.4 x 5 m. There was no difference in Marandu response variables between treatments with seedbed preaparation and no seedbed preparation; however, there was a decrease in Marandu herbage accumulation (1.9 vs. 1.4 Mg ha^-1), leaf area index (2.9 vs. 2.0 m² m^-2), and tiller density (1080 vs. 870 tillers m^-2) when pintoi peanut was seeded into the plots. There was no difference in pintoi peanut plant frequency (13 plants m^-2) and ground cover (4.7 %) between prepared seedbed and no seedbed preparation but there was an increase in plant frequency from 9.0 to 16.7 plant m^-2 and ground cover from 3.5 to 4.5 % from February to May, respectively. Pintoi peanut herbage accumulation (0.2 Mg ha^-1) and proportion of pintoi peanut /Marandu in the harvested forage (15%) at the termination of the experimental period were similar between the seeded treatments. This data implies that it may not be necessary to prepare the seedbed after glyphosate treatment to seed pintoi peanut into established Marandu pastures in the Amazon region of Tocantins State in Brazil.