Estimativa da produção de forragem em pastagem de brachiaria decumbens

Abstract

It was compared the visual estimate, foliage heights and cut methods in forage yield estimation of Brachiaria decumbens Stapf. pasture, in an area of the Agricultural, Environmental and Biological Sciences Center of UFRB. In the visual estimate method, forage estimations were done within an iron quadrat of 0.25 m2, 10 double samples of visual (x) and true weight (y), being sample 1= smaller forage weight or lack of forage; sample 10= higher forage weight; samples 2 to 9= intermediary weights. It was carried out a regression analysis with the values of visual (x) and true (y) estimates obtaining the equation y= 1.85 + 0.82x, and observing a linear relationship between the variables x and y using t test. In the forage estimations using foliage height measurements it was done 10 double samples, being 10 of the mean foliage height (x) and 10 of the true forage weight (y), done within cited iron quadrat, obtaining the equation y= 1.55 + 0.41x and verifying a linear relationship between the two variables (p<0.01) by t test. Afterwards, utilizing four parallels linear transections, spaced of 15 m, using the 0.25 m2 iron quadrat were sampled 25 points, spaced of 5 m, resulting in 100 points of sampling comparing the three methods. There was not significance by F test (p>0.05) among the evaluated methods, making possible to estimate forage yield of a B. decumbens pasture by visual estimates and foliage heights measurements, utilizing a linear regression equation.