REN R110 Lecture Notes - Lecture 20: Livestock Grazing Comparison, Rangeland, Quadrat
6 Apr 2016
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Estimated grazing or browsing by ocular appraisal. Establish a # of random cages near grazing areas. Post grazing, clip both caged and grazed plots then calculate utilization as percentage. Ex: average forage on ungrazed plots (1m2) is measured as 725g while average forage on grazed plots is 470g: utilized forage= ungrazed-grazed = 725g-470g=255g/plot, forage utilization= 255g/725= 35. 2% Expressed in kg/hecatres: 255 g x 10 000m. Establish a # of plots and weigh biomass before and after grazing. There are some issues: regeneration, clipping and weighing is destructive removes available forage. Can do ocular assessment and use regression to predict biomass before and after. Based on a % of twigs browsed and % reduction in length of browsed twigs. Ex: % of twigs browsed = 30%, length of browsed twigs=10cm, length of unbrowsed twigs =20cm: therefore total loss due to browsing is 30% x 50% = 15% Based on the weight and number of twigs browsed and unbrowsed.
