Methods of measuring grassland and forage grass and legume dry matter and organic matter yields are described with reference to sampling procedures, destructive techniques, non-destructive techniques (direct visual estimation, height + density, capacitance, spectral analysis/remote sensing, and modelling). Methods suitable for shrubs and trees, for determining the composition of the yield, for estimation of growth and utilization, and the use of exclosures are included. It is concluded that the selection of a suitable method for determining biomass depends on the scale of the experiment, the purpose for which the data are required, the accuracy required and the resources available.

The prediction of pasture and animal production using a series of mathematical equations based on various biophysical inputs which influence or control production is outlined. These equations are arranged in a computer program and know as a model. The terminology and concepts used in models are discussed. Types of models and the user groups to which they apply are described. Getting started as a model user and as a model builder are outlined. Full details are given of a basic soil-plant-animal model with pasture, animal and economic submodels.

The methods available for the determination of the botanical composition of grasslands are reviewed with reference to a range of objectives for which such a study may be carried out. Studies at the global, national/regional, farm, paddock and patch scale are discussed. While it is possible using GIS to scale up from detailed studies, it is not yet possible to scale down from global to detailed studies. Sampling strategies and sampling methods are described, including the determination of quadrat size. The use of transects and point quadrats is also discussed. Sections are provided on the properties of grassland vegetation, patterns, diversity and species richness, ground cover, plant density, presence/absence data, and the analysis of seed banks.

Techniques used for the measurement of sward structure are reviewed with special consideration of vertical and horizontal structure. Basic factors affecting sward structure, such as herbage growth and grazing, are discussed. Methods for measuring vertical structure described include clipping, point quadrat, foliage orientation methods, light transmission methods, near-infrared reflectance methods, and laser methods. Sampling methods, scale and pattern, and geo-referencing are discussed in relation to horizontal structure.

Topics discussed in this chapter include sampling, sample preparation, chemical analysis, cell wall analysis, bioassays (in vitro digestibility techniques, in situ rumen degradability, and in vitro fermentation with rumen fluid), near infrared reflectance spectroscopy, and determination of tannins, minerals and trace elements in fresh and conserved forages.