s:810:"TI Roots: length, biomass, production and mortality 
AU van Noordwijk, M. 
AB In both crops and natural vegetation a substantial proportion of net primary production occurs below ground in the root system. This proportion varies with vegetation type, developmental stage, soil conditions and cultural practices. Shoot:root ratios on a dry matter basis are typically between 5:1 and 10:1 for annual crops at maximum standing biomass. For perennial crops and natural vegetation, values vary between 1:2 and 5:1. Uptake of water and nutrients are related to root surface area rather than root weight. Distribution and periodicity of root length is important to evaluate whether or not crop demand for nutrients and water coincides in space and time with the available supply (synchrony and syn localization). 
";