ABSTRACT
Whereas agricultural productivity is based on the conversion of radiant solar energy into the chemical energy which is stored in the carbon-to-carbon bonds of organic matter, environmental and managerial factors strongly influence its biological and economic potential. An estimate of potential vegetative productivities on a global basis can be obtained by examining incident solar radiation, efficiency of conversion of solar radiant energy into plant dry matter, and the duration of periods of partial and full light interception by crop canopies. Actual dry-matter production is usually substantially lower than aforementioned estimates of potential and maximum productivity. A major limitation to crop productivity of field-grown crops may be root dry-matter accumulation and development rather than ground factors, but very little is known about the effects of root growth on dry-matter accumulation of field-grown crops.
