Toward an energy budget model of photosynthesis predicting world productivity

1573-5052

Crop Energy Budget Model ; Phytosynthesis Productivity ; World Population

Springer Online Journal Archives 1860-2000

Biology

Summary In order to provide an initial estimate of the probable potential (no lack of soil water, fertilizer, pest and disease controls, advanced cultivation techniques, etc.) agricultural and primary productive ceilings of this planet, a series of deductive models of optimum net photosynthesis is constructed. The concern is with the generalized global trends of productivities representing many types of plants. Because a worldwide treatment of productivity is preferred at this time, a relatively simple, basic model had to be utilized in order to stay within reasonable limits of financial contraints. The findings presented in the body of the text thus represent a tentative ‘economic answer’ to a pressing question of mankind. Four models have been developed: 1 for a high-efficiency C4 plant, 2 for a C3 type agricultural crop, 3 for a broadleaf woody species and 4 for a needleleaf species. The prediction of the leaf temperature is considered the crux of the testing of the energy budget portion of the models. The four models are applied to 1 650 worldwide climatological stations. The results are discussed. Some considerations are given on the estimation of theoretical maximum crop yields. From these maximum human population figures are estimated on a high-protein diet basis, with a prediction of 4.5×109 people for the world as a whole.

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