Carbohydrate‐Protein Ratio of Peas in Relation to Fertilization with Potassium, Calcium, and Nitrogen

WHILE the increased production of food is the major objective of agronomic research, such an objective does not exclude concern about the role of food in better health. In simpler terms, better health depends on better nutrition, namely, better edibles in service for growth, work, and maintenance of the vital processes. Only plants have the ability to synthesize from water and carbon dioxide the carbohydrates—stored in the plants and also transformed into fats—as the major source of food for energy. Only the plant can combine, through various reactions aided by soil fertility, the carbohydrates with nitrogen, phosphorus, and sulfur to give the amino acids. These are almost two dozen in number and are the structural units of proteins. These are the big group of nitrogenous substances essential for reproduction, growth, and repair of the .protoplasmic tissues of the higher forms of life. The carbohydrate-protein ratio has long been a factor in animal and human nutrition. Emphasis has been given to the shortage of protein and the problem of supplementing the readily procurable carbohydrates with it. Little attention, however, has been given to the fact that, in the synthetic .processes of plants, the carbohydrates seem to be the common and major product on most any soils. The proteins, however, are the output by the plants growing on only the more fertile soils. We have appreciated legumes for their high nitrogen contents. But they have not been so commonly recognized as highly dependent on the fertility for help in protein synthesis. We have therefore not looked at the problem of balancing the carbohydrates with proteins in the rations as one of managing the plant's physiology to help it grow more of the latter in place of the excessive amounts of the former by balancing the fertility to bring about that result within each of the different food and feed plants. When calcium is commonly associated with nitrogen in provoking protein production by plants, and when potassium is associated with carbohydrates, then the balance between the amounts and activities of these three elements within the soil may be the control of the carbohydrate-protein ratio of the crop. In support of the foregoing hypothesis, the following study of the common garden peas and their contents of carbohydrates and proteins in relation to varied amounts of exchangeable potassium, calcium, and nitrogen in the soil was undertaken. HISTORICAL