Productive potential of soybean crop under rainfed at high altitudes

Abstract

Soybean (Glycine max (L.) Merrill) is the main source of protein in animal feed concentrates and various products for human consumption. However, its production has been focused in tropical climate zones and little research has been done in different environments. Therefore, the objective of this study was to evaluate the productive potential and grain quality of soybean crop in high altitude environments. To do this, under a randomized complete block design in five locations that covered an altitudinal gradient of 1900 to 2700 masl, the agronomic performance of eight varieties was evaluated under rainfed conditions. Days to flowering, biomass production and chemical quality of the grain were quantified. The average yield in the environment at 2040 m was 1.1 t ha^-1, the oil and protein content was 18 and 31%, respectively. At an altitude of 2526 m, all varieties completed their cycle, with an average yield of 0.1 t ha^-1, 15% oil and 31% crude protein. At an altitude of 2079 m, only the earliest variety completed its cycle; the other varieties delayed their flowering, causing this stage and the grain formation period to be affected by frosts. Biomass production also decreased with altitude. It is concluded that soybeans have productive potential up to altitudes of 2000 m, because at higher altitudes the yield decreases, although the protein content remains constant.