Agronomic and economic potential of manure in Bolivian valleys and highlands

The staple diet of the rural population of Bolivia consists of potatoes and maize. Spanish colonization and agrarian reform radically changed the Inca agricultural system. The use of imported fertilizers in potato growing is becoming more widespread. Average potato production is failing, and in 1980 stood at 4.67 tons ha⁻¹. In 1982, potato farmers needed to produce more than double the amount of potatoes compared with the previous year in order to buy the same quantity of imported fertilizer. The results of comparative experiments with fresh and composted organic manures and chemical fertilizers carried out in two potato-producing regions with different climatic and soil characteristics are shown in this paper. At high altitudes with acid soils, fresh manure and chemical fertilizer gave good results. On the other hand, higher yields were obtained with compost in the valley of Cochabamba, which has a neutral soil. Organic manures are deficient in phosphorus. The use of phosphate rock and bone meal is proposed, both of which can be obtained locally, to increase the phosphorus content of organic manures.     

Pflanzliche Zellkulturtechniken als Züchtungsschritt am Beispiel Raps

A supplementation of classical plant breeding is now necessary due to the limitations imposed by available genetic variability and the slowness of the method. Therefore, cell culture techniques could play an important role in the future. Using rape seed, in which plants derived from anther culture and in vitro mutagenesis are already field tested, it has been shown that, in this case, somatic genetics is very close to becoming a practical method. For most of the other crop plants, in particular the cereals, no such unconventional breeding techniques have yet been satisfactorily established for commercial use.