VARIABILITY OF YIELD AND STRESS FACTORS IN LEGUMES
The article is a review paper which considers the role of legumes in modern crop farming and soil management and analyzes the factors which cause yield variability and limit yield capacity and stability in these crops. The FAO data on production status and yield levels of the main leguminous crops in the world and in particular countries were used, moreover, research papers devoted to searching and analysis of factors limiting the yield formation of soybean and some other legumes were thoroughly studied. The role of legumes in modern arable farming is enhanced due to the need to increase plant protein production for the processing industry, livestock development, as well as for balanced diet of people. Growing legumes has a long-term positive impact on productivity and production quality of subsequent crops in a crop rotation, the environmental situation being improved. Legumes use atmospheric nitrogen through symbiosis with bacteria of Rhizobium class. The consumption of carbohydrates for nitrogen fixation designates lower yields of these crops. Any stress factor which reduces nitrogen fixation (inadequate inoculation, low pH, drought, etc.) can cause a nitrogen deficiency and result in yield losses. The applied mineral nitrogen is used by plants, but inhibits the formation and development of nodules. The article reflects the importance of knowledge of all the features of the production process when growing legumes and also of the use in agricultural production of high-yielding varieties and technologies, adapted to the specific environmental conditions.