Maluk T. Optimization of nitrogenous nutrition of intensive pear plantings on vegetative rootstocks under the irrigated conditions of Ukraine's South

Object - natural rules of influence of nitrogen nutrition system usage and hydrothermal conditions upon the processes of southern chernozem nitrogen regime formation, productivity and fruit quality induces of intensive pear plantings. Purpouse - optimization of nitrogen nutrition of intensive pear plantings under irrigation thanks to improving the southern chernozem nourishing regime by determing the optimal dozes, terms and methods of nitrogen fertilization for effective usage of nitrogen by plants, better productivity, economy of fertilizers together with the preservation of clean environment. Methods - field, laboratory, mathematical and statistical, calculating methods. Theoretical results - the theoretical ways for solving the problem of nitrogen nutrition process optimization within intensive pear plantings on vegetative rootstocks with irrigation, basing on the usage of complex approach to the estimation of tree reaction on soil nitrogen regime changes under fertilizers influence have been developed; some new mathematical models that detect the correlation between the meanings of soil nitrogen regime indices and pear plantings productivity have been suggested; the optimal level of pear nitrogen nutrition during the vegetation for the formation of fruit with better biochemical and commercial qualities has been determined. Practical results - some practical methods for the development of optimal nitrogen fertilization system in intensive pear plantings under the conditions of Southern Steppe of Ukraine, basing on improvement of plant nitrogen nutrition by using the rational dozes, terms and methods of fertilization have been substantiated; it is suggested to use water sprinklers for adding fertilizers by fertigation within fruit plantings, that enables to improve the exactness of nitrogen dozage together with the economy of working and material resources. Novelty - firstly under the conditions of Ukraine's Southern Steppe for the optimization of nitrogen nutrition in intensive pear plantings on vegetative rootstocks en southern chernozem under irrigation, the expedience of local nitrogen fertilization fragmentally during the vegetation in the periods when fruit crops need nitrogen mostly was substantiated. Some natural rules of soil nitrogen regime formation in pear orchards with nitrogen fertilization have been defined. Firstly the migration of nitrates on southern chernozem to 500 sm deepness during the fertilization of pear orchards with fallow soil-keeping and irrigation has been determined. The dependence of growing processes intensity and pear productivity on soil prodiveness with mineral nitrogen forms has been determined as well as some models for yield estimation if knowing the content of nitrogen within the soil in certain periods of vegetation have been suggested. Degree of application - the results of researches were implemented in Research Farm "Melitopolskoye" of Melitopol district of Zaporozhskiy region on the square of 10 hectares. The field is agricultural.