Trus O. Change of humus state of podzolic chernozem of the Right-Bank Forest-Steppe of Ukraine under condition of long-term application of fertilizers

Object - changes of humus content, its reserves, fractional-group composition, labile part and colloidal forms of humus, fertility parameters of podzolized heavy clay loamy chernozem, productivity of field crop rotation under various fertilizer rates and fertilizer systems. Purpose - to detect the changes in parameters of humus status of the podzolized heavy clay loamy chernozem under a long-term application of fertilizers in the field rotation, to establish efficient levels of saturation of crop rotation with organic and mineral fertilizers and their combination to ensure the optimal physical and chemical parameters of the soil, nutrition conditions of agricultural crops and environmental protection. Methods - field study, laboratory research, mathematic-statistical, computational-comparative methods. Theoretical results - theoretical approaches have been elaborated as to the application of reasonable rates of mineral and organic fertilizers on podzolized heavy clay loamy chernozem in field rotation on the basis of the content, reserves, dynamics and balance of humus, physical and chemical properties of the soil. It is very important for increasing crop productivity and implementation of environmentally sound and cost-effective technology of fertilizers application under conditions of the Right-bank Forest-Steppe of Ukraine. Practical results - a tight correlation between humus accumulation in the podzolized chernozem and the level and manner of a long-term anthropogenic influence on the transformation of its properties and the change of parameters towards recovery of its fertility was revealed. Taking into consideration parameters of the content, reserves and quality of humus it enables to monitor the formation of soil and to choose methods for increasing the productivity of field crop rotation. In order to maintain the optimal parameters of humus status of the soil the following recommendations should be taken into account in production: no less than 60 - 70% of non-market part of the yield should be left on the field as an organic fertilizer under application of mineral fertilizers at the rate of N45 - 90P45 - 90K45 - 90 on 1ha and 10 - 30 % in the organic fertilizer system at the rate of 9 - 18 t. Under application of organic matter at the rate of 4,5 - 13,5 t in combination with mineral fertilizers (N23 - 68P43 - 101K18 - 54) this part should make up no less than 30 - 50 %. Novelty - it has been established that the organic matter content in the soil increases from mineral to organic-mineral fertilizer system and also with the use of each system in case of increasing fertilizer rates with the exception of a small rate (N45P45K45), where the content and reserves of humus are the same. It has been substantiated that soil is formed under a long-term application of fertilizers and develops in the direction of the recovery of podzolized chernozem, the level of which is defined by the rate of fertilizers at the most and by fertilizer systems in the least which is proved by the yields of different crops and productivity of crop rotation in general. Degree of application - the results of the thesis were implemented in 2009 by the private enterprise "Papuzhyntsi" in Talne district Cherkasy region on the area of 1350 ha and by the farm enterprise "Bazys" in Uman district Cherkasy region on the area of 1286 ha. The results are also used by Cherkasy state design and technology centre which is in charge of soil protection and quality of products. The field is agriculture.