COMPONENTS OF WATER SAVING REGIME OF IRRIGATION OF INTENSIVE APPLE PLANTATIONS UNDER DRIP METHOD OF WATERING

Abstract

It was found in the studies that there was lack of rainfall in the area of unstable humidity during the most spend of moisture in the intensive apple plantations but this moisture should be compensated by irrigation for receiving stable high yields. Lack of rainfall during a vegetation period on average over the period of research was recorded in April, May, July and August and happened at major critical periods of the apple tree development. The main mass of a root system of an apple tree on the vegetative wilding M.9 under a fallow land system in the garden was located at a depth of 0-40 cm where 84% of the total length of roots was concentrated. 83% of the total length of roots was concentrated in the direction of row-spacing at a distance of 0-100 cm from the trunk. It was found that on average one apple tree consumed 87% of soil moisture from the layer of 0-40 cm during a vegetation period. Depth of active moisture exchange did not change during a vegetation period, and the value of water consumption varied depending on its presence in the soil. Depth of soil soaking when watering should be 40 cm taking into consideration the depth of active moisture exchange. It is advisable to change the level of soil moisture taking into account the reduction of total water consumption by an apple tree in the second half of a vegetation period according to its biological characteristics. The most optimal was variable regime of irrigation with keeping soil moisture not less than 80% of moisture rate in the first half of a vegetation period and 70% of moisture rate in the second period.Such water saving regime of irrigation in combination with mulching of the lines near the trunks made it possible to receive the yield at the level of 30.8 t/ha under saving of 62% of irrigation water. The amount of irrigation water which was used for a unit of additional product was much smaller - 22 m3/t under these conditions. Irrigation rate was 220 m3/ha. Irrigation regime under before-watering threshold of 70% of moisture rate in combination with mulching of the lines near the trunks made the conditions for getting the yield of 27.2 t/ha under efficient use of irrigation water. However, use of such irrigation regime requires economic grounding in specific conditions of farming. Irrigation is a determinant factor in forming the yield of apple regardless of the availability of the vegetation period with rainfall. Systems of soil maintenance in the garden have much less impact which varies depending on the availability of a vegetation period with rainfall and it is from 10 to 2%.