Formation of yield and quality of Jerusalem artichoke tubers at different periods of planting and harvesting of green mass

At present, Jerusalem artichoke is considered as a valuable raw material for the food industry due to the unique biochemical composition of its tubers. The lack of developed zonal cultivation technologies prevents wide introduction of this crop into industrial production. In certain regions of Russia, Belarus and Uzbekistan, studies on establishing the optimal timing of spring planting, as well as its comparative evaluation with early winter planting, have been conducted. Scientific novelty of the research is to establish the yield and quality indicators of Jerusalem artichoke tubers at different terms of planting in combination with the timing of harvesting green mass in the soil and climatic conditions of the Middle Ural. Two-year studies were conducted on sod-podzolic medium loamy medium-cultured soils according to generally accepted methods and State Standards. Agrotechnique generally accepted for the Non-Chernozem zone, Jerusalem artichoke planting technology is a ridge planting. It is established that the tuber formation process of Jerusalem artichoke passes in the period from the phase of budding to the phase of full flowering. At this time there is a significant increase in the number of tubers in the bush - by 15.4 units and the average weight of a tuber - by 19.1 g. After the phase of full blooming until the first harvesting of green mass after 10 days, the number of tubers in the bush is reduced by 35%, and the average mass of a tuber increases within another 20 days. The highest yield of Jerusalem artichoke tubers can be obtained at spring planting - 21.3 t/ha and at harvesting the haulm 20 days after the phase of full flowering - 19.0-21.2 t/ha. The high yield of tubers at spring planting is due to the higher density of plants before harvesting - 0.9 units/m2, and at late harvesting terms of green mass - higher productivity of the bush - 141.7-191.3 g. In the spring planting the share of tubers of medium and large fraction increased by 7% and 8%, the content of water-soluble sugar - by 2.2%. The higher content of dry matter - 22,3% and crude protein - 9,4% was noted in cutting of green mass before tubers harvesting, and crude ash - 1,42% and crude fat - 1,86% at harvesting green mass in 10 days after full flowering.