Experiences were spent in 2009, 2010 and 2012 years in the research-and-production center of Chuvash agricultural academy. Before landing of tubers to 2 and 4 variants brought mineral fertlizers with the subsequent cultivation. Tubers landed on depth of 6-8 sm under the scheme 70х40 sm. The purpose of our researches was studying influence of the harvest period and fertilizers on yield of Jerusalem artichoke.

Yield of Jerusalem artichoke substantially defined by terms of the mowing of plants and presence of nutrients in ground [1-5]. Term of mowing of Jerusalem artichoke and mineral fertilizers influence many major parameters - rates of growth and development of plants, yield of green and dry weight, and also gathering of tubers. In 1 year of researches yield of above-ground weight in 1 variant has made 21.0 ton/hectares, at entering mineral fertilizers this parameter has increased up to 29.3 ton/hectares (table 1).

Table 1 - Yield of green mass of Jerusalem artichoke, t/ha

In 3 variant at late mowing gathering weights of  leaves and stalks has decreased up to 18.2 ton/hectares and in 4 variant yield was 25.3 ton/hectares. In 2010 the drought has led to decrease in yield. Optimum conditions for growth and developments of plants were in 2012. In a control variant the weight of leaves and stalks by time of mowing was 23.5 ton/hectares - that more than in 2 times exceeds parameters of droughty 2010. In 4 variant at late mowing with entering fertilizers the parity is less, a difference in 1.5 times. Nevertheless, also in this variant the increase in yield of above-ground weight in comparison with 2010 was essential and was equaled 9.3 ton/hectares.

On the average for 3 years of researches low gathering of green weight were observed in 1 and 3 variants, that it is without application of fertilizers. Late mowing did not promote an increase in productivity of leaves and stalks. Entering of fertilizers into norm N₆₀P₆₀K₉₀ promotes powerful development of plants of Jerusalem artichoke. Both in the second, and in the fourth variants the significant increase of above-ground weight - accordingly on the average for 3 years on 6.7 and 6.0 ton/hectares is observed.

It is necessary to note, that using of fertilizers promotes substantial increase of gathering of tubers (table2).

Table 2 - Gathering of tubers, t/ha

Application of mineral fertilizers in norm N₆₀P₆₀K₉₀ has led to additional gathering of tubers at a rate of 7.2 ton/hectares in early term of mowing and 11.0 ton/hectares at late term of mowing. At later term of mowing yield of tubers is increased. So, in 3 variant at mowing in the beginning of October gathering of tubers is equaled 15.2 ton/hectares, that on 3.0 ton/hectares it is more, than in 1 variant at excavation of tubers in the middle of September. The dispersive analysis shows, that with 95 %-s' probability the difference between all variants is essential. In droughty 2010 the least yield of tubers is received.

Conclusions. On grey soils of Chuvashiya  the productivity of Jerusalem artichoke depends on terms of harvesting of the culture and of fertilizers. The best results are reached when contributing of fertilizers in rate N₆₀P₆₀K₉₀. The high productivity of above-ground  masses is received when mowing at the end of the august. The influence of the mineral fertilizers depended on forming of the conditions. At arid year gain from contributed fertilizers in yields both above-ground  mass, and tubers was a low.

2. Kochnev N. Kalinicheva V. M. Jerusalem artichoke – biopower culture of the ХХI centu-ry.- Moscow: NTF "Ares", 2002.- 76 p.

3. Lapshina T. B. Biological characteristics and methods of cultivation of Jerusalem arti-choke in the conditions of middle taiga zone of the Komi ASSR - Leningrad-Pushkin, 1983.- 17 p.

4. Lukashov V. N., Ostrovsky M. N., Shiyanov G. N. The Jerusalem artichoke in conditions of irrigation in South and South-East of Kazakhstan.- Alma-Ata: Kainar, 1989.- 16 p.

5. Skoblina V. I. Jerusalem artichoke.- Moscow: Armada-press, 2001.- 32 p.