Abstract

The influence of planting time on the photosynthetic productivity, yield and quality of potato tubers in the forest-steppe zone of the Chelyabinsk region has been studied. The objects of study were two varieties of potatoes of different ripening periods: Rosara (early season) and Kuzovok (mid-season). It was established that the optimal period for planting potatoes is the second decade of May. This planting period provides favorable dynamics of the formation of the leaf surface and the maximum photosynthetic potential of agrophytocenosis: Rosara - 3.220 and Kuzovok - 4.178 million m2/ha/day. When planting on May 12 to 15, the yield of dry Rosara biomass (9.8 t/ha) was 26.6% higher than in the variant of planting potatoes on June 5 to 12 and Kuzovok (11.0 t/ha) by 20.2% more than late planting. Potato yield during spring planting changed insignificantly. Late planting led to a significant decrease in the productivity of the studied varieties: Rosara by 5.1 t/ha (16.9%) and Kuzovok by 6.2 t/ha (19.1%) compared with the first planting time. Planting potatoes in the second decade of May led to increased photosynthetic activity of plants, increased potato yields. The quality of the crop improved. The dry matter content in variety Rosara tubers increased by 3.5 %, the Kuzovok variety by 2.7 % compared to late planting, the starch content in tubers increased by 2.66 and 1.94%, respectively, and the accumulation of nitrates in tubers decreased by 2.0 and 2.4 times compared to planting on June 5-12. The coefficient of assimilation of photosynthetically active radiation during the growing season (May-August) for the Rosara at the first planting time was 3.2 %, and at the third - 2.6 %, for the Kuzovok - 3.6 and 3.0 %, respectively.