TY JOUR TI Ways of improving the use of photosynthetically active radiation in potato cultivation in the middle Volga steppe KW leaf surface KW photosynthetic potential (PP) KW potatoes KW yield KW starch KW vitamin C KW nitrates. JO Vestnik of Kazan State Agrarian University AU Vladimirov, S.. PY 2014 IS 8 PB Kazan state agrarian University