Assessment of photosynthetic productivity of new perennial forage crops in forest-steppe conditions of Western Siberia

Abstract

The article presents the results of six years of experience in comparative evaluation of perennial forage crops (Sida hermaphrodita Rusby., Silphium perfoliatum L., Polygonum divaricatun L., Polygonum weyrichii Fr. Schmidt, Helianthus tuberosus L., Rhaponticum carthamoides (Willd.), Symphytum asperum Lep., Urtica dioica L., Isatis tinctoria L., Rumex tianschanicus L. × Rumex patientia L.) on parameters of photosynthetic activity and dry matter yield in the forest-steppe conditions of Western Siberia. These crops are characterized by environmental plasticity, longevity (up to 25 years), high productivity (30-100 t/ha of green mass). And they have a versatile economic use. The experiment’s purpose is to assess the potential of crop cultivation and recommend species for inclusion in the regional cropping system. It was found that the largest area indicators of the assimilable apparatus (131.4-149.3 thousand m2 / ha) and photosynthetic potential (4.5–4.6 million m2 day/ha) were in S. hermaphrodita and S. perfoliatum crops, which exceeded the maize values by 1.2–2.4 times. A significant increase in leaf area in these crops contributed to a 23% decrease in net photosynthesis productivity compared to maize. By collecting dry matter for two mowings, these crops surpassed maize by 65-85% with a relatively high indicator of EER PAR (1.2 - 1.4%).