Elements of the Technology of Reproduction of Robinia Pseudoacacia L. for Protective Afforestation under Conditions of Land Degradation and Desertification

The effect of mineral fertilizers and a growth biological stimulant on the development and fruiting of the species Robinia pseudoacacia (Robinia pseudoacacia L.) is analyzed. The introduction of robinia into plantations of various types has been performed from 1904 to the present time. It has been revealed that this North American species successfully grows and develops under arid conditions of Volgograd oblast, is adapted to local soil and climatic conditions, and is stable. Observations were performed in the Kirov Forestry of Volgograd oblast and in the production nursery of the Federal State Unitary Enterprise Volgogradskoe of the Federal Scientific Center for Agroecology, Complex Melioration, and Protective Afforestation of the Russian Academy of Sciences. The studies enabled us to determine the effect of treatment with preparations Biostim and Agrovit on reproductive ability, biometric parameters of young and mature robinia plants, and germination of seeds. Seeds of Robinia pseudoacacia are needed for 2633 ha in Volgograd oblast and for 192 ha in the semi-desert zone. The need for seeds for the entire area of protective forest plantations in Astrakhan oblast and the Republic of Kalmykia is 333 and 2594 kg, respectively. The testing of the Biostim Start growth biostimulant has shown that it optimal treatment rate for robinia seeds is 15 mL/L. A higher rate causes a decrease in vitality and mold development on seeds. The use of the Agrovit preparation causes an increase in the growth and diameter of trees in 10-year-old plantations. Application of the preparation in combination with mineral fertilizers causes a growth to 40 cm of young frost-tolerant plants and to 60 cm of tall trees. The crown diameter of frost-tolerant plants increases to 6.2 cm. The research results show the possibility of sowing robinia seeds at the rate of 2 kg/ha and at a distance of 2.5 m between rows with the use of Agrovit fertilizer.