Effects of phosphorus fertilization on the growth and nutrient accumulation of Robinia pseudoacacia germination forests

Fertile soil is an important guarantee for the efficient growth of Robinia pseudoacacia plantations. Nowadays, cultivating second-generation sprouting forests is an important way to build high-quality Robinia pseudoacacia plantations. However, there is currently little research on the fertilization effect of young Robinia pseudoacacia sprouting forests and a lack of relevant application technology research. Therefore, a study was conducted on the fertilization effect of second-generation Robinia pseudoacacia sprouting forests to explore the optimal phosphorus application rate and fertilization method for promoting the growth of second-generation Robinia pseudoacacia sprouting forests, providing feasible technical solutions for precise fertilization of young Robinia pseudoacacia sprouting forests.

Using 8-year-old second-generation Robinia pseudoacacia sprouts as experimental materials, a two factor randomized block design was adopted for different fertilization methods and amounts. The growth indicators and nitrogen (N), phosphorus (P), and potassium (K) element contents of the tested Robinia pseudoacacia leaves were continuously monitored.

The results showed that the application of phosphorus fertilizer had a significant promoting effect on the growth of second-generation Robinia pseudoacacia sprouting forests; For different cultivation goals of Robinia pseudoacacia, precise cultivation and management can be achieved by adopting different fertilization amounts and methods. For example, for cultivating energy forests, 75 g/plant P₂O₅ can be applied, while for cultivating high-quality building timber forests, 50 g/plant P₂O₅ can be applied; For the juvenile Robinia pseudoacacia sprouting forest, the application of 75 g/plant P₂O₅ treatment resulted in the maximum values of diameter at breast height, volume, biomass, and nitrogen, phosphorus, and potassium nutrient content in the upper leaves of Robinia pseudoacacia, which were significantly higher than other treatments; Under the treatment of applying 100 g/plant P₂O₅, the tree height reached its maximum value; The content of P and K nutrients in the lower leaves reached its maximum value under the treatment of 50 g/plant P₂O₅ application.

Based on the comprehensive evaluation of the measured indicators, this study concludes that broadcasting 75 g of P₂O₅ per tree is the most effective fertilization treatment for promoting the growth of young Robinia pseudoacacia coppice stands.