The Research Of Utilization Technology For Tetraploid Robinia Pseudoacacia

The objective of this research was to provide theoretical foundation for the plantation of tetraploid Robinia pseudoacacias in Northern Shaanxi. Tetraploid Robinia pseudoacacias planted in Shanbei were studied on their biomass, dynamic change of nutrition, mowing times and utilizing time, aiming to provide utilization technology for tetraploid Robinia pseudoacacias. This study included three experiments:Experiment 1: Study on the biomass and nutrition dynamic change of tetraploid Robinia pseudoacaciasTo reveal growth rules of the tetraploid Robinia pseudoacacias, 150 local planted tetraploid Robinia pseudoacacias was selected and divided into 5 experimental plots with 3 three replicates in each plot. Their accumulation of biomass and main nutrients were determined at 1, 2, 3, 4, 5 months after germination, thereby analyzing the growth and development patterns of tetraploid Robinia pseudoacacia. The results showed below:1. Growth rate of the plant height in the early growing season(the first two months) is relatively slow, then peaked at the mid-growing season(the third month). After that, the growth rate declined into the slow growth period(last two months) before stopped.2.The water content of leaf, stem and whole plant were the highest in the early growth of the whole period, then were reduced to varying degrees.3. The accumulation of leaf biomass was not balanced, and it had two growth peaks. The first one occurred at the second month(from May 23 to June 22), while the second one happened at the fourth month(from July 23 to August 22) which was smaller than the first one.4. The biomass of stem was grown with the growth period and reached the maximum rate at the fifth month.5. In the first three months, the growth rate of leaf was significantly higher than that stem, while in the next two months, growth rate of stem was far higher than leaf.6. The ratio of leave and stem reached the maximum at the early growth stage, and then declined gradually with the growth period;7. Although the GE concentration of leaf changed a little bit, it showed a growth trend of low-high-low among the studied months. The GE concentration of stem barely changed except at the first month, which was lower than the other four months.8. The CP content of leaf and stem peaked at the first month, and then declined sharply at the second month. In the three following months, CP content of leaf only showed a small decrease, while CP content of stem was showed a linear decrease.Experiment 2: Effects of mowing frequency on the yearly accumulated biomass and nutritive value of tetraploid Robinia pseudoacacia.To study the appropriate mowing frequency of tetraploid Robinia pseudoacacia, 180 local planted tetraploid Robinia pseudoacacia were selected and divided into three plots with three replicates each plot. The plots were mowing once, twice and three times a year, respectively. According to the mowing plan, the biomass and nutrient of tetraploid Robinia pseudoacacia were determined to compare the mowing schemes. The results showed that, mowing twice achieved the highest biomass and nutrient value of leaf, stem and whole plant, which were significantly higher than other schemes.Experiment 3: Effects of mowing time on the growth rate and intensity of tetraploid Robinia pseudoacaciaTo obtain the optimal harvest time of tetraploid Robinia pseudoacacias, 100 local planted tetraploid Robinia pseudoacacias was selected and divided into three plots with mowing scheme of 45d+75d, 60d+60d, 75d+45d, respectively. The accumulation rate and intensity of biomass were calculated and compared. The results showed below:When tetraploid Robinia pseudoacacias is mowed twice a year, the first optimal harvest time is in spring 45 to 60 days after germination and the second appropriate cutting time is after the rapid growth period of leaf, which is 120 days after germination.In summary, to maximize the feeding value of tetraploid Robinia pseudoacacias, taking the preference of ruminant on fresh leaves into consideration, and to feed the livestock with fresh leaf as much as possible, the mowing program should be flexible.