A Study On Suitable Site, Rational Density And Biomass Of The Energy Plantations Of Caragana Microphylla Lam In Loess Hilly Region Of The Northwest Shanxi Province

Caragana microphylla Lam..widely distributed and cultivated in arid and semi-arid northern China,is a species of Caragana genera.Leguminous family.It is characterized as fast growing,high calorific value, high yield,large sprouting amounts,strong adaptability,etc..and widely cultivated in the loess gully region, China.Suitable trees species,site conditions for Caragana microphylla Lam.,reasonable and rational density of Caragana microphylla Lam.in Pianguan County,Shanxi Province were studied in this paper. Also,a new method for measuring biomass of Caragana microphylla Lam.was proved to be workable using multi-spectral radiometer.The main research results of this paper were as follows:(1)In loess gully region.Caragana microphylla Lam.is a more suitable tree species than C. korshinskii kom.because of its larger branching numbers,larger biomass.But the nutritional components between them were very small.The average annual biomass single cluster of 4-year-old Caragana microphylla Lam.was 0.51 kg.70 percent higher than that of 14-year-old of C.korshinskii Kom.in loess hills shade steep slope,and the average annual biomass per unit area were 2.12t/hm²,3.4 times higher than that of C.korshinskii Kom.The average annual biomass per unit area of 4-year-old of Caragana microphylla Lam.was 1.19 t per hectare,1.12 times higher than that of 14-year-old of C.korshinskii Kom. in loess hills sunny steep slope.(2)The studies of suitable site of Caragana microphylla Lam.in Loess Hilly Region of Northwest Shanxi Province,by comparison the biomass of Caragana microphylla Lam.in the rational density and the same density but different sites,showed that:shade steep slope in loess hills was the best site for Caragana microphylla Lam.,sunny steep slope hills followed,but the shade slope gentle syncline center,shade slope, and beam top was three sites unsuitable for Caragana microphylla Lam.in Loess Hilly Region.But the area of Caragana microphylla Lam.in latter three sites accounted for more than 70%of the whole area,so these sites were very important in production practice.(3)The rational density in every site were that:3301-5000 clusters per hectare in loess beam top whose biomass was 7.28 t per hectare.3301-5000 clusters per hectare in loess hills gentle sand whose biomass was 11.54 t per hectare.3301-5000 clusters per hectare in loess hills shade slope whose biomass was7.86 t per hectare.2501-3300 clusters per hectare in loess hills sunny slope whose biomass was 6.32 t per hectare.3301-5000 clusters per hectare in loess hills shade steep slope whose biomass was 14.44 t per hectare,5000-10000 clusters per hectare in loess hills sunny steep slope whose biomass was 13.88 t per hectare.(4)The biomass of the entire region of Pianguan County was estimated by the investigated data and the second-class inventory data of Pianguan county.The results showed that the biomass of Caragana microphylla Lam.in Pianguan county was 82500 t,in which feeding-biomass of Caragana microphylla Lam.was 21700 t.and the energy-biomass was 60800 t which was equivalent of 373001 standard coal.The biomass of Caragana microphylla Lam.in the Northwest Shanxi Province is 714400 t,in which feeding-biomass of Caragana microphylla Lam.was 188200 t.and the energy-biomass was 526200 t which was equivalent of 322800 t standard coal.The biomass of Caragana microphylla Lam.in Shanxi Province is 985600 t,in which feeding-biomass of Caragana microphylla Lam.was 259700 t,and the energy-biomass was 725900t which was equivalent of 445300 t standard coal.(5)Correlation coefficient between 560nm spectra measured with CROPSCAN and aboveground dry biomass of Caragana microphylla Lam.reached 0.635 which was the largest among the 7 bands.So,the regression models between spectra at 560nm and aboveground biomass of Caragana microphylla Lam. were established,which were remarkable significant at the level of a=0.01.The regression models and their characteristic values between spectra and fresh biomass of Caragana microphylla Lam.were as follows: w=1.653r^0.62of loess hills shade slope with relative error 2.54%and the root mean square error(RMSE) 0.501,w=2.108+0.5013r of loess hills sunny slope with relative error 7.59%and RMSE 0.524, w=1.89 1r^0.535of the whole loess hills area with relative error 6.2%and 0.438.The regression model and their characteristic values between spectra and dry biomass of Caragana microphylla Lam.were as follows:w=0.965r^0.626of loess hills shade slope with the relative error 1.81%and RMSE 0.279,w=1.056+0.243r of loess hills sunny slope with the relative error 10.64%and RMSE 0.395, w=0.937+0.9491nr of the whole loess hills area with the relative error 21.17%and RMSE 0.565.The suitable site and their rational density of Caragana microphylla Lam.forest for energy used were selected and determinated in the loess gully region in this paper,which provided an important theoretical and practical basis and significance for next research on Caragana microphylla Lam.energy-plantation.In conclusion,the research,development and utilization of Caragana microphylla Lam.plantations for energy-used shoud be enhanced in our country for scientific and rational management of Caragana microphylla Lam.energy plantations,and for the current energy security we facing,and the ecological environment improving.