Study On Caloric Value Of Three Main Shrub Species In The Dry Valley Of The Upper Minjiang River

Caloric value is an important index of primary production, and it indicates the capability of plants to fix solar radiation. Meanwhile calorific value can reflect the physiological activities and environmental factors change in its organs. Study on caloric value was the foundation to evaluate ecosystem and its components fix energy, conversion and utilization efficiency. It was very important for improving productivity and input-output efficiency of ecology system. Based on three main shrub species in the Dry Valley of the Upper Minjiang River, through analysis in laboratory and field investigation, in order to explore the changes of caloric value among and within shrub species and organs between sunny and shady slopes from Campylotropis wilsonii Schindl, Caryopteris terniflora Maxim and Artemisiasacrorum, as well as the factors affecting this variation, including sunlight, soil physical and chemical properties, and the intrinsic factors such as ash content, total organic carbon and total nitrogen. The results show that :(1) The three main shrub species have different calorific values, the order of gross caloric values(GCV) from the largest to the smallest was: Campylotropis wilsonii Schindl > Artemisiasacrorum > Caryopteris terniflora Maxim. Affected by the ash content, the order of ash-free caloric values(AFCV) was different from GCV: Artemisiasacrorum>Caryopteris terniflora Maxim>Campylotropis wilsonii Schindl. AFCV can eliminate the effect of ash content, so it was reflect the energy of plant accurately. The Average AFCV of the three main shrub species in the dry valley of the upper Minjiang River(20.09 k J.g-1) were higher than the terrestrial plant of the whole world significantly(17.77 k J.g-1).(2) Calorific value of the three main shrub species were different in leaf, stem and root.The order by calorific value in organs from the largest to the smallest, Campylotropis wilsonii Schindl: stem>root > leaf, Caryopteris terniflora Maxim and Artemisiasacrorum: leaf > stem > root.(3) Compared calorific value of the same shrub specie between sunny and shady slopes, calorific value in the leaf of Artemisiasacrorum on sunny slope was significantly higher than it on shady slope. Calorific value in leaf, stem and root of Caryopteris terniflora Maxim and Campylotropis wilsonii Schindl on shady slope were significantly higher than they on sunny slope.(4) The correlations among calorific value and element content were different. Both GCV of Campylotropis wilsonii Schindl and Caryopteris terniflora Maxim on sunny and shady slope were found to be significantly negative and positive correlated with ash contents; Both GCV and AFCV of Campylotropis wilsonii Schindl on sunny and shady slope were found to be significantly positive correlated with total organic carbon; Both GCV and AFCV of Campylotropis wilsonii Schindl on sunny and shady slope were found to be significantly negative correlated with total nitrogen. On the contrary,both GCV and AFCV of Caryopteris terniflora Maxim and Artemisiasacrorum on sunny and shady slope were found to be significantly positive correlated with total nitrogen.(5) Both soil organic matters and total nitrogen were found to be significantly positive correlated with calorific value of shrubs, especially for their roots. meanwhile the impact of total organic matter and total nitrogen on sunny slope was deeper than shady slope.The total phosphorus in silo were found not to be significantly correlated with calorific value of the three main shrub species.