The Research On Carbon Storage Of Populus-crop Intercropping System In The Huanghuaihai Plain

The research on carbon cycle is one of the most important issues that the ecologists give more and more attention, because it is related with the global climate changing, and carbon storage and balance is the first for the research. In the recent years large-scaled research on carbon balance is widely used to analyze the status of carbon in many countries and regions, biology community, especially the carbon cycle of forest and soil in the land system is the hot issue, but the carbon balance and cycle of agro-forestry has little research, this paper used agro-forestry in the Huanghuaihai plain as its object , divided to forest, agriculture and soil system, respectively studied on the carbon storage of forest, the intercrop and soil, which provided some support for this effective and sustainable soil utilization measure, furthermore, provided part support in theory and research data.This paper practically chose Populus– crop intercropping system as its object, adopted the methods of standard proving ground and regression and so on, investigated on the biomass of populus plantation in the HuangHuaihai plain at different ages of 3, 5, 9, 11, 13 and 17 years old, and the biomass of intercrop, meanwhile, brought back the samples of soil in each proving ground to mensurate carbon content, then evaluated the carbon storage, the results showed that:(1) The investigation on biomass in the Populus– crop intercropping systemThe biomass of Populus in the HuangHuaihai plain at different ages of six respectively were 12.71,16.35,90.49,92.82,127.82,162t/hm~2, and their biomass distributions were: trunk>branch>root>leaves, the total biomass and the biomass of trunk, branch and leaves were both positively correlative with the age of forest markedly and extremely , and the biomass of root was positively correlative with the age of forest markedly.The yearly biomass of the intercrop in each system respectively was 7.92,7.4,6.96,6.51,6.14,5.79 t/hm~2, the production of the crop declined gradually with the time of intercropping increasing, which showed that menace effect become obvious as time goes, and the crop's biomass was negative correlative with the age of intercropping.The biomass of forest litter respectively was 0.68,0.97,2.14,4.82,6,7.06 t/hm~2·a, 11, 13 and 17 Populus– crop intercropping system had relatively high forest litter biomass.(2)The investigation on carbon content of Populus in the Populus– crop intercropping systemThe carbon content of Populus was trunk0.4527,branch 0.4574,leaves0.4482,root0.4587, hull 0.4364, and the average was 0.4507, the average of forest litter was 0.4359, their distribution were: root>branch>trunk>leaves>hull>forest litter.(3)The investigation on carbon content of soil in the Populus– crop intercropping systemThe average carbon content in the soil from 0 to 60cm in each proving ground respectively was 0.493%,0.517%,0.562%,0.608%,0.638%,0.651%, and was as 2.43～3.2 times as cropland (0.203%), in the vertical distribution they all declined with the depth of soil increasing, the difference of carbon content between each floor reached the level of markedness, but the difference reduced with the depth of soil increasing.(4)The analysis of carbon storage in the Populus– crop intercropping systemThe carbon storage in each intercropping system was 40.97,45.55,51.06,55.94,60.49,63.83 t/hm~2, they had the same rule as carbon content, and the storage mainly centralized from 0 to 40cm, and occupied the total's 77.6%-83.5% in each system, the storage increased with the age of forest increasing, and they reached the level of markedness, in the same floor the storage increased with the age of intercropping increasing, and they reached the level of markedness, too.The carbon storage of Populus was 6.09,7.86,42.07,44.11,60.71,76.69 t/hm~2, the trunk's was the biggest, and the storage of leaves and forest litter was small, the storage of trunk(including hull) occupied the most with the age of forest increasing, which could be 35%～57.9%, but branch and leaves were opposite, the total carbon storage in each system was positively correlative with the age of forest markedly.The carbon storage of intercrop respectively was 7.92,7.4,6.96,6.51,6.14,5.79 t/hm~2, every year it could absorb CO26.8 t/hm~2, the carbon storage of the wheat occupied 35.5%-38.2%, and the earthnut was 61.8%-64.5%, the wheat's was lower than the earthnut's by 38.6%, which showed that earthnut had higher carbon accumulation.(5)The total carbon storage and distribution in the Populus– crop intercropping systemThe total carbon storage in each intercropping system respectively was 54.98,60.81,100.09,106.76,127.34,146.31 t/hm~2, and the carbon storage of Populus and soil was principal part that accounted for 85.1%～93.9%, moreover, the storage proportion of soil, Populus, crop and forest litter sub-system respectively was 33%,57%,8%,2%, of them soil was the largest, then Populus, crop, and forest litter was the smallest, soil storage proportion was as 1.73 times as Populus's, which showed vegetation and soil are the most significant carbon carbon pool in the land ecosystem.