Effects of Biochar on Organic Carbon Storage in Farmland Soil-Plant System

CHEN Yaojun; ZHANG Di; HU Xueyu; ZHANG Yangyang; CHEN Wei; ZOU Juan

doi:10.3969/j.issn.1003-6504.2017.11.002

Abstract：To investigate the effects of biochar addition on organic carbon reserve in farmland soil and fixed-carbon storage of crop,a field experiment of corn/wheat crop-rotationpattern was conducted in yellow-brown soil located in the areas of mid/lower reaches of Yangtze River.Soil organic carbon content,crop mass,crop photosynthetic carbon fixation was measured with the different doses of biochar added,i.e.[0.0 kg/(m2·a)-(CK),0.5 kg/(m2·a)-(BC1) and 4.5 kg/(m2·a)-(BC2)];and the organic carbon storage in soil-plant system under the test condition was also estimated.Findings of the investigation indicated that in the soil layer of 0～20 cm in depth,compared with CK treatment (the control),the soil organic carbon storage of the corn in two harvest seasons under BC2 treatment (3.72 and 3.77 kg/m2) increased by 18.93％ and 19.23％ respectively.The soil organic carbon storage of wheat by BC2 treatment was 3.43 kg/m2,12.83％ higher than that by CK;the soil organic carbon storage of BC1 treatment was more than that by CK,but not very much;and so soil organic carbon content is the basis that resulted in the increase of soil organic carbon storage.Treated by BC1,carbon fixation of individual crop of corn in two harvest seasons was not remarkably higher than that by CK,and compared with CK treatment,the carbon fixation of single crop treated by BC2 (80.06 and 80.69 g/strain) increased by 6.46％ and 7.16％ respectively;during the wheat season,the carbon fixation of s single crop with the two biochar treatments was higher than that of CK,especially by BC2 treatment,the carbon fixation of individual crop was 3.06 g/strain,which was 16.17％ higher than that of CK;thus crop biomass positively impacted on carbon fixation of individual corp.The organic carbon storage of soil-plant system,when corn treated by BC2 were 4.42 and 4.50 kg/m2 respectively in two harvest seasons,which were significantly higher than those of CK,the increases being 16.75％ and 17.09%.When treated by BC2,soil organic carbon storage of wheat in the soil-plant system was 3.70 kg/ m2,which was higher than CK by 13.07％.Soil organic carbon storage accounts for 80-93％ of the total soil-plant system carbon storage in the three-season crop,and soil was the main source of carbon sink for farmland ecosystems.In conclusion,reducing soil carbon emissions could result in more carbon fixation of the whole cropland ecosystem.