Corbeels Marc, Marchão Robelio Leandro, Neto Marcos Siqueira, Ferreira Eliann Garcia, Madari Beata Emöke, Scopel Eric, Brito Osmar Rodrigues
Agro-ecology and Sustainable Intensification of Annual Crops, CIRAD, Avenue Agropolis, 34398 Montpellier cedex 5, France.
Embrapa-Cerrados, PO Box 8233, 73301-970 Planaltina, DF, Brazil.
Sci Rep. 2016 Feb 24;6:21450. doi: 10.1038/srep21450.
The Brazilian government aims at augmenting the area cropped under no-tillage (NT) from 32 to 40 million ha by 2020 as a means to mitigate CO2 emissions. We estimated soil carbon (C) sequestration under continuous NT systems in two municipalities in the Goiás state that are representative of the Cerrado. A chronosequence of NT fields of different age since conversion from conventional tillage (CT) was sampled in 2003 and 2011. Soil C levels of native Cerrado and pasture were measured for comparison. After about 11 to 14 years, soil C stocks under NT were highest and at the levels of those under natural Cerrado. Average annual rates of soil C sequestration estimated using the chronosequence approach were respectively 1.61 and 1.48 Mg C ha(-1) yr(-1) for the 2003 and 2011 sampling, and were higher than those observed using repeated sampling after eight years. The diachronic sampling revealed that the younger NT fields tended to show higher increases in soil C stocks than the older fields. Converting an extra 8 million ha of cropland from CT to NT represents an estimated soil C storage of about 8 Tg C yr(-1) during 10 to 15 years.
巴西政府旨在到2020年将免耕种植面积从3200万公顷增加到4000万公顷，以此作为减少二氧化碳排放的一种手段。我们估算了戈亚斯州两个代表塞拉多地区的市在连续免耕系统下的土壤碳固存情况。2003年和2011年对自传统耕作（CT）转变而来的不同年限免耕农田的时间序列进行了采样。测量了原生塞拉多和牧场的土壤碳水平以作比较。大约11至14年后，免耕条件下的土壤碳储量最高，且达到了天然塞拉多地区的水平。使用时间序列方法估算的2003年和2011年采样的土壤碳固存年均速率分别为1.61和1.48 Mg C ha(-1) yr(-1)，高于八年后重复采样观测到的速率。历时采样表明，较年轻的免耕农田土壤碳储量的增加往往比老农田更高。将额外800万公顷的农田从传统耕作转变为免耕，预计在10至15年内土壤碳储量约为8 Tg C yr(-1)。
