The Research Of Effects Of Carbon Source/Sink

The experiment began in September2010, as a long-term test, and all treatments wereconducted in no-till conditions with re-split plot design. The paper researched the effects ofstraw mulching and fertilizer treatments on farmland soil CO₂emissions, soil temperature,soil moisture, soil organic carbon content and crop yield under different rotation modes（Winter wheat-summer maize, winter wheat-summer soybean, winter rape–summer maize,winter wheat-summer fallow）, and analyzed farmland carbon sourse and sink, furtherscreened suitable rotation modes with low emission and high sink for the GuanzhongIrrigation region.The result showed that:Soil CO₂emission rate of4rotation modes compared that winter wheat-summer maizerotation was the highest, followed by winter wheat-summer soybean and winter wheat-summer fallow rotations, and winter rape-summer maize rotation was the lowest. Averagesoil temperature compared that winter wheat-soybean rotation was the highest, followed bywinter wheat-summer maize and winter wheat-summer fallow rotations, and winter rape-summer maize rotation had the minimum temperayure. Average soil moisture content from0to100cm compared that winter rape-summer maize rotation was the maximal, followed bywinter wheat-summer fallow and winter wheat-summer maize rotations, and winter wheat-summer soybean rotation was the minimum.Average soil organic carbon increasing amounts under different rotation treatmentsregistered as winter wheat-summer soybean rotation> winter wheat-summer maizerotation> winter wheat-summer fallow rotationt> winter rape-summer maize model, andthe increasing amount were1.02,1.01,0.92,0.78g·kg^-1, respectively.Crop carbon sequestration amounts under different rotation modes compared that winterwheat-summer maize rotation had the highest crop carbon uptake with141098.29kg C hm^-2, followed by winter rape-summer maize rotation with122,472.45kg C hm^-2cropcarbon sequestration amount, winter wheat-summer soybean and winter wheat-summerfallow rotations had the lowest carbon uptake with99688.52and77647.89kg C hm^-2. Farmland carbon sequestration amounts compared that winter wheat-summer maizerotation was the highest, followed by winter wheat-summer soybean and winter rape-summer maize rotations, and winter wheat-summer fallow rotation was the lowest. Farmlandcarbon emissions in the production process showed as winter wheat-summer maize rotation> winter wheat-summer soybean rotation> winter wheat-summer fallow rotation> winterrape-summer maize rotation. Farmland carbon net fluxes showed that winter wheat-summer maize rotation was the biggest, followed by winter wheat-summer soybeans andwinter wheat-summer fallow rotations, and winter rape-summer maize rotation was theminimum.