Effect Of Bed Widths On Soil Respiration Of No-tillage With Ditch Paddy

A field experiment was conducted to investigate effects of different tillage models (no-tillage with ditch) on soil respiration and its components, and also to assess its influencing factors in a rape-rice rotation system in central China. Six treatments included0.6m (W1),1.2m (W2),1.8m (W3) and2.5m (W4) width of beds, flat no-tillage (FNT) and conventional tillage (T). Soil respiration and its components were estimated both at the center and edge of the beds. This study would be conducive to evaluate effects of soil microenvironment on soil respiration and components and to popularize the technology of cropping pattern with low carbon and high yield. Main results were summarized as follows.(1) No-tillage with ditch pattern changed distribution characteristics of ecological influential factor as light and heat in paddy. Accumulated temperature at FNT,T, and bed edge of W1, W2, W3, W4, were2155℃,2173℃,2183℃,2033℃,2218℃,2133℃, from8July to27September. Accumulated temperature on bed edge of W2was significantly lower than those of W1, W3and T by7.3%,10.7%and6.8%(P＜0.05).(2) CO2emission presented a three-peak pattern in the rice growing season. CO2emission of W1, W2, W3, W4, FNT and T were1046g/m2,1556g/m2,950g/m2,976g/m2,1077g/m2and1466g/m2. T and W2had a significantly higher level of emission fluxes than Wl, W3and FNT(P<0.05), therefore tillage improve CO2emission fluxes. Difference in heterotrophic respiration of different patterns were significant. T had a significantly higher level of heterotrophic respiration than FNT, W1, W2, W3and W4. Heterotrophic respiration of W1, W2, W3, W4, FNT and T were543g/m2,702g/m2,596g/m2,581g/m2,499g/m2and1136g/m2. Autotrophic respiration of W2was significantly higher than those of others (P＜0.05).(3) Crop growth was influenced by no-tillage with different ditch patterns. Carbon nitrogen ratio of W1,W2, W3, W4, FNT and T were31.9%,29.8%,28.9%,35.5%,30.3%and31.2%. W2had a significantly lower Carbon nitrogen ratio than W4(P＜0.05). Accumulated temperature had significant negative correlations with soil respiration flux (P＜0.05), and significant positive correlations with yield (P＜0.05).(4) Yield of W1, W2, W3, W4, FNT and T were9.43t/ha,9.14t/ha,12.03t/ha,8.83t/ha,10.74t/ha and12.02t/ha. W3, FNT and T had higher yields than other patterns (P＜0.05).(5) W3had lower CO2emission fluxes and higher yield than other patterns, which is worth for further study.