| The plant height, LAI and yield of oats, triticale and ryegrass planting in winter fallow field were investigated, and effects of forage rotation on rice agronomic traits, yield and soil environment were studied. The results indicated that:1. Compared with oats and triticale, ryegrass has higher fresh/dry ratio and LAI in filling stage, which was 3.62 and 4.12 respectively. In the case of mowing once in filling, the Pn rate of triticale was 12.03μmolCO2m-2s-1, following as oat, 10.58μmolCO2m-2s-1 and the least was that of ryegrass, which was 9.96μmolCO2m-2s-1. The fresh yield of ryegrass was highest, which up to 83333.33 kg/hm2 for one-time mowing in filling, total fresh yield was 77206.67 kg/hm2 of three-times mowing2. The tiller number, leaf area index, photosynthetic rate, dry matter accumulation and yield of rice treated with previous forage crops were significantly higher than that of winter fallow treatment. The rice tiller number in flowering stage under the treatment of ryegrass mowed thrice was biggest, which was 160.80 /667m2, and the LAI under the ryegrass treatment of mowed once and thrice was also relative higher, was 5.39 and 5.37, respectively, Pn rate of those was also relative higher, which both was 2.14μmolμmolCO2m-2s-1. The dry matter of ryegrass under treatment of mowed once and thrice was 2359.7kg/hm2 and 1769.82kg/hm2 higher than those of winter fallow treatment. Oat crop treatments whether mow once or thrice have neither significant effect on rice dry matter accumulation in rice flowering stage. At rice maturity stage, the dry matter accumulation under treatment of ryegrass rotation mowed thrice was highest, which was up to 15434.9kg/hm2. the rice dry matter accumulation under treatment of ryegrass mowed once or thrice, triticale mowed once or thrice was higher 14.4%,13.2%,11.1%和10.8% than that of CK, respectively. In additional, the rice yield of succession stubble under treatment of ryegrass rotation mowed once and thrice was the highest, which was higher 10.2%,9.9% than that of CK, respectively.3.The diurnal variation of methane released was similar among various treatments. The treatment of ryegrass rotation with mowed once enhanced methane discharge significantly. The diurnal variation trend of Carbon Dioxide Flux was similar among all treatments, the diurnal variation range of Carbon Dioxide Flux of CK was biggest. At 6:00 on first and second day, Carbon Dioxide Flux of CK was the highest, which was up to 3.34mol/m2/s and 2.72μmol/m2/s, respectively. Whereas the diurnal variation range of Carbon Dioxide Flux of ryegrass rotation treatment with mowed once was relatively lower. The indoor CO2 concentrations of all treatments presented U shape, and CO2 concentration was relatively lower and varied more dramatically, which variation scope was 252.66μmol/mol. The soil temperature varied more acutely on CK, at 14:00, the soil temperature of CK was higher 16.8%,15.5%,8.2% than those of ryegrass rotation treatments with mowed once, triticale rotation treatments with mowed once and oat rotation treatments with mowed once.4.Grassy rotation treatments could increase soil organic carbon and soil microorganism carbon significantly, compared with winter fallow treatment. In 0-10cm soil layer, soil organic carbon content of ryegrass rotation with mowed once treatment was the highest, which was 25.1g/kg. The soil microorganism carbon contents of ryegrass rotation with mowed once treatment, triticale rotation with mowed once treatment and oat rotation with mowed once. treatment was higher 22.4%,6.2%,2.5% than that o CK.5.Compared with winter fallow treatment, forage grass rotation treatments lowered soil bulk density and improved porosity. The soil bulk density of CK was 1.242, which higher 3.1% than that of ryegrass rotation treatment with mowed thrice. The soil porosity of ryegrass rotation treatment mowed either once or thrice was relatively higher. In 10-15cm soil layer, the soil moisture content of CK was the highest, which was 33.3%.
|
PDF Full Text Request