| In order to explore the seeding time and seeding amount of intercropping Italian ryegrass(Lolium multiflorumL.)into paddy rice field in central area of Jiangsu.With common Italian ryegrass tetraploid varieties as experimental material,we studied the effects of sowing date and sowing amount on growth of Italian ryegrass intercropping into paddy rice field by field experiment.And with pot experiment,we studied the growth and physiological characteristics under different shading intensity,shading duration,and after shading stress.The test results are as follows.1.In pot experiment,the SOD,POD and CAT enzyme activity and biomass and plant height,tiller number and decreased of Italian ryegrass was significant reduction with the enhancement of shading stress.MDA content was significantly increased with the enhancement of shading stress(P<0.05).Chlorophyll content in 47.5%and 30.6%homogeneous full sun light were higher than control,and 10.7%homogeneous full sun light was significantly lower than control(P<0.05).The SOD,POD and CAT activities of Italian ryegrass were increased in different degrees after the shading stress ended,and the contents of MDA,chlorophyll a,chlorophyll b and carotenoid was decreased after the shading stress.SOD,POD,CAT,MDA and carotenoid content was no significant difference compared with the controls under 47.5%and 30.6%full sun light treatment for 14 days removed stress(P>0.05).POD,CAT,MDA and chlorophyll b content is no significant difference compared with the controls in each shading treatment for 21 days removed stress(P>0.05).The results showed that different shading intensity had a significant effect on growth and development of Italian ryegrass.And Italian ryegrass could survival and growth slowly in 30.6%full sun light(L2 treatment),and which could return to normal growth for 14～21 days removed stress.2.The different sowing dates had a great influence on growth of Italian ryegrass.The plant biomass,tiller number and plant height was significantly decreased along as sowing time went on in pot experiment(P<0.05).There was no significant differences in antioxidant enzyme activities and chlorophyll content between different sowing dates(P<0.05).In field experiment,the plant height,tiller number,stem diameter,dry matter yield,NDF,ADF and CP content of Italian ryegrass were decreased as sowing time went on,and IVDMD increased significantly in both two cuts(P<0.05).The number of seedlings of Italian ryegrass in plot sowed 25 days before paddy rice harvest was significantly greater than that in plot sowed 15 days and 0 day before paddy rice harvest(P<0.05).In addition,the daily increase in DMY,plant height and tiller number of two cuts of Italian ryegrass in plot sowed 25 days before paddy rice harvest was significantly higher than that in plot sowed 15 days and 0 day before paddy rice harvest(P<0.05).The DMY,tiller number and quality of the first crop and the growth rate of the second crop in plot sowed 25 days before paddy rice harvest was the highest among the three sowing dates.The results showed that although the quality of Italian ryegrass in plot sowed 25 days before paddy rice harvest was lower than another two sowing date treatments,the early seeding forage could have a longer growth duration and a bigger mowing population density.Therefore the DMY and nutrient yield of both two cuts were significantly greater than another two later sowing date treatments(P<0.05).The experiment showed that the Italian ryegrass could be sowed 25 days into paddy rice field before paddy rice harvest in central area of Jiangsu.3.In field experiments,the different sowing amount had a significant influence on the performance of the Italian ryegrass.The DM Y and CP content of both two cuts had a significantly increased with the increase of sowing amount(P<0.05),and the NDF content of the first cut had a significantly lower with the increase of sowing amount(P<0.05).Field statistics showed that the number of seedlings of Italian ryegrass was increased significantly with the increase of sowing amount(P<0.05)after 15 days sowing,after winter and mowing.In addition,the sowing amount of Italian ryegrass had a significantly influence on DMY and nutrient accumulation,and the DMY,DDMY and CP yield had a significant increase of both two cuts with the increase of seeding amount(P<0.05).The results showed that the higher of sowing amount could obviously increase the number of seedlings,DMY and nutrient yield(P<0.05).The optimum sowing amount of Italian ryegrass into paddy rice field in central area of Jiangsu should be 30.0kg/hm2.In conclusion,intercropping Italian ryegrass into paddy rice field in central area of Jiangsu can obviously increase the DMY and nutrient yield.In my experiment,the Italian ryegrass could be sowed 25 days into paddy rice field before paddy rice harvest in central area of Jiangsu,and the optimum sowing amount should be 30.0kg/hm2. |
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