【作者】 李照全；

【导师】 周卫军；

【作者基本信息】 湖南农业大学 ， 农业遥感与资源利用， 2008， 硕士

【摘要】 本文以长期定位试验为依托,通过对田间杂草调查及水稻整个生育期田间土壤采样分析,探讨了长期不同农田管理措施对稻田杂草种群组成及其生物多样性的影响,研究了水稻不同生育期农田管理措施下土壤养分含量的差异,及不同农田管理措施下土壤养分动态变化规律,分析了不同农田管理措施对水稻产量的影响。研究主要结果如下:1.水稻整个生育期,不同种植制度下冬泡处理土壤pH值和速效养分含量最高。冬泡处理土壤pH值在5.11-5.55之间,冬油菜处理和冬绿肥处理分别在4.93-5.44和4.91-5.40之间;冬油菜处理土壤碱解N含量最低,早稻成熟期与晚稻成熟期较冬泡处理低28.1 mg/kg和21.8 mg/kg;冬绿肥处理土壤速效P含量最低,早稻移栽前与晚稻成熟期较冬泡处理低4.3 mg/kg和2.7 mg/kg;而土壤速效K含量冬油菜处理和冬绿肥处理都较低。不同施肥措施下单施化肥土壤pH值与速效P含量最高,土壤碱解N、速效K含量最低,高量有机肥处理土壤碱解N、速效K含量最高,但速效P含量却最低。早稻成熟期与晚稻成熟期,化肥处理土壤速效P含量较高量有机肥处理高14.8mg/kg和5.4 mg/kg,而土壤碱解N含量较高量有机肥处理低31.0 mg/kg和41.3 mg/kg,土壤速效K含量低27.8 mg/kg和29.0 mg/kg。不同地下水位间土壤pH值和速效养分含量均没有差异。2.水稻整个生育期,不同农田管理措施下土壤pH值、碱解N、速效P及速效K变化趋势均基本一致。早稻移栽前到早稻返青期,土壤pH值与速效养分均有明显升高。早稻返青期到早稻分蘖期,土壤pH值明显降低,早稻成熟期到晚稻分蘖期,土壤pH值都有明显上升趋势,而早稻分蘖期到成熟期及晚稻分蘖期到成熟期,田间土壤pH值变化幅度不大。早稻返青期到分蘖期,土壤碱解N含量明显降低,早稻分蘖期到成熟期及晚稻分蘖期到成熟期,土壤碱解N含量变化幅度不大。早稻返青期到成熟期,土壤速效P含量先降后升,早稻成熟期到晚稻齐穗期,土壤速效P含量有较大幅度的降低。早稻返青期到齐穗期及晚稻分蘖期到齐穗期,土壤速效K含量呈降低趋势,早稻齐穗期到成熟期,土壤速效K含量降低幅度较小,而晚稻齐穗期到成熟期有所增加。3.不同种植制度下冬泡处理早稻及晚稻产量分别为5031kg/hm~2和6568 kg/hm~2,较冬油菜和冬绿肥处理低。不同施肥处理下早稻产量没有差异,晚稻产量以化肥处理最低,为6481 kg/hm~2,而高量有机肥处理和常量有机肥处理没有差异。不同地下水位间早稻和晚稻产量都没有差异。4.不同农田管理措施下田间杂草密度及优势杂草种类发生了变化。早稻田间不同种植制度及施肥措施下杂草的三种生物多样性指数(物种丰富度指数、均匀度指数、物种多样性指数)都存在差异,晚稻田间不同施肥措施下高量有机肥和化肥处理间物种多样性指数存在差异。而不同地下水位间早稻、晚稻田间三种生物多样性指数均无差异。5.种植制度对早稻田间杂草种群组成影响最大,施肥措施对晚稻田间杂草种群组成影响最大,地下水位对早稻、晚稻田间杂草种群组成影响均为最小。更多还原

【Abstract】 Based on a long-term experiment, the influence of different agricultural practices on the weed community composition and biodiversity, changes of soil available nutrient in different growth stage of rice and soil available nutrient change trends, and rice yields under different agricultural practices were studied in rice-cropping ecosystems. The result showed as the follows:1. During different growth stage of rice, the soil pH and soil available nutrient content were highest under rice-rice-winter flooded fallow cropping system among three cropping systems, its soil pH was 5.11 to 5.55, while 4.93 to 5.44, 4.91 to 5.40 under rice-rice-rape and rice-rice-green manure cropping systems, respectively. The soil available N content was the lowest under rice-rice-rape cropping system, the decreased amount of 28.1 mg/kg and 21.8 mg/kg were observed in the maturity stage of early rice and maturity stage of late rice, compared with rice-rice- winter flooded fallow cropping system. The soil available P content was the lowest under rice-rice-green manure cropping system, compared with rice-rice- winter flooded fallow cropping system, it reduced by 4.3 mg/kg and 2.7 mg/kg before the early rice transplants and in maturity stage of late rice. However, the soil available K content under rice-rice-rape and rice-rice-green manure cropping systems was lower than rice-rice-winter flooded fallow cropping system. In the treatment of chemic fertilizer, the soil pH and soil available P content were the highest under different fertilization systems, while the soil available N and K content were the lowest; the soil available N and K content were the highest under high rate applying of organic manure, however, the soil available P content was the lowest. Under the treatment of chemic fertilizer, the soil available P content was high by 14.8 mg/kg and 5.4 mg/kg, the soil available N content was low by 31.0 mg/kg and 41.3 mg/kg, and the soil available K content was low by 27.8 mg/kg and 29.0 mg/kg compared with high rate applying of organic manure, respectively. Between higher and lower groundwater table, the different of the soil pH and soil available nutrient content was not found.2. During different growth stage of rice, their changed tendency was all similar about soil pH and soil available nutrient content under different agricultural practices. The soil pH and soil available nutrient content was increased from the early rice transplants to recovery stage of early rice. The soil pH was reduced from recovery stage to tillering stage of early rice, and increased from the maturity stage of early rice to tillering stage of late rice. From the tillering stage to maturity stage of early rice and from tillering stage to maturity stage of late rice, the remarkable different of soil pH was not observed. There was reduced trend of soil available N content from recovery stage to tillering stage of early rice, and no obvious change from tillering stage to maturity stage of early rice and tillering stage to maturity stage of late rice. The changed rule of soil available P showed reduced-increased trend from recovery stage to maturity stage of early rice, while there was obviously reduced trend from maturity stage of early rice to heading stage of late rice. The soil available K content gradually reduced from recovery stage to heading stage of early rice and from tillering stage to heading stage of late rice, no obvious change from heading stage to maturity stage of early rice, and a little increment was found from heading stage to maturity stage of late rice.3. The rice yield was lower under rice-rice-winter flooded fallow cropping system than other two cropping systems, and its yield of early rice and late rice were 5031kg/hm²and 6568 kg/nm² under rice-rice-winter flooded fallow cropping system, respective. There was not different of early rice yield among three fertilization systems, however, the late rice yield was lower under the treatment of chemic fertilizer than other two fertilization systems, the late rice yield was 6481 kg/hm² under the treatment of chemic fertilizer. The groundwater table did not affected the rice yield.4. The agricultural practices obviously affected the weed density and preponderant weed. The evidently different of three weed biodiversity indexes (Margalef’s D_MG, Shannon’s E, Shannon’s H’) was observed in early rice crops among different cropping systems and fertilization systems. Between the treatment of high rate organic manure and chemic fertilizer, the only different of Shannon’s H’ was found. The groundwater table did not affected the three weed biodiversity indexes.5. The cropping systems was the most important factor that caused the weed community composition during early rice among agricultural practices, on the other hand, the fertilization systems caused the weed community composition change in late rice crops. The influence of the different groundwater table was lowest during the rice growth.更多还原