论文部分内容阅读
定点系统观察川水地区油菜田几种主要杂草苣荬菜、艹扁 蓄、荞麦蔓、酸模叶蓼等。田间发生总密度 331 .84万株 /hm2 ,杂草种类多样性指数为 0 .7648。多年生杂草苣荬菜发生量为 1 2 2 .34万株 /hm2 ,4月上旬开始出苗 ,7月下旬终止 ,历经 1 1 4d左右 ,出苗高峰期在 5月上旬。一年生杂草艹扁 蓄、荞麦蔓、酸模叶蓼 ,田间发生量分别为 74.83万株 /hm2 、51 .5万株 /hm2 、3933万株 /hm2 ,4月上旬开始出苗 ,5月下旬终止 ,历经 53d左右 ,有两个出苗高峰期 ,第一个峰期在 4月上旬 ,第二个峰期在 5月上旬。这三种一年生杂草在田间出苗最适深度 1 993年分别为 1— 3cm、2— 3cm、1— 3cm ;1 999年分别为 3— 5cm、2— 4cm、2— 3cm。出苗深度变化与5月份降水量 ,田间土壤干湿有密切关系
Point-by-point system to observe the Rape Hedysarum field several main weeds, such as cabbage 艹 flat, buckwheat vine, Polygonatum Polygonatum and so on. The total density in field was 3.1884 million plants / hm2, and the weed species diversity index was 0.7648. Perennial weed borneo occurred 12.2344 plants / hm2, beginning in early April, ending in late July, after about 114 days, the peak of emergence in early May. Annual weeds 艹 flat storage, buckwheat vine, Polygonatum, the amount of field were 748,300 plants / hm2, 51 .5 万 plants / hm2, 39,330,000 / hm2, beginning in early April emergence, termination in late May, After about 53d, there are two peak emergence period, the first peak in early April, the second peak in early May. The three annual weeds in the field the optimum depth of emergence in 1993 were 1 - 3cm, 2 - 3cm, 1 - 3cm; 1 999 were 3 - 5cm, 2 - 4cm, 2 - 3cm. The change of emergence depth is closely related with the precipitation in May and the dry and wet soil in the field