高寒地区多年生禾草人工草地杂草种群动态研究

青藏高原高寒地区——甘肃省天祝县金强河地区多年生禾草人工草地杂草种群动态研究表明：该区多年生人工草地的主要杂草为灰绿藜(Chenopodium glaucum)、香薷(Elsholtzia patrini)、微孔草(Microula sikkimensis)和野胡萝卜(Osmorhiza aristata)，草地建植当年，高大杂草微孔草和野胡萝卜的生长速度动态呈7，8月中旬较高的双峰型，低矮杂草香薷和灰绿藜的生长速度动态呈7月下旬较高的单峰型，所有杂草群落的生物量生长率动态呈7月中下旬较高的单峰型；草地建植第2年，杂草的生长速度动态与第1年完全相同，微孔草和灰绿藜的生物量生长率动态呈6月下旬、8月上旬较高的双峰型，香薷的生物量生长率动态呈7月中下旬相对较高的单峰型，野胡萝卜的生物量生长率动态几乎呈截距为。的水平线．杂草与栽培禾草的生长速度、生物量生长率大小比较及人工草地群落的组分动态分析表明：对青藏高原高寒地区多年生人工草地而言，灰绿藜、香薷和微孔草等杂草是重点防除对象(杂草)，生长季初期是杂草防除的关键时期，建植第1年是杂草防除的关键年份．

Dynamics of weeds community on artificial grasslands in alpine regions of Qinghai-Tibetan plateau

Dynamics of weeds community in artificial grasslands were studied in Jinqianghe Alpine Region of Tibetan Plateau. The results show that major weeds in the artificial grasslands are Chenopodium glaucum, Elsholtzia patrini, Microula sikkimensis and Osmorhiza aristata.The former two weeds germinate around the 5th of May and the latters germinate around the 15th of May, all of which die around the 15th of September. During the first establishment year growth speeds of 2 tall weeds,Microula sikkimensis and Osmorhiza aristata,have double peaks,appearing around middle July and middle August respectively. Those of 2 small weeds,Chenopodium glaucum and Elsholtzia patrini,have a single peak, appearing around late July. And biomass growth rate of all weeds have a single peak, appearing around middle-late July. During the second establishment year growth rate of weeds repeats the pattern in the first establishment year. The biomass growth rates of Chenopodium glaucum and Microula sikkimensis show 2 peaks in late June and early August respectively,that of Elsholtzia patrini shows a slowly creeping peak in middle-late July,and that of Osmorhiza aristata nearly approaches zero. The comparison on the growth rates and biomasses growth rates between the weeds and grasses and the analysis on the dynamics of the communities in artificial grassland indicate that the critical time for weeds control in the growing season is around the germination stage,and the critical year for weeds control is the first establishment year.