耕作措施和施肥方式对麦田杂草密度和生物量的影响

Weed density and its biomass in wheat field under effects of different tillage and fertilization modes

为明确我国华北地区麦玉轮作系统小麦免耕的推广和施肥方式的改变对麦季杂草生长的影响,在免耕实施5年后,调查了麦田杂草密度、单株质量和生物量。结果表明:华北地区小麦生长早期,免耕有降低麦田杂草总密度和优势种播娘蒿密度趋势,但差异并不显著;相对于传统耕作,免耕秸秆覆盖和不覆盖处理总杂草生物量显著降低,其中播娘蒿生物量分别降低了57%和73%;免耕也使播娘蒿单株质量降低了27%～53%;免耕秸秆覆盖和不覆盖处理播娘蒿的株高分别比传统耕作降低了25%和19%;但一般情况耕作方式并没有显著影响离子草和麦家公生长;相对于分次施肥,集中施肥杂草生物量降低了21%～68%,播娘蒿生物量降低了58%～65%,麦家公降低91%;免耕在一定程度上抑制了某些杂草的生长,但追肥促进了杂草的快速生长。

To understand the effects of different tillage and fertilization modes on the weed growth in wheat-maize rotation system in North China Plain,an investigation was made on the no-tillage wheat field which is set up 5 years ago. No-tillage had a trend of decreasing the total density of weeds and the density of dominant species flixweed at the early stage of wheat growth,but the difference between traditional tillage and no-tillage was not significant. The weed biomass under no-tillage with straw remained and with straw removed decreased significantly,in which the flixweed biomass decreased by 57% and 73%,respectively,compared with that under traditional tillage. No-tillage also decreased the dry weight per flixweed plant by 27%-53%. Compared with conventional tillage,no-tillage with straw remained and with straw removed decreased the flixweed height by 25% and 19%,respectively. Generally,tillage mode had little effects on the growth of purple mustard and corn gromwell,while concentrated fertilizing decreased the total biomass of weeds by 21%-68%,flixweed biomass by 58%-65%,and corn gromwell biomass by 91%,compared with repeated fertilization. It was concluded that no-tillage could inhibit the growth of several weeds,while topdressing could promote the rapid growth of weeds.