江苏省移栽油菜田杂草防治阈期研究

THRESHOLD PERIOD OF WEED CONTROL IN TRANSPLANTED RAPE IN JIANGSU PROVINCE

综合多点试验,建立移栽油菜栽后有草或无草天数与油菜产量损失率之间的函数关系,研究了江苏省油菜田杂草的防治阈期。结果表明:油菜栽后有草天数(x)与油菜产量损失率(y)之间符合方程y=26.09/(1+43.35e^(-0.0417x)),栽后无草天数(x)与油菜产量损失率(y)之间符合方程y=0.00001+26.52e^(-0.0227x)。江苏省油菜田杂草的防治闽期约为栽后41～96d,相当于油菜全生育期的19.5％～45.7％,油菜处于7～9叶期,此前田间杂草的发生量占总量的90％左右。在此阈期内保持田间无草,既能保证杂草造成的减产率低于3％,又能充分发挥杂草在田间生态系统中所起的积极作用。

Field experiments were conducted in Jiangsu Province to determine the functional relationships between the weedy or weed-free days and the yield loss of transplanted rape and the critical period of weed control in rape field. The results indicated that the relationship between the weedy days (x ) after transplanting and rape yield loss (y) can be described with the equation y = 26.09/(1 + 43.35e-0.0417x), and the relationship between the weed-free days after transplanting and rape yield loss with the equation y - 0.00001 + 26.52e-0.0227x. The critical period for weed control in transplanted rape was about 41 (rape at the 7-leaf stage ) to 96 (rape at the 9-leaf stage) days after transplanting which was about 19. 5% - 45. 7% of whole rape growth season. About 90% of weeds had emerged before the critical period . This critical period could not only assure rape yield loss less than 3% level, but also maximally utilize the role of the weed in field ecology system.