马唐密度对旱直播稻生长和产量性状的影响及其防治经济阈值

Influence of Digitaria sanguinalis density on growth and yield components of dry direct-seeded rice and its economic threshold

【目的】探究马唐对旱直播稻生长和产量性状的影响以及其防治经济阈值,为旱直播稻田马唐的防除提供理论依据。【方法】以常规稻象牙香占为试验材料,设置1 m ^(2)独立池为1个小区,每小区播种旱直播稻32穴。对马唐设置8个不同密度(0(CK),2,4,8,16,32,64和128株/m^(2))处理,将其均匀种植在相邻4株旱直播稻的中心位置,每处理重复3次,随机区组排列,研究马唐密度对旱直播稻分蘖数、株高、田间透光率及产量性状的影响,采用不同回归模型拟合马唐密度(x)与水稻产量损失率(y)间的函数关系,并根据经济危害允许水平计算马唐在旱直播稻田的防治经济阈值。【结果】随着马唐密度的增加,旱直播稻的分蘖数、株高和田间透光率均明显下降;与CK相比,当马唐密度为128株/m^(2)时,旱直播稻播种后60 d的分蘖数减少了83.5%,播种后74 d的株高降低24.4%,播种后75 d的田间透光率(离地75 cm)降低80.91%。马唐对旱直播稻的有效穗数、穗粒数、结实率、千粒质量和产量均可造成影响,当马唐密度为2~128株/m^(2)时,旱直播稻产量损失率为5.95%~90.92%。相关性分析结果表明,马唐密度与旱直播稻的有效穗数、穗粒数、结实率、千粒质量和产量均呈极显著负相关(P<0.01)。指数函数y=91.7837(1^(-e-0.0525 x))更好地拟合了马唐密度(x)与旱直播稻产量损失率(y)之间的关系。结合不同除草方式的经济危害允许水平,人工防除马唐的经济阈值为3.79株/m^(2),植保无人机和背负式喷雾器喷施10%噁唑酰草胺防治马唐的经济阈值分别为0.63和1.06株/m^(2)。【结论】马唐可通过影响旱直播稻的生长和产量性状导致旱直播稻严重减产,利用植保无人机防治马唐具有明显的经济优势,其防治经济阈值为0.63株/m^(2)。

【Objective】The influence of Digitaria sanguinalis on growth and yield components of dry direct-seeded rice(DDSR)and its economic thresholds were investigated to provide basis for the control of D.sanguinalis in DDSR field.【Method】Individual pools with an area of 1 m 2 were set up and 32 holes were included in each plot for planting a conventional rice variety of Xiangyaxiangzhan.To evaluate the effects of D.sanguinalis on tiller number,plant height,light penetration rate and yield components of DDSR,the experiment included eight D.sanguinalis treatments of 0(CK),2,4,8,16,32,64 and 128 plant/m^(2) in a complete randomized block design with three replicates.D.sanguinalis plants were uniformly distributed in the center of four adjacent DDSR plants.Regression models were used to fit the functional relationship between D.sanguinalis density(x)and yield loss rate(y)of DDSR,and economic thresholds for controlling D.sanguinalis in DDSR fields were calculated according to the corresponding economic infestation levels.【Result】The tiller numbers,plant heights and light penetration rates of DDSR decreased significantly with the increase of D.sanguinalis density.When D.sanguinalis density was 128 plant/m^(2),the tiller number,plant height and light penetration rate(75 cm above ground)of DDSR declined by 83.5%,24.4%and 80.91%at 60,74 and 75 d after planting,respectively.D.sanguinalis could influence the effective panicle,grain number,seed setting rate,thousand-grain weight and yield of DDSR.When D.sanguinalis density was 2-128 plant/m^(2),the yield loss rate of DDSR was 5.95%-90.92%.The correlation analysis showed that D.sanguinalis density had significantly negative correlation with effective panicle,grain number,seed setting rate,thousand-grain weight and yield of DDSR(P<0.01).The best relationship between D.sanguinalis density(x)and yield loss rate(y)of DDSR was the exponential model of y=91.7837(1-^(e-0.0525 x)).Based on the economic infestation levels of different management methods,the economic threshold for hand weeding was 3.79 plant/m^(2),and the thresholds for spraying 10%metamifop using plant protection drone and knapsack sprayer were 0.63 and 1.06 plant/m^(2),respectively.【Conclusion】D.sanguinalis had serious negative effect on growth and yield components of DDSR,resulting in great yield loss.There were obvious economic advantages to control D.sanguinalis by chemical herbicide with plant protection drone,and the economic threshold was 0.63 plant/m^(2).