摘要:
[目的]研究稻田千金子对水稻生长和产量性状的影响及其防治经济阈值,为稻田千金子科学防除提供技术指导.[方法]在大田条件下,研究不同密度(0、1、2、5、10、20、40和80株/m2)千金子对水稻田间透光率、水肥吸收和水稻产量性状的影响,采用模型拟合法分析不同密度千金子与水稻产量损失率间的函数关系,并根据经济危害允许水平推导千金子的防治经济阈值.[结果]随着千金子密度的增加,其株高显著增高(P<0.05,下同),并通过株高优势争夺水稻田间光照,当千金子密度≥10株/m2时,离地70 cm处的透光率显著降低至10.00%以下,离地25 cm处田间透光率低于1.00%.千金子可同时竞争稻田土壤的水肥营养,进而影响水稻生长,导致水稻有效穗数、穗长、实粒数和千粒重等产量性状显著降低,水稻产量锐减,产量损失率增加.相关性分析结果表明,水稻各产量性状间,除穗长和空秕粒数无显著相关性外(P>0.05),其他产量性状间的相关性均达显著或极显著(P<0.01)水平.二次曲线模型y=-0.0151x2+2.2760x+0.8114能较好地拟合千金子密度与水稻产量损失率间的关系.根据经济危害允许水平和二次曲线模型,人工防除千金子的经济阈值为5.39株/m2,10%氰氟草酯EC化学防除的经济阈值为0.76株/m2.[结论]千金子可竞争水稻的田间光照和土壤水肥,影响水稻的产量性状,导致水稻严重减产.采取化学防治稻田千金子具有显著的经济优势.
Abstract:
[Objective]Influence of Leptochloa chinensis(L.)Nees. on the growth and yield properties of rice and its control economic threshold were studied in order to provide technical guidance for the scientific control of L. chinensis in rice field.[Method]The effects of different densities of L. chinensis(0,1,2,5,10,20,40,80 plant/m2)on light penetration rate of rice,absorption of water and nutrition,yield properties of rice were investigated in field conditions. Then the func-tional relationship between different densities of L. chinensis and rice yield loss rate was researched by using model fitting method. Finally,economic thresholds for control of L. chinensis were derived on the basis of economic infestation levels (EIL).[Result]With the increasing density of L. chinensis,its plant height increased significantly(P<0.05,the same be-low). L. chinensis competed for the light in rice field with advantage of plant height. When the density of L. chinensis was≥10 plants/m2,the light penetration rate at 70 cm above the ground was less than 10.00%and at 25 cm was less than 1.00%. At the same time,L. chinensis competed with rice for water and nutrition in the soil of rice field,which affected the growth of rice and decreased yield properties of rice such as effective ear number,ear length,full grain number and weight of 1000 grains. The rice yield sharply decreased and rice yield loss rate increased. The result of correlation analysis showed that among all yield properties of rice,except ear length and blighted grain number had no significant correlation (P>0.05),the correlation of other yield properties all reached significant level or extremely significant(P<0.01)level. The quadratic curve model(y=-0.0151x2+2.276x+0.8114)could well fit the relationship between the density of L. chinen-sis and rice yield loss rate. According to EIL and the quadratic curve model,the economic threshold for artificial control of L. chinensis was 5.39 plant/m2,and the economic threshold for chemical control by 10% cyhalofop-butyl EC was 0.76 plant/m2.[Conclusion]L. chinensis competes with rice for light,water and nutrition of soil in the rice field,and affects the yield properties of rice,resulting in the serious yield reduction. Chemical control for L. chinensis has obvious economic ad-vantage.
百度学术
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