Occurrence Characteristic And Chemical Control Of Weeds On Dichondra Repens And White Clover Turfs In Nanjing Area

With the rapid development of turf industry,management and maintenance of turf gain more and more attention.The control of weeds exercises a key role in establishing a good turf.In this paper,the occurrence characteristics and the damage of weeds on the Dichondra repens and white clover(Trifolium repens) turfs were studied in Nanjing,and the weeds control by chemical methods were also explored.The results were as follows:1.There are two occurrence peaks in a year for the weeds on Dichondra repens turf in Nanjing,namely Spring-Summer peak and Autumn-Winter peak.The occurrence of the weeds and the community keep changing with seasonal variation.There are 37 kinds of weeds from 18 families on the Dichondra repens turf.The weeds that occur usually and cause damage in spring and summer include Echinochloa crusgalli,Amaranthus lividus, Cyperus rotundus,Mollugo pentaphylla,Digitaria sanguinalis,Acalypha australis and Commelina communis.In autumn and winter,the weeds cover Veronica persica,Lamium amplexicaule,Vicia sativa,Alopecurus japonicus,Cyperus rotundus,Eragrostis pilosa and Malachium aquaticum.The weeds occurred the most frequency are Cyperus rotundus, Amaranthus lividus,Acalypha australis,Veronica persica and Lamium amplexicaule,of which Veronica persica and Cyperus rotundus can grow year-round.There are 9 kinds of weeds from 7 families on white clover turf in Nanjing,including Lamium amplexicaule,Veronica persica,Capsella bursa-pastoris,Cephalanoplos segetum,and Euphorbia helioscopia.Lamium amplexicaule and Veronica persica are the majority,and could cause severe damage to the white clover turf.2.The seeding growth of Dichondra repen is more sensitive to herbicides than the white clover.It is safe to spray fifty percent Benazolin-ethyl SC under the recommended dose of 200～300ml/hm~2 for the seeding growth of two turfs,spary twenty five percent ehtametsulfuron WP at dosage of 18.75～21.00g/hm~2 for Dichondra repen and 18.75～22.50g/hm~2 for white clover. 3.It is easy to control grass weeds on Dichondra repens and white clover turfs by sparying five percent quizalofop-thyl EC at dosage of 42ml/hm~2.The stem control effect of weeds is one hundred percent and there is not any injury to the two turfs.4.Fifty percent Benazolin-ethyl SC at dosage of 240～280ml/hm~2 have good effects in controlling sedge and broadleaf weeds on Dichondra repens turf,all the stem control effect on weeds could over ninety percent;Using twenty five percent ehtametsulfuron WP at dosage of 14g/hm~2 to control sedge and all weeds,reached the stem control effect over eighty precent;All of the weeds control effects on fresh and dry weight are over ninety percent.It was effective to spary the mixture of twenty five percent ehtametsulfuron WP at dosage of 7g/hm~2+fift),percent Benazolin-ethyl SC at dosage of 140ml/hm~2+five percent quizalofop-thyl EC at dosage of 42ml/hm~2 to control weeds quantity,frish and dry weight. Mixed twenty percent fluroxypyr EC and fourty eight percent bentazone AS before spraying could control Cyperus rotundus,Acalypha australis and Commelina communis.The weeds on Dichondra repens turf could be controlled by using Benazolin-ethyl+ ehtametsulfuron+quizalofop-thyl in a large scale combined of fluroxypyr+bentazone upon fixed-point.5.The stem control effect of sedge and broadleaf weeds by spraying fifty percent Benazolin-ethyl SC at dosage of 200～240ml/hm~2 and twenty five percent ehtametsulfuron WP at dosage of 10g/hm~2 reached more than eighty precent,which proved that,if combined with five percent quizalofop-thyl EC at dosage of 42ml/hm~2,it could be used to control all weeds and safety to the white clover turf.