21. 



TREATMENT FOR A PEW SPECIAL WEEDS. 



Quack Grass. This is the most difficult weed to exterminate in 

 Iowa. There is no easy method. It can be removed by giving 

 the field a shallow plowing, in the summer follow with a harrow, 

 bringing the roots to the surface and continue discing and har- 

 rowing until most of the "roots" are destroyed. Late summer 

 and fall is the time to do this. The next season this may be 

 followed with a crop of sorghum sown very thickly. This will 

 probably remove most of the quack grass, but not all. Hemp 

 may be sown in place of sorghum. Dewey claims that several 

 fields where quack grass was abundant, the hemp plant has ma- 

 terially held the quack grass in check. The pasture method has 

 been recommended by Prof. Spillman and what I have seen in 

 Iowa would lead me to believe that it is an excellent method. 

 The field containing quack grass is put in meadow and pastured 

 for two or three years in this way. This method causes the 

 roots to come to the surface. They spread less freely in the 

 meadow than in cultivated ground. The soil is plowed two to 

 three inches deep in the summer, then harrowed two or three 

 times to bring the "roots" to the surface; these may then be 

 removed from the soil and burned. If the season is favorable, that 

 is dry, two or three harrowings will accomplish the killing, but if 

 wet some "roots" will keep alive and it may be necessary to plow, 

 say not less than six inches. After this has been done two or three 

 times the land will be nearly free from quack grass. The field 

 should be watched and when quack grass appears, it may be re- 

 moved by digging up and hoeing. Deep plowing will also destroy 

 the roots, but this can seldom be done well and some "roots" 

 are to be seen near the surface which will develop new plants. 

 The roots of quack grass are shallow rooted. 



The Cover Method. The cover method can be applied when 

 the patch is a small one. For this use tarred paper overlapping 

 the edges. Leave the paper on the quack grass for six months. 

 A heavy coating of straw, six inches to one foot, will also be 

 serviceable, this brings the roots to the surface where they can be 

 raked off and burned; then plow, harrow and cultivate. 



Canada Thistle and Horse Nettle. These weeds are deep rooted 

 and in order to destroy them it will be necessary to plow the 

 field, follow with a harrow two or three times and keep the field 

 clean for the rest of the season. The work should be done in 

 midsummer; if all of the plants cannot be reached by the har- 

 row it may be necessary to cut the plant off with a hoe. Sodium 

 arsenite and iron sulphate may also be used. It is sometimes ad- 

 visable if the patch of thistle occurs in a field to get it in pasture 

 and place a lot of salt around the Canada thistle. Stock will 



