THE MONTHLY BULLETIN. 55 



Crop rotation is becoming universally recognized as absolutely neces- 

 sary. The rotations vary with local conditions, but in general a good 

 rotation should cover at least four years and should provide at least one 

 tilled crop, one of clover or alfalfa, and others depending on what the 

 locality produces to best advantage. 



For the eradication of special weed pests such as Bermuda grass, 

 morning glory, yellow star thistle or water grass, crop rotation is 

 invaluable. To get the best results from land covered with Bermuda 

 grass or other troublesome grasses, attach a shear to the front of the 

 plow, which will cut the rootstocks and top of the plant. Plow six to 

 eight inches deep, turning the earth over clean. After harrowing rake 

 together and destroy all the rootstocks possible. Sow the field to barley, 

 rye, or some other thick shade crop. It is the shade, as much as any- 

 thing else, that keeps the grass down. As soon as the grain is harvested 

 plow again and seed to vetch or ^Melilotus clover for a winter cover crop. 



In case of yellow star thistle the best crops to use are hoe crops. Plant 

 the land to beets, beans, potatoes, corn or other valuable crops and culti- 

 vate with a peg-tooth harrow or cultivator as often as possible, going 

 over the field with a hoe between times. 



In all agricultural work, whether it be for weed eradication or other 

 purposes, the word "thorough" should be the password. Half the 

 trouble from our insect, fungous, and weed pests could be avoided if 

 the farmers and orchardists would do their work thoroughly. 



ERADICATION OF SPECIAL WEEDS. 



Water Grass {Echinochloa crus-galli). — This w^eed infests low 

 marshy places, frequently becoming a pest in alfalfa fields where the 

 drainage is not good. It is not apt to be serious when the conditions 

 for the alfalfa and the stand of alfalfa are good. In rice this grass has 

 become a very serious pest. Chas. E. Chambliss^ says: 



"During the past three years this grass has taken complete pos- 

 session of more than 2,000 acres of rice land in Sacramento valley, 

 and is now present in alarming quantities on a considerable acreage, 

 which will soon be rendered unprofitable for rice growing unless 

 active steps are taken for its complete eradication or control." 



The seed germinates at the same time as the rice and the plants grow 

 to maturity in about sixty-five days. If this first crop is allowed to go 

 to seed a second crop will develop before the rice is ready to harvest. 



Control. — To prevent the further spread of this grass sow clean 

 seed. It would be well if this could be an absolute command to the 

 prospective rice planter. Have seed tested by the county horticultural 

 commissioner or the farm adviser, and if it is not clean seed do not 

 buy it. 



When water grass is present, prevent it from going to seed if pos- 

 sible. Individual plants will produce as many as 40.000 seeds. 



Plow, harrow and irrigate land in the fall. This will tend to germ- 

 inate weed seeds and leave the land clean for spring sowing. In bad 

 cases crop rotation Avill be necessary, using, if possible, some hoe crop. 

 Summer fallowing is also practiced with good results. 



^U. S. Dept. of Agriculture. Farmer.s' Bui. 6SS. 

 2— 215S2 



