20 CIRCULAR NO. 126, BUREAU OF PLANT INDUSTRY. 



readily indicated by the poor growth of alfalfa. Manure or other 

 fertilizer can be appUed to these areas until their fertihty is equal 

 to that of the remainder of the field. 



BERMUDA GRASS. 



Bermuda grass, an introduced plant, has proved an exceptionally 

 troublesome weed. In the Southern States, where it does not produce 

 seed, it is considered a valuable forage grass, but in the vicinity of 

 Yuma it produces seed abundantly. It generally covers the ditch 

 banks, and as a consequence the seeds fall into the irrigation water, 

 which acts as an effective distributmg agent. Bermuda grass makes 

 an excellent pasture, but is far inferior to alfalfa for this purpose. 



On account of its tenacious character, the grass is difficult to 

 eradicate when it once acquires a foothold m a field. The best 

 method of killing it so far found has been to give a thorough shallow 

 plowing during the summer months, followed by an occasional disking 

 in order to cut up and clry out the furrow slice. This method has 

 been used successfully on the experiment farm. A strong moldboard 

 plow having a cutting edge on the land side is a useful implement for 

 turnuig over Bermuda-grass sod. If the work is well done, a clean 

 field can be had b}' fall. It is essential that all irrigation water be 

 kept off the land while this treatment is being applied. If the 

 eradication is not complete, the land can be irrigated late in the fall 

 and a crop of small gram grown, since Bermuda grass does not grow 

 during the winter months. If the eradication has not been complete, 

 the process should be repeated the following summer. The cultiva- 

 tion given to a growing crop of cotton has also been found very 

 effective in Bermuda-grass eradication. 



Bermuda grass will grow where the underground water during the 

 flood stage of the Colorado River comes practically to the surface, a 

 condition disastrous to most other crops. It also mthstands a 

 rather high alkali content in the soil, and on account of the rapidity 

 with which it spreads when it once secures a scattered foothold it 

 should prove useful in reclaiming alkali areas. On such areas, where 

 alfalfa does not do well, Bermuda grass has a distinct value as a pas- 

 ture crop, since the forage is highly nutritious and the plants very 

 resistant to the eft"ects of close grazing. 



COTTON. 



For several years much emphasis has been placed on cotton work 

 in an effort to develop varieties adapted to the clmiatic conditions 

 of the arid Southwest. The high price which Egyptian cotton com- 

 mands aiul the smiilarity of the conditions in the irrigated sections 



[Cir. 126] 



