Relation of Weather to Crops 81 



grasses will not germinate, ordinarily, even though given abundant 

 irrigation. 



Johnson grass and Bermuda grass are considered by farmers to 

 be the two chief weed pests of the region. Both are dormant in 

 winter, but grow vigorously throughout the summer. Bermuda 

 grass is a fair lawn grass and presents a good appearance during tlie 

 heat of summer when blue grass is either dead or in very poor 

 condition. A good combination for lawns for the warmer val- 

 leys of the vState is Bermuda grass and Australian rye grass, the 

 former for summer growing and the latter for winter and spring. 

 Australian rye grass is an annual under our cliinatic conditions, 

 and is sown thickly and raked into Bermuda grass sod in Sep- 

 tember. With abundant irrigation it germinates readily and 

 soon forms a velvety carpet which should be mowed during the 

 winter and spring months. In early summer the rye grass dies out 

 and is gradually replaced by Bermuda grass. 



White clover is used to some extent for lawn purposes. It 

 endures a wide range of temperatures since it grows both in summer, 

 when it requires abundant and heavy irrigation, and in winter. 

 Like blue grass it grows best in partly shaded lawns at altitudes 

 below 2500 feet. ^^bove altitudes of 3000 feet both these lawn 

 plants grow well with most ordinary care. Lippia nodiflora, 

 a member of the Verbena family, also grows well at lower altitudes 

 for lawn purposes. • This is a low trailing plant with an abundance 

 of small, whitish flowers resembling those of the whit-e clover. It 

 will grow with less water than most other lawn plants and thrives 

 in shallow soils that contain considerable broken caliche. It does 

 best with moderate irrigation and should be cut with a lawn mower 

 the same as lawn grasses. 



Rhodes grass and Sudan graSs have been introduced recently 

 and are very promising as forage crops. Rhodes grass is believed 

 to be native to southern Africa and is injured with winter tem- 

 peratures of 5^ F. or lower. It spreads from its roots by means of 

 stolons which grew above ground and in a single season it usually 

 forms a continuous turf. There is no danger of its becoming a pest 

 like Johnson grass since with one plowing it can be eradicated. 

 It has not been grown in rich alluvial soils, but in ordinary mesa 

 soil on the University grounds it has outyielded alfalfa several times, 

 and with the most ordinary care makes a growth from early spring 

 until late fall. Its heaviest growth appears to be made in July 

 and August. 



