MULCHED-BASIN SYSTEM OF IRRIGATED CITRUS CULTURE. 



9 



The treatments included (1) spreading manure broadcast in the 

 irrigated space between the tree rows and'disking it in; (2) burying 

 the manure in a circular trench 18 inches wide and 12 inches deep, 

 located under the drip of the tree; (3) applying the manure as a 

 surface mulch in the basin, which was approximately 15 feet in diam- 

 eter, with the tree in the center; (4) trenches containing alfalfa in 

 place of manure; (5) basins mulched with alfalfa in place of manure; 



(6) sweet clover as an irrigated cover crop between the tree rows; 



(7) barley as an irrigated cover crop; and (8) the usual disk culti- 

 vation and furrow irrigation as a check. The treatments were also 

 repeated with the addition per tree of about 100 pounds of flue dust 

 from the neighboring cement works, having the following compo- 

 sition (analysis by J. F. Breazeale) : 



Per cent. 



Calcium carbonate 53. 40 



Calcium oxi.d 13. 16 



Calcium sulphate 8. 89 



Phosphoric acid (P2O5) .18 



Potash (K 2 0) .95 



Insoluble (in dilute HC1) 13.73 



Twenty cubic feet of manure per tree were used in each of the 

 manure experiments, and one bale of alfalfa per tree (about 125 

 pounds) was used in each experiment with alfalfa. A row of orange 

 trees (about 48 trees) was used for each treatment, and each alter- 

 nate row was left untreated as a guard. 



Table II. — Average percentages of total soil moisture to a depth of 3 feet in the 

 Vivienda grove, California, in 1915. 





Dates of sampling before and after irrigation. 



Soil treatment. 



o 



a 

 a 



< 



a 



•2 



<o 

 CO 



a 

 a 

 >-> . 



fc.<M 

 < 



"3 



■2 



o 



pq 



3 

 >-> 



UN 

 O 



< 



< 



•8 



o 



pq 



<D 

 < 



p. 

 <s 

 m 



£**' 



•3 



<D 



pq 



<s 

 02 . 



<B 



< 



O 



<s 



o 



< 



o 



O 



1~ CO 



pq 



Manure: 



12.2 

 11.3 

 12.8 

 12.9 



7.9 

 8.9 

 7.5 

 9 

 10.0 



9.2 

 9.7 

 10.6 



6.7 

 6.0 



6.7 

 5.9 

 8.5 

 8.5 



14.2 

 14.8 

 11.7 

 12.9 

 14.4 



14.8 

 12.2 



13.8 



13.9 

 13.5 



14.2 

 13.9 

 14.9 

 14.5 



7.4 

 8.0 

 7.4 

 9.2 

 9.0 



7.5 



8.7 



10.4 



4.8 

 4.9 



5.7 

 5.6 

 7.5 



7.7 



14.0 

 13.1 

 6.5 

 11.6 

 12.8 



8.7 

 11.5 

 12.8 



15.1 

 14.4 



0) 



7.1 

 8.2 

 3.3 



8.5 

 9.2 



3.4 

 8.5 

 10.3 



6.9 

 5.3 



9.7 

 8.5 

 4.8 

 12.2 

 14.8 



3.4 

 11.5 

 13.5 



(*) 



( l ) 



7.4 

 6.7 

 6.6 

 8.1 

 9.4 



3.0 



7.8 

 9.8 



(') 



0) 



0) 

 12.3 

 13.7 



( l ) 

 11.7 

 13.9 









Same, plus lime 













7.8 , 12.8 

 7.8 14.1 



6.3 





8.6 



Alfalfa: 



14.0 

 12.4 







6.8 14.0 

 9.7 ; 12.3 



6.2 





9.7 



Sweet clover: 



Cover crop - 



Same, plus lime 



Barley: 



13.1 

 11.3 



12.2 

 11.7 

 12.5 

 12.0 





















Same, plus lime 















14.2 

 13.1 



6.2 

 5.7 



8.8 

 7.9 



5.5 



4.7 



0) 



(») 















! 





i Basined. 



68279°— Bull. 499—17- 



