MULCHED-BASTN SYSTEM OP IRRIGATED CITRUS CULTURE. 27 



Table X. — Percentage of humus in the first and in the second 8 feet of soil in. 

 the Sunny Mountain grove, California, in 1915 — Continued. 





Basins near upper 

 end of tract. 



Basins near lower 

 end of tract. 



Av- 

 erage, 



Furrow system 



near upper end of 



tract. 



furrow system 



near lower end of 



tract. 



Av- 



Depth and 









bo tli 











both 



























A 



fl 



fl 





A 



A 



A 





of 



si , 



A . 



A . 





A . 



xl . 



A , 





of 







































£ ° 



*-, o 



.« o 



.2 ° 



> a 



t: o 

 o,2 





.2 ° 



1> bo 



«j<3 



tract. 



3 ° 



.-. o 



•5 ° 



^ a 





• H O 



M| 



>% 



tract. 





h 



N 



02 



<J 



to 



h 



02 





^ 



In 



m 



< 



PH 



h 



02 



< 





Second 3 feet: 







































Apr. 9... 



0. 07 0. ( 



0. 05 



0.06 



0.12 



o. or. 



0. 03 



0.07 



0.06 



0.05 



0.02 



Tr. 



0.02 



0.07 



0.04 



0.03 



0.05 



0. 04 



June 15.. 



.09 



.04 



.03 



.05 



.06 



.03 



.03 



.04 



.05 



.05 



.03 



0.03 



.04 



.13 



.08 



.05 



.OS 



.06 



July 10.. 



.07 



.04 



.04 



.05 



.07 



.04 



.04 



.05 



.05 



.06 



.05 



.04 



.05 



.13 



.11 



.05 



.11) 



.07 



Aug. 6... 



.12 



.05 



.05 



.07 



.OS 



.06 



.04 



.06 



.07 



.07 



.05 



.04 



.05 



.18 



.09 



.08 



.12 



.08 



Sept. 21. 



.08 



.03 



. 03 . 05 



.11 



.05 



.03 



.06 



.05 



.06 



.04 



.03 



.05 



.09 



.06 



.06 



.07 



.06 



Aver- 





































age.. 



.09 



.04 



.04 .06 



.09 



.05 



.03 



.06 



.06 



.06 



.04 



.03 



.04 



.12 



.08 



.05 



.08 



.06 



VIVIENDA GROVE. 



Determinations of the average percentage of humus in the first 

 3 feet of soil in the Vivienda experimental tract are presented in 

 Table XI. Samples taken in October, about four months after the 

 mulch was applied, showed an appreciable increase in the humus 

 content of the soil in the basins. The mulch was carefully removed 

 before sampling, so that only the soil itself was taken up. The 

 percentage increase in humus was about the same in the basins 

 mulched with manure and with alfalfa. 



The plat in which the barley was disked showed a marked increase 

 in humus 50 days after the green cover crop was incorporated with 

 the soil. The changes in humus content were all confined to the 

 surface foot of soil. 



Table XI. — Average percentage of soil humus to a depth of 3 feet when various 

 treatments were given in the Vivienda grove, California, in 1915. 



Soil treatment. 



June 

 23. 



July 16. 



Aug. 9. 



Sept. 4. 



Oct. 4. 



Oct. 

 30. 



Manure: 



0.15 

 .19 

 .15 

 .18 



.12 

 .18 



.14 

 .22 



.16 

 .18 

 .16 

 .22 



0.16 



.17 



0.16 

 .20 

 .12 

 .16 



.13 

 .13 



.15 

 .21 



.15 

 .16 



0.14 

 .16 

 .15 

 .19 



.13 

 .19 



.13 

 .23 



.25 

 .25 

 .19 

 .19 



C 1 ) 

 0) 

 0.18 



.24 



.24 

 .30 



0) 

 O 



C 1 ) 



C 1 ) 



( l ) 











0.21 





.31 



Alfalfa: 



.20 





.26 



Sweet clover: 









Barley: 



Disked in July 16 













Same, plus lime 









