74 CALIFORNIA VEGETABLES 



soils sometimes make a great surface show of saturation when the 

 lower layers have really far less than their holding capacity, because 

 percolation is slow, not only by nature of the soil but by the lack of 

 thorough tillage which would help to hold a large precipitation 

 until the soil could absorb it; third, our soils dispose of moisture 

 very rapidly during the dry intervals of the rainy season, and this 

 can be increased by winter cultivation which should not aim to fine 

 the surface but to open it to the air; fourth, by their active winter 

 growth, the plants themselves pump from the surface layer volumes 

 of water, the escape of which opens the way for capillarity to re- 

 lieve lower layers of their surplus, and thus the active roots help to 

 prepare the way for their own farther extension. 



Really then what California soils need for winter garden pur- 

 poses in natural surface drainage, viz., downward into thirsty lower 

 layers; upward into the air by evaporation from earth-surfaces or 

 plant-surfaces. Where this is not adequate to the relief of surface 

 saturation and consequent preparation for seed sowing, very simple 

 artificial surface drainage is usually effective. This can be mainly 

 accomplished with the plow, first by opening drainage furrows at 

 proper intervals, and this is often all that is needed to dispose of 

 surplus water; second, by ridging with the plow which prepares 

 long seed beds a little above the general surface and at the same 

 time leaves channels for the escape of the water ; third, by opening 

 deeper surface-drains to act directly or to receive and speed the 

 departure of the outflow from the open furrows. All of these forms 

 of treatment, selected according to the degree of the need of drain- 

 age, have proved widely satisfactory and have facilitated magnifi- 

 cent winter growth of vegetables upon heavy adobe soils in some 

 of our regions of heaviest winter rains. The action is quicker than 

 underdraining because percolation is notably slow in such soil. It 

 removes the surplus from the surface just at the time that its absence 

 is most desirable and it leaves the moisture stored below to rise as 

 the demand for it advances. On the other hand underdrainage, 

 where it is not imperatively demanded by exceptional conditions, has 

 clearly acted too slowly to bring the surface speedily into satis- 

 factory condition and has acted too long in drawing away more 

 water than desirable from below and has then continued as a very 

 effective hot-air system for farther drying of soil-substance which 

 should have retained more moisture to supply the plant and foster 

 capillary action from still lower layers. In the writer's own ex- 



