4 CIKCULAR NO. 127, BUREAU OF PLANT INDUSTRY. 



CROPPING SYSTEMS. 



The principal crops gi-own are potatoes, barley, beans, and onions. 

 A large acreage is also devoted to asparagus, and celery is gi-owii to 

 some extent. The principal cash crop of the region is potatoes, 

 52,000 acres being devoted to this crop in the delta region in 1912. 

 The barley acreage, while large, usually gives a much lower acreage 

 return than potatoes. 



The present cropping system on the San Joaquin side of the delta 

 is based principally on a 2-year rotation of potatoes and barley. In 

 many cases tenants holding term leases grow barley hay, beans, 

 and onions instead of barley in alternation with potatoes, but in a 

 majority of cases the barley-potato rotation is the accepted one, the 

 effort usually being to devote as much land to potatoes as possible, 

 although the exigencies of the potato market and the decrease in 

 potato yields sometimes cause individual owners to hold their lands 

 in, barley for more than one season in an effort to improve conditions. 

 The lands are farmed largely on an annual tenancy system, the 

 potato tenant moving from farm to farm with the rotation of the 

 crops, while the barley tenant farms each year an aggregate area 

 comprising five or more potato farms. The unit area of potato farm- 

 ing is from 100 to 300 acres. 



Potatoes are planted from the latter part of March till early June, 

 the bulk of the planting being done in April and May. The harvest 

 ordinarily extends from the last of September to the first of January, 

 the potatoes being dug as the market requires them. 



The land is given a preliminary plowing in the early spring to 

 check the weeds and improve the soil tilth and is then allowed to lie 

 from one to three months. Planting is done while plowing, the seed 

 being dropped by hand in the alternate furrows. The seed piece is 

 commonly cut to two eyes. The spacing is from 30 to 32 inches 

 between the rows and 8 to 12 inches between hills, giving about 

 20,500 plants to the acre as a maximum stand. The ground is 

 harrowed from one to three times before the plants are large enough 

 to be damaged. When the plants are large enough to defhie the rows, 

 ditches 10 inches wide with an average depth of 18 inches are cut 

 between two rows 60 to 70 feet apart. Water is later run into these 

 ditches from the head ditches, regulated to fill them nearly full, 

 and irrigation is accom})lished by lateral percolation. Three to 

 five irrigations are given during the gi-owing season, the number 

 depending on the soil and climatic conditions and the h(nght of the 

 ground-water table. The crop is given one or two hand hoeings, 

 one to three cultivations, and one hilling. Ilarvesthig is done by 

 hand with ])otato hooks, the sorting being done during the digging, 

 the culls usually being left in the field. This method, while tedious, 



LCir. 127 j 



