MAINE AGRICULTURAL EXPERIMENT STATION. 19 



flood waters. During the growing season the water is kept at 

 the required level by means of ditches and pumps. Additional 

 water needed for irrigation during the summer months is 

 brought over the levees by siphon's or through by means of 

 head gates. Various crops are grown, but potatoes, of which 

 there ■are annually planted some 40,000 or .50,000 acres, is the 

 principal one. 



These land's, like many others in California, are divided into 

 large holdings, frequently dating back to the original Spanish 

 grants. As a rule, they are not farmed by their owners, but are 

 rented mostly to Japanese growers, and the work is done large- 

 ly by Japanese and Chinese laborers, who live in camps in the 

 fields. The largest potato grower in the United States is one 

 of these Japs, who has planted as high as 6,000 or 7,000 acres 

 a year. Land rental is high, often amounting to $30 or $40 

 per acre per year. Consequently the grower has absolutely no 

 interest in the land itself, except to get all he Can out of it as 

 long as it pays him. Then he moves on to fresh land which is 

 constantly being reclaimed. 



For the first three years after reclamation the lands are 

 cropped with potatoes every year. Then it is barley alternat- 

 ing with potatoes until great reductions in the yields of the 

 latter crop make it no longer profitable. If this system is per- 

 sisted in, yields which, in the beginning, run from 350 to 550 

 bushels per acre, drop to as low as 60 bushels per acre. As far 

 as I could learn absolutely no fertilizer is applied and the dis- 

 eased or cull potatoes are left on the ground as a source of 

 infection to future crops. 



The effects of leaving culls on the ground are even worse 

 than they would be in a 'more rigorous climate. On account of 

 the mild winters on the deltas the cull potatoes produce a large 

 volunteer crop in the barley so there is a continuous growth of 

 potatoes on the land from year to year. Thus diseases, once 

 introduced, have abundant opportunity to live over and in- 

 crease. The tenants move from camp to camp from year to 

 year and carry their seed with them. In fact, no better method 

 could t>e devised to propagate and spread potato diseases in 

 this region. 



As might be expected, wilt and Rhizoctonia are rampant. A 

 Government expert on the ground estimated that the losses 



