COMMON METHODS OF CULTIVATION UNSATISFACTORY. 9 



the combined harvester and the beginning of the practice of summer- 

 fallowing the land. 



The change to the combined harvester, about 1880, was due largely 

 to labor conditions existing at that time. It was difficult to secure 

 enough men to properly handle the grain, and the methods of har- 

 vesting were unsatisfactory. The climatic conditions, as well as 

 the general contour of the land, were found to be favorable to the 

 use of the combined harvester. This machine reduces to the mini- 

 mum the number of men employed and at the same time utilizes the 

 power of mules and traction engines. 



Proper methods of summer-fallowing the land are not yet generally 

 practiced. Summer-fallowing became necessary on account of the 

 foul condition of the soil which had been produced by continuous 

 cropping to wheat. The use of the combined harvester, however, has 

 partly offset the cleaning effect of the fallow. This method of tillage 

 is beneficial, especially when it precedes a particularly dry season, as 

 in this way a large amount of the rainfall for two years is retained in 

 the soil. At first it was found necessary to summer-fallow the land 

 every third year only, but later, every second year. 



Other changes which have been taking place during recent years 

 are the reduction in size of a few grain farms and an increase in the 

 depth of plowing on the part of some farmers. These changes, how- 

 ever, occur in individual instances only and are not general in their 

 nature. 



BAD RESULTS OF PAST AND PRESENT METHODS. 



We now have in many sections of California, as a result of the com- 

 mon methods of wheat culture, a soil which refuses to produce profit- 

 able crops of the commonly grown varieties of wheat. The general 

 practice of single cropping has depleted the soil in humus and nitrates 

 and made it very foul with weeds. 



Soil Low in Humus and Nitrates. 



There are large sections of California which have been sown in 

 wheat and barley under the commonly practiced methods for the 

 past thirty or forty years. These crops rapidly deplete the soil in 

 humus and nitrates. Humus is the decaying organic material which 

 gives body to the soil and is essential in retaining the soil moisture. 

 It also affects the temperature of the soil, producing somewhat higher 

 temperatures in winter and lower temperatures in summer, according 

 to Wollny, as cited by Hilgard. a The nitrates of the soil are very 

 essential in the production of wheat, as they form an important part 

 of the necessary plant food. A soil low in nitrates usually tends to 



"Hilgard, E. W. Soils, 1906, p. 306. 

 178 



