There are many causes for this rapid development. In the first place, the Japanese as a rule are ambitious. They do not rest satisfied, like the Chinese and the Mexicans, with being employed as farm laborers. They save money or form partnerships with well-to-do friends, and start independent farms. This is made easy by a form of tenancy which prevails in California. That is, the landowner advances the required sum of money to a tenant, offers him tools and shelter, and in return receives rent from the sale of the crops. This is a modified form of crop contract, but it is decidedly more secure for the owner, because he assumes less risk. It is more profitable to the tenant because he gets a due reward for his effort. On account of the ease with which this kind of lease is obtained, ambitious Japanese farm laborers soon become tenants, and when successful--and usually they are--they buy a piece of land with the intention of making a permanent settlement. That Japanese farmers are usually favorably regarded by landowners is an important factor in their success. Although there have been cases in which the Japanese provoked the hatred of landowners by not observing promises or failing to carry out contracts, on the whole, the Japanese are preferred to other races, because they are more peaceful, take better care of the land, and pay higher rent.[30] The reason why Japanese take better care of the land and can pay higher rent than ordinary farmers may be found in their previous agricultural training in Japan. There the farming is conducted on the basis of intensive cultivation. Moreover, in order to prevent exhaustion of land the farmers are accustomed to taking minute care that the soil's fertility be retained. This habit of intensive cultivation and the minute care of the soil, which are really inseparable, are maintained by the Japanese farmers when they undertake agriculture in California. Furthermore, it so happens that the climate and soil of California are especially suited for intensive cultivation. Such products as vegetables and berries, which grow so abundantly in California, are precisely the kinds of crops which demand careful and intensive cultivation. The notable success of Japanese farmers in this form of production, therefore, is not an accident. By the introduction of methods of intensive cultivation they have been able to take good care of the land and to pay high rent to the landowners. That the Japanese are good farmers is attested by the fact that they actually produce more per acre than the other farmers. The Japanese-American Year Book of 1918 has the following comment to make regarding the efficiency of Japanese farmers in California: