RICE 363 



principal reason for this is that it would reduce the area of 

 rice grown. Nevertheless continuous rice-culture leads 

 ultimately to unprofitable yields. Farmers who have long 

 grown rice continuously on the same land are now being 

 forced to adopt a rotation to free the land of noxious weeds 

 and to add some vegetable matter for the rejuvenation of 

 the soil. An excellent practice is to grow, once every three 

 years, an intertilled crop like corn together with cowpeas 

 seeded at the last cultivation. 



While many kinds of fertilizing materials are employed 

 for rice in oriental countries, the land is seldom fertilized 

 for this crop in the United States. This is partially due to 

 the common impression that the flooding of the rice fields 

 restores to the soil as much plant-food as is removed by 

 the crop. If the irrigation water carries a large amount 

 of sediment this is probably true, but it is not the case 

 where flooding is done with pure water. Usually the 

 irrigation water carries a large quantity of potash and a 

 partial supply of nitrogen, but very little phosphoric acid. 

 That the yield of rice may be materially increased by the 

 use of a phosphate fertilizer, and the proper hardening of 

 the grain aided by the use of a potash fertilizer, are in- 

 dicated by experiments in Louisiana. 



While little is known as to the fertilizer requirements of 

 rice, certainly in most cases, the permanent productiveness 

 of rice lands can be maintained only when at least a part of 

 the fertility removed by the crop is replaced. The best 

 method of doing this must be determined by each planter 

 according to his conditions. 



447. Preparation of the seed-bed. Soil conditions, 

 particularly as regards moisture, are so variable in the 

 rice-belt that no one method of preparation is applicable 

 to all cases. In wet culture the land is usually plowed in 



