3^2 



THE CEREALS IN AMERICA 



of interjecting some other crop about once in four years, prefer- 

 ably a cultivated crop, such as maize, or merely permitting the 

 plantation to grow up to dry land weeds. 



509. Fertilizers. — Many kinds of fertilizing material are 

 commonly employed in oriental countries ; in the United States 



DRAINAGE DITCH. 



Plat of rice field in Raywood plantation showing nnethod of irrigation in southwesterr 

 Louisiana and southeastern Texas The different tracts are on different levels. Watcf 

 enters at measuring flume, floods first tract, passes over fieid levee. floods second tract. 

 and so on unti' the who'e fieid is flooded. Water is removed througn drainage ditch b; 

 opening field levees On this plantation the water in the mam canal shown in illustratirr 

 has been raised a total of sixty-five feet by means of three pumping stations. At the 

 initial station the canal is I 50 feet wide. (After Bond.) 



the land is seldom manured for rice. The irrigation of the land 

 presents problems concerning nitrification and supply of fertil- 

 izmg constituents from the water that have not been fully 



