344 PRINCIPLES OF AGRICULTURAL CHEMISTRY 



be purchased as necessary, together with supplementary small 

 amounts of nitrogen. Field crops, especially grasses and clovers, 

 utilize insoluble phosphates fairly well. 



Corn. A suitable rotation, including careful saving of all 

 manure, together with the use of phosphoric acid, will maintain 

 corn lands at a good level of productiveness, or increase the yields. 

 The phosphoric acid may be supplied in 200 pounds per acre of 

 acid phosphate applied annually, or 2,000 pounds of rock phos- 

 phate applied every five or six years. An application of nitrogen, 

 such as contained in 200 pounds cottonseed meal, may also be 

 effective. Potash is needed on some soils. The ordinary corn 

 and cotton fertilizer used in the South contains 8 to 10 per cent, 

 available phosphoric acid, 1.65 to 2.5 per cent, nitrogen, and I to 

 3 per cent, potash. It is used at the rate of 100 to 400 pounds 

 per acre. 



Oats. Oats in a rotation often receive benefit from 100 pounds 

 acid phosphate applied at the time of planting, and a top dressing 

 of 100 pounds nitrate of soda when the plants begin their vigorous 

 spring growth. 



Wheat. Same as oats. Clover uses much potash and is often 

 benefited by 100 pounds acid phosphate and 50 pounds muriate of 

 potash per acre. Timothy may receive the same application as 

 clover and in addition a top dressing of 100 pounds nitrate of 

 soda in the spring. Alfalfa requires lime and draws heavily on 

 the potash of the soil. A good application is 200 pounds acid 

 phosphate, 20 pounds nitrate of soda, and 100 pounds muriate of 

 potash applied just before planting. This may be supplemented 

 by 300 pounds acid phosphate and 200 pounds muriate of potash 

 per acre per year. Peanuts are similar to alfalfa. A great deal 

 depends on the soil. 



Cotton. Acid phosphate is used at the rate of 100 to 200 

 pounds per acre on land which produces a good stalk but does 

 not fruit well. An application of 200 to 400 pounds cottonseed 

 meal gives good results on many soils. The Georgia Experiment 

 Station recommends for old worn uplands, a mixture of 1,000 

 pounds acid phosphate, 671 pounds cottonseed meal, and 296 



