TEXAS AGRICULTURAL EXPERIMENT STATION. 



It is evident that the average quantity of nitrates produced is large. 



The losses from cropped land would, of course, be much less than 

 these given here. The nitrates formed would be absorbed by the crops. 

 The percolation would be reduced, both by the water evaporated from 

 the crop?, and by water running off on the surface. 



Nevertheless, considerable losses of plant food may occur from bare, 

 uncropped soils during the winter months. The nitrates are not all 

 taken up by the plants, and a portion of the water percolates from the 

 soil. 



NITRATES FROM MANURE. 



Table No. 16 shows the nitric nitrogen, in milligrams per pot, perco- 

 lating from the manured and unmanured pots. As previously stated, 

 manure was added at the rate of 30 grams of dried sheep excrement per 

 pot, on October 15 or March 15. This represented an application of 

 9.15 tons per acre of manure containing 80 per cent water. The quan- 

 tity of nitrogen added was equal to 456 milligrams per year, October 

 15, and 474 milligrams March 15, or 55.6 pounds per acre for the 

 former. 



An examination of the table shows that, with one exception, more 

 nitrates percolated from the manure applied October 15 than from 

 that applied March 15. This may be compared with the fact, dis- 

 cussed elsewhere in this Bulletin, that the manure applied October 15 

 decreased evaporation better than that applied March 15. The dif- 

 ference may be partly due to the fact that some of the pots to which the 

 manure was applied March 15 did not percolate properly. 



The average quantity of nitric nitrogen per year produced from the 

 manure applied October 15 is as follows: 



