117 



Station during the past two years to determine the rate of nitrification 

 on the different soils and at different depths, and on soils yariously 

 treated. 



In every instance nitrification was most abundant at a depth of three 

 to four inches, decreasing in depth until at two feet it was practically 

 naught. In lands in good tilth, or manured with stable manure broad- 

 cast, or with a good growth of cow peas, nitrification was rapid and 

 copious. It was more abundant on the ridge of the rows than in the mid- 

 dles. Drainage could almost be measured by the rate of nitrification. In 

 badly drained soils it was almost entirely absent, while high dry ridges 

 gave abundant evidence of the activity of the microbes. An immersion 

 of the soil for a few hours, by a heavy downpour of rain, suspended for 

 two days the process of nitrification. It was more abundant in soils 

 lightly stirred than in those cultivated with the plough. 



Soils stirred daily gave increased quantities of nitrogen over those 

 stirred weekly, and more in the latter than in those stirred bi-weekly. 



In fact, good drainage and frequent surface cultivations were prime 

 iactors in rapid nitrification. 



Preparation of Soil. 



With this knowledge of our soils we can now proceed to apply the 

 well-established principles of preparation of all crops. 



Since these soils are so strongly silty and clayey, and being level, are 

 without natural drainage, it is manifest that they should be placed in a 

 condition of artificial drainage, to insure warmth and necessary condi- 

 tions of bacterial growth. Every operation should look to the mainte- 

 nance of these conditions. Hence flat culture is unsuccessful. They 

 should be broken as deeply as possible to admit air to assist in drying 

 out excessive water, and most important, to give as large an area as 

 possible for the foraging of the roots of the cane, since experiments have 

 shown that in stiff lands but few roots pass beyond the broken soil. 

 They should be broken as early in the fall as possible, thrown into high 

 ridges and the middles, quarter-drains and ditches well cleaned out, for 

 the quick removal of winter rains. 



The spring should find each row in the condition of an ash bank, and 

 the planter should endeavour to keep it so by proper cultivation through- 

 out the season. 



We break land to prevent the natural tendency of all soils to return 

 "to rocks, evidenced frequently in the hardpan just beyond the plow. We 

 break land to destroy weeds and grasses and relieve the soil of 

 foulness, preparatory to the growth and sustenance of the cultivated 

 crop. 



We break land to control moisture, throwing up in high ridges to re- 

 lieve excessive moisture and flushing or ploughing flat to conserve the 

 winter's rainfill for the summer's crop, on dry soils. If the work of 

 preparation has been properly done, in accordance with the nature of 

 the soil and the demands of climate, subsequent planting and cultiva- 

 tion are simple processes. 



If, however, our work has been imperfectly performed then subse- 

 -quent cultivation must be directed to the acquirement of tilth, which is 

 simply obtaining the best conditions for the growth of crops. 



Tilth, however, should always be obtained, if possible before planting 



