182 SYSTEMS OF PERMANENT AGRICULTURE 



When spreading across a forty-acre field, the loaded wagon 

 should either be hauled to the middle line of the field, or half of the 

 loads should be hauled to one side and the other half to the oppo- 

 site side of the field, using an extra wagon. The spreader hopper 

 should hold at least 1000 pounds on the half-rod machines, or 1333 

 pounds on the n-foot machines, so that by driving 80 rods, the 

 load will amount to at least two tons per acre. Starting from the 

 middle of the field, one hopperful will spread to the side (40 rods) 

 and back, when the spreader must be backed up to the wagon and 

 refilled. Four such drives (320 rods) with the half-rod machine, or 

 three drives (240 rods) with the n-foot machine, will spread a 

 two-ton load over an acre. 



If the roads are good, two tons can be hauled at a load with a 

 good team and wagon. If necessary to draw the loaded wagon to 

 the middle line of the field, a four-horse team is provided by adding 

 the spreader team. 



For making applications from one half ton to two or three tons 

 per acre of limestone or rock phosphate, an arrangement of this 

 sort is very satisfactory. For heavier applications one can go over 

 the ground twice, or it can be spread by hand. For longer dis- 

 tances, one or more additional teams are needed on the road. 



Where manure is to be spread, rock phosphate may well be spread 

 with it. The phosphate may be sprinkled over the manure from 

 day to day as it is being made in the stall or covered feeding shed, 

 or the manure spreader may be partly filled with manure, phosphate 

 then being sprinkled on sufficient for the load, the load com- 

 pleted, and then spread on the land. It should be kept in mind, 

 however, that, if any leaching occurs after the phosphate is mixed 

 with the manure and before the manure is spread on the land, some 

 loss may ensue of the added phosphate; while if the phosphate is 

 taken directly from the car and spread on the land where manure 

 has been or is to be applied, it can later be plowed under with the 

 manure with no danger of loss of phosphate. 



NOTE. Limestone is soluble in soil water containing carbonic acid, and if 

 ground to pass a sieve with about 10 meshes to the linear inch, it is sufficiently 

 fine, provided the product contains all of the finer material. Fineness correlates 

 with loss by leaching as well as with " availability," while the coarser particles 

 are more durable and serve as centers of alkalinity. (See pages 174, 198, 561.) 



