GRAYLING INSTITUTE. 329 



and the conditions favorable to active plant growth and development, the 

 wider the range of knowledge and skill required to secure the full benefits of 

 its valuable contributions to farm practice. 



Science points out the road to success and we may safely follow its sugges- 

 tions in devising the best paying methods of cultivation and general 

 management. 



We have been told that one of the marked defects of the plain soils is a 

 deficiency in organic matter caused by the fires which have left only the ash 

 residue of previous vegetation. 



The obvious remedy for this defect is to grow a variety of crops in regular 

 succession, to make use of every available element of fertility and thus accu- 

 mulate root residues in the soil as a resource for future production. 



A variety of crops of different habits of growth and root development will 

 give a greater aggregate yield than can bs obtained, at the same cost, with a 

 single crop frequently repeated. 



In the Rothamsted experiments, wheat was grown sixteen years in continu- 

 ous succession. On another plat wheat was alternated with fallow for six- 

 teen years, and on another wheat and beans were alternately grown for six- 

 teen years. In each of these cases the total amount of wheat produced in 

 the sixteen years of the experiment was practically the same, and the beans 

 were evidently a net gain of produce without diminishing the yield of 

 wheat. 



The crop rotations should be planned to keep the soil occupied, without 

 intermission, with growing plants of economic value. The process of nitrifi- 

 cation is constantly going on under suitable conditions of temperature and 

 moisture, and the nitrates formed are liable to be wasted by leaching if they 

 are not immediately taken up by the roots of growing plants. Sir John 

 Lawes and Dr. Gilbert claim that the waste of nitrates after a crop of cereals 

 has been harvested is a more important factor in soil exhaustion than the 

 amount of fertilizing constituents removed in the crop. 



To fill up the interval between the main crops of a rotation catch or stolen 

 crops should be introduced. Eye or turnips are quite generally grown as 

 catch crops, and on the soils of the plains white mustard and spurry may be 

 mentioned as well worth trying. 



White mustard is a quick growing crop on light soils, from four to six 

 weeks only being required for its growth. From seven to twelve pounds of 

 seed per acre is usually sown. It is said to be a valuable feed for sheep, and 

 when fed off, or plowed under, is a good preparation for wheat or other crops. 

 Mr. Curtis, the entomologist, says a crop of mustard will destroy wire worms. 



In Essex from thirty to forty bushels per acre of white mustard seed is the 

 usual yield. Black or brown mustard is not grown, as it proves a troublesome 

 weed. In Norfolk wheat following a crop of white mustard yielded from six 

 to eight bushels per acre more than when one-fourth ton of rape cake per acre 

 had been applied as manure. As a green crop after wheat it has been found 

 a good preparation for a spring crop. 



In Northamptonshire two or three crops of white mustard are grown in 

 succession, instead of a fallow, and fed off as a preparation for wheat. It is 

 also sown after peas and plowed under as a green manure for the following 

 wheat crop. 



Spurry {Spergula arvensis) is an annual which grows wild in Great Britain, 

 where it is usually called a weed. 



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