"THROW ING-OUT" OF THE WHEAT PLANT. 95 



soil, it is essential that, on the plants having again fairly 

 taken to the land, hoeing and top-dressing should be done, 

 to loosen the soil, and to expose it with its chemical ferti- 

 lisers to the atmospheric influences, when the accelerated 

 growth takes place. Professor Buckman points out that 

 the best way to obviate the evils of this expansion of soils, 

 in heavy lands, is to raise as large green crops as possible, 

 and to plough in all the leaves. By this means a more 

 equitable pulverisation of the soil is obtained, and by the 

 gradual admixture of vegetable matter a loamy soil is ulti- 

 mately produced. Farmyard dung, when in a fresh state 

 not decomposed and rotten sometimes acts in increasing 

 the expansive lifting action of soils, as the long straws act 

 as media for conveying water into the soil, and which, 

 becoming frozen and expanding, lifts the soil. In the 

 stiff and argillaceous soils of the Lias and Oxford clays, 

 the rain acts not by crumbling and lifting, but by en- 

 larging the plastic mass of soil, so that it is compressed 

 very tightly round the roots of the wheat plants, depriving 

 them of their free power of growth and action. This plas- 

 tic element in soil, as pointed out by Professor Buckman, 

 is most injurious to wheat, from the comparative slowness 

 with which decomposition proceeds, air and light being 

 kept out. Coldness is also a marked characteristic of such 

 soils, from their retentiveness of water. The remedy in 

 such cases is thorough drainage, mixing the soil with burnt 

 clay, dressing with town-refuse, coal ashes, &c., the use of 

 fresh long farmyard manure, and of all other means by 

 which the texture will be lightened, and the soil made 

 friable and pulverised. Stiff soils are peculiarly liable to 

 crack in dry weather, which is very injurious to the de- 

 licately-formed roots and fibres of wheat. If, after a long 

 continuance of dry March winds, the soi^gets cracked, the 

 fibres are rent and the secondary growth is impeded, so 

 that when the return of more propitious weather fills up 

 the cracks, and restores ihe soil to its proper condition for 

 the maintenance of growth, that growth is given for some 

 time in repairing its condition, in place of aiding the general 



