400 M (I rhet-Garden Soila and Crops 



Composition. The brown sand formation is characterized by its 

 high percentage of coarser particles. Thus stones and fine gravel 

 average 13-9 per cent, while the coarse sand is 55-2 per cent. The fine 

 silt and clay fractions are very small and the clay contains a large 

 percentage of iron. 



Chemical analysis reveals a great deficiency of calcium carbonate, 

 a great uniformity in the percentage of potash (-22 per cent.) and a 

 fairly high percentage of phosphoric acid. The content of calcium and 

 magnesium salts is extremely small, but the available plant food is 

 decidedly above the average. Probably there has been a storage of 

 plant food due to excessive manuring, for these soils in jjusture show 

 only small (quantities of available potash and phosphoric acid. 



The success of the crops on this sand formation depends to a large 

 extent on the rainfall during the period of growth. The soils are so 

 coarse that little rise of subsoil water can take place. The problem 

 is to introduce sufficient organic matter into the soil to conserve the 

 water. The organic matter must be, however, of such a nature as will 

 not open up the soil too much and let out the moisture. 



3. The Gault Series. 



(rt) P\ire clay soil for mat ion. 



This soil formation occurs as a narrow strip luiining between the 

 redland soil formation and tlie boulder clay hills from Gamlingay to 

 Sutton. Small areas also occur near Henlow and Stanford. 



It is a particularly heavy bluish clay which is invariably wet and 

 badly drained. This is noticeably so of the Gamlingay strip, where 

 the drainage waters from the boulder clay hills find their way on 

 to the surface of the gault which has been scooped out to form 

 a long narrow depression. This soil is too heavy for market-garden 

 crops and consequently it is used for ordinary farming purposes. It is 

 generally farmed in conjunction with a strip of lighter land such as 

 redland or the boulder clay on greensaiul formation. When drained 

 it grows good wheat crops which, however, thrash somewhat lightly, 

 the average yield heiug a little over 3 quarters per acre. 



Horse beans, mangel seed, wheat and clover are the chief crops grown 

 on the formation. Clover and sainfoin do well on this soil and give 

 two good cuts a year. 



Composition. The gault clay formation is characterized by a very 

 high percentage of clay, 29-3 per cent., and a high percentage of calcium 



