LIMESTONE SOILS 77 



According to fineness of the rock particles present, common 

 soils may be arranged as follows : clay, heavy clay loam, clay loam, 

 loam, sandy loam, light sandy loam, fine sand, medium sand, 

 coarse sand, gravel (P. 73). 



Special Use of Sandy Loam. Sandy soils are usually poor in 

 plant food as compared with clayey loams. Because of their loose, 

 open texture they do not hold water well. Air passes through 

 them readily and, if the weather is dry, crops will suffer for want 

 of moisture on such soils sooner than on those containing more 

 clay. Because of their loose, open texture sandy soils are quicker 

 to warm in spring by the entrance of warm air. This makes them 

 well adapted for use in the growing of early spring vegetables. 

 Market gardeners find such soils most profitable. In wet seasons 

 sandy soils are much to be preferred for general farming, as crops 

 do not suffer so much from heavy rains. Their drainage is natural 

 and they dry out quickly. They seldom become cloddy, even if 

 plowed during wet weather. 



Heavy Clay Loams. When clay soils are wet they are sticky 

 and likely to become cloddy if plowed before they are sufficiently 

 dry. It is difficult to keep such soils in proper condition. They 

 are well adapted to the growth of grains and grasses, and are used 

 for general farming, hay and grazing. They are very properly 

 called "cold soils," because moisture and air do not pass through 

 them readily. In dry seasons general crops may suffer less than 

 on sandy soils, but if much clay be present the surface is likely 

 to become baked and crusty. This is very detrimental to the 

 best growth of crops. Great care must be exercised to keep the 

 surface in proper condition by tillage. Because of the difficulty 

 in plowing clay soils, and because of their sticky condition, they 

 are spoken of as "heavy soils'' in contrast with sandy soils, which 

 are called "light." Clay soils with much gummy substance are 

 often called gumbo. 



Limestone Soils. Soils derived from limestone contain the 

 important plant food calcium. Lime is usually considered a 

 valuable asset in soils. It improves the physical condition of 

 both heavy and light soils. It aids in the decay of vegetable 

 matter and in the liberation of plant food from it. It neutralizes 

 acids and certain other poisonous substances in soil. The texture 

 of limestone soils is usually very good. They are easy to work 

 and usually well adapted to general crops and fruits. 



Lime may be added to soils in a caustic condition in such 



