UTILIZING OUR SOIL RESOURCES — SALTER 331 



limiting values, it is only a matter of time until it will. Continued 

 cropping to wheat combined with fallowing and row-crop cultiva- 

 tion has already resulted in the loss of one-third or more of the 

 organic matter and nitrogen originally present in these rich soils. 



So far we have not been able to develop a system that will main- 

 tain soil organic matter and nitrogen in this area. We still do not 

 have a legume crop adapted to the 200 million acres of dry land in the 

 semihumid regions. Productivity cannot be maintained under our 

 present system. From the standpoint of long-time food and feed sup- 

 plies in this country, the problem of maintaining the soils in the dry- 

 land area is one of the most serious we face. 



Northeast and north central. — In the northeastern and north cen- 

 tral States soil deterioration is widely varied. In the Northeast, 

 where soils were naturally infertile, soil productivity is now on the 

 upgrade on hundreds of thousands of farms. In the Midwest, how- 

 ever, prevailing farm practices have led to a progressive decline in 

 the organic matter and nitrogen content of the soil. In places this 

 loss has amounted to as much as one-third to one-half of the original 

 content. And the decline is still going on at rates estimated as high 

 as 1 percent per year in the middle Corn Belt. 



This has the effect of impairing drainage, water infiltration, soil 

 aeration, and ability of soil to yield up nutrients to crops. Crops 

 seem to suffer more in dry weather. Many farmers have found it 

 necessary to install additional tile lines on land that once drained 

 satisfactorily. On sloping soils, erosion is taking a heavier toll, as 

 compaction slows intake of water and increases runoff. 



Here we know how to manage soils so as to maintain organic 

 matter and nitrogen. The problem is to get these management prac- 

 tices into widespread use. 



Southeast. — In the southeastern States, conservation and rehabili- 

 tation of soil resources probably offer as great a challenge — and oppor- 

 tunity — as anywhere in the country. Soils here were already highly 

 leached before they were put to agricultural production. High rain- 

 fall and temperatures continued to favor rapid organic-matter decom- 

 position and loss of soil minerals by leaching and erosion. 



It has been estimated that in the Piedmont region, two-thirds of 

 the land that has been cultivated has lost part or all of its topsoil, 

 and in many cases some of the subsoil. Erosion and gullying have 

 been so severe that thousands of acres have been abandoned for crop 

 production. 



Most of these soils, however, are very responsive to fertilization 

 and other good management practices. They can serve as excellent 

 media for plant growth. Climatic conditions that have made these 

 soils what they are also offer unusual opportunities for increasing 

 levels of productivity. 



