good, as it contains about 300 parts of soluble matter per 100,000, of 

 which over half are harmful salts the condition of the water vary- 

 ing from 200 parts per 100,000 to 500 parts per 100,000. With 500 

 parts per 100,000, or one-half of 1 per cent, the solution contains one- 

 fourth of 1 per cent of harmful salts ; 1 per cent being the limit of 

 endurance of crops. There is considerable salt already in the soil, 

 therefore, but little evaporation is required at such time to concen- 

 trate the soil moisture beyond the limit of endurance. Furthermore, 

 with the conditions so near this limit, vegetation is not as healthy or 

 as thrifty as could be desired and crops are subject to disease. Dur- 

 ing the winter the water is constantly evaporating from the reser- 

 voirs, and if the inflow is small it may be concentrating. This water, 

 in its worst condition, is applied to the young and tender plants just 

 at the time when the water should be best. The first summer floods 

 bring down large quantities of alkali which have accumulated on the 

 surface of the ground of the Upper Pecos, and these floods seldom 

 improve the water. In later floods the water is better and reaches 

 its best condition. 



THE SOILS OF THE CARLSBAD AREA. 



The soils of the Carlsbad (formerly Eddy) area have been divided 

 into four types : 



1. Sand-dune soils. 



2. Pecos loams. 



3. Pecos conglomerate soils. 



4. Gypsum soils. 



(1) Along the banks of the river, filling up the tortuous bends of 

 its course, are found large areas of sand soils drifting with the winds 

 as dunes. These sands are composed of a very uniform grade of 

 clean grains, rounded by attrition. When cultivated, these soils 

 drain easily, owing to their favorable situation near the banks of the 

 river. Quantities of salt are to be found in these soils before irriga- 

 tion, though little damage has been done by this alkali, due to the 

 ready leaching by the irrigation water. 



(2) Pecos loams cover by far the largest and most important part 

 v bf the Carlsbad district. They are identical in texture and physical 

 properties with the loams described as forming the uplands at Ros- 

 well. They are formed, much in the same way as the Pecos loams 

 at Roswell, from the sediments of an ancient lake. This loam con- 

 tains a large proportion (10 to 20 per cent) of carbonate of lime, and 

 from 1 to 2 per cent of sulphate of lime or gypsum. No accumula- 

 tion of alkali was found within this area, though borings were made 

 to a depth of 20 feet, except in the draws, where the seepage from 

 the surrounding country, together with evaporation, have accumu- 

 lated large quantities of alkali in concentrated solution. There are 



