THE DIVERSIFIED 



87 



The products of this decomposition are 

 ammonia, carbonic acid and water. The 

 agencies in this work are micro-organisms 

 in the soil. The ammonia is converted by 

 other micro-organisms into nitrous and 

 nitric acid. The carbonic acid acts on the 

 mineral elements of the soil and aids in 

 rendering them more soluble and available 

 to the plant. 



The work of these lower organisms is 

 important. German and French investi- 

 gators have found from 500,000 to 900,000 

 germs in a gram of soil (less than half a 

 cubic inch). 



These micro-organisms can only exist 

 where organic matter is present and will 

 be many or few as organic matter is 

 abundant or scarce. They are dormant 

 when the temperature of the soil is below 

 39 F. or above 115 F. ; dormant when the 

 moisture content of the soil falls below 8 

 to 10 per cent, or about one inch in depth 

 of water to one foot in depth of soil; dor- 

 mant when the soil is fully saturated with 

 water and dormant when air is excluded 

 either by too much water in the soil or 

 by soil compaction. They are most act- 

 ive when the soil is about half saturated, 

 i. e. , from 20 to 30 per cent of the bulk 

 of soil, or say 16 to 20 pounds of soil, and 

 when the temperature of the soil is 75 to 

 90 F. and the air has free access to sup- 

 ply oxygen. 



Many farmers consider the destruction 

 of weeds the important object of cultiva- 

 tion, but this is secondary to the mainte- 

 nance of those favorable conditions in the 

 soil that will secure the presence of air, 

 water and heat, so related as to promote 

 the highest development of the plant. 



In applying stable manure to the soil 

 organic matter is being supplied for the 

 bacteria to work upon, and to get the most 

 value out of the manure, soil conditions 

 favorable to the nitrifying processes must 

 be maintained or much of this valuable 

 promoter of fertility will be wasted. 



We have little control over the tempera- 

 ture of the soil, except as it is warmed in 

 the early spring by cultivation, or lowered 

 at mid-summer by shading the ground 

 with green foliage. Our soil tempera- 

 tures are not excessive even in mid- sum- 

 mer if a corresponding proportion of water 

 is maintained, but a deficiency in the 

 water supply makes a lowering of the soil 

 temperature desirable while the deficiency 

 exists. 



The air is always within reach and avail- 

 able when the soil is in permeable condi- 

 tion. 



Time to Irrigate. When to irrigate is 

 a serious problem with many, especially so 

 with new settlers. To lay down an inflex- 

 ible rule for irrigation would be absurd. 

 One answer is, to watch the appearance of 

 the crop and give water as the condition 

 demands it. Root crops will thrive best 

 if irrigated frequently. Corn when small 

 should have but little water, quite fre- 

 quently none until it is several inches high, 

 but when it is earing out it will require a 

 great deal of water. This is true of all 

 crops when the grains are filling out and 

 the most rapid growth is being made. The 

 water should be shut off when the grain is 

 hardening. 



To allow water to stand about the plants 

 with a hot sun shining on them is often 

 fatal. Cabbage and even alfalfa in some 

 soils can be killed in this way. The ap- 

 plication of water to growing crops is a 

 matter that requires a great deal of inves- 

 tigation. There are so many conditions to 

 be considered and different objects to be 

 accomplished that comparatively little is 

 known as yet of this science. Both qual- 

 ity and quantity are regulated by the use 

 of water; then what is best in some soils 

 is not good in others, so that the old timer 

 even finds new difficulties to contend with 

 when he changes his location, even though 

 but a few miles away. 



Winter Water Reservoirs. The win- 

 ter rains and snows are a constant source 

 of waste of water that might be held in 

 natural basins or easily constructed reser- 

 voirs for use in irrigating during the com- 

 ing season. There is no better time than 

 the present for irrigators to investigate the 

 subject of securing an independent source 

 of water supply. Land without water is 

 almost worthless in many sections of the 

 West, yet with a sufficient supply to meet 

 all the demands for irrigation the land be- 

 comes valuable in proportion to its location 

 and fertility. 



If the soil is of a character to admit of 

 constructing catchment reservoirs every 

 available location should be used. In the 

 foothills of most mountain valleys are base- 

 ments covering from one to fifty acres 

 where, with a little work, a large body of 



