SOILS AND FERTILIZERS 405 



times, be of a relatively small importance. The size of the crop de- 

 pends on the condition least favorable to its growth. The controlling 

 condition may be excess or deficiency of water, too low or too high 

 a temperature, too much or top little light, the depth of the soil, 

 the physical character or condition of the soil, the quantity avail- 

 able of any given plant food, acidity of the soil, insect pests, or plant 

 diseases, kind of seed, etc. 



The controlling condition may not be constant. At one period 

 during the growth of the crop, excess of water may control. At an- 

 other time deficiency of, say, phosphoric acid, may control. Later 

 on, drought may set in, and deficiency of water become the con- 

 trolling condition. 



The conditions of plant life are not independent, but affect one 

 another. An excess of water interferes with the elaboration of 

 plant food. The physical condition or character of the soil affects 

 the amount of water it retains. A liberal supply of plant food may 

 economize water, and so on. The practical farmer must study the 

 limiting conditions, and endeavor to raise the limit to a higher one. 

 A knowledge of the limiting condition, thus, is of prime importance. 



A study of the relation of Texas soils to water is, we believe, 

 of great importance. Moisture and other climatic conditions, are 

 the great controlling conditions. Methods of removing surplus wa- 

 ters, and of storing and conserving water in the soil, should be 

 learned and practiced by the farmer. 



(Authorities. Mass. E. S. B. 51; Conn. E. S. Kept. 1900, 

 1902, 1903, 1905, 1907; Bu. of Soils B. 55; Univ. Wis. B. 180; 

 N. H. Col. B. 83; Tex. E. S. Bs. 85, 112, 138; F. Bs. 44, 56, 65, 

 245, 259, 398; Bu. Pit. Ind. Bs. 58, 441, 692; Mass. Ag. Col. B. 45; 

 Ala. Dept. Ag. Bs. 2, 9; Univ. Vt. B. 154; Univ. 111. B. 129; Cor- 

 nell Univ. B. 201; Cornell Univ. Cir. 7; Univ. Calif. Bs. 157, 173, 

 179; 0. E. S. B. 159; N. H. E. S. B. 5; W. Va. E. S. Bs. 5, 51, 80, 

 114; La. E. S. B. 31; Fla. E. S. B. 20; Purdue Univ. Bs. 10, 92; 

 Wash. Univ. Bs. 19, 37; Ky. Univ. B. 140; N. J. E. S. B. 157; 

 Univ. Tenn. B. 86; Univ. Tenn. Kept. 1899; Mass. Ag. Col. B. 14; 

 Mass. E. S. Kept. 1907; F. B. 329; Ala. Ag. Dept. B. 10; Cornell R. 

 Course No. 9; 0. E. S. B. 124; Purdue Univ. B. 106; Univ. Wash. 

 B. 98; Conn. E. S. Rept. 1906, 1908; W. Va. Univ. B. 97; O. E. S. 

 B. 184; Clemson Col. Bs. 4, 19; Univ. Tenn. B. 92; Univ. 111. B. 

 109; Tex. E. S. B. 107; Univ. Calif. Bs. 187, 194; O. E. S. Bs. 54, 

 83, 182; Clemson Col. Bs. 12, 15; Ga. Ag. Col. B. 72; N. H. E. S. B. 

 123; Minn. E. S. B. 47.) 



FARM MANURES. 



Value of Farm Manures. The fertility of the soil would re- 

 main practically unchanged if all the ingredients removed in the 

 various farm products were restored to the land. This is to a large 

 extent accomplished by feeding the crops grown on the farm to 

 animals, carefully saying the manure and returning it to the soil, 

 and where it is practicable to pursue a system of stock feeding in 

 which those products of the farm which are comparatively poor in 

 fertilizing constituents are exchanged in the market for feeding 



