THE USE OF IRRIIGATION FOR DIFFERENT CROPS 



of others as they appear in print, or are demonstrated in garden, field and orchard, but 

 do not look upon the practice of other men on other lands as a thing to be imitated by 

 you without thought to see whether the plants show you that they are fully suited and 

 thus prove to you that your conditions are like those of the other men. When his is 

 done there is often much to be gained by imitation. 



To know a plant's condition by its looks is not always easy or simple, but the 

 beginner must learn to do it. Of course, for this brief outline we must rule out all 

 unthrift of plants caused by insects or plant diseases, or by alkali or other defects 

 of the soil. Attention must be confined wholly to the influences of adequate moist- 

 ure and of the lack of it. 



Indications of adequate moisture are: 



(a) Full and free growth of each plant according to its nature and one must 

 learn by experience what that growth should be. 



(b) Good size, substance and color of leaf; freedom from curling or drooping or 

 other indication of distress; in the case of vegetables, freshness and crispness. 



(c) Satisfactory size, quality and commercial acceptability of fruit, grain, or 

 vegetable. This is the ultimate test of adequate moisture and is assurance that 

 moisture remains until the close of the season which is a most important considera- 

 tion. 



The opposite of the foregoing indicate the need of more water; and, if irrigation 

 is practiced, either the use of more water or the application at shorter intervals is 

 ' necessary. 



These are also indications of excess of water either from natural retention in an 

 undrained soil, or from excessive amount or frequency of irrigation. 



(a) Too lush and rank growth causing weak stems and lack of erectness in the 

 plant, or watery, flavorless condition in esculent parts. 



(b) Failure to set fruit because of excessive vegetative activity, as in the case 

 of the tomato. 



(c) Disease of the root resulting in decay thereof, manifested by the dying back 

 of the spring growth and by gumming and dying back of branches later in the sea- 

 son. Dieback is also caused by drought, but is then preceded by other signs of suffer- 

 ing. 



These things being true, it follows that any rule for the irrigation of any plant 

 will fail in many cases because it cannot include consideration of all soils; and any 

 rule for the irrigation of any soil will fail in many cases because it cannot include 

 consideration of all plants. The only rule which will be universal is that the amount 

 or frequency of irrigation must vary in accordance with the character of the soil, the 

 requirements of the plants and the dryness of the air at the time — which is merely 

 a formula of variables and no rule at all. 



And yet one should not be discouraged by such a confession. It is proof that irri- 

 gation is a rational proceeding and cannot be mastered without close local observa- 

 tion and earnest thought. Growing plants by irrigation is a higher art than growing 

 them by rainfall; it produces richer results and reaches them with greater certainty. 

 Nature is intensely cruel to plants. Nature, for example, destroyed the finest forests 

 which she ever grew, and yet Nature operating according to her own plans and select- 

 ing plants for different situations, produces better results than when man choses the 

 plants and situations to meet his own desires and calls upon Nature to nourish them 

 without effort on his own part to assist in bringing plant food and water to meet the 

 needs of the plant. People sometimes exalt the beneficence of Nature in agriculture, 

 forgetful of the fact that even before the dawn of history man had learned that agri- 

 culture is in its very nature artificial and not natural and that the grandest work of 

 Nature is the mind of man with power to direct natural forces and assemble them for 

 his own purposes. This same mind of man which learned the advantage of Irriga- 

 tion in the Garden of Eden, must still give its best powers to determining what are the 

 best uses of water for every plant desired; upon every acre chosen for its growth; in 

 every climate which presents desirable temperatures. This is the most important 

 lesson the intending Irrigator has to learn and the sooner he makes it the foundation 

 for his future courses the wiser he is and the more prosperous he will be. 



Berkeley, California, January, 1905. 



a 



