Fig. 74.—Beets from corresponding positions in the above field.

Effect of Differences in Composition of Alkali Salts on Beets.—The marked differences which may occur as the result of even slight variations in the proportions of the several salts is well illustrated in the subjoined diagram of observations made by Dr. G. W. Shaw, of the Cal. Expt. station, upon beet fields in the neighborhood of Oxnard, Cal. The lands lie not far from the seashore, and saline water underruns them for considerable distance inland. The soil and subsoil are quite sandy, so that it takes irrigation water only about seven hours to penetrate from the surface to bottom water at seven feet depth. The land on which these observations were made are apparently level to the eye, though probably the alkali belts on which the sugar beets were “poor” are slightly depressed swales.

It will be noted that here the beets were “good” where the sulfate (Glauber’s salt) ranged up to .8%, with .10 to .20 of common salt; but that so soon as the latter rose above .20, the beets were poor despite the low percentage of Glauber’s salt; then became “good” again so soon as the common salt fell below .20%, although the Glauber’s salt increased.

TOLERANCE OF VARIOUS CROP PLANTS.

The following table, compiled by Dr. R. H. Loughridge mainly from his own observations,[176] gives the details of the tolerance for various culture plants as ascertained at the several experiment substations in California, as well as at other points in that State and in Arizona where critical cases could be found. It is thought preferable to investigate analytically such cases in the field, rather than to attempt to obtain results from small-scale experiments artificially arranged, in which sources of error arising from evaporation and other causes are most difficult to avoid.

The table is so arranged as to show the maximum tolerance thus far observed for each of the three single ingredients, as well as the maximum of total salts found compatible with good growth. In view of the extremely variable proportions between the three chief ingredients found in nature, this seems to be the only manner in which the observations made can be intelligibly presented, until perhaps a great number of such data shall enable us to evolve mathematical formulæ expressing the tolerance for the possible mixtures for each plant. For it is certain that the tolerance-figures will be quite different in presence of other salts, from those that would be obtained for each salt separately; or for the calculated mean of such separate determinations, proportionally pro-rated. It must also be remembered that in all alkali soils, lime carbonate is abundantly present, as is, nearly always, a greater or less amount of the sulfate (gypsum). As already stated, according to the investigations of Cameron not only these compounds, but also calcium chlorid, exert a protective influence against the injury to plant growth from compounds of sodium and potassium. The figures here given can therefore be regarded only as approximations, subject to correction by farther observation. They are arranged from the highest tolerances downward, for each of the three ingredients, as well as for the totals. The latter are not, of course, the sums of the figures given in the preceding columns, but independent data.

HIGHEST AMOUNT OF ALKALI IN WHICH
FRUIT TREES WERE FOUND UNAFFECTED.[177]

Arranged from highest to lowest.
Pounds per acre in four feet depth.

Sulfates
(Glauber’s Salt).		Carbonate
(Salsoda).		 Chlorid
(Common Salt).		Total Alkali.
Grapes 40,800Grapes 7,550Grapes 9,640Grapes 45,700
Olives 30,640Oranges 3,840Olives 6,640Olives 40,160
Figs 24,480Olives 2,880Oranges 3,360Almonds 25,560
Almonds 22,720Pears 1,760Almonds 2,400Figs 26,400
Oranges 18,600Almonds 1,440Mulberry 2,240Oranges 21,840
Pears 17,800Prunes 1,360Pears 1,360Pears 20,920
Apples 14,240Figs 1,120Apples 1,240Apples 16,120
Peaches 9,600Peaches 680Prunes 1,200Prunes 11,800
Prunes 9,240Apples 640Peaches 1,000Peaches 11,280
Apricots 8,640Apricots 480Apricots 960Apricots 10,080
Lemons 4,480Lemons 480Lemons 800Lemons 5,760
Mulberry 3,360Mulberry 160Figs 800Mulberry 5,760

OTHER TREES.
Kölreuteria 51,040Kölreuteria 9,920Or. Sycamore 20,320Kölreuteria 73,600
Eucal. am. 34,720Or. Sycamore 3,200Kölreuteria 12,640Or. Sycamore 42,760
Or. Sycamore 19,240Date Palm. 2,800Eucal. am. 2,960Eucal. am. 40,400
Wash. Palm 13,040 Eucal. am. 2,720Camph. Tree 1,420Wash. Palm 15,200
Date Palm 5,500Wash. Palm 1,200Wash. Palm 1,040Date Palm 8,328
Camph. Tree 5,280Camph. Tree 320 Camph. Tree 7,020

SMALL CULTURES.
Saltbush 125,640Saltbush 18,560Modiola 40,860Saltbush 156,720
Alfalfa, old 102,480Barley 12,170Saltbush 12,520Alfalfa, old 110,320
Alfalfa, young 11,120Bur Clover 11,300Sorghum 9,680Alfalfa, young 13,120>
Hairy Vetch 63,720Sorghum 9,840Celery 9,600Sorghum 81,360
Sorghum 61,840Radish 8,720Onions 5,810Hairy Vetch 69,360
Sugar Beet 52,640Modiola 4,760Potatoes 5,810Radish 62,840
Sunflower 52,640Sugar Beet 4,000Sunflower 5,440Sunflower 59,840
Radish 51,880Gluten Wheat 3,000Sugar Beet[178] 10,240Sugar Beet 59,840
Artichoke 38,720Artichoke 2,760Barley 5,100Modiola 52,420
Carrot 24,880Lupin 2,720Hairy Vetch 3,160Artichoke 42,960
Gluten Wheat 20,960Hairy Vetch 2,480Lupin 3,040Carrot 28,480
Wheat 15,120Alfalfa 2,360Carrot 2,360Barley 25,520
Barley 12,020Grasses 2,300Radish 2,240Gluten Wheat 24,320
Goat’s Rue 10,880Kaffir Corn 1,800Rye 1,720Wheat 17,280
Rye 9,800Sweet Corn 1,800Artichoke 1,480Bur Clover 17,000
Cañaigre 9,160Sunflower 1,760Gluten Wheat 1,480Celery 13,680
Ray Grass 6,920Wheat 1,480Wheat 1,160Rye 12,480
Modiola 6,800Carrot 1,240Grasses 1,000Goat’s Rue 11,800
Bur Clover 5,700Rye 960White Melilot 440Lupin 11,200
Lupin 5,440Goat’s Rue 760Goat’s Rue 160Cañaigre 9,360
White Melilot 4,920White Melilot 480Cañaigre 80Onions 38,480
Celery 4,080Cañaigre 120 Potatoes 38,480
Saltgrass 44,000Saltgrass 136,270Saltgrass 70,360Saltgrass 381,110