Soils, their formation, properties, composition, and relations to climate and plant growth in the humid and arid regions - Eugene W. Hilgard

	CALIFORNIA.
	Merced Falls.	Overhiser San Joaquin Co.	Tulare County.		Kern Island
	Merced Falls.	Overhiser San Joaquin Co.	Visalia	Expt. Station. Tulare.	Kern Island
Potassium Chlorid, KCl
Potassium Sulfate (K₂SO₄)		20.23	3.95	10.13
Potassium Carbonate. K₂CO₃
Sodium Sulfate, Na₂SO₄	4.67	13.00		25.28	88.42
Sodium Nitrate, NaNO₃	12.98			19.78
Sodium Carbonate, Na₂CO₃	75.95	52.22	65.72	32.58	0.42
Sodium Chlorid, (NaCl)	1.46	33.00	3.98	14.75	0.51
Sodium Phosphate, HNa₂PO₄	4.94	1.78	8.42	2.25
Magnesium Sulfate, MgSO₄			1.65		0.52
Calcium Chlorid
Magnesium Chlorid
Ammonium Carbonate, NH₄CO₃				1.41
	100.00	100.00	100.00	100.00	100.00

	CALIFORNIA.
	Mojave Plateau	Hunts, near San Bernardino	Westminster near Santa Ana.	Imperial
Potassium Chlorid, KCl				1.15
Potassium Sulfate, K₂SO₄	0.92	5.31	20.62
Potassium Carbonate. K₂CO₃			6.59
Sodium Sulfate, Na₂SO₄	43.34	66.08
Sodium Nitrate, NaNO₃				8.21
Sodium Carbonate, Na₂CO₃	15.38	15.85	62.22	.58
Sodium Chlorid, (NaCl)	39.34	11.47	10.57	31.82
Sodium Phosphate, HNa₂PO₄	1.02
Magnesium Sulfate, MgSO₄		0.59
Calcium Chlorid				58.42
Magnesium Chlorid				2.81
Ammonium Carbonate, NH₄CO₃
	100.00	100.00	100.00	100.00

	WASHINGTON.
	Yakima Co. on Atahnam Creek	Kittitas Valley.	Whitman Co., Lake Creek.	Spokane Co., Cottonwood Springs.
Potassium Chlorid, KCl	3.90	0.16	4.53	6.27
Potassium Sulfate, K₂SO₄	18.44	15.17	15.90
Potassium Carbonate. K₂CO₃
Sodium Sulfate, Na₂SO₄
Sodium Nitrate, NaNO₃	75.61	80.36	77.10	87.14
Sodium Carbonate, Na₂CO₃	0.52	1.76	1.34	4.03
Sodium Chlorid, (NaCl)	1.53	2.55	1.13	2.56
Sodium Phosphate, HNa₂PO₄
Magnesium Sulfate, MgSO₄
Calcium Chlorid
Magnesium Chlorid
Ammonium Carbonate, NH₄CO₃
	100.00	100.00	100.00	100.00

	MONTANA.
	Upper Missouri Valley.
	Upper Missouri Valley near Centerville	Prickly Pear Plain. Helena.	Ford on Sun River.	Fort Benton.	Robert’s Creek, Musselshell Valley.
Potassium Sulfate, K₂SO₄	2.37	3.07	1.77	8.59	3.07
Sodium Sulfate, Na₂SO₄	56.54	43.38	83.35	47.10	76.79
Sodium Nitrate, NaNO₃	9.39
Sodium Carbonate, Na₂CO₃				.71	13.99
Sodium Chlorid, NaCl	27.47	14.60	0.91	.18	6.15
Magnesium Sulfate, MgSO₄	4.23	38.94	13.97	43.42
Potassium Chlorid, KCl
	100.00	100.00	100.00	100.00	100.00

	NEVADA.
	Near Reno.		Churchill County.
Potassium Sulfate (K₂SO₄)
Sodium Sulfate, Na₂SO₄	52.15	80.30	0.55
Sodium Nitrate, NaNO₃
Sodium Carbonate, Na₂CO₃	45.37	15.24	96.78
Sodium Chlorid, NaCl	2.48	4.46	2.67
Magnesium Sulfate, MgSO₄
Potassium Chlorid, KCl
	100.00	100.00	100.00

	WYOMING.
	Sweet Water Valley.		Laramie Farm.
	Independence, Rock Lake.	Saint Mary’s Station.	Alkali.	Waste Irrigation Water.
Potassium Sulfate (K₂SO₄)
Sodium Sulfate, Na₂SO₄	73.17	88.93	59.29	41.19
Sodium Nitrate, NaNO₃
Sodium Carbonate, Na₂CO₃	22.98
Sodium Chlorid, NaCl	3.85	11.63	17.01	2.18
Magnesium Sulfate, MgSO₄			23.70	43.82
Potassium Chlorid, KCl
	100.00	100.00	100.00	100.00

	COLORADO.
	Near Denver.	Grand Junction.	Rocky Ford.	Rocky Ford.
Potassium Sulfate (K₂SO₄)			0.10	13.74
Sodium Sulfate, Na₂SO₄	93.40	56.05	62.54	17.36
Sodium Carbonate, Na₂CO₃		18.97	2.08	5.53
Sodium Chlorid, NaCl	6.60	24.98	3.86	11.53
Magnesium Sulfate, MgSO₄			31.42	44.43
Magnesium Chlorid, MgCl₂				5.76
Magnesium Phosphate				1.65
	100.00	100.00	100.00	100.00

	NEW MEXICO.
	Pecos Valley.
	Roswell Region.			Carlsbad Region.
	Bremond	Michelet	Roswell	Carlsbad	Delaware River
Potassium Sulfate (K₂SO₄)
Sodium Sulfate, Na₂SO₄	54.61	2.62	67.46	35.16	37.11
Sodium Carbonate, Na₂CO₃
Sodium Chlorid, NaCl	51.60	65.16	10.00	26.88	34.31
Magnesium Sulfate, MgSO₄	13.79	32.22	22.54	38.06	28.58
Magnesium Chlorid, MgCl₂
Magnesium Phosphate
	100.00	100.00	100.00	100.00	100.00

Nutritive Salts in Alkali.—With them, however, there are almost always associated, in varying amounts, sulfate of potash, phosphate of soda, and nitrate of soda, representing the three elements—potassium, phosphorus, and nitrogen—upon the presence of which in the soil in available form, the welfare of our crops so essentially depends, and which we aim to supply in fertilizers. The potash salt is usually present to the extent of from 5 to 20 per cent of the total salts; phosphate, from a fraction of one to as much as 4 percent; the nitrate from a fraction of one to as much as 20 percent. In black alkali the nitrate is usually low, the phosphate high; in the white, the reverse is true. Both relations are readily intelligible from a chemical and bacteriological point of view.

Estimation of Total Alkali in Land.—The investigations detailed above having shown that in California at least, outside of the axes of valleys no practically important amount of alkali salts is usually found at a depth exceeding four feet, it became possible to determine approximately the amounts of salts that would have to be dealt with when irrigation and evaporation should bring the entire amount to or near the surface; a necessary prerequisite to the determination of possible cultures. While, as already shown, the salts occur lower down in very sandy lands, yet the diagram on p. 435 shows that even then, an estimate on this basis would not be very wide of the truth. It is at least probable that the same is measurably true of level alkali lands elsewhere, when not underlaid by geological deposits impregnated with salts.