3.4% of the state’s area. The lands available for agriculture are the lowlands and the mountain parks and valleys.
Speaking generally, irrigation is essential to successful cultivation, but wherever irrigation is practicable the soil proves richly productive. Irrigation ditches having been exempted from taxation in 1872, extensive systems of canals were soon developed, especially after 1880. The Constitution of Colorado declares the waters of its streams the property of the state, and a great body of irrigation law and practice has grown up about this provision. The riparian doctrine does not obtain in Colorado. In no part of the semi-arid region of the country are the irrigation problems so diverse and difficult. In 1903 there were, according to the governor, 10 canals more than 50 m. in length, 51 longer than 20 m., and hundreds of reservoirs. In 1899 there were 7374 m. of main ditches. The average annual cost of water per acre was then estimated at about 79 cents. The acres under ditch in 1902 were greater (1,754,761) than in any other state; and the construction cost of the system was then $14,769,561 (an increase of 25.6% from 1899 to 1902). There are irrigated lands in every county. Their area increased 8.9% in 1899-1902, and 80.9% from 1890 to 1900; in the latter year they constituted 70.9% of the improved farm-land of the state, as against 48.8 in 1890. The land added to the irrigated area in the decade was in 1890 largely worthless public domain; its value in 1900 was about $29,000,000. As a result of irrigation the Platte is often dry in eastern Colorado in the summer, and the Arkansas shrinks so below Pueblo that little water reaches Kansas. The water is almost wholly taken from the rivers, but underflow is also utilized, especially in San Luis Park. The South Platte is much the most important irrigating stream. Its valley included 660,495 acres of irrigated land in 1902, no other valley having half so great an area. The diversion of the waters of the Arkansas led to the bringing of a suit against Colorado by Kansas in the United States Supreme Court in 1902, on the ground that such diversion seriously and illegally lessened the waters of the Arkansas in Kansas. In 1907 the Supreme Court of the United States declared that Colorado had diverted waters of the Arkansas, but, since it had not been shown that Kansas had suffered, the case was dismissed, without prejudice to Kansas, should it be injured in future by diversion of water from the river. The exhaustion, or alleged exhaustion, by irrigation in Colorado of the waters of the Rio Grande has raised international questions of much interest between Mexico and the United States, which were settled in 1907 by a convention pledging the United States to deliver 60,000 acre-feet of water annually in the bed of the Rio Grande at the Acequia Madre, just above Juarez, in case of drought this supply being diminished proportionately to the diminution in the United States. As a part of the plans of the national government for reclamation of land in the arid states, imposing schemes have been formulated for such work in Colorado, including a great reservoir on the Gunnison. One of the greatest undertakings of the national reclamation service is the construction of 77 m. of canal and of a six-mile tunnel, beneath a mountain, between the canyon of the Gunnison and the valley of the Uncompahgre, designed to make productive some 140,000 acres in the latter valley.
Apart from mere watering, cultivation is in no way intensive. One of the finest farming regions is the lowland valley of the Arkansas. It is a broad, level plain, almost untimbered, given over to alfalfa, grains, vegetables and fruits. Sugar-beet culture has been found to be exceptionally remunerative in this valley as well as in those of the South Platte and Grand rivers. The growth of this interest has been since 1899 a marked feature in the agricultural development of the state; and in 1905, 1906 and 1907 the state’s product of beets and of sugar was far greater than that of any other state; in 1907, 1,523,303 tons of beets were worked—more than two-fifths of the total for the United States. There are various large sugar factories (in 1903, 9, and in 1907, 16), mainly in the north; also at Grand Junction and in the Arkansas valley. The total value of all farm property increased between 1880 and 1900 from $42,000,000 to $161,045,101 and 45.9% from 1890 to 1900. In the latter year $49,954,311 of this was in live-stock (increase 1890-1900, 121.1%), the remaining value in land with improvements and machinery. The total value of farm products in 1899 was $33,048,576; of this sum 97% was almost equally divided between crop products and animal products, the forests contributing the remainder. Of the various elements in the value of all farm produce as shown by the federal census of 1900, live-stock, hay and grains, and dairying represented 87.2%. The value of cereals ($4,700,271)—of which wheat and oats represent four-fifths—is much exceeded by that of hay and forage ($8,159,279 in 1899). Wheat culture increased greatly from 1890 to 1900. Flour made from Colorado wheat ranks very high in the market. As a cereal-producing state Colorado is, however, relatively unimportant; nor in value of product is its hay and forage crop notable, except that of alfalfa, which greatly surpasses that of any other state. In 1906 the state produced 3,157,136 bushels of Indian corn, valued at $1,578,568; 8,266,538 bushels of wheat, valued at $5,373,250; 5,962,394 bushels of oats, valued at $2,683,077; 759,771 bushels of barley, valued at $410,276; 43,580 bushels of rye, valued at $24,405; and 1,596,542 tons of hay, valued at $15,167,149. The value of vegetable products, of fruits, and of dairy products was, relatively, equally small (only $7,346,415 in 1899). Natural fruits are rare and practically worthless. Apples, peaches, plums, apricots, pears, cherries and melons have been introduced. The best fruit sections are the Arkansas valley, and in the western and south-western parts of the state. Melons are to some extent exported, and peaches also; the musk-melons of the Arkansas valley (Rocky Ford Canteloups) being in demand all over the United States. The fruit industry dates practically from 1890. The dairy industry is rapidly increasing. In the holdings of neat cattle (1,453,971) and sheep (2,045,577) it ranked in 1900 respectively seventeenth and tenth among the states of the Union; in 1907, according to the Yearbook of the Department of Agriculture, there were in the state 1,561,712 neat cattle and 1,677,561 sheep. Stock-raising has always been important. The parks and mountain valleys are largely given over to ranges. The native grasses are especially adapted for fodder. The grama, buffalo and bunch varieties cure on the stem, and furnish throughout the winter an excellent ranging food. These native grasses, even the thin bunch varieties of dry hills, are surprisingly nutritious, comparing very favourably with cultivated grasses. Large areas temporarily devoted to cultivation with poor success, and later allowed to revert to ranges, have become prosperous and even noted as stock country. This is true of the sandhill region of eastern Colorado. The grass flora of the lowlands is not so rich in variety nor so abundant in quality as that of high altitudes. Before the plains were fenced large herds drifted to the south in the winter, but now sufficient hay and alfalfa are cut to feed the cattle during the storms, which at longest are brief. An account of Colorado agriculture would not be complete without mentioning the depredations of the grasshopper, which are at times extraordinarily destructive, as also of the “Colorado Beetle” (Doryphora decemlineata), or common potato-bug, which has extended its fatal activities eastward throughout the prairie states.
Minerals.—Colorado is pre-eminently a mineral region, and to this fact it owes its colonization. It possesses unlimited supplies, as yet not greatly exploited, of fine building stones, some oil and asphalt, and related bituminous products, a few precious and semi-precious stones (especially tourmalines, beryls and aquamarines found near Canyon near the Royal Gorge of the Arkansas river), rare opalized and jasperized wood (in the eastern part of the El Paso county), considerable wealth of lead and copper, enormous fields of bituminous coal, and enormous wealth of the precious metals. In the exploitation of the last there have been three periods: that before the discovery of the lead-carbonate silver ores of Leadville in 1879, in which period gold-mining was predominant; the succeeding years until 1894, in which silver-mining was predominant; and the period since 1894, in which gold has attained an overwhelming primacy. The two metals are found in more than 50 counties, San Miguel, Gilpin, Boulder, Clear Creek, Lake, El Paso and