Of the Acacias, the tall-growing A. melanoxylon (“black acacia”) resists pretty strong alkali, even on stiff soil; as can be seen at Tulare and Bakersfield, California, where there are trees nearly two feet in diameter. The beautiful A. lophantha (Albizzia) has in plantings made along the San Joaquin Valley railroad shown considerable resistance, likewise; but it is quite sensitive to frost.
Of other Australian trees, one of the Australian “pines,” (Casuarina equisetifolia), is doing well on fairly strong alkali land in the San Joaquin Valley.
A remarkably alkali-resistant shrub or small tree is the pretty Kœlreuteria paniculata from China, which at Tulare is growing in some of the strongest alkali soil of the tract. Unfortunately it is available mainly for ornamental purposes; its wood, while small, is very hard and makes excellent fuel.
Of trees indigenous to the Atlantic and East Central United States, the Tulip tree, the Linden, and most other trees of the humid region, including the English oak (Quercus pedunculata) become stunted in alkali soils. The honey locust, being particularly adapted to calcareous lands, does moderately well on alkali lands, but its thorns and imperfect shade render it not very desirable. The black locust and the elms have on the whole done best. The eastern maples are not successful; but the California maple (Acer macrophyllum) and the box elder (Negundo californica) have done fairly well in the lighter alkali lands of the San Joaquin Valley.
The Conifers—Pines, firs, cedars, cypress, etc., are very sensitive to black alkali and will not endure much even of the “white” salts. Even the native juniper of the mesas carefully adheres to the portions—breaks and upper slopes, hilltops, etc.—which are more or less leached by the scanty rains of these regions.
INDUCEMENTS TOWARD THE RECLAMATION
OF ALKALI LANDS.
The expense involved in the reclamation of strong alkali lands naturally gives rise to the question whether adequate advantages are likely to be derived from such expenditure; specially when the last resort—underdraining and leaching—has to be adopted.
Those familiar with the alkali regions are aware how often the occurrence of alkali spots interrupts the continuity of fields and orchards, of which they form only a small part, but enough to mar their aspect and cultivation. Their increase and expansion under irrigation frequently renders their reclamation the only alternative of absolute abandonment of the investments and improvements made, and from that point of view alone it is of no slight practical importance. Moreover, the occurrence of vast continuous stretches of alkali lands within the otherwise most eligibly situated valley lands of the irrigation region forms a strong incentive towards their utilization.
1st year, 2d year, 3d year, Fourth year—42 bushels.