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Vast areas of abandoned or sub-marginal land exist. In Quebec alone it has been estimated that there are about 1,400,000 acres of abandoned farmland (32). Some of this land is being turned into tree farms and more of it could be so utilized if some problems could be overcome. The chief difficulties existing are mainly those of uneven topography, poor drainage and low fertility status of the soil. This latter problem could be possibly the easiest difficulty to overcome provided adequate knowledge existed of the effects of fertilization on reforested areas. To assess relative fertility levels of soils for purposes of reforestation methods of soils analysis as well as plant analysis may be useful. These must be developed in conjunction with fertilizer application experiments either in the field or in the greenhouse under a controlled environment.

The advent of radioactive isotopes as tracers in fertilizers, led to a new concept of determining availability of soil nutrients to the plant (Fried and Dean, 1952; Larson, 1952). [...]

Water in clay soils is considered to be held by capillary and swelling forces. Both forces are operative but the importance of each force depends upon the water content. This relationship was assessed from water retention, swelling pressure, and volume change studies using samples of different aggregate sizes compacted to different porosities. [...]

Inadequate drainage is a challenging problem in both humid and arid regions of the world. In arid regions water logging is the basic cause of salinity and alkalinity, and they go hand in hand. One of these conditions usually indicates the presence of the other. [...]

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No description available.

No description available.

No description available.