Abstract: Absorbent polymeric compositions are prepared by graft polymerizing acrylonitrile onto flour or other starch-containing substrates and then subjecting the flour-polyacrylonitrile graft copolymers to alkaline saponification. Compositions prepared from gelatinized flour absorb from 1800-3000 times their weight of deionized water.

Abstract: Natural soil is formed into clods ranging in size from a minimum dimension of about 5 mm to a maximum dimension of about 10 cm, and a hydrophobic agent is applied to the surface of the clods to increase the contact angle of water on the exposed grain surfaces of the clods to an angle greater than 90.degree., which makes the clods water repellent. The clods thus treated are employed to form the top layer of soil. The treated clods conserve soil water by allowing maximal intake of water and by constituting a barrier which reduces water evaporation. Such soil water conservation together with other advantages enable farming on land in regions which could never successfully be farmed before.An apparatus for forming and treating the clods has a lifting device for lifting the top layer of soil of a field to a screening device for breaking up the soil to have a maximum dimension of about 10 cm and to drop the broken up soil back to the field.

Abstract: A process and combination for improving the growth of plants and preventing the plant support medium from retaining too great a quantity of water. A foraminous body is placed in the bottom of the container and prior to the time it is placed therein, it is perforated to form cylindrical conduits vertically completely through the foraminous body wherein the perforations are about 1-5 mm in diameter and are spaced apart about 1-8 mm. Soil is placed on top of the foraminous body, a plant is germinated or planted, watered and fertilized to grow in the container. The water will be retained in the sponge-like foraminous body around the conduits and be available to the plant roots. The conduits themselves will be free of water and will provide a reservoir of oxygen for the roots.

Abstract: An agricultural soil composition for the growing of plants and the like is provided in which a means is included for controlling and regulating the distribution of water throughout the growing zone. This composition is characterized by including in the agricultural soil a critical proportion of hydrophobic particulate material.

Abstract: The dilute clay-containing slimes waste, formed in the hydraulic mining of phosphate mineral, is flocculated by mixing with an aqueous extract of fertile topsoil or with fertile topsoil which is the uppermost 2 feet or more of overburden that contains at least 200 parts per million of organic matter extractable by water. Water is recovered from the flocculated mixture. The dewatered floc is preferably disposed at a land reclamation site and covered with overburden to restore the original stable soil profile, i.e. an upper layer of soil with good drainage and a lower layer having poor drainage.

Abstract: Starch-containing polymer compositions are prepared which absorb amounts of water equaling up to more than 1000 times their own weight. The compositions find many applications including their incorporation into products such as disposable diapers, surgical pads and sheets, and paper towels.

Abstract: Culturing an alga with known flocculant production capability on the soil for the purposes of aggregating soil particles is disclosed. According to the disclosure, flocculant producing algae are known in liquid culture medium as disclosed in pending application Ser. No. 421,527 filed Dec. 4, 1973. The nitrogen in the culture medium is maintained so that cellular nitrogen does not fall below 10%. The algae are then inoculated onto soil which is provided with supplemental nutrients and moisture sufficient to produce a multiplication on the order of several hundred fold. The nutrients other than nitrogen are provided in sufficient quantity to permit a further period of growth during which algal flocculants are produced which have the property of binding soil particles into workable aggregates.

Abstract: Cultivation of algae to produce long chain polymers having flocculating properties is disclosed. Algae are cultivated in an aqueous nutrient medium until relatively high culture densities are achieved and thereafter under conditions in which the cells become deficient in nitrogen thereby causing the cells to shift from a growth phase in which protein production predominates to a growth phase in which extracellular polymer production predominates. An adequate supply of other nutrients as well as CO.sub.2 and light are maintained in the culture medium during the latter phase to insure that a change in cell metabolism is produced by a deficiency in nitrogen. The algae then produce high molecular weight polymers exhibiting strong flocculating activity.