Use of waste building sludge in water management of agricultural soils.

The use of Waste building sludge (WBS) for improving water accumulation and retention of water was studied on two standard soils: i) clayey-loam soil (CA) with a high content of clay fraction and a high specific surface area (S_BET) value; ii) sandy-loam soil (SA) with prevailing particle fraction of 0.05 - 2 mm and an order of magnitude lower S_BET compare to CA. Two different WBS (from the production of concrete (B) and from the production of artificial stone (TS)) were applied to soils in amounts of 1 and 10% wt. Natural clinoptilolite (CL) as a reference material was used in the same manner. The accumulation of water in soils enriched with the defined amount of additive was measured after 2 and 24 hours. The addition of B increased the water absorption by up to 34% for SA and up to 12% for CA. With the addition of CL, water absorption increased by up to 15% in SA and up to 7% in CA. The addition of TS showed the lowest effect on increasing water absorption, i.e. about 1% in SA and less than 3% in CA. Water retention was studied on the identical samples after their saturation with water (24 h). The saturated soil columns were subjected to the evaporation in air at laboratory temperature (20 °C) to the constant weight. The addition of B extended the water retention time by up to 336 hours in the case of SA, and up to 72 hours for CA. The addition of TS and CL led to extending water retention by up to 168 hours for SA and up to 72 hours for CA. The ability of WBS to improve the water management of soils declined in the order: B> CL> TS. [ABSTRACT FROM AUTHOR]