Submitted to: International Conference on Land Degradation
Publication Type: Proceedings
Publication Acceptance Date: 9/1/2001
Publication Date: 9/17/2001
Citation: WALLACE, B.H., ELTZ, F.E., REICHERT, J.M., NORTON, L.D. EVALUATION OF SURFACE CRUSTING ON BRAZILIAN TYPIC PALEUDALF USING AMENDMENTS. CD-ROM. Rio de Janeiro, Brazil: INTERNATIONAL CONFERENCE ON LAND DEGRADATION. 2001. Interpretive Summary:
Technical Abstract: Soil crusts inhibit seedling emergence and water penetration. Agricultural land degradation occurs from crusting and erosion of the soil when surface roughness, residues, or amendments are not counteracting high intensity precipitation events. A field study was conducted in Brazil with the Sao Pedro soil series. Surface thin sections were collected after rainfall to compare crust formation on phosphyogypsum (PG), polyacrylalmide (PAM) and control treated soils. PG is a by-product of the conversion of rock phosphate to phosphorus fertilizer, and its composition and behavior is similar to mined-gypsum, which improves infiltration of soils through serving as an electrolyte source. Anionic PAM is a synthetic macromolecule and the configuration used was 12 Mg mol**-1 molecular weight and 30 percent charge density. Microphotographs were taken of thin sections and comparisons were made using digital analysis software. The data indicate the amendments PG and PAM maintained high porosity compared to control; with pore space values averaging 35, 32 and 5 percent, respectively. Reduction of crusting may improve sustainable agriculture productivity through enhancing water infiltration and stabilizing seedling emergence.