Abstract
Organic matter plays an important and multi-faceted role in soil. Physically, organic matter influences soil structure and all associated properties. Chemically, soil organic matter affects the cation exchange capacity and the capacity for buffering changes in soil pH. Biologically, organic matter acts as the nutrient and energy supply for microbial biomass and higher plants. A soil which is biologically and chemically fertile but which cannot physically support crop development will not fulfill its agronomic potential. Soil productivity is, therefore, determined by a combination of organic matter's influence on physical, chemical, and biological soil properties. It has been shown that the incorporation of crop residues into soil is beneficial to soils, improving one or more essential soil attributes. The effect of the addition of barley straw on a loam soil was observed over a two-month period: soil properties were measured weekly to determine whether the presence of additional organic residues induced an improvement in soil fertility or productivity. Results indicate no significant difference in the initial infiltration rate, pH, phosphorus, or potassium concentration as a result of straw incorporation. The concentration of nitrate-N in the soil was significantly lower in the presence of added organic matter.