Effects of selected amendments on soil properties and emergence of wheat seedlings

Abstract

Crusting can have a prominent effect on seedling emergence. Crust formation at the soil surface is a common feature of many soils including the silty loam soil (Aquic Haplocalsids) from the Konya plain examined in this investigation. The effects of different soil amendments on modulus of rupture and aggregate stability in water were measured in a pot experiment in the laboratory. Seedling emergence of wheat (Triticum durum Desf.) and penetration resistance was investigated in a microplot experiment in the greenhouse. Portland cement, barnyard manure (dairy cattle), city waste compost (municipal refuse) and wheat straw were used in the pot experiment, and Portland cement and barnyard manure were investigated in the microplot experiment. Soil amendments were added to the soil samples at rates of 0, 2, 4 and 6% (wt/wt) and the samples including a control were incubated at about field capacity water content for up to 100 d in the laboratory. The moduli of rupture values and water stable aggregates were measured after 25, 50, 75 and 100 d of incubation. All the soil amendments reduced the modulus of rupture compared with the control soil sample. The modulus of rupture of the control and mixes with Portland cement, barnyard manure, city waste compost and wheat straw (6%, wt/wt) after 100 d of incubation were 726, 0, 494, 564 and 113 kPa, respectively. Aggregate stabilities of the control and the soil amended with Portland cement, barnyard manure, city waste compost and wheat straw (6%, wt/wt) after 100 d of incubation were 5.16, 55.02, 10.82, 8.44 and 34.98%, respectively. Seedling emergences of wheat and penetration resistances of the control and the soil amended with Portland cement and barnyard manure (6%, wt/wt) in the microplots were 29, 80 and 36%; 489, 0 and 471 kPa, respectively. Key words: Surface sealing, aggregate stability, seedling emergence, penetration resistance.