A comparative study of the effects of clumping, substrate, light, depth of burial and soil moisture upon the germination of seeds of weeds and crops grown in the sudan gezira.

Abstract

The influence of the number of seeds per clump upon germination of oryza sativa L., Gossypium hirsutum L., Brachiaria eruciformis (Sm.) Griseb, Dinbera retroflexa (Vahl) Panz. and Echinochloa colonum (L.) Link was investigated on filter paper and in sand and clayey soil. The substrates did not affect the germination or the seeds of the crops of the weeds. Neighbour effects and interference were examined between rice and B. eruciformis and between cotton and E. colonum seeds sown at different densities and clumps in the clayey soil. Germination of seeds of crops was not affected by increasing density, while that of the weeds was affected by diversity and increasing density. The germination of seeds of crops was not affected by light. The weed seeds were light sensitive and only germinated on the surface of the soil, under a wide range of moisture levels. The implications of the results are discussed in relation to weed control in the Gezira.