The influence of soil physical and mechanical factors on seed germination with special reference to soil moisture.

Seed germination as influenced by soil physical and mechanical factors with particular reference to soil moisture has been studied. An inconsistency concerning the influence of moisture potential on seed germination existed in the relevant literature. The influence of matric potential (a component of moisture potential) on seed germination was apparent at very small reductions in the free energy of the soil water; however, quite large reductions in the free energy of the soil water were required to produce a similar effect when the moisture potential was controlled, by vapour pressure or by the osmotic potential. It was therefore difficult to attribute the influence of matric potential on seed germination to its control of the water supply to the seed in terms of soil water free energy. Seed germination as influenced by soil physical and mechanical factors with particular reference to soil moisture has been studied. An inconsistency concerning the influence of moisture potential on seed germination existed in the relevant literature. The influence of matric potential (a component of moisture potential) on seed germination was apparent at very small reductions in the free energy of the soil water; however, quite large reductions in the free energy of the soil water were required to produce a similar effect when the moisture potential was controlled, by vapour pressure or by the osmotic potential. It was therefore difficult to attribute the influence of matric potential on seed germination to its control of the water supply to the seed in terms of soil water free energy