The influence of arthropods and earthworms upon root growth of direct drilled cereals.
Abstract
Intact profiles of soil from a field in UK that had been direct-drilled for 5 years and from the same soil that had been regularly ploughed were sterilised with dichloropropane-dichloropropene (D-D). After aeration, profiles from the direct-drilled soil were inoculated with either Lumbricus terrestris, Allolobophora longa, a mixture of A. caliginosa and A. chlorotica, or a mixture of soil arthropods, in numbers similar to average populations. Two sterilised profiles from direct-drilled soil and two from ploughed soil were left without animals. Barley seeds were sown in slits to simulate direct-drilling. The numbers of seedlings emerging, heights of plants and oven-dry weights of roots were all greater in the profiles from ploughed soil and in those from direct-drilled soil inoculated with animals than in those with no animals. Root distributions were closely associated with the characteristic zones of activity of the animals.<new para>ADDITIONAL ABSTRACT:<new para>Intact profiles of soil from a field that had been direct drilled for 5 yr and from the same soil that had been regularly ploughed were sterilized with DD. After aeration, profiles from the direct drilled soil were inoculated with either the earthworms Lumbricus terrestris, Allolobophora longa, a mixture of A. caliginosa and A. chlorotica, or a mixture of soil arthropods, in numbers similar to av. populations. 2 sterilized profiles from direct drilled soil and 2 from ploughed soil left without animals. Barley seeds were sown in slits to simulate direct drilling. The numbers of seedlings emerging, ht. of plants and oven-dry wt. of roots were all greater in the profiles from ploughed soil, and in those from direct drilled soil inoculated with animals, than in those with no animals. Root distributions were closely correlated with the characteristic zones of activity of the animals.