Profile Modification and Root Yield, Distribution, and Activity1
- Harold V. Eck and
- Ronald G. Davis2
Deep plowing or other profile medication of a soil may alter root yield and distribution. Root systems of plants grown on soil rotary tilled 20 cm deep; plowed 90 cm deep; and plowed 90 cm deep with 22,400 kg/ha of Na2CO3 were sampled to (i) determine effects of treatments on yield and distribution of roots, and (ii) examine relationships between root yields and root activity as indicated by toproot ratios and Sr85 uptake.
Deep plowing tended to decrease root yields of sudangrass (Sorghum sudanense), sugarbeets, (Beta vulgaris), and soybeans (Glycine max) but had little effect on those of cabbage (Brassica oleracea var. ‘capitata’). Root yields decreased with depth on soil rototilled to 20 cm or moldboard plowed to 90 cm, but roots tended to be evenly distributed throughout the 90 cm profile when 22,400 kg/ha of Na2CO3 was applied at the 90-cm plow depth.
Root activity, as measured by top-root ratios, was enhanced by profile modification. Top-root ratios are shown to be better indicators of root activity than top or root yields alone.
Sr85 uptake data indicated that roots in the 70- to 90-cm zone were as active as those in the O- to 20-cm zone. Na2CO3 tended to increase root weights in its zone of application but reduced radiostrontium uptake about eightfold compared with uptake from similarly placed radiostrontium without Na2CO3, indicating a Na2CO3-induced decrease in root activity.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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