Soil water and nitrogen availabiity to corn in relation to root distribution as affected by tilage depth
1985
Quirol, B.F.
The pattern of corn root distribution and the availability of soil water and nitrogen to corn under three tillage depth treatments were investigated in Lipa clay soil with a traffic pan of about 17 cm thick situated 8 cm below the soil surface. The tillage treatments employed included the conventional disc plowing to 15 cm depth, zero tillage, and subsoiling to a depth of 30 cm. Conventional and deep tillage improved the soil physical properties of the cultivated zone, reducing bulk density and penetrometer resistance while increasing saturated hydraulic conductivity, drainage porosity and amount of available water. As a consequence, conventional and deep tillage promoted early deep root penetration within and beyond the otherwise compacted soil layer (15-30 cm). However, deep tillage produced more fine and well-proliferating root systems with presumably greater total root surface area deep in the soil profile. This enhanced significantly greater water and nitrogen utilization in the deeper soil horizons of deep-tilled soil. The comparatively better plant-water relations and nitrogen nutrition provided by deep tillage to corn plants resulted in the production of more dry matter, heavier and fully-filled grains to effect a yield increase of about 15% and 26% relative to the conventinal and zero tillage treatments. Grain yield in the zero, conventional and deep tillage treatments were 2.45, 2.70, and 3.11 tons/ha, respectively
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