Corn Root Growth and Distribution as Influenced by Tillage and Nitrogen Fertilization
1987
Anderson, E. L.
Tillage alters both soil physical and chemical properties, which in turn alter the environment for root growth and may impact on plant growth, nutrient uptake, and yield. The objective was to compare corn (Zea mays L.) root morphology and distribution in plots under minimum tillage (MT) for 7 JT to conventional tillage (CT) at N fertilization treatments of 0 and 180 kg N/ha. The 3-yr field study was conducted in the Maryland Piedmont area on a Delanco silt loam (Aquic Hapludult). Three soil cores per plot were taken at vegetative, silking, and dough stages of plant development. A 76- mm-diam steel tube was used to sample to a depth of 0.6 m in the plant row, at midrow (0.38 m), and half way between (0.19 m). The roots collected to 0.6 m accounted for an average of 82% of the total root weight present after grain harvest. Tillage did not significantly affect plant growth or grain yield. Conventional tillage significantly increased root dry weight in only 1 yr. Minimum tillage and N fertilization both increased root weight in the 0- to 0.07-m layer in 2 of the 3 yr. Root mass decreased 90% in the 0- to 0.07-m depth when samples were compared from in the row to 0.19 m away. Nitrogen fertilization decreased milligrams per meter of root and root radius in 2 of the 3 yr, allowing root length to increase in response to N without altering the weight of roots. Root growth was observed under drought and N stress conditions when shoot growth and yield were limited. The period of most rapid root development occurred in the 8 weeks following planting.
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