Maize is classified as a grass having a fibrous root system, rather than a tap root. The following explains root development in relation to nutrient uptake. Remember that factors such as weather, soil properties, fertiliser and pests can influence the growth, distribution and coordination of the root system within the soil.
The total end-on-end root length can be up to 126,500 km per Ha!
There can be differences in root growth patterns between maturity groups. Maturity groups are greater than individual hybrids. Given similar growing conditions, a full season hybrid will produce a higher root mass and a corresponding higher yield potential.
Two to five weeks after pollination, from blister to full milk/dent the kernel fills rapidly and the balance of nutrient uptake occurs. The root system begins to senesce and die off. By the end of grain fill up to 40% of the root mass will have died. This is shown above ground level as the plant gets rid of 'excess baggage' as it nears maturity.
Die-back continues as the plant channels photosynthate into developing grain. Almost no nutrient uptake occurs and there can be potash leaching as leaf tissue dies and if rain falls.