Effect of Soil Type and Bulk Density on the Above Ground Properties Associated with Lodging and on the Anchorage Strength of Wheat.

Wheat, along with other cereals is susceptible to falling over – known as lodging - during or after grain-filling when their ears are at their most heavy.  This can cause economic loss by reducing harvestable yield, increasing harvest time and the drying time of the crop.   In wheat grown in the United Kingdom root lodging (whereby the anchorage fails, allowing the stems to topple over and lie flat) is more likely than stem lodging (whereby the stems buckle and fail towards their base, causing the stem to fall over) as the stems are usually strong enough to resist damage.     Reducing the incidence of root lodging is a goal of growers, whilst maintaining high yields.  One means of achieving this aim is to increase the anchorage strength of the plants – which depends upon both properties of the basal anchorage coronal roots and also the physical properties of the soil. A ‘pot’ experiment was conducted to investigated the influence of sandy loam and clay loam soils at low, moderate and high wet bulk densities on soil shear strength, penetration resistance, plant anchorage strength and the above ground properties which factor in lodging susceptibility (stem height, plant fresh weight, ear weight, number of tillers, self-weight moment, safety factor, stem diameter, centre of gravity and stem strength) of winter wheat. Soil shear strength and penetration resistance are proportional to soil bulk density. Soil texture and bulk density have a significant effect on the above ground plant properties. Anchorage failure in wheat is predominant as a “safety factor” calculated against stem failure was greater compared to that for anchorage failure. Plant anchorage strength (resistance to overturning) was soil strength dependant but unaffected by soil type.