The aim of this paper is to explore the effects of combinations of abiotic and nutrient stresses on the growth of wheat. The effects of nutrient stress and abiotic stress are commonly investigated in isolation. In this paper we first discuss the effect that soil physical condition has on root proliferation within the soil profile. To fully appreciate how soil physical conditions influence rooting patterns we first explore the nature of soil strength in the field.
We continue to discuss the combined effects of root impedance due to strong soil, and the availability of N and P. We show that root impedance and stunted shoot growth occurs irrespective of nutrient status. The most likely explanation for this phenomenon is root mediated changes in hormonal signalling which can inhibit shoot growth. Root impedance has the effect of reducing the number of tillers and stunting leaf elongation. Finally, we report some data on the interaction between soil physical conditions and nitrogenous fertilisation in the field. The effects of soil management, including the preceding crop, can be greater than any genetic contribution to yield.