Several studies have reported the allelopathic depressive effect of crop residues on yields (grains, straw) of a crop in succession. This effect is more amplified with the practice of conservation agriculture (such direct sowing), because of the accumulation of residues on the soil. Many crops expressed proven allelopathic properties such as barley, bread-wheat, durum-wheat, oats, grain-sorghum and rye.
Allelopathy interacts with various environmental stresses, such as high temperatures, irradiation, nutrient limitation and pest attack, which increase the production of allelochemicals as a defense mechanism. Production of allelochemicals at high rates induces resistances in crops against abiotic stresses, helping them to grow vigorously. A large number of compounds have been identified as having a role in allelopathic activity in higher plants in general and in crops in particular. Among these compounds are alkaloïds (hordenin, gramin), phenolic acids, hydroxamic acid, jasmonic acid, benzoxazinone and L-tryptophan.
The study of the allelopathic potential of cultivated species in an agricultural system allows a more oriented choice of agronomic sequences and offers the possibility of using allelochemical substances as "natural pesticides" in the control of weeds and pests of crops. Such an approach could overcome the extensive use of chemicals behind environmental pollution and resistance developed by certain pests.