In organic farming, the adoption of the conventional tillage (CT) technique is considered by many farmers to be necessary to control weeds. Such tillage system, in fact, permits to bury weed seeds deep in the soil by means of soil inversion with moldboard plowing and to eliminate the weed plants that gradually emerge by means of the secondary tillage operations. However, it is also true that intensive tillage progressively reduces the soil organic matter content and the stability of soil aggregates, thus increasing the risk of soil erosion (Six et al. 2000). This is in contrast with one of the basic principles of organic agriculture, which is the conservation of soil fertility. Alternatively to CT, the no tillage (NT) technique can maintain or even enhance soil fertility by increasing C storage, soil biological activity, and soil aggregate stability, but, as a matter of fact, its application relies on herbicide use as the primary weed control mechanism (Gattinger et al. 2011). In the light of these considerations, efforts must be made to revisit the NT technique to make it applicable in organic farming. Without prejudice to the fact that this challenge should be addressed through a systemic approach (Peigné et al. 2007), one possible option could be to take advantage of the possibility given by the NT technique to sow the crop in an earlier period than what usually the farmer does when adopts the CT technique. Anticipating the sowing time would allow operating when most of the weed plants are still poorly developed, so that the sowing operation itself can kill many of them. Moreover, sowing early, when temperatures are still relatively mild, could accelerate the initial growth, thus reducing the period during which the crop is particularly vulnerable to weed competition. Usually, early sowing in the CT systems is not possible since a proper seedbed preparation needs time so that clods formed as a result of plowing could be broken down by natural weathering processes and by one or more secondary tillage operations. Therefore, an experiment was performed under organic management to study the effects of NT compared to CT on durum wheat (Triticum durum Desf.) grain yield, and to verify whether early sowing under NT conditions, compared to sowing at the ordinary time for the study area, can provide an advantage to the crop by increasing its competitiveness against weeds. Furthermore, the above effects were investigated on two durum wheat genotypes highly different for pheno-morphological and agronomic characteristics, assuming for them different competitiveness against weeds.
|Numero di pagine||3|
|Stato di pubblicazione||Published - 2018|