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Conservation tillage (CT) can be beneficial for soil, water and soil organic matter
conservation in Mediterranean areas that are prone to soil erosion and where water
availability for crops is the main factor for sustainability. CT is the best option to
protect the soil from erosion, improve infiltration, reduce soil evaporation and so
conserve rainwater to increase crop water use (WU) and also water use efficiency
(WUE). While CT can play an important role in reaching the stability and sustainability
of these agricultural systems, performance depends upon the choice and
adoption of an appropriate soil management (tillage) system. In rainfed areas of
the Ebro Valley, winter cereals are the main crop sown. This paper presents the
results of 15 years of research in different soil and climatic conditions of the area of
CT on water conservation, WU and WUE. Long-term experiments, comparing
different tillage systems, were established in 1987, 1990 and 1992, at three locations
in the Ebro Valley, chosen according to their degree of aridity (Selvanera,
Agramunt and El Cano´s). Results reveal that CT was most effective in increasing
yield under the driest conditions at Agramunt (10–15%), still effective with
a smaller advantage under slightly wetter conditions at El Cano´s (5–10%) but
ineffective at Selvanera, the wettest site. CT only increased WU in some years at
Agramunt and never at the other two sites. The benefits of CT to both increased
yield at Agramunt and El Cano´s were determined by improved WUE arising from
changes in the pattern of WU before and after anthesis.
This work was funded by the Comisión Interministerial de Ciencia y Tecnología, AGR91-312, AGF94-198, AGF98- 261-C02 and AGL2004-7763-C02 projects |
