Optimizing forage production in double‐annual cropping systems under irrigated Mediterranean conditions

Abstract

AbstractDouble‐annual cropping systems can increase the productivity of farmland and simultaneously confer environmental benefits, but the optimal combination of crops and cultivation strategies is likely to be region‐specific. For instance, because of the low precipitation and specially in the summer, in Mediterranean environments irrigation is usually needed to grow two crops within a year. In the present 3‐year study, a double‐annual cropping system for forage production (winter crops and maize) was evaluated under irrigated Mediterranean conditions. Eight winter varieties (including barley, Italian ryegrass, oats, oats plus vetch, triticale and wheat) were harvested in April or May. Maize was sown few days after each harvest time. The average forage yield of the winter crops harvested in April was 6.3 Mg/ha dry matter (DM), with an average crude protein (CP) content of 16.4% and a digestibility of 63.4%. The average yield was significantly higher for the crops harvested in May (10.0 Mg/ha DM) but with lower forage quality and digestibility (10.8% CP and 52.8%, respectively digestibility). Maize yields were higher (27.6 Mg/ha DM) in the May than in the April (25.1 Mg/ha DM) sowing date, while the forage quality was similar (7.1% CP, 64.5% digestibility). The total annual forage yield was 31.3 Mg/ha DM for April harvest/sowing date (weighted quality = 8.7% CP, 64.9% digestibility) and 37.6 Mg/ha DM for May harvest/sowing date (weighted quality = 8.2% CP, 60.5% digestibility). Therefore, under conditions of the present research in Mediterranean environments, the May harvest/sowing date was the most convenient strategy to produce forage in double‐annual cropping systems and specially the triticale–maize rotation.