Intercropped wheat (Triticum aestivum L.) and bean (Vicia faba L.) as a whole-crop forage:: effect of harvest time on forage yield and quality

Sole crops and intercrops of wheat (Triticum aestivum L.) and bean (Vicia faba L.), at three harvest dates, representing successive growth stages, were evaluated for biomass production of whole-crop forage and quality characteristics of crude protein (CP), neutral-detergent fibre (NDF), acid-detergent fibre (ADF), water-soluble carbohydrate (WSC) concentrations and ash content. These tests were carried out for two field experiments, respectively, drilled during the spring of 1997 and autumn of 1997 on Imperial College Farm, Wye, UK. Results indicated that optimum forage yield and quality were obtained from the second to third harvest dates for the spring-drilled experiment and the second harvest for the autumn-drilled experiment. Wheat and bean intercrops were higher in total forage dry matter (DM) yield than either wheat or bean grown as sole crops. Field bean intercropped with wheat led to increased forage quality (CP and NDF concentrations) compared with sole wheat, and higher WSC concentrations compared with sole bean. Intercrops also enhanced weed suppression compared with sole bean. It is suggested that winter wheat-bean intercrops may have considerable potential as a moderate-yielding, relatively high-quality, low-input and environmentally benign forage crop with considerable potential with regard to yield and quality and warrant further study.