Aiming for 45 t/ha per annum: yield of supplementary feed crops grown in sequences designed for maximum productivity.

and rape are less risky options over a range of latitudes, but must be fed ‘in situ’. Winter cereals and annual ryegrass are also important options in cropping systems because of their flexibility of use as grazed feed, cut and carry feed or silage (Densley et al. 2006; Hogg et al. 2002). These crops can provide high energy supplement for extending autumn lactation (Waghorn 2007) or be utilised for winter or spring feeding. To achieve high productivity, crops selected for forage should match the intended environment. Many studies have shown that productivity is related to radiation use efficiency. Therefore, high yield is expected from crops with their growth duration occurring largely during periods of high radiation. Crops such as kale with extended growth durations have also given high yields, but their average daily productivity may be lower than that of short-term crops like spring cereals. Crop potential modelling has shown that productivity depended on latitude and therefore the temperature pattern (Brown et al. 2007a). Also, the relative contributions of C4 and C3 species changed with choice of sowing time and location (Brown et al. 2007a). Appropriate sowing dates and cultivars or hybrids (Densley et al. 2005a) will be important for achieving close to potential yield. Techniques that reduce the transition time between crops will also ensure that annual productivity will be close to optimum (Brown et al. 2007a). This paper describes cropping sequences suitable for implementation on dairy platforms or runoffs as the model system for maximising crop yield. The experiment tested the practical productivity limits using cropping sequences that would fit within current farming practices, have minimum impacts on the environment and provide a 2-year break between pasture to pasture in renewal programmes.