Intermediate wheatgrass (KernzaTM) as a pre-crop for beetroot and carrot

Sammanfattning

This study is laid out with the background of some of today’s biggest societal needs: climate change resilient agricultural systems, and food chains less reliant on fossil fuels and more irrepressible to political change. The interest for perennial incorporation into crop cycles is due to their dual use, in that they often can be harvested both for seed and straw. However, knowledge gaps concerning how perennial grasses function as pre-crops need filling before such crops can be fully utilized. Through a study design using carrot and beetroot as subsequent crops to KernzaTM (cropped for six consecutive years) comparison of pre-crop qualities with a conventional annual cereal crop cycle was made. Looking at soil parameters such as water content and organic matter content, where measurements were significantly higher for the perennial treatment with KernzaTM, pre-crop qualities seem high. However, the findings of this field study also show a significantly lower harvest weight of subsequent crops, compared with the harvest of subsequent crops following conventional cereal crops (referred to as the annual treatment). Bulk density and pH do not differ significantly between the treatments, although respiration is significantly higher in the perennial treatment. These results indicate that the soil processes following the use of perennial crops, and the effects of management such as termination timing and depth of tillage, have intricate ways of influencing subsequent crops, most likely in the establishment phase as well as harvest weight. Looking at the results of this field study, together with the literature study, it is still clear that KernzaTM needs more research focus as a pre-crop to be fully utilized in crop circles that include perennial cereals as well as annual crops for direct human consumption.