Nutrient uptake of catch crops under non-limiting growth conditions

Abstract

Background: Catch crops enhance nutrient cycling of cropping systems. Considering possible limitations of catch crop studies in field and greenhouse experiments, a new approach was chosen to combine the advantages of both systems in quantifying the potential for nutrient retention by catch crops. Aims: This study aimed at identifying N, P, and K uptake of different catch crop species grown in monoculture and as a mixture under non-limiting growth conditions in terms of water and nutrient availability. Methods: Catch crops were cultivated under semi-controlled conditions in large containers (August to November 2020). Shoot N, P, and K uptake, leachate accumulation, and soil Nmin, CAL-P, and CAL-K (0–30 cm) were quantified after harvest. After washing, root parameters were quantified with a root scanner. Results: Nutrient uptake of N, P, and K was highest for phacelia. The mixture of seven different catch crops performed equally well. Nutrient uptake was closely related to root length and root surface area. Conclusions: Under non-limiting growth conditions, phacelia has the highest potential to conserve N, P, and K for a succeeding crop; however, the low C : N ratio of the frost-sensitive crop could promote nutrient losses during winter. We conclude that growing a single catch crop can be as effective in reducing the nutrient leaching potential as cultivating a mixture of catch crops when nutrients and water are no growth-limiting factors.