TY - JOUR

T1 - Precrop functional group identity affects yield of winter barley but less so high carbon amendments in a mesocosm experiment

AU - van Duijnen, Richard

AU - Roy, Julien

AU - Härdtle, Werner

AU - Temperton, Victoria Martine

N1 - Funding Information: This research was funded by the Federal Ministry of Education and Research (BMBF) initiative ‘BonaRes—Soil as a sustainable resource for the bioeconomy’ through the project INPLAMINT. We thank Thomas Niemeyer for construction of the leachate setup and other technical support, Justin Raeder, Benjamin Delory, Rafael Weidlich, Emanuela Weidlich, and the student helpers Phong Hong, Farida Samad-zada, Arthur César Coares, Douglas Henrique (all four funded by the DAAD RISE or AIESTE programs), Hannes Eggerts and Isabel Rosen for help with the field work and sample processing. We also thank Steffen Rothardt and Henning Kage of the CAU Kiel for supplying the soil and HCAs, and Saatzucht Breun, NPZ, Nordsaat Saatzucht, and Feldsaaten Freudenberger for supplying the seeds free of charge. Funding Information: This research was funded by the Federal Ministry of Education and Research (BMBF) initiative ‘BonaRes—Soil as a sustainable resource for the bioeconomy’ through the project INPLAMINT. Publisher Copyright: © 2018 van Duijnen, Roy, Härdtle and Temperton.

PY - 2018/7/3

Y1 - 2018/7/3

N2 - Nitrate leaching is a pressing environmental problem in intensive agriculture. Especially after the crop harvest, leaching risk is greatest due to decomposing plant residues, and low plant nutrient uptake and evapotranspiration. The specific crop also matters: grain legumes and canola commonly result in more leftover N than the following winter crop can take up before spring. Addition of a high carbon amendment (HCA) could potentially immobilize N after harvest. We set up a 2-year mesocosm experiment to test the effects of N fertilization (40 or 160 kg N/ha), HCA addition (no HCA, wheat straw, or sawdust), and precrop plant functional group identity on winter barley yield and soil C/N ratio. Four spring precrops were sown before winter barley (white lupine, faba bean, spring canola, spring barley), which were selected based on a functional group approach (colonization by arbuscular mycorrhizal fungi [AMF] and/or N2-fixing bacteria). We also measured a subset of faba bean and spring barley for leaching over winter after harvest. As expected, N fertilization had the largest effect on winter barley yield, but precrop functional identity also significantly affected the outcome. The non-AMF precrops white lupine and canola had on average a positive effect on yield compared to the AMF precrops spring barley and faba bean under high N (23% increase). Under low N, we found only a small precrop effect. Sawdust significantly reduced the yield compared to the control or wheat straw under either N level. HCAs reduced nitrate leaching over winter, but only when faba bean was sown as a precrop. In our setup, short-term immobilization of N by HCA addition after harvest seems difficult to achieve. However, other effects such as an increase in SOM or nutrient retention could play a positive role in the long term. Contrary to the commonly found positive effect of AMF colonization, winter barley showed a greater yield when it followed a non-AMF precrop under high fertilization. This could be due to shifts of the agricultural AMF community toward parasitism.

AB - Nitrate leaching is a pressing environmental problem in intensive agriculture. Especially after the crop harvest, leaching risk is greatest due to decomposing plant residues, and low plant nutrient uptake and evapotranspiration. The specific crop also matters: grain legumes and canola commonly result in more leftover N than the following winter crop can take up before spring. Addition of a high carbon amendment (HCA) could potentially immobilize N after harvest. We set up a 2-year mesocosm experiment to test the effects of N fertilization (40 or 160 kg N/ha), HCA addition (no HCA, wheat straw, or sawdust), and precrop plant functional group identity on winter barley yield and soil C/N ratio. Four spring precrops were sown before winter barley (white lupine, faba bean, spring canola, spring barley), which were selected based on a functional group approach (colonization by arbuscular mycorrhizal fungi [AMF] and/or N2-fixing bacteria). We also measured a subset of faba bean and spring barley for leaching over winter after harvest. As expected, N fertilization had the largest effect on winter barley yield, but precrop functional identity also significantly affected the outcome. The non-AMF precrops white lupine and canola had on average a positive effect on yield compared to the AMF precrops spring barley and faba bean under high N (23% increase). Under low N, we found only a small precrop effect. Sawdust significantly reduced the yield compared to the control or wheat straw under either N level. HCAs reduced nitrate leaching over winter, but only when faba bean was sown as a precrop. In our setup, short-term immobilization of N by HCA addition after harvest seems difficult to achieve. However, other effects such as an increase in SOM or nutrient retention could play a positive role in the long term. Contrary to the commonly found positive effect of AMF colonization, winter barley showed a greater yield when it followed a non-AMF precrop under high fertilization. This could be due to shifts of the agricultural AMF community toward parasitism.

KW - Arbuscular mycorrhizal fungi

KW - Barley

KW - Crop rotation

KW - High carbon amendment

KW - Immobilization

KW - Nitrate leaching

KW - Plant functional group

KW - Rhizobia

KW - Biology

KW - Ecosystems Research

UR - http://www.scopus.com/inward/record.url?scp=85049633240&partnerID=8YFLogxK

U2 - 10.3389/fpls.2018.00912

DO - 10.3389/fpls.2018.00912

M3 - Journal articles

C2 - 30018627

AN - SCOPUS:85049633240

VL - 9

JO - Frontiers in Plant Science

JF - Frontiers in Plant Science

SN - 1664-462X

M1 - 912

ER -