Root system-based limits to agricultural productivity and efficiency: the farming systems context

TY - JOUR

T1 - Root system-based limits to agricultural productivity and efficiency

T2 - the farming systems context

AU - Thorup-Kristensen, Kristian

AU - Kirkegaard, John

N1 - © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: [email protected].

PY - 2016/10

Y1 - 2016/10

N2 - BACKGROUND: There has been renewed global interest in both genetic and management strategies to improve root system function in order to improve agricultural productivity and minimize environmental damage. Improving root system capture of water and nutrients is an obvious strategy, yet few studies consider the important interactions between the genetic improvements proposed, and crop management at a system scale that will influence likely success.SCOPE: To exemplify these interactions, the contrasting cereal-based farming systems of Denmark and Australia were used, where the improved uptake of water and nitrogen from deeper soil layers has been proposed to improve productivity and environmental outcomes in both systems. The analysis showed that water and nitrogen availability, especially in deeper layers (>1 m), was significantly affected by the preceding crops and management, and likely to interact strongly with deeper rooting as a specific trait of interest.CONCLUSIONS: In the semi-arid Australian environment, grain yield impacts from storage and uptake of water from depth (>1 m) could be influenced to a stronger degree by preceding crop choice (0·42 t ha(-1)), pre-crop fallow management (0·65 t ha(-1)) and sowing date (0·63 t ha(-1)) than by current genetic differences in rooting depth (0·36 t ha(-1)). Matching of deep-rooted genotypes to management provided the greatest improvements related to deep water capture. In the wetter environment of Denmark, reduced leaching of N was the focus. Here the amount of N moving below the root zone was also influenced by previous crop choice or cover crop management (effects up to 85 kg N ha(-1)) and wheat crop sowing date (up to 45 kg ha(-1)), effects which over-ride the effects of differences in rooting depth among genotypes. These examples highlight the need to understand the farming system context and important G × E × M interactions in studies on proposed genetic improvements to root systems for improved productivity or environmental outcomes.

AB - BACKGROUND: There has been renewed global interest in both genetic and management strategies to improve root system function in order to improve agricultural productivity and minimize environmental damage. Improving root system capture of water and nutrients is an obvious strategy, yet few studies consider the important interactions between the genetic improvements proposed, and crop management at a system scale that will influence likely success.SCOPE: To exemplify these interactions, the contrasting cereal-based farming systems of Denmark and Australia were used, where the improved uptake of water and nitrogen from deeper soil layers has been proposed to improve productivity and environmental outcomes in both systems. The analysis showed that water and nitrogen availability, especially in deeper layers (>1 m), was significantly affected by the preceding crops and management, and likely to interact strongly with deeper rooting as a specific trait of interest.CONCLUSIONS: In the semi-arid Australian environment, grain yield impacts from storage and uptake of water from depth (>1 m) could be influenced to a stronger degree by preceding crop choice (0·42 t ha(-1)), pre-crop fallow management (0·65 t ha(-1)) and sowing date (0·63 t ha(-1)) than by current genetic differences in rooting depth (0·36 t ha(-1)). Matching of deep-rooted genotypes to management provided the greatest improvements related to deep water capture. In the wetter environment of Denmark, reduced leaching of N was the focus. Here the amount of N moving below the root zone was also influenced by previous crop choice or cover crop management (effects up to 85 kg N ha(-1)) and wheat crop sowing date (up to 45 kg ha(-1)), effects which over-ride the effects of differences in rooting depth among genotypes. These examples highlight the need to understand the farming system context and important G × E × M interactions in studies on proposed genetic improvements to root systems for improved productivity or environmental outcomes.

U2 - 10.1093/aob/mcw122

DO - 10.1093/aob/mcw122

M3 - Journal article

C2 - 27411680

SN - 0305-7364

VL - 118

SP - 573

EP - 592

JO - Annals of Botany

JF - Annals of Botany

IS - 4

ER -