bannière © iEES Paris logo_UPMC logo_UPEC logo_Paris-Diderot logo_CNRS-INEE logo_IRD Accueil Accueil

Suivez nous sur

twitter
facebook

Rechercher



Accueil du site > Actualités

Making better use of the third dimension of agricultural land to sustainably intensify agricultural production

In this prospective article, an international consortium coordinated by researchers from the University of Copenhagen examines the prospects for using the “third dimension” of agricultural land, i.e. the possibility, without resorting to new land, of increasing the volume of soil exploited by the root system of crops, thereby increasing the resource base available for agricultural production while minimizing the undesirable externalities frequently associated with current agroecosystems.


In response to the challenge of growing food demand in a context of global climate change and shrinking land availability, few options exist to sustainably intensify agricultural production. Among these options, a largely neglected aspect consists of increasing the use of deep soil resources through the selection of new genotypes and the development of cropping systems whose effective rooting depth is significantly greater than that of the systems current. This article thus explores the prospects for extending the “3rd dimension’’ of agricultural land, i.e. the possibility, without resorting to new land, of increasing the volume of soil exploited by crops’ root system, thereby increasing the resource base available for agricultural production while minimizing losses of external input. More particularly, we thus examine : (i) the modalities through which deeper rooted crops could be obtained, (ii) the potential impact of deep rooting on the acquisition of usually untapped resources, (iii) the possible effects of a deeper-rooted agriculture on soil fertility, ecology and C storage. We conclude that current knowledge of deep roots of crops and wild plants clearly indicates that there is a potential to extend the third dimension of agricultural land and that improvement in the utilization of deeper soil resources could be achieved in various ways. It is clear that the most significant improvements may be reached by relying more on inherently deep rooted species, which could result from a shift from annual to perennial crop species. However, improving deep rooting of current crop species is more likely to bring significant improvements in the shorter term.

Key-words : sustainable intensification ; deep roots ; perennial crops

JPEG - 90.9 ko
Diagram Illustrating Soil Exploitation by Crop Roots in Time
Diagram Illustrating Soil Exploitation by Crop Roots in Time and Depth of Three 5-Year Example Rotations, Assuming Typical Root Depth Development of the Crops, without Physical Barriers to Root Growth. The black areas of the figures indicate soil without active roots, the green areas soil with active roots. The dark green is rooted soil within the 0–2 m soil layer, the light green shows rooted soil in the 2–4 m soil layer. Integrated root occupancy is calculated as % of soil occupied by roots in time and space, in the 0–2 and 2–4 m soil layers. In example 1, common crops are chosen. Example 2 is also using common crops, but optimized by choosing deep-rooted species. In example 3, a perennial grain crop is included in three of the 5 years. The examples illustrate how markedly root exploitation by crops can be affected, even when relying on common crops, and the extra potential offered by including deep-rooted perennials.

Publication :
Thorup-Kristensen et al., “Digging Deeper for Agricultural Resources, the Value of Deep Rooting.” Trends in Plant Science.
DOI :
https://doi.org/10.1016/j.tplants.2...

Contact :
Mél : Alain Pierret, chargé de recherches ; IRD