Does undersowing winter wheat with a cover crop increase competition for resources and is it compatible with high yield?

• Published in: Field crops research Vol. 115; no. 1; pp. 9 - 18
• Main Authors: Picard, D., Ghiloufi, M., Saulas, P., de Tourdonnet, S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2010; [Amsterdam]: Elsevier; Elsevier
• Subjects: Agricultural sciences; cover crops; crop production; Cropping system; cultivars; Festuca rubra; genetic variation; grain yield; leaf area index; Life Sciences; Light interception; nitrogen; Nitrogen nutrition; nutrient use efficiency; plant competition; plant growth; plant-water relations; Triticum aestivum; turf grasses; winter wheat; France; France, Paris Basin; Light interception; Nitrogen nutrition; Cropping system; light interception; nitrogen nutrition; cropping system
• ISSN: 0378-4290; 1872-6852
• DOI: 10.1016/j.fcr.2009.09.017

The sustainability of cropping systems can be increased by introducing a cover crop, provided that the cover crop does not reduce the cash crop yield through competition. The cover crop may be sown at the same time as a cash crop in the crop rotation. We carried out an experiment in 1999–2000 and 2000–2001 in the Paris Basin, to analyze the effects of simultaneously sowing winter wheat (
Triticum aestivum L.) and red fescue (
Festuca rubra L.), a turf grass. Competition between wheat and fescue was analyzed with one variety of red fescue,
Sunset, and two varieties of wheat,
Isengrain and
Scipion, each sown at a density of 150
plants
m
−2. In this study, we evaluated the effect of undersown fescue on wheat yield and analyzed the competition between the two species in detail. The undersown red fescue decreased wheat yield by about 12% for
Isengrain (8.7
t
ha
−1 for undersown
Isengrain versus 9.8
t
ha
−1 for
Isengrain alone) and 7% for
Scipion (7.4
t
ha
−1 for undersown
Scipion versus 8.0
t
ha
−1 for
Scipion alone). During the early stages of wheat growth (up to the ‘1
cm ear’ stage, corresponding to stage 30 on Zadoks’ scale), undersown fescue and fescue sown alone grew similarly. However, fescue biomass levels were much lower (5.6 and 4.7
g
m
−2 for fescue grown alone and undersown fescue) than wheat biomass levels on the undersown plots (120
g
m
−2 for
Isengrain and 111
g
m
−2 for
Scipion). From the e1 stage onwards, the wheat canopy rapidly extended, whereas that of red fescue remained sparse. The time lag between the beginning of the rapid increase in LAI and PAR interception by wheat grown alone and that for fescue grown alone was 590
dd in the second year. This resulted in much slower growth rates for undersown fescue than for undersown wheat. Biomass production rate was therefore low for undersown fescue (12% those of fescue grown alone, on average, at the time of wheat harvest), as were levels of water and nitrogen use. Neither the water deficit that occurred during the second experiment nor the nitrogen nutrition status of the wheat on plots with undersown fescue significantly affected wheat biomass production after anthesis.
The global interception efficiency index IG
ɛ
i
indicated that the fraction of the PAR
o intercepted by the wheat during its growth (255 days) was 0.35.