The intensity of water stress dictates whether the N status of temperate-type perennial grass swards is affected by drought

Errecart, Pedro Manuel; Marino, María A.; Agnusdei, M. G.; Lattanzi, Fernando A.; Durand, J. L.

doi:10.1016/j.fcr.2020.107928

Cited by 3 publications

(6 citation statements)

References 95 publications

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“…Neither N fertilization nor hard grazing to control flowering affected root biomass, which was large (7 Mg DM/ha) and concentrated in the upper 10 cm soil horizon (Figure 2). Transient increases in spring root mass in response to fertilizers have been observed (Dodd & Mackay, 2011), but most studies have found little or no short‐term effects of N fertilization on tall fescue root mass (Bélanger et al., 1992, 1994; Errecart et al., 2020; Gonzalez‐Dugo et al., 2005). Likewise, in the only study we are aware of, Lolium perenne showed a small and short‐lived decrease in root mass in response to hard grazing to control flowering (Matthew, 1992, pp.…”

Section: Discussionmentioning

confidence: 99%

“…57–87). Lack of root response could in part be due to the off‐setting effects of increased allocation belowground under nutrient deficiency (Bélanger et al., 1994; Errecart et al., 2020). Furthermore, in perennial species with large root systems, the long lifespan of roots (Robin et al., 2021; Yang et al., 1998) would buffer short‐term changes in growth.…”

Section: Discussionmentioning

confidence: 99%

“…Deep and functional root systems may delay water stress by providing a continuous supply of water during droughts (Garwood & Sinclair, 1979; Ludlow et al., 1989; Volaire et al., 1998), and thus strengthen dehydration avoidance in summer‐dry environments (Norton et al., 2016). Deep roots could help resolve the trade‐off between growth potential and dehydration survival during summer in non‐dormant plants (Keep et al., 2021) by accessing moist soil horizons (Errecart et al., 2020; Gonzalez‐Dugo et al., 2005), and deeper rooting is a sought‐after trait in breeding programs (Crush et al., 2007; Ludemann & Chapman, 2019; Qu et al., 2022).…”

Section: Introductionmentioning

confidence: 99%

“…One possibility is that these factors affect the size and morphology of the root system, and hence the ability to cope with water deficits. For instance, root systems have been found to be smaller in N‐deficient grass swards, particularly in the upper layers (Bélanger et al., 1992; Lorenz & Rogler, 1967; Oswalt et al., 1959), even in spite of increases in assimilate allocation to roots (Bélanger et al., 1994) and in specific root length (Errecart et al., 2020; Powell, 1974). Likewise, ryegrass swards cut at head emergence or anthesis grew more roots than when seedheads were either removed before head emergence or left uncut (Matthew, 1992).…”

Section: Introductionmentioning

confidence: 99%

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Tall fescue tiller survival over summer in a subtropical environment: The role of the size and depth of root systems

Jáuregui,

Michelini,

Sevilla

et al. 2024

J Agronomy Crop Science

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Pasture persistence is a key determinant of the economic and environmental performance of pastoral animal production systems. Large and deep root systems that help resist summer water stress have been proposed as a relevant trait for vegetative persistence of perennial temperate forage species growing in subtropical climates or under future climatically challenging scenarios. In a previous study [Jauregui et al., 2017. Persistence of tall fescue in a subtropical environment: Tiller survival over summer in response to flowering control and nitrogen supply. Grass and Forage Science 72, 454–466] we have shown that nitrogen fertilization and grazing management aimed at ‘control flowering’ increased the survival of tall fescue tillers during harsh summers in Uruguay (lat. 32°S). Here we assessed: (i) to what extent tiller survival is mediated by root system size in spring and (ii) what consequences tiller survival entails for root mass, depth and morphology the following autumn. In two field experiments, significant increases in tiller survival in response to nitrogen fertilization and grazing management (+60% and +80% in 2011/12 and 2012/13, respectively) were not related to concomitant effects on the size or depth of the root system in spring (p > .10). Even when six‐fold within‐treatment variation in root mass was observed, within‐treatment variation in summer tiller survival was little affected (<15%, p = .08). In turn, differences in tiller survival over summer affected little root system characteristics the following autumn. Therefore, we found scant support for the hypothesis that large and deep root systems contribute to survival of tall fescue tillers in this subtropical humid climate. Except for soils with less than 30 mm of plant available water holding capacity, summer water deficits did not induce severe tiller mortality in tall fescue in this climate.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tall fescue tiller survival over summer in a subtropical environment: The role of the size and depth of root systems

Jáuregui,

Michelini,

Sevilla

et al. 2024

J Agronomy Crop Science

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“…Low N availability characteristic of HHM environments has negative consequences on resource capture (e.g., radiation, water) and, therefore, on forage production (Agnusdei et al., 2010; Errecart et al., 2020). Thus, N addition can be a high‐impact technological tool to increase forage production in these environments (Cicore et al., 2017).…”

Section: Introductionmentioning

confidence: 99%

Halo‐hydromorphism alters nitrogen fertilization responses of tall wheatgrass pastures: Capture and use of resources, tiller dynamics and forage production

Fina,

Bertram,

Gatti

et al. 2024

J Agronomy Crop Science

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Halo‐hydromorphism limits productivity in approximately 100 million hectares worldwide. Tall wheatgrass (Thinopyrum ponticum) is a species widely used in these environments for its seeding potential, being the addition of nitrogen a considered technological tool to increase forage quality and production. The objective of the study was to determine the impact of nitrogen fertilization on the capture and use of resources (radiation, water and nitrogen) in a cool season perennial sward growing in contrasting halo‐hydromorphic conditions. Cultivated pastures from three independent sites were used. Sites were described according to the degree of halo‐hydromorphism using soil salinity and water table attributes (salinity and depth) as environmental indicators: low HHM site [electrical conductivity (EC1:2.5) 0.97 dS/m; water table salinity 2.03 dS/m; depth 85 cm], intermediate HHM site (EC1:2.5 3.86 dS/m; water table salinity 7.40 dS/m; depth 134 cm) and high HHM site (EC1:2.5 4.49 dS/m; water table salinity 7.85 dS/m; depth 31 cm). At each site, a late spring regrowth (~750°Cd) was studied by applying two treatments (n = 5): without (N0) and nitrogen fertilization (N150; 150 kg/ha of nitrogen in the form of urea). The response of tall wheatgrass to nitrogen fertilization in halo‐hydromorphic conditions depends on soil salinity and water table attributes. N150 treatments production was twice as high as in N0 in low HHM and intermediate HHM environments (from 1750 to 3500 kgDM/ha and from 1080 to 1985 kgDM/ha, respectively). Meanwhile, in high HHM conditions, forage production was only 40% higher when nitrogen was added (from 625 to 870 kgDM/ha). In low HHM the higher N150 production was related to tiller density and size, whereas in intermediate HHM and high HHM was linked only to tiller size. In N150 treatments, the nitrogen nutrition index was negatively affected with the increase in HHM conditions (0.77, 0.62 and 0.55 for low HHM, intermediate HHM and high HHM, respectively). Instead, nitrogen nutrition index of N0 was similar in all the environments (~0.42). In N150, forage production capacity analysed in terms of radiation and water use efficiency (RUE and WUE, respectively) was similar in low HHM and intermediate HHM environments (RUE ~0.81 gDM/Mj and WUE ~13 kgDM/mm). These findings emphasize the importance of conducting analyses based on resource use and capture to understand productive responses to the increase in growth‐limiting factors. Furthermore, they contribute to the identification of environments suitable for nitrogen fertilization.

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Rainfall events stimulate episodic associative nitrogen fixation in switchgrass

Vizza,

Belanger,

Jones

et al. 2024

Biogeochemistry

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Associative N2 fixation (ANF) is widespread but poorly characterized, limiting our ability to estimate global inputs from N2 fixation. In some places, ANF rates are at or below detection most of the time but occasionally and unpredictably spiking to very high rates. Here we test the hypothesis that plant phenology and rainfall events stimulate ANF episodes. We measured ANF in intact soil cores in switchgrass (Panicum virgatum L.) in Michigan, USA. We used rain exclusion shelters to impose three rainfall treatments with each receiving 60 mm of water over a 20-day period but at different frequencies. We concurrently established a treatment that received ambient rainfall, and all four treatments were replicated four times. To assess the effects of plant phenology, we measured ANF at key phenological stages in the ambient treatment. To assess the effects of rainfall, we measured ANF immediately before and immediately after each wetting event in each treatment involving rainfall manipulation. We found that the previous day’s rainfall could explain 29% of the variation in ANF rates within the ambient treatment alone, and that bulk soil C:N ratio was also positively correlated with ANF, explaining 18% of the variation alone. Wetting events increased ANF and the magnitude of response to wetting increased with the amount of water added and decreased with the amount of inorganic N added in water. ANF episodes thus appear to be driven primarily by wetting events. Wetting events likely increase C availability, promote microbial growth, and make rhizosphere conditions conducive to ANF.

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The intensity of water stress dictates whether the N status of temperate-type perennial grass swards is affected by drought

Cited by 3 publications

References 95 publications

Tall fescue tiller survival over summer in a subtropical environment: The role of the size and depth of root systems

Tall fescue tiller survival over summer in a subtropical environment: The role of the size and depth of root systems

Halo‐hydromorphism alters nitrogen fertilization responses of tall wheatgrass pastures: Capture and use of resources, tiller dynamics and forage production

Rainfall events stimulate episodic associative nitrogen fixation in switchgrass

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