Calibration and validation of optical chlorophyll‐measuring devices for use in predicting crude protein concentration in tropical grass herbage

Hughes, Martin; Lallo, Cicero H. O.; Mlambo, Victor; Jennings, P. G.

doi:10.1111/gfs.12219

Cited by 4 publications

(6 citation statements)

References 16 publications

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“…The NVDI and MTCI indices are estimations of the physiological status of plants when they are measured. Although neither index gives direct DM or chlorophyll content values of DMA, they provide values associated with these variables (Dash and Curran, 2004; Barati et al, 2011; Clevers and Kooistra, 2012; Hughes et al, 2017). The NVDI is derived from physical plant properties, such as the leaf area index (leaf area/ground area), the developmental stage, and accumulated biomass (Carlson and Ripley, 1997).…”

Section: Discussionmentioning

confidence: 99%

Phenotypic Variation of Cold Stress Resistance‐Related Traits of White Clover Populations Naturalized in Patagonian Cold Environments

2018

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White clover (Trifolium repens L.) is the main forage legume species in grazing pastures in central, central‐southern, and southern regions of Chile and many other temperate regions of the world. The selection of cold stress resistance genotypes is an important step for breeding cultivars to improve the clover growth curve and extend the grazing season in early spring and autumn. The objective of this work was to phenotypically characterize a population of 192 white clover genotypes selected for cold stress resistance under three contrasting regional winter‐cold conditions (mean daily minimum air temperatures of 2.5, 1.6, and −1.4°C) during the coldest month. An α‐lattice experimental field design was used, with 24 incomplete blocks and two replicates. Morphological, physiological and biochemical traits were evaluated at different dates over three growing seasons from 2013 to 2016. A high degree of variability was found among the genotypes for all the characteristics studied. There was no effect of environment when the experimental sites were considered as a source of variation, but comparison of measurements taken at dates separated by a winter showed that there was a decrease in stolon length and diameter, petiole length, leaflet size, and dry matter accumulation in response to cold conditions. The normalized difference and medium resolution imaging spectrometer terrestrial chlorophyll vegetation indices (NDVI and MTCI, respectively) and water‐soluble carbohydrate concentrations in stolons also varied among genotypes and were affected by winter cold. The high degree of phenotypic variability allows for the use of this population as a genetic source for cold stress resistance in white clover.

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Section: Discussionmentioning

confidence: 99%

Phenotypic Variation of Cold Stress Resistance‐Related Traits of White Clover Populations Naturalized in Patagonian Cold Environments

2018

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“…Cultivation and management of both grass species were previously described 16,17 . Brachiaria hybrid cv.…”

Section: Methodsmentioning

confidence: 99%

“…Cultivation and management of both grass species were previously described. 16,17 and sown in seedling trays filled with a commercial medium in a greenhouse. After germination, the seedlings were manually watered with a watering can at approximately 8:00 a.m. and 3:00 p.m. daily.…”

Section: Forage Management and Samplingmentioning

confidence: 99%

Optimum nitrogen fertilization rate and nitrogen use efficiency forBrachiariahybrid andMegathyrsus maximusvaries with stage of regrowth

2022

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Background Traditionally, recommended nitrogen (N) fertilization rates that maximize biomass yield and nutritive value in tropical grass forages tend to be fixed and do not consider possible stage of maturity‐induced variations. Therefore, this study investigated biomass yield and nutritive value of Brachiaria hybrid and Megathyrus maximus at different stages of maturity in response to incremental levels of N fertilizer. Both grasses were fertilized with urea at rates equivalent to 0, 25, 50, and 75 kg N ha−1 and harvested after 4‐, 8‐, and 12‐week regrowth. Results Crude protein (CP) had a linear response to increasing N fertilization at all stages of regrowth. Herbage yield of M. maximus was optimized with 57.1–63.0 kg N ha−1, while herbage yield in 4‐weeks regrowth Brachiaria hybrid was optimized with 59.1 kg N ha−1. The combination of herbage yield, 24 h in‐vitro organic matter digestibility, and CP were optimized with 59.1 and 68.2 kg N ha−1 in 4‐weeks regrowth Brachiaria hybrid and 8‐week regrowth M. maximus, respectively. The efficiency of N fertilizer use for herbage and CP yield was highest with 25 and 75 kg N ha−1, respectively except for 8‐weeks regrowth Brachiaria hybrid. Conclusion It was concluded that the herbage yield and nutritive value of 4‐week regrowth Brachiaria hybrid and 8‐week regrowth M. maximus are optimized with 59.1 and 68.2 kg N ha−1, respectively, while all other stages of regrowth were optimized with 75 kg N ha−1.

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“…Conduct of this investigation received the approval of the UWI Research Ethics Committee (Ref: CREC-SA.0993/05/2021). The experimental procedures were previously described (Hughes et al, 2016(Hughes et al, , 2017. P. atratum (Cv.…”

Section: Cultivation and Managementmentioning

confidence: 99%

“…The study lasted in the open field between April to August. Rainfall during this period was previously described by Hughes et al (2016).…”

Section: Cultivation and Managementmentioning

confidence: 99%

Interactive effects of growth stage and nitrogen fertilization on herbage characteristics and nutritive value of Paspalum atratum

2021

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Paspalum atratum is a tropical grass with potential to contribute to forage availability in areas dominated by waterlogged acidic soils. However, little is known of the interactive effect of N fertilization and stage of harvest on its nutritive value.Therefore, the objectives of this study were to evaluate the interactive effects of N fertilization and harvesting stage on herbage characteristics and nutritive value of P. atratum (Cv. Ubon) and to determine the optimum N fertilization rate at each stage of regrowth. P. atratum seedlings were planted in 18,631-cm 3 plastic pots containing growth media amended with 0, 25, 50, and 75 kg N/ha. Forage was harvested after 6-and 12-weeks regrowth. Nitrogen fertilizer had a significant effect (p < 0.05) on herbage yield, sward height, crude protein yield, crude protein concentration, and 12-and 24-h in vitro ruminal organic matter digestibility (IVOMD). P. atratum fertilized with 50 kg N/ha produced the highest dry matter yield (1,133 kg DM/ha) at 12-week regrowth. Crude protein (CP) was highest (133 g/kg DM) in 6-week regrowth forage that received 50 kg N/ha. IVOMD at 12 and 24 h of incubation was highest in 6-week regrowth forage amended with 0 and 50 kg N/ha, respectively. Herbage characteristics and nutritive value of P. atratum showed a quadratic response to N fertilization at both regrowth stages. Response surface optimization indicated that N fertilizer application rates of 56.0 and 52.3 kg N/ha maximized P. atratum herbage yield, CP content, and 12-h IVOMD at 6-and 12-week regrowth, respectively. It was, therefore, concluded that the herbage yield and nutritive value of 6-and 12-week regrowth P. atratum is optimized with N fertilizer rates of 56.0 and 52.3 kg N/ha, respectively.

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Calibration and validation of optical chlorophyll‐measuring devices for use in predicting crude protein concentration in tropical grass herbage

Cited by 4 publications

References 16 publications

Phenotypic Variation of Cold Stress Resistance‐Related Traits of White Clover Populations Naturalized in Patagonian Cold Environments

Phenotypic Variation of Cold Stress Resistance‐Related Traits of White Clover Populations Naturalized in Patagonian Cold Environments

Optimum nitrogen fertilization rate and nitrogen use efficiency forBrachiariahybrid andMegathyrsus maximusvaries with stage of regrowth

Interactive effects of growth stage and nitrogen fertilization on herbage characteristics and nutritive value of Paspalum atratum

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