03237naa a2200277 a 450000100080000000500110000800800410001902200140006002400350007410000150010924501770012426000090030150006640031052016830097465300360265765300110269365300090270465300290271365300200274270000200276270000180278270000150280070000160281570000170283177301110284810642492023-07-12       2023    bl uuuu     u00u1 u    #d  a0021-85967 a10.1017/S00218596230003332DOI1 aORTEGA, G.  aMonitoring herbage mass and pasture growth rate of large grazing areasba comparison of the correspondence, cost and reliability of indirect methods.h[electronic resource]  c2023  aArticle history: Received 20 December 2022; Revised 15 May 2023; Accepted 24 May 2023; Published online by Cambridge University Press 14 June 2023. -- Correspondence author: G. Ortega; Email: gortegaconforte@gmail.com -- License:  This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/) . -- FUNDING: This project was funded by the Agencia Nacional de Investigación e Innovación (ANII) and Red Tecnológica Sectorial de Lechería (RTS) (project number ANII-RTS_X_2014_1_3) who also funded post-graduate scholarship awarded to G. Ortega (POS_NAC_2018_1_151491). --  aTimely grazing decision-making requires routine information on the herbage mass (HM) and pasture growth rate (GR). The aim of this study was to compare the correspondence, cost, and reliability of two indirect methods -the comparative yield method (COMPYLD) and the pasture-meter (CDAX)- to estimate HM and weekly GR of a 42 ha grazing area. Weekly assessments from Apr 2017 to Oct 2018 were made with both methods to estimate HM and GR of 13 individual paddocks. In addition, estimated GR were compared to aerial net primary productivity (ANPP) estimated using remote sensing (SAT). Estimated HM was 22% lower for COMPYLD than CDAX (HMCOMPYLD=33+0.78*HMCDAX, R2=0.61, CV=17%, RMSE=291 kgDM/ha). The correspondence between methods of estimated weekly GR of individual paddocks was weak (GRCDAX=0.18*GRCOMPYLD+19.1, R2=0.05, CV=73%, RMSE=21.8 kgDM/ha/d). However, when integrated in three-week moving-averages, over the complete grazing area, COMPYLD and CDAX yielded similar GR up to 35 kg DM/ha/d. Accumulating GR of the grazing area over one year resulted similar to annual SAT-estimated ANPP. These results imply that, on one hand, decisions based on nominal HM, such as target HM and grazing strip size, would need to be adjusted depending on the method, but on the other hand, decisions based in temporal trends or GR, such as size and timing of setaside areas for reserves, would be unaffected by method. Compared with COMPYLD, CDAX would be advantageous whenever high labour costs offset higher amortization, maintenance and fuel costs, provided there is an alternative in place to monitor during downtime periods. © 2023 Cambridge University Press. All rights reserved.  aAerial net primary productivity  aCattle  aCDAX  aComparative yield method  aMilk production1 aCHILIBROSTE, P.1 aGARRIDO, J.M.1 aWALLER, A.1 aFARIÑA, S.1 aLATTANZI, F.  tThe Journal of Agricultural Science, 2023, 1-10. https://doi.org/10.1017/S0021859623000333  -- OPEN ACCES.