Soybean irrigation requirements and canopy-atmosphere coupling in Southern Brazil

Evandro H.F.M. da Silva, Alexandre O. Gonçalves, Rodolfo A. Pereira, Izael M. Fattori Júnior, Luiz R. Sobenko and Fábio R. Marin

Agricultural Water Management, 2019, vol. 218, issue C, 1-7

Abstract: The lack of base information on crop water requirements under tropical conditions is one of the causes for inefficient water use and inadequate irrigation management. The crop coefficient (Kc) approach is universally adopted for scheduling and quantifying the water management and, recently, its relation with the evaporative atmosphere demand has been included in this approach to improve the decision-making on irrigation management. In this paper, we measured crop evapotranspiration (ETc) in two experiments as evaporative heat flux from a centre pivot-irrigated soybean plantations in tropical Brazil to quantify the crop water needs. Irrigation requirements were determined by comparing ETc with reference evapotranspiration (ETo), derived from FAO-56 (Allen et al., 1998). In this study, the average Kc value obtained was 0.92, which is nearly 20% lower than those recommended by the FAO-56 (Allen et al., 1998) and varied inversely as a function of ETo. Based on aerodynamic and leaf diffusive resistance (rs) data, Ω was computed and presented values relatively high compared to other crops, which means a relatively poor coupling of soybean canopies to the atmosphere. Throughout both experiments, the Kc value decreased by up to 44.8% when the ETo increased from 2 to 4 mm d−1, depending on the phenological phase, indicating the need for taking into account the ETo values when selection the Kc values for improving the irrigation management in tropical soybean.

Keywords: Crop coefficient; Water use; Leaf conductance; Canopy-atmosphere coupling (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (4)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0378377418315506
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:agiwat:v:218:y:2019:i:c:p:1-7

DOI: 10.1016/j.agwat.2019.03.003

Access Statistics for this article

Agricultural Water Management is currently edited by B.E. Clothier, W. Dierickx, J. Oster and D. Wichelns

More articles in Agricultural Water Management from Elsevier
Bibliographic data for series maintained by Catherine Liu ().