Improving the drainage and irrigation efficiency of lowland soils: land-forming options for southern Brazil.

Authors: BUENO, MARCOS - Federal University Of Pelotas; DE CAMPOS, ALEXSSANDRA - Federal University Of Pelotas; DA SILVA, JAQUELINE - Federal University Of Pelotas; Massey, Joseph; TIMM, LUIS - Federal University Of Pelotas; FARIA, LESSANDRO - Federal University Of Pelotas; PARFITT, JOSE - Embrapa Clima Temperado

Submitted to: Journal of Irrigation and Drainage Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2020
Publication Date: 5/21/2020
Citation: Bueno, M.V., De Campos, A.S., Da Silva, J.T., Massey, J., Timm, L.C., Faria, L.C., Parfitt, J.M. 2020. Improving the drainage and irrigation efficiency of lowland soils: land-forming options for southern Brazil.. Journal of Irrigation and Drainage Engineering. 146. https://doi.org/10.1061/(ASCE)IR.1943-4774.0001483.
DOI: https://doi.org/10.1061/(ASCE)IR.1943-4774.0001483

Interpretive Summary: Land-leveling is used to improve surface drainage and irrigation. In this research, seven commercial rice fields (20 to 60 acres each) located in southern Brazil were studied. Three leveling approaches were evaluated: uniform slope (control), land forming–drainage (LFD) and land forming–irrigation (LFI). The approaches were evaluated according to the amounts of soil that would be moved, maximum cut in 99% of the area, and length and number of levees. Results indicate that both LFD and LFI models would reduce costs and require less soil disturbance compared to leveling to uniform slopes. LFD would require less soil movement and lower maximum cuts than LDI but LDI would reduce the lengths and numbers of rice levees relative to LFD which could have long-term benefits not captured in these analyses. These results demonstrate that all possible alternatives should be thoroughly examined before undertaking land-leveling or land-forming operations. These results will be useful to engineers and producers in evaluating options to improve the agricultural productivity of Brazil's lowland soils.

Technical Abstract: Land-leveling is used to correct soil surface irregularities to improve surface drainage and irrigation and make the area more manageable for an array of agricultural activities. The objective of this work was to evaluate two models of land-forming, one aimed at drainage and the other at surface irrigation using fields with reliefs typical of the lowlands of southern Brazil. Seven commercial rice fields ranging in size from 7 to 26 ha were randomly selected and digital elevation models created for each. Land-leveling projects were developed using three models: uniform slope (control), land forming–drainage (LFD) and land forming–irrigation (LFI). Performance comparisons between the different models were evaluated through impacts on soil movement, maximum cut in 99% of the area, and length and number of levees. Results indicate that both LFD and LFI models would reduce costs and require less soil disturbance compared to leveling to uniform slopes. LFD would require less soil movement and lower maximum cuts than LDI but LDI would reduce the lengths and numbers of rice levees relative to LFD which could have long-term benefits not captured in these analyses. These results demonstrate that all possible alternatives should be thoroughly examined before undertaking land-leveling or land-forming operations. Study outcomes will be useful to engineers and producers in evaluating options to improve the agricultural productivity of lowlands in southern Brazil.