Reduction of evaporation from bare soil using plastic and gravel mulches and assessment of gravel mulch for partitioning evapotranspiration under irrigated canola
P. Dlamini A B , I. B. Ukoh A , L. D. van Rensburg A and C. C. du Preez A
+ Author Affiliations
- Author Affiliations
A Department of Soil, Crop and Climate Sciences, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa.
B Corresponding author. Email: dlaminiphesheya646@gmail.com
Soil Research 55(3) 222-233 https://doi.org/10.1071/SR16098
Submitted: 12 April 2016 Accepted: 6 September 2016 Published: 17 October 2016
Abstract
Partitioning of evapotranspiration (ET) into its components of evaporation (E) and transpiration (T) is difficult, yet important for managing unproductive and productive water losses under irrigated agriculture. A lysimeter experiment (Expt 1) was conducted on sandy Clovelly and sandy loam Bainsvlei soils in Bloemfontein, South Africa where plastic sheet and dolerite gravel mulches were applied to lysimeters to determine to what extent they restricted E from the soil surface compared with a bare soil control. No crops were grown in the lysimeters for Expt 1. Gravel mulch on Clovelly-filled lysimeters reduced E by 33% and by 41% for Bainsvlei-filled lysimeters compared with bare soil. Based on these results, lysimeter Expt 2 was undertaken on gravel mulched and unmulched bare soil lysimeters to assess the effectiveness of gravel mulch in partitioning ET into E and T using the Tanner and Sinclair (1983) method embedded in the soil water balance. In Expt 2, canola (Brassica napus L.) was grown in the lysimeters for 168 days. Gravel mulch had a significant effect on water use (WU) by suppressing the E component of ET, resulting in WU being on average 11% lower from gravel-mulched lysimeters than the unmulched lysimeters, and this translated to an improved average WU efficiency of 11.91 kg ha–1 mm–1 for canola. Taken together, these results reinforce the potential for gravel mulch as a viable management option for soil water conservation, which is crucial for plant available water, a major limiting factor for plant growth in arid and semiarid lands.
Additional keywords: arid and semiarid, evapotranspiration, gravel mulch, lysimeter, partitioning, water use.
References
Allen RG, Pereira LS, Raes D, Smith M (1998) ‘Crop evapotranspiration – guidelines for computing crop water requirements.’ (FAO: Rome)Assouline S (2002) The effects of micro-drip and conventional drip irrigation on water distribution and uptake. Soil Science Society of America Journal 66, 1630–1636.
| The effects of micro-drip and conventional drip irrigation on water distribution and uptake.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xnt1GrurY%3D&md5=c531f356703cdb3b9c212ea68d954171CAS |
Backeberg GR (2003) Water usage and irrigation policy. In ‘The challenge of change: agriculture, land and the South African economy’. (Eds L Nieuwoudt, J Groenewald) pp. 11–44. (University of Natal Press: Pietermaritzburg, South Africa)
Baldocchi DD, Meyers PT (1991) Trace gas exchange above the floor of a deciduous forest 1. Evaporation and CO2 efflux. Journal of Geophysical Research 96, 7271–7285.
Bennie ATP, Coetzee MJ, Van Antwerpen R, van Rensburg LD, Burger RDT (1988) A water balance model for irrigation based on profile water supplying rate and crop water requirement. WRC Report No. 144/88/1. Water Research Commission, Pretoria, South Africa [in Afrikaans].
Bennie ATP, Hofmann JE, Coetzee MJ, Vrey HS (1994) Storage and use of rainwater in soil for stabilising plant production in semi-arid areas. WRC Report No. 227/1/94. Water Research Commission, Pretoria, South Africa [in Afrikaans].
Beven K (2006) Searching for the Holy Grail of scientific hydrology: Qt = H(S, R, Δt)A as closure. Hydrology and Earth System Sciences 10, 609–618.
| Searching for the Holy Grail of scientific hydrology: Qt = H(S, R, Δt)A as closure.Crossref | GoogleScholarGoogle Scholar |
Bhattarai SP, Pendergast L, Midmore DJ (2006) Root aeration improves yield and water use efficiency of tomato in heavy and saline soils. Scientia Horticulturae 108, 278–288.
| Root aeration improves yield and water use efficiency of tomato in heavy and saline soils.Crossref | GoogleScholarGoogle Scholar |
Boast CW, Robertson TM (1982) A micro-lysimeter method for determining evaporation from bare soil: description and laboratory evaluation. Soil Science Society of America Journal 46, 689–696.
| A micro-lysimeter method for determining evaporation from bare soil: description and laboratory evaluation.Crossref | GoogleScholarGoogle Scholar |
Bowen IS (1926) The ratio of heat losses by conduction and by evaporation from any water surface. Physical Review 27, 779–787.
| The ratio of heat losses by conduction and by evaporation from any water surface.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaB28XisFSitQ%3D%3D&md5=e02502d2b72f2615d1d2a43784fc561dCAS |
Campbell GS, Calissendorff C, Williams JH (1991) Probe for measuring soil specific heat using a heat-pulse method. Soil Science Society of America Journal 55, 291–293.
| Probe for measuring soil specific heat using a heat-pulse method.Crossref | GoogleScholarGoogle Scholar |
Canola Council of Canada (2005) Effects of moisture on canola growth. Available at http://www.canolacouncil.org/crop-production/canola-grower’s-manual-contents/chapter-4-effects-of-moisture/ [accessed 26 September 2016].
Carr G, Nortcliff S, Potter RB (2008) Urban wastewater use for irrigated agriculture in Jordan: soil sustainability, perceptions and management. In ‘8th World Wide Workshop for Young Environmental Scientists WWW-YES. Urban waters: resource or risk?’ 13–16 May 2008, Créteil, France. (Ed. D Thevenot) pp. 1–9.
Čermák J, Kučera J, Nadezhdina N (2004) Sap flow measurements with some thermodynamic methods, flow integration within trees and scaling up from sample trees to entire forest stands. Trees 18, 529–546.
| Sap flow measurements with some thermodynamic methods, flow integration within trees and scaling up from sample trees to entire forest stands.Crossref | GoogleScholarGoogle Scholar |
Corey AT, Kemper WD (1968) ‘Conservation of soil water by gravel mulches. Vol. 30.’ (Colorado State University: Fort Collins, CO)
Day PR (1965) Particle fractionation and particle-size analysis. In ‘Methods of soil analysis. Part 1’. Agronomy Monograph No. 9. (Ed. CA Black) pp. 545–567. (American Society of Agronomy: Madison, WI)
De Wit CT (1958) Transpiration and crop yields. Versl. Landbouwk. Onderz. No. 64.6. Institute of Biological and Chemical Research on Field Crops and Herbarge, Wageningen, Netherlands.
Denef K, Stewart CE, Brenner J, Paustian K (2008) Does long-term center pivot irrigation increase soil carbon stocks in agro-ecosystems. Geoderma 145, 121–129.
| Does long-term center pivot irrigation increase soil carbon stocks in agro-ecosystems.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXmtlCmur8%3D&md5=e37afebfefabc7cc9e832a1cca27df8aCAS |
Ehlers L, Bennie ATP, du Preez CC (2003) The contribution of root accessible water tables towards the irrigation requirements of crops. WRC Report No. 1089/1/03. Water Research Commission, Pretoria, South Africa.
Evett SR, Warrick AW, Matthias AD (1995) Wall material and capping effects on microlysimeter temperatures and evaporation. Soil Science Society of America Journal 59, 329–336.
| Wall material and capping effects on microlysimeter temperatures and evaporation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2MXlt12qurs%3D&md5=6eff5690ff15f129d465958357a2c37dCAS |
Fairbourn ML (1973) Effect of gravel mulch on crop yields. Agronomy Journal 65, 925–928.
| Effect of gravel mulch on crop yields.Crossref | GoogleScholarGoogle Scholar |
Fares A, Polyakov V (2006) Advances in crop water management using capacitive water sensors. Advances in Agronomy 90, 43–77.
| Advances in crop water management using capacitive water sensors.Crossref | GoogleScholarGoogle Scholar |
Fisher RA (1935) ‘The design of experiments.’ (Oliver and Boyd: London)
Fritschen LJ, Fritschen CL (2005) Bowen ratio energy balance method. In ‘Micrometeorology in agricultural systems’. Agronomy Monograph No. 47. (Eds JL Hatfield, JM Baker) pp. 397–405. (American Society of Agronomy: Madison, WI)
Gebler S, Hendricks Franssen H-J, Pütz T, Post H, Schmidt M, Vereecken H (2014) Actual evapotranspiration and precipitation measured by lysimeters: a comparison with eddy covariance and tipping bucket. Hydrology and Earth System Sciences Discussions 11, 13797–13841.
| Actual evapotranspiration and precipitation measured by lysimeters: a comparison with eddy covariance and tipping bucket.Crossref | GoogleScholarGoogle Scholar |
Gebregiorgis MF, Savage MJ (2006) Determination of the timing and amount of irrigation of winter cover crops with the use of dielectric constant and capacitance soil water content profile methods. South African Journal of Plant and Soil 23, 145–151.
| Determination of the timing and amount of irrigation of winter cover crops with the use of dielectric constant and capacitance soil water content profile methods.Crossref | GoogleScholarGoogle Scholar |
Grey D (1998) Water-use efficiency of canola in Victoria. In ‘Proceedings of the 9th Australian Agronomy Conference’, Wagga Wagga, Australia. Available at http://www.regional.org.au/au/asa/1998/5/181grey.htm#TopOfPage [verified 27 September 2016].
Hanks RJ (1983) Yield and water use relationships: an overview. In ‘Limitations to efficient water use in crop production’. (Eds HM Taylor, WR Jordan, TR Sinclair) pp. 393–412. (American Society of Agronomy: Madison, WI)
Hanks RJ (1992) Soil evaporation and transpiration. In ‘Managing plant and soil systems’. (Eds RJ Hanks, JT Ritchie) pp. 245–271. (American Society of Agronomy: Madison, WI)
Hannes M, Wollschläger U, Schrader F, Durner W, Gebler S, Pütz T, Fank J, von Unold G, Vogel H-J (2015) High-resolution estimation of the water balance components from high-precision lysimeters. Hydrology and Earth System Sciences Discussions 12, 569–608.
| High-resolution estimation of the water balance components from high-precision lysimeters.Crossref | GoogleScholarGoogle Scholar |
Hatfield JL, Sauer TJ, Prueger JH (2001) Managing soils to achieve greater water use efficiency: a review. Agronomy Journal 93, 271–280.
| Managing soils to achieve greater water use efficiency: a review.Crossref | GoogleScholarGoogle Scholar |
Heitman JL, Horton R, Sauer TJ, De Sutter TM (2008a) Sensible heat observations reveal soil–water evaporation dynamics. Journal of Hydrometeorology 9, 165–171.
| Sensible heat observations reveal soil–water evaporation dynamics.Crossref | GoogleScholarGoogle Scholar |
Heitman JL, Xiao X, Horton R, Sauer TJ (2008b) Sensible heat measurements indicating depth and magnitude of subsurface soil water evaporation. Water Resources Research 44, W00D05
| Sensible heat measurements indicating depth and magnitude of subsurface soil water evaporation.Crossref | GoogleScholarGoogle Scholar |
Hillel D (2004) ‘Introduction to environmental soil physics’. (Elsevier Academic Press: New York, NY)
Howell TA, Schneider AD, Dusek DA, Marek TH, Steiner JL (1995) Calibration and scale performance of Bushland weighing lysimeters. Transactions of the ASAE. American Society of Agricultural Engineers 38, 1019–1024.
| Calibration and scale performance of Bushland weighing lysimeters.Crossref | GoogleScholarGoogle Scholar |
Iritz Z, Lindroth A, Gärdenäs A (1997) Open ventilated chamber system for measurements of H2O and CO2 fluxes from the soil surface. Soil Technology 10, 169–184.
| Open ventilated chamber system for measurements of H2O and CO2 fluxes from the soil surface.Crossref | GoogleScholarGoogle Scholar |
Jara J, Stockle CO, Kjelgaard J (1998) Measurement of evapotranspiration and its components in a corn (Zea mays L.) field. Agricultural and Forest Meteorology 92, 131–145.
| Measurement of evapotranspiration and its components in a corn (Zea mays L.) field.Crossref | GoogleScholarGoogle Scholar |
Johnston AM, Entz MH, Brant SA, Lefond GP, Campbell CA (1996) Management of water use by crops in crop rotation on the Canadian prairies. In ‘Workshop on Soils and Crops’, Saskatoon, Canada. pp. 384–393.
Kaseke KF, Mills AJ, Henschel J, Seely MK, Esler K, Brown R (2012) The effects of desert pavements (gravel mulch) on soil micro-hydrology. Pure and Applied Geophysics 169, 873–880.
| The effects of desert pavements (gravel mulch) on soil micro-hydrology.Crossref | GoogleScholarGoogle Scholar |
Kool D, Agam N, Lazarovitch N, Heitman JL, Sauer TJ, Ben-Gal A (2014) A review of approaches for evapotranspiration partitioning. Agricultural and Forest Meteorology 184, 56–70.
| A review of approaches for evapotranspiration partitioning.Crossref | GoogleScholarGoogle Scholar |
Kosgei JR, Jewitt GPW, Kongo VM, Lorentz SA (2007) The influence of tillage on field scale water fluxes and maize yields in semi-arid environments: a case study of Potshini Catchment, South Africa. Physics and Chemistry of the Earth 32, 1117–1126.
| The influence of tillage on field scale water fluxes and maize yields in semi-arid environments: a case study of Potshini Catchment, South Africa.Crossref | GoogleScholarGoogle Scholar |
Lal R, Shukla M (2004) ‘Principles of soil physics.’ (CRC Press: New York, NY)
Lascano RJ, Hatfield JL (1992) Spatial variability of evaporation along two transects of a bare soil. Soil Science Society of American Journal 56, 341–346.
| Spatial variability of evaporation along two transects of a bare soil.Crossref | GoogleScholarGoogle Scholar |
Lascano RJ, Van Bavel CHM, Hatfield JL, Upchurch DR (1987) Energy and water balance of a sparse crop: simulated and measured soil and crop evaporation. Soil Science Society of America Journal 51, 1113–1121.
| Energy and water balance of a sparse crop: simulated and measured soil and crop evaporation.Crossref | GoogleScholarGoogle Scholar |
Lawrence DM, Thornton PE, Oleson KW, Bonan GB (2007) The partitioning of evapotranspiration into transpiration, soil evaporation, and canopy evaporation in a GCM: impacts on land–atmosphere interaction. Journal of Hydrometeorology 8, 862–880.
| The partitioning of evapotranspiration into transpiration, soil evaporation, and canopy evaporation in a GCM: impacts on land–atmosphere interaction.Crossref | GoogleScholarGoogle Scholar |
Le Roux PAL, du Preez CC, Strydom MG, van Rensburg LD, Bennie ATP (2007) Effect of irrigation on soil salinity profiles along the lower Vaal River, South Africa. Water SA 33, 473–478.
Li XY (2003) Gravel-sand mulch for soil and water conservation in the semiarid loess region of northwest China. Catena 52, 105–127.
| Gravel-sand mulch for soil and water conservation in the semiarid loess region of northwest China.Crossref | GoogleScholarGoogle Scholar |
Li XY, Gong JD, Wei XH (2000) In situ rainwater harvesting and gravel mulch combination for corn production in the dry semi-arid region of China. Journal of Arid Environments 46, 371–382.
| In situ rainwater harvesting and gravel mulch combination for corn production in the dry semi-arid region of China.Crossref | GoogleScholarGoogle Scholar |
Li QS, Qu JJ, Li XZ (2014) The sand deposition of artificial gravel beds on the protection of the Magao Grottoes. Scientific Reports 4, 1–8.
Liu LY, Liu YZ, Li XY, Wang JH, Peng HM (1999) Effect of gravel mulch restraining soil deflation by wind tunnel simulation. Journal of Desert Research 19, 60–62. [In Chinese with an English abstract]
Liu C, Zhang X, Zhang Y (2002) Determination of daily evaporation of winter wheat and maize by large-scale weighing lysimeter and micro-lysimeter. Agricultural and Forest Meteorology 111, 109–120.
| Determination of daily evaporation of winter wheat and maize by large-scale weighing lysimeter and micro-lysimeter.Crossref | GoogleScholarGoogle Scholar |
McDonnell J, McGuire K, Aggarwal P, Beven K, Biondi D, Destouni G, Dunn S, James A, Kirchner J, Kraft P, Lyon S, Maloszewski P, Newman B, Pfister L, Rinaldo A, Rodhe A, Sayama T, Seibert J, Solomon K, Soulsby C, Stewart M, Tetzlaff D, Tobin C, Troch P, Weiler M, Western A, Wörman A, Wrede S (2010) How old is the water? Open questions in catchment transit time conceptualization, modelling and analysis. Hydrological Processes 24, 1745–1754.
| How old is the water? Open questions in catchment transit time conceptualization, modelling and analysis.Crossref | GoogleScholarGoogle Scholar |
Mellouli HJ, van Wesemael B, Poesen J, Hartmann R (2000) Evaporation losses from bare soils as influenced by cultivation techniques in semi-arid regions. Agricultural Water Management 42, 355–369.
| Evaporation losses from bare soils as influenced by cultivation techniques in semi-arid regions.Crossref | GoogleScholarGoogle Scholar |
Musgrave RB, Moss DN (1961) Photosynthesis under field conditions. I. A portable, closed system for determining net assimilation and respiration of corn. Crop Science 1, 37–41.
| Photosynthesis under field conditions. I. A portable, closed system for determining net assimilation and respiration of corn.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaF38XptlWi&md5=e9aa8a77d3b9f0955dc6d17bd7e09c08CAS |
Nachtergaele J, Poesen JW, van Wesemael B (1998) Gravel mulching in vineyards of southern Switzerland. Soil & Tillage Research 46, 51–59.
| Gravel mulching in vineyards of southern Switzerland.Crossref | GoogleScholarGoogle Scholar |
Newman BD, Wilcox BP, Archer SR, Breshears DD, Dahm CN, Duffy CJ, McDowell NG, Phillips FM, Scanlon BR, Vivoni ER (2006) Ecohydrology of water-limited environments. A scientific vision. Water Resources Research 42, W06302
| Ecohydrology of water-limited environments. A scientific vision.Crossref | GoogleScholarGoogle Scholar |
Ogindo HO, Walker S (2004) The determination of transpiration efficiency coefficient for common bean. Physics and Chemistry of the Earth 29, 1083–1089.
| The determination of transpiration efficiency coefficient for common bean.Crossref | GoogleScholarGoogle Scholar |
Peel MC, Finlayson BL, MacMahon TA (2007) Updated world map of the Köppen-Geiger climate classification. Hydrology and Earth System Sciences 11, 1633–1644.
| Updated world map of the Köppen-Geiger climate classification.Crossref | GoogleScholarGoogle Scholar |
Pérez-Priego O, Testi L, Orgaz F, Villalobos FJ (2010) A large closed canopy chamber for measuring CO2 and water vapour exchange of whole trees. Environmental and Experimental Botany 68, 131–138.
| A large closed canopy chamber for measuring CO2 and water vapour exchange of whole trees.Crossref | GoogleScholarGoogle Scholar |
Philip JR (1957) Evaporation and moisture and heat fields in the soil. Journal of Meteorology 14, 354–366.
| Evaporation and moisture and heat fields in the soil.Crossref | GoogleScholarGoogle Scholar |
Poesen J, Lavee H (1994) Rock fragments in top soils: significance and processes. Catena 23, 1–28.
| Rock fragments in top soils: significance and processes.Crossref | GoogleScholarGoogle Scholar |
Qiu Y, Xie Z, Wang Y, Ren J, Malhi SS (2014) Influence of gravel mulch stratum thickness and gravel grain size on evaporation resistance. Journal of Hydrology 519, 1908–1913.
| Influence of gravel mulch stratum thickness and gravel grain size on evaporation resistance.Crossref | GoogleScholarGoogle Scholar |
Rockström J, Barron J, Fox P (2003) Water productivity in rainfed agriculture: challenges and opportunities for smallholder farmers in drought-prone tropical agro-systems. In ‘IWMI Workshop on Water Productivity in Agriculture’, 12–14 November 2003, Delft, Netherlands. p.145. (International Water Management Institute: Colombo, Sri Lanka)
SAS Institute Inc. (1999) ‘SAS/STAT User’s Guide, Version 8.’ (Cary: NC, USA)
Scanlon TM, Kustas WP (2010) Partitioning carbon dioxide and water vapor fluxes using correlation analysis. Agricultural and Forest Meteorology 150, 89–99.
| Partitioning carbon dioxide and water vapor fluxes using correlation analysis.Crossref | GoogleScholarGoogle Scholar |
Scanlon TM, Sahu P (2008) On the correlation structure of water vapor and carbon dioxide in the atmospheric surface layer: a basis for flux partitioning. Water Resources Research 44, W10418.
| On the correlation structure of water vapor and carbon dioxide in the atmospheric surface layer: a basis for flux partitioning.Crossref | GoogleScholarGoogle Scholar |
Seetseng KA (2009) Effect of water application and plant density on canola (Brassica napus L.) in the Free State. MSc thesis, University of the Free State, Bloemfontein, South Africa.
Šimůnek J, Šejna M, Saito H, Sakai M, Van Genuchten MT (2008) ‘The HYDRUS-1D software package for simulating the movement of water, heat, and multiple solutes in variably saturated media, Version 4.08.’ HYDRUS Software Series 3. (Department of Environmental Sciences, University of California Riverside: Riverside, CA)
Soil Classification Working Group (1991) ‘Soil classification: a taxonomic system for South Africa.’ Memoirs on the Agricultural Natural Resources of South Africa No 15. (Department of Agricultural Development: Pretoria, South Africa)
Soil Survey Staff (2003) ‘Keys to soil taxonomy.’ (United States Department of Agriculture, Natural Resource Conservation Service: Washington, DC)
Stannard DI, Weltz MA (2006) Partitioning evapotranspiration in sparsely vegetated rangeland using a portable chamber. Water Resources Research 42, W02413.
| Partitioning evapotranspiration in sparsely vegetated rangeland using a portable chamber.Crossref | GoogleScholarGoogle Scholar |
Sutanto P, Wenninger J, Coenders-Gerrits AMJ, Uhlenbrook S (2012) Partitioning of evaporation into transpiration, soil evaporation and interception: a comparison between isotope measurements and a HYDRUS-1D model. Hydrology and Earth System Sciences 16, 2605–2616.
| Partitioning of evaporation into transpiration, soil evaporation and interception: a comparison between isotope measurements and a HYDRUS-1D model.Crossref | GoogleScholarGoogle Scholar |
Tanner CB, Sinclair TR (1983) Efficient water use in crop production: research or re-research. In ‘Limitations to efficient water use in crop production’. (Eds HM Taylor, WR Jordan, TR Sinclair) pp. 1–20 (American Society of Agronomy: Madison, WI)
Taylor AJ, Smith CJ, Wilson IB (1991) Effect of irrigation and nitrogen fertilizer on yield, oil content and water use of canola (Brassica napus L.). Fertilizer Research 29, 249–260.
| Effect of irrigation and nitrogen fertilizer on yield, oil content and water use of canola (Brassica napus L.).Crossref | GoogleScholarGoogle Scholar |
Tesfamariam EH, Annandale JG, Steyn JM (2010) Water stress effects on winter canola growth and yield. Agronomy Journal 102, 658–666.
| Water stress effects on winter canola growth and yield.Crossref | GoogleScholarGoogle Scholar |
Tesfuhuney W, van Rensburg LD, Walker S, Allemann J (2015) Quantifying and predicting soil water evaporation as influenced by runoff strip lengths and mulch cover. Agricultural Water Management 152, 7–16.
| Quantifying and predicting soil water evaporation as influenced by runoff strip lengths and mulch cover.Crossref | GoogleScholarGoogle Scholar |
Todd RW, Evett SR, Howell TA, Klocke NL (2000) Soil temperature and water evaporation of small steel and plastic lysimeters replaced daily. Soil Science 165, 890–895.
| Soil temperature and water evaporation of small steel and plastic lysimeters replaced daily.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXosFOitLw%3D&md5=519aaa0a78485d8325b14642efc60840CAS |
Ukou Haka IB (2010) Quantifying evaporation and transpiration in field lysimeters using the soil water Balance. PhD thesis, University of the Free State, Bloemfontein, South Africa.
Unger PW, Payne WA, Peterson GA (2006) Water conservation and efficient use. In ‘Dryland agriculture’. (Eds GA Peterson, PW Unger, WA Payne) p. 39. (American Society of Agronomy: Madison, WI)
Unger PW, Baumhardt RL, Arriaga FJ (2012) Mulch tillage for conserving water. In ‘Soil water and agronomic productivity (advances in soil science)’. (Eds R Lal, BA. Stewart) pp. 427–454. (CRC Press, Taylor and Francis Group: New York, NY)
van der Meulen ES, Nol L, Cammeraat LH (2006) Effects of irrigation and plastic mulch on soil properties on semiarid abandoned fields. Soil Science Society of America Journal 70, 930–939.
| Effects of irrigation and plastic mulch on soil properties on semiarid abandoned fields.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XksVyksrk%3D&md5=147281f765198e8ea9c94ee30b5c52efCAS |
van Rensburg LD (1996) Interaction between nitrogen and water uptake by wheat and maize. PhD thesis, University of the Free State, Bloemfontein, South Africa [in Afrikaans].
van Rensburg LD (2010) Advances in soil physics: application in irrigation and dryland crop production. South African Journal of Plant and Soil 27, 9–18.
| Advances in soil physics: application in irrigation and dryland crop production.Crossref | GoogleScholarGoogle Scholar |
van Wesemael B, Poesen J, De Figueiredo T (1995) Effects of rock fragments on physical degradation of cultivated soils by rainfall. Soil & Tillage Research 33, 229–250.
| Effects of rock fragments on physical degradation of cultivated soils by rainfall.Crossref | GoogleScholarGoogle Scholar |
van Wesemael B, Poesen J, Kosmas CS, Danalatos NG, Nachtergaele J (1996) Evaporation from cultivated soils containing rock fragments. Journal of Hydrology 182, 65–82.
| Evaporation from cultivated soils containing rock fragments.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28XkslGqsbc%3D&md5=65f9cfc8594fb18fb17d171804c4c666CAS |
Walker GK (1983) Measurement of evaporation from soil beneath crop canopies. Canadian Journal of Soil Science 63, 137–141.
| Measurement of evaporation from soil beneath crop canopies.Crossref | GoogleScholarGoogle Scholar |
Wang L, Caylor KK, Villegas JC, Barron-Gafford GA, Breshears DD, Huxman TE (2010) Partitioning evapotranspiration across gradients of woody plant cover: assessment of a stable isotope technique. Geophysical Research Letters 37, L09401.
| Partitioning evapotranspiration across gradients of woody plant cover: assessment of a stable isotope technique.Crossref | GoogleScholarGoogle Scholar |
Wang Y, Xie Z, Malhi SS, Vera C, Zhang Y (2014) Gravel-sand mulch thickness effects on soil temperature, evaporation water use efficiency and yield of watermelon in semi-arid Loess Plateau, China. Acta Ecologica Sinica 34, 261–265.
| Gravel-sand mulch thickness effects on soil temperature, evaporation water use efficiency and yield of watermelon in semi-arid Loess Plateau, China.Crossref | GoogleScholarGoogle Scholar |
Wilcox BP, Breshears DD, Seyfried MS (2003) Water balance on rangelands. In ‘Encyclopedia of water science’. (Eds Stewart BA, Howell TA) pp. 791–794. (Marcel Dekker Inc.: New York, NY)
Wilson KB, Hanson PJ, Mulholland PJ, Baldocchi DD, Wullschleger SD (2001) A comparison of methods for determining forest evapotranspiration and its components: sap-flow, soil water budget, eddy covariance and catchment water balance. Agricultural and Forest Meteorology 106, 153–168.
| A comparison of methods for determining forest evapotranspiration and its components: sap-flow, soil water budget, eddy covariance and catchment water balance.Crossref | GoogleScholarGoogle Scholar |
Wright JL (1991) Using weighing lysimeters to develop evapotranspiration crop coefficients. In ‘Lysimeters for evapotranspiration and environmental measurements’. (Eds GG, Allen, TA Howell, WO Pruitt, IA Walter, ME Jensen) p. 456. (American Society of Civil Engineers: New York, NY)
Xie ZK, Wang YJ, Wei XH, Zhang ZS (2006) Impacts of a gravels and mulch and supplemental drip irrigation on watermelon (Citrullus lanatus [Thunb.] Mats. & Nakai) root distribution and yield. Soil & Tillage Research 89, 35–44.
| Impacts of a gravels and mulch and supplemental drip irrigation on watermelon (Citrullus lanatus [Thunb.] Mats. & Nakai) root distribution and yield.Crossref | GoogleScholarGoogle Scholar |
Xie ZK, Wang YJ, Cheng GD, Malhi SS, Vera CL, Guo ZH, Zhang YB (2010) Particle-size effects on soil temperature, evaporation, water use efficiency and watermelon yield in fields mulched with gravel and sand in semi-arid Loess plateau of northwest China. Agricultural Water Management 97, 917–923.
| Particle-size effects on soil temperature, evaporation, water use efficiency and watermelon yield in fields mulched with gravel and sand in semi-arid Loess plateau of northwest China.Crossref | GoogleScholarGoogle Scholar |
Yamanaka T, Inoue M, Kaihotsu I (2004) Effects of gravel mulch on water vapour transfer above and below the soil surface. Agricultural Water Management 67, 145–155.
| Effects of gravel mulch on water vapour transfer above and below the soil surface.Crossref | GoogleScholarGoogle Scholar |
Yuan C, Lei T, Mao L, Liu H, Wu Y (2009) Soil surface evaporation processes under mulches of different sized gravel. Catena 78, 117–121.
| Soil surface evaporation processes under mulches of different sized gravel.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXntVylt7w%3D&md5=9d33eaff17eac71bc70034ccdc31f68dCAS |
Yunusa IAM, Walker RR, Lu P (2004) Evapotranspiration components from energy balance, sapflow and microlysimetry techniques for an irrigated vineyard inland Australia. Agricultural and Forest Meteorology 127, 93–107.
| Evapotranspiration components from energy balance, sapflow and microlysimetry techniques for an irrigated vineyard inland Australia.Crossref | GoogleScholarGoogle Scholar |
Zhang Y, Liu C, Shen Y, Kondoh A, Tang C, Tanaka T, Shimada J (2002) Measurement of evapotranspiration in a winter wheat field. Hydrological Processes 16, 2805–2817.
| Measurement of evapotranspiration in a winter wheat field.Crossref | GoogleScholarGoogle Scholar |
