Mulches form a barrier to the heat and vapour flow from the soil and thereby inhibit heat and moisture exchanges with the atmosphere (Rosenberg et al., 1983; Wilken, 1972). Mulching decreases the evaporation rate, enhances infiltration, and thus increases moisture conservation. Hopkins (1954) showed that the moisture infiltration over two hours was 183% greater for mulched sites than for un-mulched areas. Dhaliwal et al. (2019) also showed that soil moisture was 4.2 per cent higher in mulched sites than in un-mulched sites. Kader et al. (2017) state that mulching buffered extreme soil moisture and temperature fluctuations. Fang et al. (2009) researched the effects of straw mulching on the microclimate, and the results showed that straw mulching had a dramatic impact on surface temperature and soil temperature. Straw mulch increased surface sensible heat flux but decreased latent heat flux and soil heat flux, so water evaporation from the soil was restricted, and moisture accumulation was increased accordingly. Mulching avoids the fluctuations in temperature in the first 20 to 30 centimetres depth of the soil. This favours root development, and the soil temperature in the planting bed is raised, promoting faster crop development (Moreno & Moreno, 2008).

Mulching materials, should where as much as possible be composed of locally available materials (crop residues or other organic matter) that do not compete as source for animal fodder, home consumptive or sellable produce. Extending the examples provided above are tree leaves such as banana for nutrient input (Lekasi et al., 2001) and mango (Das and Dutta, 2018), husk of rice or other grains. Black polythene (or low-density polyethylene (LDPE)) has for many crops and in many different agro-climatic zones proven to be highly affective and application is (still) very widespread. However, the associated environmental impact should be considered, as common practice is that these are not reused (or reusable) and simply become non-degradable waste problem.

References Das, K., Dutta, P. (2018). Effects of Mulching on Soil Properties and Post Harvest Quality of Mango Cv. Himsagar Grown in New Alluvial Zone of West Bengal. International Journal of Agriculture, Environment and Biotechnology, 11(2), 259–264. https://doi.org/10.30954/0974-1712.04.2018.6

Dhaliwal, L.K., Buttar, G.S., Kingra, P.K., Singh, S., & Kaur, S. (2019). Effect of mulching, row direction and spacing on microclimate and wheat yield at Ludhiana. Journal of Agrometeorology, 21(1), 42-45.

Hopkins, H.H. (1954). Effects of Mulch Upon Certain Factors of the Grassland Rangeland Ecology & Management/Journal of Range Management Archives, 7(6), 255-258.

Fang, W.S., Zhu, Z.X., Liu, R.H., Ma, Z.H., & Shi, L. (2009). Study on microclimate characters and yield-increasing mechanism in straw mulching field. Agricultural Research in the Arid Areas, 6.

Kader, M.A., Senge, M., Mojid, M.A., & Nakamura, K. (2017). Mulching type-induced soil moisture and temperature regimes and water use efficiency of soybean under rain-fed condition in central Japan. International Soil and Water Conservation Research, 5(4), 302-308.

Lekasi, J.K., Woomer, P.L., Tenywa, J., & Bekunda, M. (2001). Effect Of Mulching Cabbage With Banana Residues On Cabbage Yield, Soil Nutrient And Moisture Supply, Soil Biota And Weed Biomass. African Crop Science Journal (ISSN: 1021-9730) Vol 9 Num 3, 9. https://doi.org/10.4314/acsj.v9i3.27596

Moreno, M.M., & Moreno, A. (2008). Effect of different biodegradable and polyethylene mulches on soil properties and production in a tomato crop. Scientia Horticulturae, 116(3), 256-263.

Rosenberg, N.J., Blad, B.L., & Verma, S.B. (1983). Microclimate: the biological environment. New Jersey, United States of America: John Wiley & Sons

Wilken, G.C. (1972). Microclimate management by traditional farmers. Geographical Review, 62(4), 544-560. https://doi.org/10.2307/213267