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42 °C in the hot-dry months. Mean annual rainfall in the area is

1800 mm, 34% of which occurs during June through August, with the highest rainfall (13.7%) in July. For satisfactory yield, it is necessary to conserve soil moisture and modify soil temperature for the cultivation of soy- bean in rain-fed condition. During the hot summer days (JulyC August), high soil temperature accelerates evaporation at soil surface and reduces soil moisture, with a consequent negative impact on the growth and development of the crop. The negative impacts of high temperature may, however, be minimized by employing mulching with suitable materials (Kader, Senge, Mojid, &

Ito, 2017). The appropriate mulching materials, by controlling soil temperature and conserving soil moisture, can provide sui- table soil microclimate for soybean cultivation in the hot summer. There are a number of mulching materials in use from organic Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/iswcr International Soil and Water Conservation Research http://dx.doi.org/10.1016/j.iswcr.2017.08.001 2095-6339/&

2017 International Research and Training Center on Erosion and Sedimentation and China Water and Power Press. Production and Hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). n Corresponding author. E-mail address: [email protected] (M.A. Kader). Peer review under responsibility of International Research and Training Center on Erosion and Sedimentation and China Water and Power Press. International Soil and Water Conservation Research

5 (2017) 302C308 and inorganic sources. The popular organic mulching materials, such as straw and grass, have been used to retain soil moisture (Chakraborty et al., 2008) by reducing soil-water consumption/loss (Zribi, Aragüés, Medina, &

Faci, 2015), maintain soil temperature (Ramakrishna, Tam, Wani, &

Long, 2006) and increase crop pro- duction (Siczek &

Lipiec, 2011). Organic materials like straw, grass and newspaper are environment friendly, and, after decomposi- tion, add nutrients and organic matter to the soil (Kader, Senge, Mojid, &

Ito, 2017). Although, plastic mulch provided better crop yield (Mehan &

Singh, 2015), but straw mulch, in many cases, has been recommended for its local availability (Yin et al., 2016). The choice of selection of an appropriate mulching material depends on local climate, cost effectiveness (Wang, Zhao, Wu, &

Chen, 2015) and crop feasibility. Cereal straw is a most common organic mulching material that has several bene?ts, and is better for soil- moisture storage than some other mulching materials (Ji &

Unger, 2001). Dry grass and newspaper are inexpensive and, in general, easily available. Farmers can easily collect these materials as an alternate option of rice straw mulching, which is limited due to its unavailability in the ?eld since this is, very often, also used for feeding ruminants or used as biofuel (INFONET-BIOVISION, 2010). Plastic mulch affects the thermal regime of a soil by altering soil temperature (Arora, Singh, Sidhu, &

Thind, 2011;

Pramanik, Bandyopadhyay, Bhaduri, Bhattacharyya, &

Aggarwal, 2015). It also reduces water loss by preventing surface evaporation (Zribi, Ara- gues, Medina, &

Faci, 2015), improves crop-water use ef?ciency (Almeida, Lima, &

Pereira, 2015) and minimizes salt build-up in the crop root zone (Dong, Li, Tang, &

Zhang, 2009). The effect of mulching on soil temperature is, however, highly variable;