Contents lists available at ScienceDirect Agricultural Water Management journal homepage: www.elsevier.com/locate/agwat Environmental and economic benefits of micro–field rain–harvesting farming system at maize (Zea mays L.) field scale in semiarid east African Plateau Fei Mo a , Jian-Yong Wang a , Hong-Xu Ren b , Guo-Jun Sun a , Levis Kavagi c , Hong Zhou a , Simon N. Nguluu d , Patrick Gicheru d , Kiprotich W. Cheruiyot a , You-Cai Xiong a, ⁎ a State Key Laboratory of Grassland Agro–Ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China b Institute of Botany, Chinese Academy of Sciences, Xiangshan, Beijing 100093, China c United Nations Environment Programme, P.O. Box 47074–00100, Nairobi, Kenya d Kenya Agricultural and Livestock Research Organization, Kabete 14733–00800, Nairobi, Kenya ARTICLE INFO Keywords: Rainfed farming Soil quality Economic benefit Maize east African Plateau ABSTRACT To explore low–cost, high–yielding and environment–friendly rainfed farming technology is critical for sus- tainable agricultural development in semiarid east African Plateau (EAP). An innovative ridge–furrow mulching system (RFMS) was first introduced to EAP, with a two–year field experiment using maize cultivar KDVI in a typical semiarid site of Kenya from 2012 to 2013. Nine treatments were designed including ridge–furrow cul- tivation with black plastic mulching (RFB), straw mulching (RFS) and without mulching (RF) under high (375 kg ha -1 ), conventional (225 kg ha -1 ) and zero fertilization rates. We found RFB and RFS significantly increased soil water storage (0–40 cm) by 10.2% and 4.8%, while lowered evapotranspiration rate and improved thermal status, compared to RF across two growing seasons. Importantly, RFB and RFS increased soil organic carbon and C/N ratio (soil organic carbon/soil total nitrogen) by 7.8% and 4.9%, 7.2% and 5.1% respectively, following two growing seasons of farming practice. As expected, grain yield and water use efficiency (WUE) were averagely increased by 63.3% and 63.8%, 27.5% and 35.9% in RFB and RFS than those of RF respectively. Additionally, net income and economic output–to–input ratio were significantly greater in RFB and RFS than those of RF. On the other hand, conventional fertilization rate achieved similar grain yield and WUE as high fertilization did. Considering environmental and economic benefits, the RFMS farming system with conventional fertilization may act as a promising option to upgrade local dryland agricultural system in EAP. 1. Introduction In semiarid east African Plateau (EAP), increasing land degradation and population growth has received extensive concerns over last dec- ades, particularly in the semiarid rainfed agricultural areas (Conway and Toenniessen, 2003). Soil conservation and rainwater collection are two major issues affecting land degradation and food security in this region (Müller et al., 2011). Most of rainfall events frequently take place in the form of short–duration but high–intensity storm, which results in serious non–productive surface runoff and soil erosion (Hatibu et al., 2003). Particularly in the Great Rift Valley of Kenya, there are a large number of slope farmlands for agricultural production, which actually enhance the challenges for rainwater retention and surface runoff management (Rockström, 2000). Local agricultural productivity universally remains at low level due to inefficient rainwater management (Pretty et al., 2011). Historically, large area reclamation for agricultural production further aggravated the en- vironmental problems aforementioned (Brown, 1981). Therefore, to upgrade local rainfed farming technology is crucial for soil and water conservation and ecosystem sustainability in semiarid EAP. Currently, only 10–15% rainwater resource is used productively for crop production in EAP (Breman et al., 2001). Exploring in situ rain- water harvesting technologies (RHTs) is a promising solution for im- proving rainfall/runoff collection and utilization in this region. For instance, in situ RHTs such as terraced fields in Ethiopia (Adgo et al., 2013), trench–style rainwater storage technique in Tanzania (Makurira et al., 2009), half moons–style rainwater saving practice in Kenya (Nyangito et al., 2008), stone bunds in Kenya and Uganda (Ellis-Jones and Tengberg, 2000) all displayed substantial advantages to improve rainwater infiltration and utilization via collecting surface runoff https://doi.org/10.1016/j.agwat.2018.05.002 Received 19 April 2017; Received in revised form 28 April 2018; Accepted 4 May 2018 ⁎ Corresponding author. E-mail address: xiongyc@lzu.edu.cn (Y.-C. Xiong). Agricultural Water Management 206 (2018) 102–112 0378-3774/ © 2018 Elsevier B.V. All rights reserved. T