Valuing increased zinc (Zn) fertiliser-use in Pakistan

Plant Soil DOI 10.1007/s11104-016-2961-7 REGULAR ARTICLE Valuing increased zinc (Zn) fertiliser-use in Pakistan Edward J. M. Joy & Waqar Ahmad & Munir H. Zia & Diriba B. Kumssa & Scott D. Young & E. Louise Ander & Michael J. Watts & Alexander J. Stein & Martin R. Broadley Received: 12 February 2016 / Accepted: 13 June 2016 # The Author(s) 2016. This article is published with open access at Springerlink.com Abstract Background and aims Use of zinc (Zn) fertilisers may be cost-effective in increasing crop yields and in alleviating dietary Zn deficiency. However, Zn fertilisers are underutilised in many countries despite the widespread occurrence of Zn-deficient soils. Here, increased Zn fertiliser-use scenarios were simulated for wheat production in Punjab and Sindh Provinces, Pakistan. Inputs and outputs were valued in terms of both potential yield gains as well as health gains in the population. Methods The current dietary Zn deficiency risk of 23.9 % in Pakistan was based on food supply and wheat grain surveys. “Disability-adjusted life years (DALYs) lost” are a common metric of disease burden; an estimated 245,000 DALYs y−1 are lost in Punjab and Sindh due to Zn deficiency. Baseline Zn fertiliser-use of 7.3 kt y−1 ZnSO4.H2O was obtained from published and industry sources. The wheat area currently receiving Zn fertilisers, and grain yield responses of 8 and 14 % in Punjab and Sindh, respectively, were based on a recent survey of >2500 farmers. Increased grain Zn concentrations under Zn fertilisation were estimated from literature data and converted to improved Zn intake in humans and ultimately a reduction in DALYs lost. Results Application of Zn fertilisers to the area currently under wheat production in Punjab and Sindh, at current soil: foliar usage ratios, could increase dietary Zn supply from ~12.6 to 14.6 mg capita−1 d−1, and almost halve the Edward J. M. Joy, Waqar Ahmad, Munir H. Zia, Diriba B. Kumssa, Martin R. Broadley Contributed equally to this paper. Responsible Editor: Ismail Cakmak. Electronic supplementary material The online version of this article (doi:10.1007/s11104-016-2961-7) contains supplementary material, which is available to authorized users. E. J. M. Joy Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel St, London WC1E 7HT, UK W. Ahmad Food and Agriculture Organization of the United Nations, NARC Premises, Park Road, Islamabad, Pakistan M. H. Zia Research & Development Section, Fauji Fertilizer Company Ltd, Rawalpindi, Pakistan M. H. Zia : D. B. Kumssa : S. D. Young : M. R. Broadley (*) School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK e-mail: M. H. Zia : D. B. Kumssa : E. L. Ander : M. J. Watts Inorganic Geochemistry, Centre for Environmental Geochemistry, British Geological Survey, Keyworth, Nottingham NG12 5GG, UK A. J. Stein Agricultural Economist, Brussels, Belgium Plant Soil prevalence of Zn deficiency, assuming no other changes to food consumption. Gross wheat yield could increase by 2.0 and 0.6 Mt. grain y−1 in Punjab and Sindh, respectively, representing an additional return of US$ >800 M and an annual increased grain supply of 19 kg capita−1. Conclusions There are potential market- and subsidybased incentives to increase Zn fertiliser-use in Pakistan. Benefit-Cost Ratios (BCRs) for yield alone are 13.3 and 17.5 for Punjab and Sindh, respectively. If each DALY is monetised at one to three fold Gross National Income per capita on purchasing power parity (GNIPPP), full adoption of Zn fertiliser for wheat provides an additional annual return of 405–1216 M International Dollars (I$) in Punjab alone, at a cost per DALY saved of I$ 461–619. Keywords Agronomic biofortification . Benefit cost ratio (BCR) . Cost-benefit analysis . Disability adjusted life year (DALY) . Fertiliser subsidy . Food security . Triticum aestivum L . Wheat Introduction Zinc (Zn) is an essential nutrient for all organisms, with potential roles in 1000s of proteins in plants and humans (Broadley et al. 2007). Crops respond to Zn fertilisers on many soil types. For example, increases in wheat yield and production at a national scale have been reported in Turkey following the adoption of Zn fertilisers (Cakmak 2008; Cakmak et al. 2010). However, Zn fertilisers remain little utilised globally, and approximately half of all soils used for cereal production are likely to be Zn deficient (Cakmak et al. 1999; Alloway 2008; Ahmad et al. 2012). These soils include widespread areas of the Indo-Gangetic Plains in South Asia, where intensive rice-wheat cropping systems are practiced (e.g. Nayyar et al. 2001). For example, soils of the Indus Plains of Pakistan are mostly derived from calcareous parent material from the Himalayas, which is deposited as alluvial material by the Indus River and its tributaries, or as loess deposits in the northern parts of the Indus Plains (FAO 1973). These calcareous soils support the majority of crop production in Pakistan, which covers 21.4 Mha (PBS 2009). These soils generally have low organic matter (0.4–0.7 %) and free calcium carbonate (CaCO3), which buffers the pH within the range of 7.5–8.4 with 100 % base saturation, and have a cation exchange capacity (CEC) dominated by Ca. These factors tend to restrict the phyto-availability of Zn and other elements such as boron (B), thereby limiting crop yields in the absence of their fertilisers. Many field studies have reported crop yield increases in response to Zn fertilisers. Using these studies, it is straightforward to monetise Benefit-Cost-Ratios (BCRs) based on increased crop output per additional input of Zn. For example, in a review of field studies in Pakistan, an application of 5 kg ha−1 (i.e. ZnSO4. H2O equivalents, containing ~33 % Zn) increased grain yields of wheat by >10 %, at a mean BCR of 7:1 (range 1.3–11:1; NFDC 1998). In addition to yield increases in the year of Zn fertiliser application, there may be beneficial residual effects of Zn fertilisers for subsequent crops for three or more years (NFDC 1998; Singh and Shivay 2013; Manzeke et al. 2014; Wang et al. 2015a). However, despite these potential financial returns, Zn fertilisers remain little utilised in Pakistan and elsewhere, for several reasons. These include a lack of quality product availability/access and farmer-awareness. There is also evidence of an unwillingness to pay for Zn fertilisers due to mistrust of product quality and labelling (NFDC 1998). The effects of subsidies that focus primarily on the supply of macronutrient fertilisers, and a lack of farmeraccess to longer-term credit, can also discourage longerterm soil fertility-building and lead to imbalanced fertiliser-use at a farm level (Khan et al. 2010). Furthermore, there are scientific knowledge gaps in terms of deploying balanced fertiliser applications in soils with multiple macro- and micro-nutrient stresses including Bdeficiency and saline/ (...truncated)