Bill Davies Centre for Sustainable Agriculture Lancaster Environment Centre The Water and Food Connection: feeding nine billion with fewer resources

Film consumption/Chemicals consumption (10000 ton) Grain yield per unit area ‘Demand for food is projected to increase by 50% by 2030 and double by 2050 ’ - Grain production and resource input in China ( Fan, Shen, Yuan, Jiang, Chen, Davies & Zhang. JXB 2011) Irrigation Plastic film Chemicals Grain area Fertilizer High yield

Vulnerable environments and people in NW China

Less and less water flowing into the lower river valley

Because there is little water in the irrigation canals, farmers have dug wells to access ground water. As a result the water table has fallen dramatically

One kilogram of rice grain requires 2500 L of water for its production. One third of the World’s freshwater is used to irrigate rice with this figure being half of all freshwater supplies for Asia.

Westgate ME, Boyer JS (1985) Planta 165: ELONGATION RATE (mm h -1 ) GROWING REGION WATER POTENTIAL (MPa) MAIZE If water is scarce… Water deficits affect all aspects of plant growth and development Significant impact on crop yield

Exploitation of plant biology Manipulation of rhizosphere processeses Manipulate the root system Root growth characteristics Root physiology Root exudation Manipulate soil biology Microorganisms, Mycorrhizae, PGPR Plant Improvement Cropping Systems (Intercropping/rotations/ Conservation Agriculture) Localized nutrient and water supply Deficit irrigation Fertigation Manipulate the environment

L.-S. Tang et al. / Agricultural Water Management 97 (2010) 1527–1533 Partial rootzone drying (PRD)

Yang and Zhang, New Phytologist 2006 Exploitation in drought stress biology in PRD Irrigation of rice Water deficit treatment Grain Yield g/m3 WW + NN802.4b WW + HN713.9c WS + NN799.7b WS + HN858.3a

The consequences of over irrigation (and climate change)

Consequences beyond the immediate area

PRD irrigation under mulch and rhizobiology

Effects of water- saving agriculture (Kang et al 2012)  By shutting wells, returning farmlands to forests and grasses and promoting water-saving irrigation techniques and patterns, irrigated area and irrigation water consumption are reduced in the upper and middle reaches, and the surface water flow into Hongyashan reservoir in the lower reaches is increasing significantly. Groundwater Extraction （ 10 9 m 3 ） Annual Decline of Groundwater Level （ m/yr ）

Xingjiang province in China has around 1 million ha of cotton plantation (8% of world total yield). Farmers can achieve a 30% saving of the irrigation water which is usually applied in this region (from 600 mm to 420 mm). Saving 180 mm water on 1 million ha area is a saving of around 2 x 10 9 cubic metres

The Royal Society – Sustainable Intensification of agriculture Conclusions No techniques or technologies should be ruled out. Global agriculture demands a diversity of approaches, specific to crops, localities, cultures and other circumstances. Such diversity demands that the breadth of relevant scientific enquiry is equally diverse, and that science needs to be combined with social, economic and political perspectives.