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Fluid Journal : Summer 2016
20 The Fluid Journal Summer 2016 Dr. Hatfield is Laboratory Director and Supervisory Plant Physiologist at the National Lab for Agriculture and the Environment in Ames, Iowa. Dr. Walthall is National Program Leader for Agricultural Systems in the Office of National Programs of USDA-ARS, Beltsville, Maryland. grain quality and its relationship to G x E x M. Another component of feeding the world is food waste, which in turn translates to wasted resources as discussed by Kummu et al. (2012). They found that one quarter of the food supply produced is lost within the food supply chain and that this lost production accounts for 24% of the freshwater resources, 23% of the total cropland area, and 23% of the global fertilizer use. They put forth the argument that reducing food losses and waste would increase food security and increase the efficiency of the resource use during food production (Kummu et al. 2012). Another challenge will be to critically examine the water footprint of agriculture as suggested by Sun et al. (2013). They suggest that the water footprint of a crop could be controlled through enhanced management of all crop production inputs, ultimately leading to increased WUE. These examples present a sample of the broad challenges to agriculture needing attention. The impact of insects, diseases, and weeds on production are part of the E and M components of this puzzle, and addressing these interactionsaspartofGxEXMis warranted. Meeting future food needs will carry some specific challenges as yield in many areas of crops are showing a plateau (Grassini et al., 2013), yield gaps are often extremely large (Lobell et al., 2009, Rijk et al. 2013, van Ittersum et al., 2013, van Wart et al., 2013; Fischer et al., 2014) and the projected yield increase varies widely, from 30 to 60% (Ray et al., 2013. Solutions to these challenges include: • Focus on soil improvement for both water supply characteristics and nutrient cycling to remove growth limiting factors (van Ittersum et al. 2003) as growth-defining factors (temperature and precipitation) will become more variable and more extreme (Tebaldi et al., 2006), and availability of water and nutrients will become more critical to achieve high yields (Liu et al., 2013). We need to reverse the trend of soil degradation and focus our attention on soil improvement to close the yield gap because the land base is decreasing and attention sh oul be focuse on yield improvement (Gregory et al, 2002; Gregory and George, 2011). • Increase the emphasis on improved nutrient management strategies and practices that increase nutrient use efficiency and reduce potential environmental impact (Spiertz, 2009). He suggested that a multi-scale approach form the plant level, crop level, farm level, watershed and landscape level, and eco-region level be undertake to enhance nutrient use efficiency. The development of the 4-R concept is a first step; however, the value of this concept in increasing production needs to be demonstrated to producers. • Incorporate multi-disciplinary science into efforts to improve yields by building transdisciplinary teams of agronomists, geneticists, plant pathologists, entomologists, weed scientists and human nutritionists to evaluate the response of different genotypes to stress and management practices for yield and grain quality, to ensureallaspectsofGxExM are addressed in a comprehensive manner. • Develop and implement more robust tools for assessing leaf photosynthetic efficiency and canopy interception of light to be able to screen increasing numbers of germ-plasm across multiple environments and management systems. Capture of solar radiation is essential to improving yields; however, food security can only be achieved when solar radiation is converted into a harvestable, high- value product. • Focus on why crops are not achieving their potential via a "Aspects of agriculture may appear to offer the conclusion that we face the impossible." comprehensive analysis, realizing that dominant factors may be different for each growing region or locality. The traditional view of universal yield limitations must yield to a more site-specific focus (Fischer et al., 2014). • Adopt new technologies, (e.g., precision agriculture, enhanced efficiency fertilizers, alternative crops), to infuse innovation into cropping systems. • Utilize crop simulation models in a robust fashion to enable a more comprehensive analysis of potential alternative scenarios under future climates and management options (Yin and Struik, 2010, Rosenzweig et al.,2013, Gu et al, 2014), and build a community of modelers (crop and climate) and experimentalists to improve the models and provide feedback on genetic and management responses. • Incorporate the producer into applied research to determine what practices are feasible from their perspective and solicit their feedback on technologies and approaches. • Characterize plant responses to different stresses and also develop rapid screening methods to allow more comprehensive comparisons across a larger number of genotypes (Abdolshahi et al., 2015; de Mezer et al., 2014, Djanaguiraman et al., 2014). It may seem like a daunting task to provide for future generations. The current literature on many different aspects of agriculture may appear to offer the conclusion that we face the impossible. We would offer that approaching the problem from a more integrated G x E x M approach can potentially achieve the goal of feeding 9 billion by 2050.