**5. Prospects for the future**

In general, technological progress improves the aggregate welfare of society by allowing the production of greater outputs at lower cost (less resource use). But productivity growth can also have important distributional effects. In the corn sector, rapid technological progress has reduced cost and stimulated supply, which in turn has pushed market prices down. As just noted, the observed decrease in real prices reported in **Figure 2** can be attributed in large part to technological progress in the corn industry. It indicates that most of the benefits of productivity gains are actually captured by consumers in the form of expanded quantities produced and lower market prices. As most corn is not directly consumed by people, but used for livestock feed and more recently fuel, these consumer gains arise from lower prices for meat, dairy products, eggs and fuel. But these lower (real) market prices contribute to

**Figure 2.** Historical price of corn, US. Source: The nominal corn price is the price received by farmers (\$/bu) as reported by USDA-NASS [6]. The real price of corn is the nominal price divided by the consumer price index (*CPI*) as reported

Interestingly, technological progress in agriculture may not benefit farmers at the aggregate if the lower output price due to increased productivity generates a decline in revenue that

Cochrane's treadmill after the originator of the theory [27]. Early adopters of new productive technologies benefit by reducing their cost of production, but later adopters will lose if, as supply expands, the output price declines more than the decrease in production costs. The

This can take place when the demand is highly price-inelastic, i.e., when the output price decline is "large enough" to imply a substantial decline in revenue that swamps the decrease in cost. This scenario is relevant as the demand for food

This process is called the technology treadmill or

declining farm revenue.

by BLS, with *CPI*

<sup>1983</sup> = 1.

18 Corn - Production and Human Health in Changing Climate

4

exceeds the reduction in production cost.4

in general and for corn in particular tends to be highly price-inelastic (e.g., [26]).

Over the last several decades, productivity growth in the corn sector has been stellar, which is good news in a world where feeding a growing world population is challenging. There are current concerns that agricultural productivity growth may be slowing down (e.g., [7, 34]). So far, such concerns do not seem to apply to corn, since US average corn yields continue to climb at a steady rate, and Chavas et al. [13] provide evidence that biotechnology has helped

<sup>5</sup> These estimates from https://www.nationalgeographic.com/what-the-world-eats/ based on UN FAOSTAT data for 2011.

increase corn productivity growth over the last two decades. Despite these continual productivity gains, challenges still exist, chief among them are resistance and climate change.

Despite these and other emerging challenges, several promising opportunities exist to continue the productivity gains for corn and agriculture more broadly, among them microbial seed treatments and gene editing techniques. Seed treatments have been used in crop production for some time, fungicides to protect seeds during storage, so that in the US all corn seed (both GE and conventional) uses fungicide seed treatments. More recently, insecticidal seed treatments became widely used in corn production, particularly neonicotinoid seed treatments, to control below-ground and early season insect pests. In the US, more than 90% of corn planted area uses neonicotinoid seed treatment [17, 55]. In addition to insecticidal properties, neonicotinoids have demonstrated plant grower regulator effects in the laboratory

Corn Productivity: The Role of Management and Biotechnology

http://dx.doi.org/10.5772/intechopen.77054

21

These chemical seed treatments have contributed to observed corn yield productivity, but significant research focus has moved to microbial seed treatments, soil microbes and fungi that increase yields. These seed treatments improve the rhizosphere around crop seedlings and plants through a variety of mechanisms, such as increasing nutrient availability, controlling diseases or nematodes, or supplying plant growth hormones [57]. Though some microbial seed treatments have been commercialized, including for corn, research needs still exist before widespread commercialization and achievement of their potential can occur [58]. An interesting possibility is to engineer microbes or fungi to enhance soil microbes for agricultural use. A variety of gene editing techniques have recently been developed (e.g., CRISPR/Cas9, TALENs, ZFNs) with agricultural applications only beginning to be realized. The cost of using gene editing techniques is relatively low compared to gene-transfer technology. Also, gene editing is likely to face lower regulatory burden, as it does not require gene transfer across species. Public acceptance exists for therapeutic human health applications and some agricultural applications as well [59, 60]. Applications to crops could include pest and pathogen control, as well as improved tolerance to abiotic stresses such as extreme heat or cold and drought, helping crop production adapt to climate change and increases in extreme weather events. Furthermore, gene editing could include the possibility of increasing the efficiency of photosynthesis in crops. Besides applications to crops directly, gene editing could be applied to other key organisms, such as to engineer soil microbes to develop new or more effective microbial seed treatments. Similarly, gene editing can be used to engineer gene drives in order to introgress select genes into populations in order to suppress or eliminate pest populations or to make herbicide-resistant weed populations susceptible to herbicides [61, 62]. Given the economic importance of corn and its existing research and commercial infrastructure, corn

seems likely to be at the frontier of the next wave of such innovations in agriculture.

1 Department of Agricultural and Applied Economics, University of Wisconsin, Madison,

2 Renk Agribusiness Institute, University of Wisconsin, Madison, WI, USA

\* and Paul D. Mitchell1,2

\*Address all correspondence to: jchavas@wisc.edu

**Author details**

Jean-Paul Chavas1

WI, USA

and are associated with increased early season vigor in the field [56].

The stellar productivity gains from commercially applying biotechnology in corn have focused on improving insect and weed management, which has created selection pressure on many pest species to evolve resistance to control. Even if farmers follow resistance management practices, pests have and will continue to evolve resistance—these practices only slow the rate of resistance evolution, they do not stop it.

Western corn rootworm (*Diabrotica virgifera virgifera*) evolved resistance to rootworm Bt corn within a few years of commercial release [35]. Rootworm Bt hybrids still have value to farmers, but their continued use requires that companies pyramid multiple rootworm traits together and that farmers use additional management practices such as crop rotation and conventional insecticides [36]. Companies have also responded by developing alternative GE traits to manage corn rootworm. Potentially the most promising is RNA interference (RNAi), which uses biotechnology so that crops create double-stranded RNA segments that interfere with transcription of specific segments of RNA found in only the target species [37–39]. The first US commercialization of RNAi in corn received EPA approval in 2017.<sup>6</sup> Also, corn has been genetically engineered to express insecticidal proteins from non-Bt bacteria and shows excellent activity for control of corn rootworm larvae [40].

Weed control in corn (as with many crops) is important, with potential yield losses without control exceeding 50% [41]. Over the last few decades, herbicide resistant weed populations have continued to develop and spread globally [42]. HT seeds do not directly cause the development of herbicide resistant weeds, as herbicide resistant weeds have evolved in regions such as Western Australia where HT crops are not used [42]. Rather, HT crops contribute by encouraging farmers to rely on fewer herbicides modes of action and less tillage, which accelerate the development and spread of resistant weed populations [43, 44]. Problems with herbicide resistant weeds continue to develop and spread globally, which is worrisome because no new herbicide modes of action have become commercially available since the early 1990s and weed populations resistant to multiple modes of action having been documented [45, 46]. How weed control in corn and other crops will evolve over the next few decades to address herbicide resistant weeds and the possible role that GE hybrids and biotechnology will play is unclear. The race between insects and weeds and our ability to develop technologies and management schemes will continue to impact agricultural productivity. Maintaining our lead in this race will require R&D investments and continued innovations in the future.

Climate change presents another challenge for agricultural productivity, with studies documenting impacts on corn yields [47]. Adaptation to climate change is a rising concern [48, 49]. Some regions will gain and some will lose productivity as climate patterns evolve and crop production shifts among regions. US farmers generally see agricultural adaptation to climate change as a private problem. They expect to respond with managerial changes, such as adjusting crops, using irrigation, modifying leases and using crop insurance, while seed companies will breed varieties and hybrids adapted to new climates [50, 51]. Breeding will certainly be important for corn, since hybrids must be adapted to new photoperiods when changing latitudes. Also, seed companies have commercialized drought-resistant corn hybrids, but these and other traits providing yield gains under extreme conditions tend to be quantitative or polygenic and can imply productivity tradeoffs [52–54].

<sup>6</sup> Official US EPA news release: https://www.epa.gov/newsreleases/epa-registers-innovative-tool-control-corn-rootworm.

Despite these and other emerging challenges, several promising opportunities exist to continue the productivity gains for corn and agriculture more broadly, among them microbial seed treatments and gene editing techniques. Seed treatments have been used in crop production for some time, fungicides to protect seeds during storage, so that in the US all corn seed (both GE and conventional) uses fungicide seed treatments. More recently, insecticidal seed treatments became widely used in corn production, particularly neonicotinoid seed treatments, to control below-ground and early season insect pests. In the US, more than 90% of corn planted area uses neonicotinoid seed treatment [17, 55]. In addition to insecticidal properties, neonicotinoids have demonstrated plant grower regulator effects in the laboratory and are associated with increased early season vigor in the field [56].

These chemical seed treatments have contributed to observed corn yield productivity, but significant research focus has moved to microbial seed treatments, soil microbes and fungi that increase yields. These seed treatments improve the rhizosphere around crop seedlings and plants through a variety of mechanisms, such as increasing nutrient availability, controlling diseases or nematodes, or supplying plant growth hormones [57]. Though some microbial seed treatments have been commercialized, including for corn, research needs still exist before widespread commercialization and achievement of their potential can occur [58]. An interesting possibility is to engineer microbes or fungi to enhance soil microbes for agricultural use.

A variety of gene editing techniques have recently been developed (e.g., CRISPR/Cas9, TALENs, ZFNs) with agricultural applications only beginning to be realized. The cost of using gene editing techniques is relatively low compared to gene-transfer technology. Also, gene editing is likely to face lower regulatory burden, as it does not require gene transfer across species. Public acceptance exists for therapeutic human health applications and some agricultural applications as well [59, 60]. Applications to crops could include pest and pathogen control, as well as improved tolerance to abiotic stresses such as extreme heat or cold and drought, helping crop production adapt to climate change and increases in extreme weather events. Furthermore, gene editing could include the possibility of increasing the efficiency of photosynthesis in crops. Besides applications to crops directly, gene editing could be applied to other key organisms, such as to engineer soil microbes to develop new or more effective microbial seed treatments. Similarly, gene editing can be used to engineer gene drives in order to introgress select genes into populations in order to suppress or eliminate pest populations or to make herbicide-resistant weed populations susceptible to herbicides [61, 62]. Given the economic importance of corn and its existing research and commercial infrastructure, corn seems likely to be at the frontier of the next wave of such innovations in agriculture.
