What Keeps GM Herbicide-Centric Agriculture in Place?

 THIRD WORLD NETWORK BIOSAFETY INFORMATION SERVICE

Dear Friends and Colleagues

What Keeps GM Herbicide-Centric Agriculture in Place?

Weed control in the U.S. Midwest has become increasingly herbicide-centric due to the adoption of genetically modified (GM) herbicide-tolerant (HT) crops in the 1990s. GM glyphosate-tolerant crops covered 94% and 89% of U.S. soybean and corn areas in 2017. Two sustainability issues confront herbicide-centric methods of weed control: (1) herbicides create negative health and environmental externalities, and (2) weed resistance to some herbicides is increasing, which creates incentives to use additional herbicides.

A study developed an economic framework to clarify the interplay among the different market failures that either contribute to the herbicidal “lock-in” or make it problematic. The study found that the current dominance of herbicide-centric weed control in U.S. Midwest crop farming is unlikely to fade any time soon in favour of more sustainable integrated weed management (IWM). IWM integrates multiple weed management methods, including not only chemical and mechanical weed control, but also ecological methods such as crop rotation, cover-cropping, intercropping, planting of competitive cultivars, and the biological control of weeds with insects and pathogens.

However, IWM adoption faces high barriers to entry, including barriers to crop rotation, interrow cultivation, and knowledge acquisition. Other barriers feature self-reinforcing effects that contribute to the lock-in of herbicide-centric weed control: (1) Incompatibilities of IWM practices with the current size of farms and farm machinery create switching costs. (2) Chemical herbicides have contributed to the simplification of crop rotations, which no longer include fodder crops. (3) There is path dependence in R&D and IWM has never been the main focus of weed science. (4) The U.S. biofuels mandate and subsidised crop insurance programs encourage corn and soybean production, and therefore discourage longer crop rotations.

While the trends of larger farms and equipment were already at play long before the advent of GM glyphosate-tolerant crops, the latter have unfortuantely reinforced this herbicide-centric path by encouraging increases in farm acreage and machinery sizes.

With best wishes,

Bullock, D. S., D’Arcangelo, F. M., & Desquilbet, M.
TSE Working Papers18-959
Toulouse School of Economics (TSE).
September 2018, revised November 2018
https://ideas.repec.org/p/tse/wpaper/32982.html

Abstract

Weed control in the U.S. Midwest has become increasingly herbicide-centric due to the adoption of herbicide-tolerant (HT) crops in the 1990s. The scarcity of the use of integrated weed management (IWM) practices, including biological and mechanical controls, is concerning for two reasons. First, herbicides create negative health and environmental externalities. Second, weed resistance to some herbicides is increasing, which creates incentives to use additional herbicides. However, it seems certain that weeds will develop resistance to those herbicides as well, so applying “herbicide upon herbicide” is socially problematic. In this context, we develop an economic framework to clarify the interplay among the different market failures that either contribute to the herbicidal “lock-in” or make it problematic. We then analyze the evidence for and perceptions of these market failures based on twenty-four semistructured interviews with farmers and experts conducted in 2017, as well as discussions in the academic literature. To this end, we put into perspective the possible self-reinforcing effects in the adoption path of HT crops, such as increasing farm size, changes in farm equipment, increasing incentives for simplified crop rotations, and the loss of practical knowledge of IWM practices.

Discussion and Conclusion

Our analysis has highlighted that the current dominance of herbicide-centric weed control in U.S. Midwest crop farming is unlikely to fade any time soon in favour of a more sustainable form of agriculture relying on IWM. Indeed, IWM adoption faces high barriers to entry, including barriers to crop rotation, interrow cultivation, and knowledge acquisition. Some of these barriers seem mostly exogenous to the dynamics of weed control. First, corn and soybeans thrive in the agricultural conditions of the U.S. Midwest, reducing private economic incentives for other rotations. Second, the high cost of qualified rural labour hampers the adoption of more time-consuming IWM practices. Third, the increase in the relative share of private agri-food R&D compared to public R&D may decrease the incentives for IWM research because of low appropriability.

Other barriers, however, are at least partly endogenous to the dynamics of weed control; they feature various self-reinforcing effects that contribute to the lock-in of herbicide-centric weed control. These lock-in effects help maintain the herbicide-centric path of weed control dynamics, despite another externality at play, which is the common-pool nature of weeds and of weed susceptibility to herbicides. This common-pool nature contributes to the decrease in herbicides’ effectiveness over time as weed resistance develops. The negative externalities of herbicides on health and the environment make this path problematic.

We have identified four types of self-reinforcing effects. First, incompatibilities of IWM practices with the current size of farms and farm machinery create switching costs. Existing machinery, such as the interrow cultivators made unnecessary by GT technology, are ill-suited to be used with today’s larger machinery. Farm size is enhanced by the availability of herbicidal weed control; the large size of farms makes it difficult to adopt IWM practices, which tend to be labour- and management-intensive.

Second, indirect network effects have resulted as chemical herbicides have contributed to the simplification of crop rotations, which no longer include fodder crops; this simplification has fostered the specialisation and separation of field crop farms and livestock farms. It would be complicated to reintroduce fodder crops on grain farms lacking livestock production, and moving fodder crops to livestock-intensive areas is expensive.

Third, there is path dependence in R&D. IWM has never been the main focus of weed science. Fourth, the U.S. biofuels mandate and subsidised crop insurance programs encourage corn and soybean production, and therefore discourage longer crop rotations. Although it was not specifically addressed in our interviews, the policy persistence of regulations pertaining to the market authorisation and use of herbicides probably also plays a role in the current price of herbicides and the high cost-effectiveness of herbicides compared with labour.

The lock-in effects that we have described do not result from GT crop adoption alone, but more generally from the much longer path of herbicidal control. GT crops may have reinforced this herbicide-centric path by encouraging increases in farm acreage and machinery sizes, but the trends of larger farms and equipment were already at play long before the advent of GT crops.

We have provided a qualitative description of the dynamic effects at play in the path of U.S. Midwest GT crop adoption. Our economic analysis of the effects of the adoption of farm innovations has shown that dynamic relationships exist between weed management choices and choices about fixed farm assets such as land and equipment. It is therefore important to account not only for the variable costs at the field scale, but also for the market-scale structural transformations brought about by these innovations. This study also underlines the interest in comparing the effect of an innovation (for example, GT crops) not only with the dominant technology in place (in our case, herbicidal control), but also with more sustainable alternatives (such as IWM) that have beneficial effects on health and the environment.