The Diffusion of the Tractor in American Agriculture: 1910-60

This paper examines the impact and diffusion of the gasoline tractor in American agriculture. A key feature of the transition from horses to tractors was a long intermediate stage when both modes of power were used on the same farm. This is largely explained in the technical limitations of early tractors. In addition, we explore how rural markets and institutions adjusted to facilitate diffusion. Our simultaneous-equation regression analysis reveals that farm scale and tractor adoption had positive, independent effects on each other. Finally, we analyze diffusion as a capital replacement problem, which reveals that the shift to the new technology came far sooner than has generally been thought.

Hog Round Marketing, Seed Quality, and Government Policy: Institutional Change in U.S. Cotton Production, 1920-60.

Between 1928 and 1960 U.S. cotton production witnessed a revolution with average yields increasing roughly threefold. In addition, the average staple length of the U.S. crop increased significantly, reversing a long-run downward trend in cotton quality. Underlying these accomplishments were major innovations in cotton marketing, wholesale changes in the varieties grown, and the emergence of a vibrant commercial seed industry. This paper analyzes the key institutional and scientific developments underlying this revolution in biological technologies, pointing to the importance of two government programs—the one-variety community crusade and the Smith-Doxey Act— as catalysts for change.

The Red Queen and the Hard Reds: Productivity Growth in American Wheat, 1800-1940

The standard treatment of U.S. agriculture asserts that, before the 1930s, productivity growth was almost exclusively the result of mechanization rather than biological innovations. This paper shows that, to the contrary, U.S. wheat production witnessed a biological revolution during the 19th and early 20th centuries with wholesale changes in the varieties grown and cultural practices employed. Without these changes, vast expanses of the wheat belt could not have sustained commercial production and yields everywhere would have plummeted due to the increasing severity of insects, diseases, and weeds. Our revised estimates of Parker and Klein's productivity calculations indicate that biological innovations account for roughly one-half of labor productivity growth between 1839 and 1909.

Hog Round Marketing, Seed Quality, and Government Policy: Institutional Change in U.S. Cotton Production, 1920-1960

Between 1928 and 1960 U.S. cotton production witnessed a revolution with average yields roughly tripling while the quality of the crop increased significantly. This paper analyzes the key institutional and scientific developments that facilitated the revolution in biological technologies, pointing to the importance of two government programs -- the one-variety community movement and the Smith-Doxey Act -- as catalysts for change. The story displays two phenomena of interest in light of the recent literature: 1. an important real-world example of the workings of Akerlof's lemons model and 2. a case where inventors, during an early phase of the product cycle, actually encouraged consumers to copy and disseminate their intellectual property.

Biological Globalization: the other Grain Invasion

Contemporary accounts of the history of globalization place the grain trade in a leading role. Narrowing price gaps for wheat in world markets serve as the key indicator of increasing market integration. And the chief example of an early policy backlash is the rising protectionism of European importers in response to the “Great Grain Invasion” of New World grain in the late nineteenth century. These accounts focus on the important role of falling transportation cost, but neglect other crucial biological innovations that allowed expanding the wheat cultivation in the new lands, what we call the “other grain invasion.” This paper documents that over the 1866-1930 the average distance of world wheat production from the core consumer markets doubled, as the wheat frontier moved on much harsher (colder and more arid) climates. Examining the detailed histories of major producers on the periphery, we show that this move involved, and indeed required extensive experimentation by farmers and crop scientists to find new suitable cultivars that could thrive in the new environments and survive the evolving pest and disease threats. Flows of germplasm and knowledge about breeding occurred not only from center to periphery, but also and importantly within the periphery and from the periphery to the center as an increasing integrated global community of crop scientists emerged over the late nineteenth and early twentieth centuries. Finally, we speculate about why in some regions pioneering plant breeders are heralded as national heroes whereas in others they are sadly under-appreciated.

Biological Innovation and Productivity Growth in the Antebellum Cotton Economy

The Cliometrics literature on slave efficiency has generally focused on static questions. We take a decidedly more dynamic approach. Drawing on the records of 142 plantations with 509 crops years, we show that the average daily cotton picking rate increased about four-fold between 1801 and 1862. We argue that the development and diffusion of new cotton varieties were the primary sources of the increased efficiency. These finding have broad implications for understanding the South's preeminence in the world cotton market, the pace of westward expansion, and the importance of indigenous technological innovation.

Productivity Growth and the Regional Dynamics of Antebellum Southern Development

Between 1800 and 1860, the United States became the preeminent world supplier of cotton as output increased sixty-fold. Technological changes, including the introduction of improved cotton varieties, contributed significantly to this growth. Measured output per worker in the cotton sector rose four-fold and large regional differences emerged. By 1840, output per worker in the New South was twice that in the Old South. The economy-wide increase is explained, in equal measure, by growth in output per worker at fixed locations and by the reallocation of labor across regions. These results offer a new view on the dynamics of economic development in antebellum America.

Probing the Inner Jet of the Quasar PKS 1510-089 with Multi-waveband Monitoring during Strong Gamma-ray Activity

We present results from monitoring the multi-waveband flux, linear polarization, and parsec-scale structure of the quasar PKS 1510-089, concentrating on eight major gamma-ray flares that occurred during the interval 2009.0-2009.5. The gamma-ray peaks were essentially simultaneous with maxima at optical wavelengths, although the flux ratio of the two wavebands varied by an order of magnitude. The optical polarization vector rotated by 720 degrees during a 5-day period encompassing six of these flares. This culminated in a very bright, roughly 1 day, optical and gamma-ray flare as a bright knot of emission passed through the highest-intensity, stationary feature (the "core") seen in 43 GHz Very Long Baseline Array images. The knot continued to propagate down the jet at an apparent speed of 22c and emit strongly at gamma-ray energies as a months-long X-ray/radio outburst intensified. We interpret these events as the result of the knot following a spiral path through a mainly toroidal magnetic field pattern in the acceleration and collimation zone of the jet, after which it passes through a standing shock in the 43 GHz core and then continues downstream. In this picture, the rapid gamma-ray flares result from scattering of infrared seed photons from a relatively slow sheath of the jet as well as from optical synchrotron radiation in the faster spine. The 2006-2009.7 radio and X-ray flux variations are correlated at very high significance; we conclude that the X-rays are mainly from inverse Compton scattering of infrared seed photons by 20-40 MeV electrons.Comment: 10 pages of text + 5 figures, to be published in Astrophysical Journal Letters in 201