The impact of cover crops on soil erosion in the US Midwest.

This study examines the impact of cover crop adoption on soil erosion levels in the United States (US) Midwest. Based on a novel county-level panel data set with information on soil erosion levels and remotely-sensed cover crop acreage, we estimate linear panel fixed effect econometric models and conduct a number of robustness checks to investigate the direct impact of cover crops on two major types of soil erosion (wind and water erosion). Although we find that counties with higher cover crop acreage have statistically lower soil erosion levels due to water, wind, or both, we believe that the magnitudes of the estimated effects are modest. Longer-term multi-year use of cover crops also do not seem to increase the soil erosion reducing effects of cover crops over time. Results from the empirical analysis provide further empirical evidence on the impact of cover crops on soil erosion based on data that captures farmer behavior at the county-level and covers a wider geographical region in the US. Our findings also give insights to policy makers in terms of further understanding the magnitude of the soil erosion benefits from cover crops.

Assessing returns to research investments in rice varietal development: Evidence from the Philippines and Bangladesh.

•This study estimates economic returns to investments in rice varietal development in the Philippines and Bangladesh.•The net returns to IRRI and national partners' investments remain strongly positive.•However, the returns are decreasing at a faster rate in the Philippines (24%) than in Bangladesh (6%).•IRRI and national partners should continue investing in rice R&D, especially to develop superior rice varieties.

Perspective: enhancing economic evaluations and impacts of integrated pest management Farmer Field Schools (IPM-FFS) in low-income countries.

Over the last few decades, the use of Farmer Field Schools (FFS) have been considered one of the best approaches to disseminate integrated pest management (IPM) practices that aim to reduce reliance on and misuse of chemical pest control methods in agriculture. However, the published empirical literature has been decidedly mixed in terms of the effectiveness of the IPM-FFS approach to improve economic outcomes in the short-term (e.g. reduce chemical use, improve profits), and the potential for scaling-up and IPM dissemination in the medium-term. This article briefly explores the empirical IPM-FFS literature and draws implications for future research directions that can potentially enhance IPM knowledge diffusion methods (including IPM-FFS) and increase the economic impact of IPM techniques in low-income countries. We find that promising research directions to improve understanding of IPM dissemination and IPM impacts will need to involve: (i) interdisciplinary long-run studies using rigorous evaluation methods; (ii) in-depth assessments of spillover effects; (iii) careful examination of IPM and IPM-FFS impact heterogeneity; (iv) evaluation of novel IPM packages with herbicide- and genetics-centered components; (v) piloting and impact assessments of alternative IPM knowledge diffusion structures; and (vi) piloting and impact analysis of IPM dissemination and learning programs with private sector involvement. © 2020 Society of Chemical Industry.

Greater sensitivity to drought accompanies maize yield increase in the U.S. Midwest.

A key question for climate change adaptation is whether existing cropping systems can become less sensitive to climate variations. We use a field-level data set on maize and soybean yields in the central United States for 1995 through 2012 to examine changes in drought sensitivity. Although yields have increased in absolute value under all levels of stress for both crops, the sensitivity of maize yields to drought stress associated with high vapor pressure deficits has increased. The greater sensitivity has occurred despite cultivar improvements and increased carbon dioxide and reflects the agronomic trend toward higher sowing densities. The results suggest that agronomic changes tend to translate improved drought tolerance of plants to higher average yields but not to decreasing drought sensitivity of yields at the field scale.