Wheat is a staple crop throughout much of India, but in many areas it is commonly sown past the optimum window for yields. Recent technologies, such as adoption of no-till practices or earlier maturing cotton and rice varieties, have enabled some farmers to sow wheat earlier, but repeatable and publicly available measurements of sow date trends are lacking. Here we utilize satellite measurements since 2000 to estimate sow dates over a decade throughout wheat growing areas in India.
An important source of uncertainty in anticipating the effects of climate change on agriculture is limited understanding of crop responses to extremely high temperatures. This uncertainty partly reflects the relative lack of observations of crop behaviour in farmers’ fields under extreme heat. We used nine years of satellite measurements of wheat growth in northern India to monitor rates of wheat senescence following exposure to temperatures greater than 34 °C.
Seeds of Sustainability is a groundbreaking analysis of agricultural development and transitions toward more sustainable management in one region. An invaluable resource for researchers, policymakers, and students alike, it examines new approaches to make agricultural landscapes healthier for both the environment and people.
Improving crop yields in major agricultural regions is one of the foremost scientific challenges for the next few decades. In Northwest India, the stagnation of wheat yields over the past decade presents a distressing contrast to the tremendous yield gains achieved during the Green Revolution. One commonly proposed way to raise yields is to reduce the often considerable gap between yield potential and average yields realized in farmers' fields, yet the likely effectiveness of different strategies to close this gap has been poorly known.
Geographic information systems (GIS) present new opportunities for empirical agronomic research that can complement experimental and modeling approaches. In this study, GIS databases of irrigation practices for more than 4000 fields were compared with wheat yields derived from remote sensing for five growing seasons in the Yaqui Valley of Northwest Mexico. Significant yield effects were observed for both number and timing of irrigations, but not for reported water volumes, suggesting that proper timing is more important to yields than total water amounts.
Trends in recent temperature observations and model projections of the future are characterized by greater warming of daily minimum (tmin) relative to maximum (tmax) temperatures. To aid understanding of how tmin and tmax differentially affect crop yields, we analyzed variations of regional spring wheat yields and temperatures for three irrigated sites in western North America that were characterized by low correlations between tmin and tmax. The crop model CERES-Wheat v3.5 was evaluated in each site and used to project future response to temperature changes.
Wheat yields in Mexico, which represent an important measure of breeding and management progress in developing world wheat production, have increased by 25% over the past two decades. Using a combination of mechanistic and statistical models, we show that much of this increase can be attributed to climatic trends in Northwest states, in particular cooling of growing season nighttime temperatures.
Improved understanding of the factors that limit crop yields in farmers' fields will play an important role in increasing regional food production while minimizing environmental impacts. However, causes of spatial variability in crop yields are poorly known in many regions because of limited data availability and analysis methods. In this study, we assessed sources of between-field wheat (Triticum aestivum L.) yield variability for two growing seasons in the Yaqui Valley, Mexico.
Increased efficiency of nitrogen (N) fertilizer use may be achieved with management practices that account for spatial variability in soil properties and temporal variability in climate. In this study, we develop a N management decision model for an irrigated wheat system that incorporates hypothetical diagnostics of soil N and growing season climate. The model is then used to quantify the potential value of these forecasts with respect to wheat yields, farmer profits, and excess N application. Under the current scenario (i.e.
Nitrate leaching from agricultural soils can represent a substantial loss of fertilizer nitrogen (N), but a large variation in losses has been reported. We report N leaching losses under four N fertilizer treatments and two farmer's fields in the Yaqui Valley, Mexico. In these irrigated wheat systems, farmers typically apply 250 kg N as anhydrous ammonia (knifed in) or urea (broadcast), with 75% applied directly before planting and 25% at the time of the first post-planting irrigation.
Nitrogen fertilization is a substantial source of nitrogen-containing trace gases that have both regional and global consequences. In the intensive wheat systems of Mexico, typical fertilization practices lead to extremely high fluxes of nitrous oxide (N2O) and nitric oxide (NO). In experiments, lower rates of nitrogen fertilizer, applied later in the crop cycle, reduced the loss of nitrogen without affecting yield and grain quality. Economic analyses projected this alternative practice to save 12 to 17 percent of after-tax profits.