- Author: Luis Espino
I recently read an interesting article that forecasts the production of greenhouse gases (GHG) from ricelands by the end of the 21st century1. The authors used data from 63 studies conducted in 30 different locations in 8 different countries.
This article prompted me to try to put rice-related global and local GHG emissions into context. In other words, what are the estimated contributions of ricelands in general and California ricelands more specifically to global GHG emissions? This information is not easy to find, so I thought it would be good to share it here. I compiled estimates from two sources, the Intergovernmental Panel on Climate Change (global data, 2005) and the California Air Resources Board (California data, 2009). There are probably other estimates out there, but I think the ones I present here are reliable.
As you can see, worldwide ricelands account for 1.3% of all GHG emissions. California agriculture and forestry account for 0.06%, and California ricelands contribute a minute amount to GHG emissions on a global basis. Even when considered on a statewide basis, ricelands emissions are only 0.1% of California's total GHG inventory.
1 Van Groenigen, K. J., C. van Kessel, and B. Hungate. 2012. Increased greenhouse gas intensity of rice production under future atmospheric conditions. Nature Climate Change (http://dx.doi.org/10.1038/nclimate1712)
- Author: Luis Espino
In 2011, the Natural Resources Conservation Service (NRCS) developed a program to assist rice producers adopt and apply conservation practices to provide and maintain shallow water wetlands, mudflats, nesting islands, and other associated wildlife structures that provide for seasonal or year-round breeding and wintering habitat for shorebirds, wading birds, and waterfowl. Here's a NRCS video giving an overview of the program.
- Author: Luis Espino
In the past few days we've seen some unusual high temperatures in the Sacramento Valley, and looks like the hot weather is going to continue for a few more days. By mid morning temperatures are reaching 80o F, by 2 pm we are close to 90o F, and late in the afternoon temperatures can easily reach 100o F or more. Rice at the moment is heading (40% headed by August 12, according the USDA's Statistics Service report), putting some rice at risk of high-temperature sterility.
Anthesis (the opening of the flowers or spikelets) is the most susceptible stage of rice to high temperature damage. Very high temperatures cause indehiscence of anthers (anthers not opening), reduce pollen production and viability, and can dry the germinating pollen tube before fertilization occurs. In rice, spikelet sterility by heat occurs during and up to 3 hours after anthesis. Once fertilization is complete, spikelet sterility does not occur. Generally, anthesis is believed to occur between 9:00 am and 2:00 pm. In one study*, anthesis in M-202 was found to occur between 9:30 and 10:30 am. Given these times, rice would be susceptible to high temperature spikelet sterility from morning to mid afternoon.
In the above referenced study, when the average daytime temperature during anthesis was 95o F, spikelet sterility increased by more than 70%. Unfortunately, the study did not indicate the temperatures right at anthesis, just the daytime average. It is believed that temperatures should be above 104o F during anthesis to cause sterility. We had a couple of days last week when temperatures reached this level, putting rice at risk of spikelet sterility. We'll have to wait to evaluate if this actually happened.
*Prasad, P. V. V., K. J. Boote, L. H. Allen Jr., J. E. Sheehy, and J. M. G. Thomas. 2006. Species, ecotype and cultivar differences in spikelet fertility and harvest index of rice in response to high temperature stress. Field Crops Research 95: 398-411
