- News Home
5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
- About Us
Fewer Chemicals, Better Tomatoes?
6 July 2004 (All day)
Replacing chemical with biological fertilizers may extend crop growth and ward off disease, a new study suggests. The finding, from experiments on tomatoes grown with a legume mulch, posits that the biological fertilizers alter gene expression to make crops more robust.
Agricultural output rose dramatically in the 1950s and '60s thanks to the high-yielding techniques of the "green revolution." But the techniques rely on chemical fertilizer and pesticides, which can harm human health, water quality, and wildlife. Some farmers and scientists have looked for ways to replace the chemicals with biological sources of fertilizer such as cover crops that can be plowed under or used as mulch to provide nutrients. While supporters claim more vigorous growth and pest resistance, critics point to a lack of a scientific explanation for that improvement.
To investigate, plant biochemist Autar Mattoo and colleagues at the U.S. Department of Agriculture's Agricultural Research Center in Beltsville, Maryland, grew tomatoes under two types of field conditions. The conventional condition included black plastic row covers for weed control and a full dose of fertilizer. The other tomatoes got a mulch of hairy vetch, a legume that provides nitrogen and controls weeds, and a half dose of fertilizer. The researchers sampled leaves three times during the season and screened for genes whose expression differed under the different growing conditions.
Leaf death and disease onset in tomatoes grown with the legume was delayed by 2 weeks compared with tomatoes grown conventionally. And legume-grown tomato leaves expressed higher levels of nitrogen uptake genes, such as rubisco and glutamine synthetase, and defense genes, such as chitinase and osmotin, the authors report online this week in the Proceedings of the National Academy of Sciences. Mattoo says the research is another prod for farmers to investigate alternative techniques, which he says could increase yields by up to 20%, at least for tomatoes.
"The study has to be done in a lot more systematic manner," says Kulvinder Gill, a crop geneticist at Washington State University in Pullman, who faults the paltry data and statistics presented. Even so, Gill says he'd be surprised if the findings are not borne out by larger, more tightly controlled experiments.