(Press-News.org) Organic matter is important for soil health and crop productivity. While an indicator of soil quality, a lot of organic matter is in extremely stable forms, and the nutrients in such forms are difficult for plants to use. The active, labile fraction, however, is a modest but important part of the organic matter.
"The labile fraction is small – usually less than 20 or even 10 percent, depending on how you define it," explains Steve Culman, lead author of a study published online Feb. 8 in Agronomy Journal. "But it is where a lot of the action happens. It's where soil nutrients are rapidly cycled and are interacting with microbial communities."
The size of the labile pool, then, can be an important predictor of corn agronomic performance. But the tests used up to this point to measure those pools, such as microbial biomass and particulate organic matter, were labor intensive and expensive. Culman, in Sieg Snapp's lab at the W.K. Kellogg Biological Station, decided to use other measurements of the labile fractions – including nitrogen mineralization and carbon mineralization – to see what information these inexpensive tests might give them. Their results suggest that simple measures of labile organic matter can reflect long-term management and short-term seasonal changes as well as predict corn performance.
To better understand labile soil organic measurements and what they could tell farmers, the researchers measured soils managed in a variety of conditions. Fields were maintained with three different management practices (conventional, integrated, and compost) and two different crop rotations (continuous corn with no cover crops and corn-soybean-wheat with cover crops). After collecting soil from the different fields, the scientists then measured carbon and nitrogen mineralization.
"What's nice about carbon and nitrogen mineralization is they're based on actual biological activity," says Culman. "You take into account the soil microbes and environment for these tests."
A long-term cropping system trial provided the perfect opportunity to test the extent to which carbon and nitrogen mineralization measurements were affected by both management practice and crop rotation. These tests, then, could be used to identify the best practices, such as fertilizer application, for a given field. This would be especially useful for nitrogen – a nutrient that is incredibly important for crop growth but is rarely measured by farmers.
"Most farmers don't test their soils for nitrogen," explains Culman. "They just basically apply a rate based on their yield goals, and excess nitrogen may be applied. The long-term goal would be to offer these as predictive tests for farmers so they can say, 'Given my soil type, management, and these measures, I should apply this amount of nitrogen.' That's the ultimate goal."
The predictive power of such tests for best management practices goes hand-in-hand with crop performance. The researchers also found that carbon mineralization was a better predictor of corn agronomic performance than other measures that are currently used (pre-sidress nitrate test and leaf chlorophyll). With these tests, Culman and his coauthors hope to provide farmers with better tools to manage their fields and increase crop yields.
Says Culman, "This could have tremendous impacts, locally, regionally, and nationally, in terms of having tools that better predict our cropping system performance based on soil properties."
###
The full article is available for no charge for 30 days following the date of this summary. View the abstract at https://dl.sciencesocieties.org/publications/aj/abstracts/0/0/agronj2012.0382.
A peer-reviewed international journal of agriculture and natural resource sciences, Agronomy Journal is published six times a year by the American Society of Agronomy, with articles relating to original research in soil science, crop science, agroclimatology and agronomic modeling, production agriculture, and software. For more information visit: www.agronomy.org/publications/aj.
The American Society of Agronomy (ASA), is a scientific society helping its 8,000+ members advance the disciplines and practices of agronomy by supporting professional growth and science policy initiatives, and by providing quality, research-based publications and a variety of member services. END
Can simple measures of labile soil organic matter predict corn performance?
2013-02-11
ELSE PRESS RELEASES FROM THIS DATE:
Study finds planned C-sections provide no advantage over planned vaginal birth of twins
2013-02-11
In a study to be presented on February 14 between 8 a.m., and 10 a.m. PST, at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting ™, in San Francisco, researchers will report findings that suggest that planned birthing of twins at 32-38 weeks by cesarean section does not decrease perinatal or neonatal death compared to planned vaginal birth.
This randomized study The Twin Birth Study: a multicenter RCT of planned cesarean section and planned vaginal birth for twin pregnancies 320 to 386/7 weeks, should help women understand that a planned vaginal ...
Study suggests genetic predisposition to brain injury after preterm birth is sex-specific
2013-02-11
In a study to be presented on February 14 between 1:15 p.m., and 3:30 p.m. PST, at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting ™, in San Francisco, researchers will report that variation in a gene involved in inflammation is associated with developmental problems after preterm birth in females, but not males.
This randomized study, Sex-specific genetic susceptibility to adverse neurodevelopmental outcome after early preterm birth, may improve understanding of how developmental problems occur after preterm birth and may help identify ...
Study suggests tightening up of criteria for definition of intrauterine growth restriction
2013-02-11
In a study to be presented on February 14 between 1:15 p.m., and 3:30 p.m. PST, at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting ™, in San Francisco, researchers will report that the practice of using an arbitrary Estimated Fetal Weight (EFW) less than the 10th centile may not be an efficient practice for defining true Intrauterine Growth Restriction (IUGR).
The study was conducted by the Perinatal Ireland Research Consortium, a nationwide collaborative research network comprising of the seven largest academic obstetric centers in Ireland. ...
Policy changes in elective delivery proven successful
2013-02-11
In a study to be presented on February 14 between 1:15 p.m., and 3:30 p.m. PST, at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting ™, in San Francisco, California, researchers will present data showing changes in elective delivery policy have been successful in reducing elective deliveries prior to 39 weeks.
Due to the troubling trend of elective delivery and induction, significant attention has been paid to the neonatal benefits of reducing elective deliveries before 39 weeks, both on the national and institutional level. Elective delivery ...
Better outcome for frozen embryo replacement vs IVF
2013-02-11
In a study to be presented on February 14 between 1:15 p.m., and 3:30 p.m. PST, at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting ™, in San Francisco, California, researchers will present findings showing perinatal outcomes of frozen/thawed embryo replacement (FER) have better outcomes compared to fresh in vitro fertilization (IVF), but worse outcomes compared to the non-IVF general population.
The study collected data from all IVF treatments in Denmark, Norway and Sweden from 1984 – 2007, then cross-linked with the Nordic Medical Birth ...
Preemptive treatment of severe morning sickness decreases suffering for moms-to-be
2013-02-11
`In a study to be presented on February 14 between 1:15 p.m., and 3:30 p.m. PST, at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting ™, in San Francisco, California, researchers will present data showing the effectiveness of preemptive treatment for hyperemesis gravidarum and severe morning sickness.
Hyperemesis gravidarum is a severe form of morning sickness which effects one in 50 pregnant women. HG is marked by persistent nausea and vomiting, and can begin early in the first trimester, continuing well into the second, third or even up ...
Differences in obstetric outcomes and care related to race and ethnicity
2013-02-11
In a study to be presented on February 14 between 1:15 p.m., and 3:30 p.m. PST, at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting ™, in San Francisco, California, researchers will present data showing racial and ethnic disparities exist for adverse obstetric outcomes.
In his study Dr. William Grobman of Northwestern University, presenting for the Eunice Kennedy Shriver National Institute of Child Health and Human Development, studied 115,502 women over a three year period to see if adverse obstetric outcomes and provisions in obstetric ...
Abnormal brain development in fetuses of obese women
2013-02-11
In a study to be presented on February 15 between 8 a.m. and 10 a.m. PST, at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting ™, in San Francisco, California, researchers from Tufts Medical Center will present findings showing the effects of maternal obesity on a fetus, specifically in the development of the brain.
The study, conducted at the Mother Infant Research Institute (MIRI) at Tufts Medical Center in Boston, Mass., looked at the fetal development of 16 pregnant women, eight obese and eight lean, to see what effects maternal obesity ...
Obstructive sleep apnea and cardiac symptoms have 31 percent incidence of cardiac dysfunction
2013-02-11
In a study to be presented on February 15 between 8 a.m., and 10 a.m. PST, at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting ™, in San Francisco, researchers will report findings that women with obstructive sleep apnea (OSA) and cardiac symptoms have a 31 percent incidence of cardiac dysfunction. The use of echocardiograms should be considered in the clinical management of these women.
OSA is characterized by abnormal pauses in breathing or instances of abnormally low breathing, during sleep. These pauses can last from at least ten seconds ...
Community health workers help type 2 diabetes care
2013-02-11
PROVIDENCE, R.I. [Brown University] — Newly published results from a randomized controlled clinical trial in the Pacific U.S. territory of American Samoa add clear evidence for the emerging idea that community health workers can meaningfully improve type 2 diabetes care in medically underserved communities.
In the U.S. territory, 21.5 percent of adults have type 2 diabetes. Meanwhile, 58 percent of families are below the U.S. poverty level. The research team, led by public health researchers from Brown and The Miriam Hospital, wanted to test whether four trained local ...