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Archive | Soil Fertility

The Soil Solution

The Soil Solutionby Graeme Sait

The UN has named 2015 International Year of Soils, and we should embrace this initiative with open hearts and willing hands. It is an incredibly timely focus in light of a series of serious challenges impacting our future and perhaps our very existence. Soil health directly affects plant, animal and human health. It also impacts topsoil erosion, water management and ocean pollution. Most importantly, it is now recognized that climate change is directly related to soil mismanagement. I believe a global soil health initiative can help save our planet.

The Top Five Threats

While in the UK, I met with a professor who shared some deeply concerning findings. He informed me that a recent survey of leading British scientists revealed that as many as one in five of the best thinkers in the country believe that we will be extinct as a species by the end of this century, or perhaps much earlier. This information should serve to spur meaningful action from every one of us. There are five core threats that need to be urgently addressed, and they all relate back to the soil. Continue Reading →

Fish Fertilizer Meets Nitrogen Needs

Organic LettuceThe authors of a new study have found that hydrolyzed fish fertilizer holds promise as an economically feasible nitrogen source for growing organic vegetables.

“Soluble organic nitrogen sources suitable for fertigation in organic vegetable production are much needed,” said lead author of the study, Charles Ogles. Ogles and colleagues at Auburn University studied the effects of three different nitrogen sources during a two-year crop sequence of yellow squash and collards. The scientists used hydrolyzed fish fertilizer, inorganic nitrogen (N) source with secondary and micronutrients, inorganic nitrogen without secondary or micronutrients and a zero nitrogen control for the study. Nitrogen was applied at recommended rates for both squash and collards, 80 percent of the recommended rates and 60 percent of the recommended rates. The study design included a zero nitrogen treatment used as the control.

“To eliminate the rotation order effect, the crops were switched each year: yellow squash-collard in year one and collard-yellow squash in year two” said Ogles. Continue Reading →

Interview: Forging a Better Path — Texas Farmer Jonathan Cobb Embraces Shift from Conventional to Biological-Based Practices

Jonathan Cobb Interview

Jonathan Cobb

Jonathan Cobb interviewed by: Chris Walters


This month’s interview swings our focus away from storied veterans to a newcomer, a young farmer trying to forge his way in the middle of Texas. Like a lot of others who dedicate themselves to rational agriculture based in soil science, Jonathan Cobb left his family’s land for a while, getting an education outside the ag school monolith, getting married and trying out urban life before coming full circle back to the land in 2007. He encountered an event in recent Texas history that felt apocalyptic at the time and still strains belief — the summer of 2011. As the worst Texas drought in about a century kicked in with a vengeance, temperatures exceeded 100 degrees for nearly three months, the land turned into brick and reservoirs dropped like a second-term president’s approval rating. As he relates, it forced a fresh look at all sorts of things. Along the way, a business Cobb ran with his wife, Jennifer Brasher, had to be folded, and he began a momentous transition away from row crops and into livestock. It also bears remembering that despite the influence wielded by the liberal enclave of Austin a mere hour away, rural Texas is not known for its open embrace of progressive ideas. For Jonathan’s refreshingly candid account of how he meets his challenges, read on.

ACRES U.S.A. Tell us about your neck of the woods near Rogers, Texas.

JONATHAN COBB. It’s Blackland prairie; really good, really rich, deep soils with a long history of farming there. My great-grandfather was a sharecropper since around 1900. My grandfather farmed it and then my Dad stayed. He was the youngest, and he stayed on the family farm. We were all gone when I decided to come back about eight years ago. I had been in Fort Worth doing landscape design and then came back and started farming. Continue Reading →

Biochar Alters Water Flow

Vincent Mina demonstrates biochar production in Maui.As more gardeners and farmers add ground charcoal, or biochar, to soil, a new study by researchers at Rice University and Colorado College could help settle the debate about one of biochar’s biggest benefits — the seemingly contradictory ability to make clay soils drain faster and sandy soils drain slower. The study, published in PLOS ONE, offers the first detailed explanation for the hydrological mystery.

“Biochar is light and highly porous,” said lead author Rebecca Barnes. “When biochar is added to clay, it makes the soil less dense and it increases hydraulic conductivity, which makes intuitive sense. Adding biochar to sand also makes it less dense, so one would expect that soil to drain more quickly as well; but in fact, researchers have found that biochar-amended sand holds water longer. … By adding our results to the growing body of literature, we show that when biochar is added to sand or other coarse-grained soils, there is a simultaneous decrease in bulk density and hydraulic conductivity, as opposed to the expected result of decreased bulk density correlated with increased hydraulic conductivity that has been observed for other soil types.” The study was summarized in the January 2015 issue of Acres U.S.A.

Boosting Corn Yields

corn.tifEnsuring that corn absorbs the right balance of nitrogen, phosphorus and potassium is crucial to increasing global yields, a Purdue and Kansas State University study finds.

A review of data from more than 150 studies from the United States and other regions showed that high yields were linked to production systems in which corn plants took up key nutrients at specific ratios — nitrogen and phosphorus at a ratio of 5-to-1 and nitrogen and potassium at a ratio of 1-to-1. These nutrient uptake ratios were associated with high yields regardless of the region where the corn was grown.

“The agricultural community has put a lot of emphasis on nitrogen as a means of increasing yields, but this study highlights the greater importance of nutrient balance,” said Tony Vyn, Purdue professor of agronomy. “We will not be able to continually boost global corn yields and achieve food security without providing adequate and balanced nutrients.” The paper was published online in the Agronomy Journal.

While U.S. corn producers have long relied on nitrogen fertilizers to improve yields, they should not overlook other nutrients such as potassium and phosphorus, Vyn said.

“Growers need to be as concerned about the amount of potassium available to their plants as they are about nitrogen,” he said. “Corn’s demand for nitrogen and potassium is similar. We need to focus on the nitrogen-potassium balance because that’s where we have the greatest deficiency in terms of application, especially in the eastern Corn Belt.”

This report appears in the November 2014 issue of Acres U.S.A.

Boron Plays Important Role in Corn Development

boron-deficiency-corn-fieldBoron deficiency is one of the most widespread causes of reduced crop yield. Missouri and the eastern half of the United States are plagued by boron deficient soil and, often, corn and soybean farmers are required to supplement their soil with boron; however, little is known about the ways in which corn plants utilize the essential nutrient. Now, researchers at the University of Missouri have found that boron plays an integral role in development and reproduction in corn plants. Scientists anticipate that understanding how corn uses the nutrient can help farmers make informed decisions in boron deficient areas and improve crop yields.

“Boron deficiency was already known to cause plants to stop growing, but our study showed that a lack of boron actually causes a problem in the meristems, or the stem cells of the plant,” said Paula McSteen, associate professor in the Division of Biological Sciences. “That was completely unknown before. Through a series of experiments involving scientists from several disciplines at MU, we were able to piece together the puzzle and reach a new conclusion.”

Meristems comprise the growing points for each plant, and every organ in the plant is developed from these specialized stem cells. Insufficient boron causes these growing points to disintegrate, affecting corn tassels and kernels adversely. When tassels are stunted, crop yields are reduced, McSteen said.

The research evaluated a group of plants stunted by its ability to grow tassels. Kim Phillips, a graduate student in McSteen’s lab, mapped the corn plant’s genome and found that a genetic mutation stunted tassel growth because it was unable to transport boron across the plant membranes, inhibiting further growth in the plants. Continue Reading →