Protecting Our Soil

Linda Benedict, Tubana, Brenda S.  |  7/26/2013 8:18:26 PM

Brenda S. Tubaña

Soil is a vital natural resource, making possible the production of food, fiber and fuel. Soil is usually perceived as a reservoir of water and plant-essential nutrients, but soil functions also as a filtering and buffering system for pollutants, keeping the environment safe and healthy for humans and other living organisms.

Soil in itself is an ecosystem of sand, silt and clay particles composed of water, air, organic matter, nutrients, living organisms and minerals. The amount and type of these components and their interactions determine soil’s ability to serve as a medium for plant growth and a natural filtering system. These components interact making soil a site for storage, immobilization and degradation of any organic and inorganic materials introduced to the system such as fertilizer nutrients, animal waste and other chemical inputs.

Soil and its components change in response to human activities, often rapidly and with far-reaching consequences. It is up to us to determine whether these human-induced changes lead to either degradation or enhancement of soil functions.

Louisiana has an estimated land area of 28 million acres of which 14 million acres are forests and 8.1 million acres are in agricultural production – 3.5 million acres in farms cultivating a wide array of crops and vegetables and the remaining 4.6 million acres used for raising livestock. In 2012, plant commodities’ total value was more than $7 billion with an additional $3 billion for animal commodities.

Soil’s contribution to protect water quality is important in Louisiana perhaps more than in any other state. Numerous bodies of water are found in and around the state. The water quality of lakes and rivers, apart from the Gulf of Mexico, is of profound importance for the fishing industry and tourism, which bring significant revenues to the state.

Without a doubt, the soil beneath our feet is slowly degrading, losing its ability to function – not to mention the acres of land in Louisiana’s coastal zone lost to erosion and the rising water level. Restoration of degraded soils and protection of those soils in use are not mere actions that will benefit future generations but our way of returning the favor to the soil.

The LSU AgCenter has taken giant steps through its research and extension programs to sustain agricultural production, while keeping the industry competitive and protecting the environment. The research takes place at research stations across Louisiana and in academic departments on campus. The extension programs ensure delivery of the research outputs through field day demonstrations, grower meetings and provisions of on-farm technical assistance.

Soil science-related research is not limited within the group of soil science faculty in the School of Plant, Environmental & Soil Sciences. Scientists from other academic departments also are involved in soil and wetland restoration programs. The School of Plant, Environmental & Soil Sciences, however, provides major facilities for faculty members who conduct research and teach. Students enrolled in the school acquire basic and applied scientific training in the major disciplines of soil science: soil chemistry, soil physics, soil classification, soil fertility and plant nutrition.

Off-campus research stations house scientists who specialize in different areas of agricultural sciences. Stations are strategically located where certain commodities are of greater importance than in other areas of the state. Stations provide field space, equipment and facilities for scientists who conduct research in many areas of agricultural disciplines including soil science. The research ensures productivity of certain commodities and ensures efficient use of agricultural inputs and conservation of soil quality.

A few of the topics addressed in research and extension programs are included in this issue of Louisiana Agriculture. The impact of different sugarcane residue management strategies on water runoff, surface water quality and carbon sequestration has been evaluated. In partnership with scientists from other universities, AgCenter faculty are investigating the influence of several farming practices on soil and air quality, which include nitrogen fertilization, burning of sugarcane residues, and application of biochar produced from sugarcane and rice stubbles. Research on management practices to help minimize phosphorus from manure waste application and erosion remediation through crop residue management has been pursued.

There is an ongoing, statewide collaborative effort to establish robust nutrient management approaches to increase fertilizer use efficiency. To keep up with the changing production technologies and adoption of high-yielding varieties, multiple field calibration trials are established every year at different locations in Louisiana. The data from these trials are used to update and validate the LSU AgCenter fertilizer recommendations for a wide array of field crops. Several scientists are evaluating new technologies associated with precision nitrogen management. The idea is to feed the soil with the right amount of nitrogen at the time when the plant needs it most. Controlled- and slowrelease nitrogen fertilizer in rice and corn and use of remote sensing to operate variable nitrogen rate technology for major row crops of Louisiana are being tested in research plots and producers’ fields. The rapid measurement of soil and plant elemental composition with the use of reflectance spectroscopy has been studied and documented. From a series of field trials, the practice of planting soybeans during the fallow period of sugarcane was documented and identified as an efficient practice for protecting soil and water resources.

The research outputs from decades of work have been instrumental in sustaining and growing the agricultural industry in Louisiana. Looking ahead, the mission of the LSU AgCenter soil science program should continue not only in delivering cutting-edge technologies in agriculture to improve farming business and maintain the quality of environment but also in educating and training future scientists so we can continue returning the favor to this vital natural resource – protecting our soil.

Brenda S. Tubaña is an associate professor in the School of Plant, Soil & Environmental Sciences.

(This article was published in the spring 2013 issue of Louisiana Agriculture magazine.)

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