Soil is composed of minerals, soil organic material (SOM), water, and air, according to the Montana State University’s soil scientists, Ann McCauley. The actual composition of these various components within soil has a big influence on the porosity; i.e., the composition affects the movement of water into and through the soil (McCauley, 2005), and the movement of water into and through soil is absolutely necessary for productive crops, and healthy ecosystems. The binding together of soil particles is called “aggregation” and when water passed into the soil aggregation, if it is healthy, will keep the porosity and water movement slow and productive, which “improves fertility and carbon sequestration in the soil” (avoiding erosion at the same time) (McCauley).
McCauley explains that the pores in the soil have a number of important functions. Soil that is coarse will have many pores and fine-textured soils; because they are “more tightly arranged” have smaller pores. When the soil has been cultivated over the long term, the soil’s porosity decreases because of a decrease in soil organic material, McCauley continues. When there is a lot of crusting on the surface of the soil, and compaction, it decreases porosity and “inhibits water entry into the soil” (McCauley). And when there is crusting, and the water cannot penetrate the soil, erosion and rapid runoff of water is in evidence. On the other hand, in Montana when the soil has good porosity, water then can get through the topsoil and fill the pores until they are saturated. Some of that water will “drain freely from the soil via gravity” and some will be held in “micropores” (called capillary forces), to be removed by the roots of plants drawing it up (“uptake”) or by evaporati...
... middle of paper ...
...teract in ways that sustain both the soil and the crops or other vegetation, no matter where on the planet this interaction might occur. In Montana, understanding the importance of soil porosity can help keep farmers from over-cultivating; and in Brazil, where tree canopy ecosystems are being burned in favor of grassy savannah, understanding those dynamics helps agricultural professionals and farmers in their efforts to maintain balanced, productive soils.
Works Cited
McCauley, Ann, and Jacobsen, Jeff. Basic Soil Properties. Retrieved June 10, 2011,
From http://landresources.montana.edu/swm/PDF/Final_proof_SW1.pdf. (2005).
Oliveira, R. S., Bezerra, L., Davidson, E. A., Pinto, F., Klink, C. A., Nepstad, D. C., and
Moreira, A. “Deep root function in soil water dynamics in cerrado savannas of central Brazil.
Functional Ecology, Vol. 19 (2005): 574-581.
Sclauser Pessoa, I. B., Costa, D., Velloso, M., Mancuzo, E., Reis, M. S., & Parreira, V.F.
Cox-Foster, D. L., Conlan, S., Holmes, E. C., Palacios, G., Evans, J. D., Moran, N. A.,…
The European settlers who first arrived at the Great Plains found hardy grasslands that held the fine-grained soil in place in spite of the long recurrent droughts and occasional torrential rains. A large number of the travelers settled down in this area and built farms and ranches. These land uses led to soil exposure and great erosion. The cattle ranches were very profitable for the settlers; unfortunately, this led to overgrazing and degradation of the soil. In addition, farmers began to plow the natural grass cover and plant their own crops. Without the original root systems of the grass to anchor the soil, much of it blew away. The wide row crops were very disastrous because between the crops, the land was kept bare; as a result, this area was exposed to the elements. Also, the nutrients in the soil were used up by the plants faster than they could be replaced. The soil had become exhausted.
Vahey, C. D., Aiken, H. L., Sloane, M. D., Clarke, P. S., and Vargas, D. (2010 Jan. 15).
Mississippi has a variety of different soils .The three general soils are 1) the river flood plain, known as the Delta, 2) a loess region, or bands of soils formed in windblown material that adjoins the Delta, and 3) Coastal Plain. The Mississippi Delta is better for growing row crop, while the loess and Coastal Plain region are better for animal production and forestry. The loess and Coastal Plain regions are divided based on similar soils, geology, climate, water resources, and land use called Major Land Resource Areas. The Mississippi Delta’s soil comes from sediments left by flooding various rivers in the region, rather than being a typical Delta formed by the mouth of a river. In the Delta most of the land is farmed, with three-fourths of the cropland to the north. Controlling surface water and drainage are major soil management issues. In the Delta soils are naturally diverse because of their alluvial origin. Particle sizes within the sediment decrease as distance from the originating stream increase. Another factor in Delta soil formation us surface water movement over time, because soils that formed under standing water have different properties than soils formed under moving water. Soils with large amounts of clay particles have unique features. When the soil is dry, small round aggregates form at the surface that look like shotgun buckshot, which is where the popular name for Delta clay soils “buckshot” came from. Soils with large clay content have very slow water filtration rates; this has led to significant aquaculture and rice production in the region. When floodwaters receded in the Delta, strong winds blew some of the dry sediment left by flooded river to the adjacent uplands to form the loess areas. Because of eas...
Forsyth, K., Taylor, R., Kramer, J., Prior, S., Richie, L., Whitehead, J., Owen, C., & Melton, M.
The rich dark soil of Texas, Oklahoma, New Mexico, Kansas, and Colorado—an area also known as the Great Plains—formed from thousands of years of soil forming factors in action (Surviving the Dust Bowl). From the beginning of human populations living in the area, the soils, for the most part, remained untouched and unscathed by the plow. Thick prairie grasses covered the area and held the soils in the ground even during the periodic times of drought. This area of land was suitable for grazing practices and it was in this area that the large cattle ranches flourished. Little did the newly arrived farmers realize that this seemingly plentiful land followed a pattern of several years of rain followed by several years of drought and high winds.
Nitrogen and Irrigation on Coastal Plains Soils. So why is it important to look at nitrogen in soils? First of all, it is a key element in organic molecules, so it is key to plant growth (Singer and Munns). Nitrogen is useful to plants in the form of nitrate because plants can take in nitrate and form organic molecules (Singer and Munns, 1993).
Ottenberg, A. L., Wu, J. T., Poland, G. A., Jacobson, R. M., Koenig , B. A., & Tilburt, J. C.
Voltarelli, J. C., Couri, C., Stracieri, A., Oliveira, M. C., Moraes, D. A., Pieroni, F., Burt,
Kobau, R., Zack, M. M., Manderscheid, R., Palpant, R. G., Morales, D. S., Luncheon, C., et al.
Ornstein, R., Rosen, D., Mammel, K., Callahan, S., Forman, S., Jay, M., Fisher, M., Rome, E., &
Whelan, R., Conrod, P. J., Poline, J., Lourdusamy, A., Banaschewski, T., Barker, G. J, Bellgrove, M. A.,
Saline soil is also vulnerable to erosion due to the death of vegetation that held the soil together. Soil that is eroded can ‘pollute’ water too.
Soil is the most important non-renewable resource on any farm. Healthy soil is key to a good