Out of several various ones, Arundo is the most promising energy plant due to its tolerance to a wide range of environmental stresses, and in addition, it can be cultivated on marginal lands which can not be used for traditional food crops. An open field experiment in a fastly eroding soil was carried out in order to evaluate Arundo agronomy and thte environmental impact of giant reed during the first 9 years of cultivation (2003-2012). The investigation took place in the Southern region of Italy, which is full of hilly, marginal lands.
Arundo can remediate soil as we know from the previous article (article legyen az előző phytoremedationos cikk a bányászati) The cultivation had favourable effects on environmental quality thanks to the improvement in soil fertiliy or mitigation of climate change.
What is soil erosion and what causes it?
Soil erosion is a naturally ocurring process that affects all landforms. In agriculture soil erosion refers to the wearing away of a field’s topsoil by the natural physical forces of water. There are 5 types of soil erosion; Splash Erosion, Sheet erosion, Rill erosion, Gully erosion, Stream Bank erosion.
Soil erosion is mainly caused by Natural forces like; running water, enormous winds or glaciers. However, you can not go by the fact that anthropogenic (Human) activities accelerate and impair soil erosion!
Arundo Agronomy Experiment
Materials and Methods
The investigation was conducted on the Centro Rotary experimental farm on the foothills of Appenine mountain range in Southern Italy. They collected Arundo rhizomes from the wild in the vicinity of the investigation plot. They planted 1 plant/m2 in a 140m2 plot. Harvests were made at the end of growth periods. In the first 4 years, the harvest happened in Autumn, mainly in October/November, however, in the fifth year they postponed the harvest season to midwinter. Cutting shoots, weighing the total biomass and separating the remaining leaves from the culms were also the part of the process. After these, they dried the Arundo’s at 70 °C.
The researchers collected soil too, for further investigation, and they made other measurements, for instance its C and N content, water balance, biomass yield, normality of distribution and homogeneity of variance.
Results and conclusion
Biomass yield was lower in the first 3 years, (the average value of 9 t ha dry weight) however, from 2007 to 2012, without any significant differences, the average biomass yield increased to a value of 18 t ha dry weight.
Effect on Soil C and N Content
C content significantly increased from the year 2004 to 2012. There were 3 layers tested, here are the results:
0-20 cm top layer: from 7.97 to 11.33 g kg−1
20-40 cm layer: from 6.98 to 8.83
40-60 cm layer: the increasing rate was near zero and the linear regression was not significant.
The Nitrogen content values until 2007 in the top layer were lower than those from 2008 to 2013. This difference may be due to the increase in N transfer to the soil through the leaf litter, as already noted for other species, because in 2007, as mentioned before, they decided to postpone harvest to full winter, thus resulting in higher leaf fall. The intermediate region (20-40 cm) did not change over the years, but surprisingly the deeper layers N content decreased.
0-20 cm top layer: from 0.8 to 1.118 g kg-1
20-40 cm layer: no change at all
40-60 cm layer: from 7.2 to 6.6 g kg−1
How can Arundo agronomy solve soil erosion?
There are plenty of ways to deal with soil erosion:
- Replant vegetation
Plant various herbaceous plants such as Arundo donax or woody stemmed plants such as Acacia tree in the eroded soil. This allows organic matter to build up. A well-established vegetation can stabilize the soil with their roots.
- Footpaths – step stones
Place step stones, gravel or mulch to exposed degradated soil. This techique is especially great for areas with heavy foot traffic in your garden. Did you know that it takes 500 years for just 2.5 cm of topsoil to be created?
Another great and effective but requiring hard-work solution for soil erosion is building terraces. This action could require professional engineering and building permit in special cases.
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