Example of a Claim: Solution to the Problem of Soil Degradation

Here is an example of a claim in an essay and it states that: soil degradation can be controlled with sustainable farming practices.

Rationale

Worldwide agriculture industries are being faced with the ever-growing demand for food, clothing and shelter. By 2050 the global population is expected to increase to 9.8 billion people and the demand on the agricultural sector will increase. To match the demand that the population increase will require, the agriculture sector will need to expand by 60%; but global warming, expansion of cities, soil degradation ,water limitations, increased pollution and inequity, there will be a global crisis if the agriculture sector does not adopt new, more sustainable practices.

Soil degradation is amongst the most severe environmental problems facing Australia. Only 10% of the 7.7 million square kilometres of Mainland Australia is suitable for pasture and crops, of the suitable land, 50% required treatment because of soil degradation. In the non-arid regions of Australia, (mostly Eastern Australia), the largest cause of soil degradation is water erosion. In the arid Regions of Australia (South Australia, Central Queensland and NSW, Northern territory), the cause of soil degradation varies significantly depending on circumstances such as wind erosion, soil salinity and vegetation degradation; however, these are more prominent because of over grazing and drought.

With new, more efficient, practices being adopted to overcome these challenges, measures need to be implemented to prevent soil degradation and its effect on the yield of a crop. To gain an understanding of this, more research needs to be conducted into sustainable ways of prevention and repair, such as contour banks, strip farming crop rotation and wind breaks.

Crop rotation has been selected as the focus of this investigation as it has multiple benefits. The main benefits of crop rotation are; nitrogen management, plants are unable to absorb nitrogen straight from the atmosphere, instead they need a fixed version. Naturally this is achieved by legumes as they have the unique ability of being able to absorb nitrogen directly from the atmosphere and attach it to the nodules on the roots. When legumes are used in crop rotation it reduces the need for nitrogen-based fertilizers, which in turn reduces the risk of run off and lessens the effect on the eco-system. The next benefit of crop rotation is increased water conversation. Crop rotation provides a good soil structure through the combination of shallow and deep roots systems, this allows water to seep underground reservoirs and lowers the risk of flooding as the soil is more absorbent. This then decreases the risk of erosion as soil exposure is at a minimum. This is because the diversity of the spacing between the rows provides cover for the topsoil from wind and sun.

Research question

To what extent does crop rotation increase the yield of wheat and chickpeas whilst simultaneously decreasing the rate of soil degradation?

Arguments and Evidence

Crop rotation is an important long-term practice to deter weeds, disease and water restrictions. Daniel et al. discusses the many possible benefits of crop rotation, yield of a wheat crop was significantly increased after the planting of chickpeas as a winter crop, this correlated directly to the increased level of nitrogen in the soil and the decreased need for additional nitrogen-based fertilisers as seen Trials were conducted at sites in Qld and NSW, and in each trial the results were almost parallel. The soil conditions of the NSW site were most likely more suited to chickpeas as the average yield was 0.4 t/ha more than the QLD site. The monoculture cropping of wheat both produced similar yields will no nitrogen fertiliser applied, although the protein percentage of the NSW sites’ wheat had a higher protein percentage than the of the Qld sites. This shows that the Nsw site was likely a clay loam, whereas the Qld site was a Loam. The wheat after chickpeas without nitrogen fertiliser showed significant improvement over the monoculture cropping of wheat. The protein levels were significantly increased, this shows that the nitrogen levels in the soil is increased by the fixation of nitrogen by chickpeas. In the secondary experiment were 75-150 kg of N/ha was applied, the yield of wheat after chickpeas was increased by 0.3 t/ha compared to monoculture cropping of wheat. This demonstrates the effectiveness of using crop rotation to decrease economic and environmental stress.

Aisthorpe concluded that through the use of a rotation system consisting of wheat and chickpeas, growers fixated approximately $55 million worth of nitrogen fertiliser just by planting chickpeas or similar legumes as a rotation crop. The results show that growers were harvesting a larger yield when chickpeas and wheat was used in a rotation system compared to monoculture cropping of wheat. This trend did not change when rates of 20, 40 and 60 kg/h of nitrogen fertiliser was applied. This shows that by using crop rotation the application of nitrogen fertiliser can be minimalised. This is a benefit as a study by Peoples et al., found that artificial nitrogen fertilisers leave large amount of residue, whereas fixated nitrogen leaves small traces, this is a positive as large traces of Nitrogen residue can affect local ecosystems.

Limitations of the Data

Although this data shows the significant benefits of wheat and chickpeas in a rotation system, it cannot be applied universally. This is because the locations of the testing were very limited, meaning there was little variance regarding the soil pH and soil type. This affects does not allow the data to be universally used as the soil conditions or the local ecosystem may not permit this combination of crop rotation. Therefore, more trials need to be conducted, in varying soil types and ecosystems, to make a more universal guide for crop rotation

Evaluation of the Claim and Recommendations

Based off the evidence presented in this article the claim has been evaluated as true, this is because the supplied evidence supported the claim. Based off this, the following recommendations should be made; Crop rotation should be used as an offset for soil degradation and chickpeas and wheat are an effective pair when used in crop rotation.

Reference List

• Looney, J. W. (1991). Land degradation in Australia: The search for a legal remedy. CIESIN.
• Watts, J. (2017, May 26). Third of Earth's soil is acutely degraded due to agriculture. Retrieved from The Gaurdian: https://www.theguardian.com/environment/2017/sep/12/third-of-earths-soil-acutely-degraded-due-to-agriculture-study Reference list
• Corporation, G.R. and D. (n.d.). Nitrogen fixation and N benefits of chickpeas and faba beans in northern farming systems. [online] Grains Research and Development Corporation. Available at: https://grdc.com.au/resources-and-publications/all-publications/factsheets/2013/07/grdc-fs-nfixation-chickpeas [Accessed 7 Jun. 2020a].
• Corporation, G.R. and D. (n.d.). Trials explore chickpea/wheat rotations. [online] Grains Research and Development Corporation. Available at: https://grdc.com.au/resources-and-publications/groundcover/ground-cover-issue-105-july-august-2013/trials-explore-chickpea-wheat-rotations [Accessed 7 Jun. 2020b].
• Daniel, R., Simpfendorfer, S., Serafin, L., Cumming, G. and Routely, R. (2011). Choosing Rotation Crops. [online] pp.1–8. Available at: https://grdc.com.au/__data/assets/pdf_file/0024/223683/grdcfsbreakcropsnorthpdf.pdf.pdf.
• Greentumble. (2019). 10 Benefits of Crop Rotation in Agriculture | Greentumble. [online] Available at: https://greentumble.com/10-benefits-of-crop-rotation/ [Accessed 7 Jun. 2020].
• Hemmat, A. and Eskandari, I. (2004). Tillage system effects upon productivity of a dryland winter wheat–chickpea rotation in the northwest region of Iran. Soil and Tillage Research, [online] 78(1), pp.69–81. Available at: https://www.sciencedirect.com/science/article/pii/S0167198704000509 [Accessed 7 Jun. 2020].
• López-Bellido, L., López-Bellido, R.J., Castillo, J.E. and López-Bellido, F.J. (2004). Chickpea response to tillage and soil residual nitrogen in a continuous rotation with wheat: I. Biomass and seed yield. Field Crops Research, [online] 88(2), pp.191–200. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0378429004000516 [Accessed 7 Jun. 2020].
• Peoples, M.B., Brockwell, J., Herridge, D.F., Rochester, I.J., Alves, B.J.R., Urquiaga, S., Boddey, R.M., Dakora, F.D., Bhattarai, S., Maskey, S.L., Sampet, C., Rerkasem, B., Khan, D.F., Hauggaard-Nielsen, H. and Jensen, E.S. (2009). The contributions of nitrogen-fixing crop legumes to the productivity of agricultural systems. Symbiosis, 48(1–3), pp.1–17.
• www.abc.net.au. (2018). Crop Rotation. [online] Available at: https://www.abc.net.au/gardening/factsheets/crop-rotation/9579146 [Accessed 7 Jun. 2020].