Agriculture is one of the oldest industries used to sustain a growing population and according to most historians gave way to the rise of modern civilization. Nonetheless, without a proper water supply, crops are unable to utilize nutrients effectively and ultimately, cease to exist. Irrigation is a common technique still practiced today as a means to supply crops with water; however, it also makes the surrounding bodies of water even more susceptible to pollution due to large-scale runoff water that contains fertilizers, herbicides, pesticides, insecticides, etc. from surrounding farms. With only 3% of the Earth’s surface containing freshwater, diffuse pollution or ‘non-point’ source pollution, is contaminating a valuable resource required for human existence that has an effect on both spatial and temporal environmental scales.
One way agricultural industries can minimize their contribution to diffuse pollution is through a Nutrient Budget (NB) evaluation. A NB not only indicates the overall performance of the farm in regard to nutrient management by assessing nutrient inputs and outputs, but can also function as an educational process and increase the farmer’s understanding of the nutrient cycle and environmental policy. Although an NB cannot account accurately for all of the inputs and outputs of the farm, they do provide basic information that can aid farm management.
The following three farms were analyzed using a ‘farm-gate’ NB: Strathmiglo Farm, Strathmore Farm and Glenrothes Farm. The farm-gate approach accounts for all the tangible nutrient inputs and outputs on the farm, while simultaneously assessing the farms performance in regard to environmental sustainability. This NB particularly focuses on the ability of the farms to efficiently use the nutrients Nitrogen (N), Phosphorus (P) and Potassium (K). N and P efficiency are of specific interest in regard to water quality, and K efficiency is mainly concerned with highlighting economic losses/profits. When analyzing the efficiency values of these farms collectively, it appears that Strathmiglo farm is the most efficient farm due to the fact that their N efficiency is relatively high in comparison to Strathmore and Glenrothes. Both Strathmore and Glenrothes have extremely high N inputs, which is known to contribute to diffuse pollution by increasing coastal hypoxia via runoff water or unmanaged irrigation pathways. Both farms appear to use too much fertilizer which is a major economic loss that can be rectified by using both non-intensive and cost-effective methods such as a simple chlorophyll meter or canopy reflectance, due to the fact that there is a direct relationship between a crops leaf greenness and its N status. A chlorophyll meter or canopy reflectance can detect N deficiency to determine if fertilizer needs to be applied. Along with observing a crops’ green vibrancy, more intensive strategies can also be utilized such as, crop rotation, crop pallet soil analysis, and water-shed faculties to recapture N lost from fields.
Although Strathmiglo farm is essentially striping P from the environment, the excessive inputs of P from Strathmore and Glenrothes farms is contributing to diffuse pollution through the eutrophication of coastal waters via runoff water and eroded soil containing the excessive input of fertilizers. To reduce the amount of P lost, the application of P fertilizers should depend on a soil analysis, while also taking into account the farms use of organic manure. Other management strategies can also be applied to reduce P loss such as riparian zones or natural barriers (grass, woodlands, etc.) around crop fields and waterways to reduce the amount of P lost to runoff.
As stated earlier, K does not directly impact water quality like N and P; however, it is taken into consideration for economic reasons. Both Strathmore and Glenrothes farms have an excessive input of K, which highlights their sizeable economic loss. Although K loss carries no environmental or health concerns, the inadequate maintenance of K can lead to poor soil productivity. In regards to Strathmiglo farm, K is also being stripped from the environment, which could reduce the crops ability to resist disease and drought as well as utilize N; additional K can be added through the use of a simple Potassium Chloride fertilizer.
Even though Strathmiglo farm appears to be the most efficient, it is important to consider the number of hectares (ha) farmed and the primary export. Strathmiglo farm is the smallest farm (134.58 ha) with a focus on crops, Strathmore farm is a medium farm (178.50 ha) with a focus on animal products and finally, Glenrothes farm is the largest farm (968.86 ha) with a focus on both crop and animal products. Economically and environmentally Strathmiglo farm has the least impact in comparison to Glenrothes farm, which produces both crops and animal product. Glenrothes farm has a larger economic and environmental impact; nonetheless, in regards to social development and population growth it is much more valuable than Strathmiglo farm. Due to the fact that Glenrothes farm is not only larger but produces a greater variety of goods without striping nutrients from the environment, one might argue that Glenrothes is more efficient when taking into consideration the size of the farm and its socio-economic value. However, strictly in regard to nutrient efficiency, Strathmiglo farm demonstrates the best use of farm management according to the NB.
Agriculture is an important industry that has always supplied the necessary products for the advancement of civilization. Given the increasing scarcity of clean water, it is important to educate farm managers to pursue more sustainable methods of farming by providing them with the tools and resources, such as a NB evaluation, to reduce their contribution to diffuse pollution. Although the agriculture industry provides a plethora of goods, without continuing access to clean water, the ability of farms to produce the needed products to support an ever growing population cannot be sustained.