In Quebec, as well as in various countries, where farming practices are subject to environmental standards, there is a Agricultural Operations Regulation (AOR) that governs fertilization practices. Thus, most farms must use the services of agronomists every year to determine an Agri-Environmental Fertilization Plan (AEFP) which includes an analysis related to the status of phophorus (phosphorus balance).
The Agricultural Operations Regulation (AOR)
The purpose of this regulation is to protect rivers and lakes and to improve water quality in general. To this end, standards are established, which are based on the capacity of watercourses and water bodies to withstand the phosphorus inputs generated by land fertilization. Thus, the application of fertilizing materials, whether of animal origin (manure, slurry) or mineral origin (mineral fertilizers), is regulated according to storage and spreading standards to avoid a surplus of fertilizing materials not only on farmland but also in watercourses.
Soil analysis of cultivated agricultural plots must be carried out at least once every five years. This information allows the fertilization plan to be drawn up.
Agri-Environmental Fertilization Plan (AEFP)
The agri-environmental fertilization plan is a personalized guide, adapted to the farm business, which, beyond the recommendations for fertilization practices, also draws up a phosphorus balance. This enables farmers to fertilize soils according to the capacity of these latter to receive phosphorus supplements of mineral or organic origin. The purpose of the plan, drawn up by an agronomist, is to adapt the fertilization practice to the needs of the soil and to control the use and quantity of fertilizing materials as well as the periods of application. The agronomist also monitors the fertilization plan.
Who must produce a AEFP ?
– The operator of a livestock site with liquid manure management
– The operator of a livestock site with solid manure management with an annual phosphorus production of more than 1 600 kilograms;
– The operator of a land with a cumulative area greater than 15 hectares, excluding pasture and meadow. In the case of vegetable or fruit production, the obligation applies to the operator of a land with a cumulative area of more than 5 hectares;
– The operator of a livestock site with solid manure management with an annual phosphorus production of 1 600 kilograms or less and a cumulative area as referred to in the previous paragraph.
Why is phosphorus under scrutiny?
From 2010 to 2012, according to a governmental survey, out of a sample of 35 streams in agricultural areas, 29 had phosphorus concentrations above the criterion defining a risk of eutrophication. The capacity of a river to host phosphorus corresponds to the impact of human activities carried out in its watershed while respecting the eutrophication criterion (agricultural, municipal and industrial activities).
In the past, in the absence of standards governing the use of fertilizers, some farming areas have seen significant amounts of phosphorus accumulated in the soil, contributing thus to phosphorus-saturated regions. Hence, in agricultural areas, phosphorus inputs from fertilization are added to the phosphorus naturally present in the soil. Some of the phosphorus from agricultural practices is carried by runoff and erosion to waterways, creating risks of eutrophication.
The phosphorus balance calculation makes it possible to determine the capacity of agricultural plots to receive additional doses of phosphorus per fertilization and to calculate the quantity of phosphorus present in the fertilizing materials (particularly in the case of manure and slurry) in order to adapt their use during spreading.
In this way, it is possible for the farmer to ensure that he properly manages the fertilizer on the land intended for application and that he has a sufficient cultivation area therefore.
Furthermore, in the case of a farmer who is not subject to a mandatory phosphorus balance and who receives manure from a livestock site subject to a phosphorus balance, the supplier’s agronomist must ensure that the recipient does not end up with a phosphorus surplus.
One of the steps in the treatment of manure using the Solugen process is to first carry out a liquid/solid separation. Following this separation, the solid fraction, which represents 10% of the initial volume of manure, concentrates 85% of the phosphorus initially contained in the manure. The residual liquid mass is treated to extract pure water, liquid ammonia nitrogen and a potassium concentrate. The separation of the different fertilizers facilitates their use as part of an agri-environmental fertilization plan, particularly in the case of phosphorus. Phosphorus is concentrated in a solid residue with 30 % dry matter, which is easier to transport and considerably less expensive if the phosphorus has to be transported to unsaturated agricultural areas.