Soil and Biodiversity

Nutrient balance (nitrogen and phosphorus)

The "Nutrient balance (nitrogen and phosphorus)" fact sheet analyses the evolution of the balance of fertilizers nitrogen and phosphorus on the soil surface.

Description: 

The incorporation of nutrients into soils, such as nitrogen and phosphorus, is essential for the promotion and maintenance of crop development.

Maintaining a healthy balance between the nutrients incorporated into the soil and the nutrients removed by the plants is essential, since, on the one hand, a deficit of nutrients in the soil can cause a fertility problem with the subsequent implications on crop quality, but on the other hand, an excess of nutrients could lead to pollution, not only of soil but also of water and air.

The calculation of the nutrient balance (nitrogen and phosphorus) results from the difference between the incorporation of these nutrients into the soil and their removal by the crops (Nutrient balance = Incorporation - Removal).

This fact sheet concerns mainland Portugal, the Autonomous Regions of Madeira and the Azores and will be updated annually.

Objectives and targets: 
  • Support agricultural and forestry practices that contribute to the improvement of the environment and the conservation of resources (water, soil, air) in articulation with sustainable and competitive agricultural production;
  • Ensure the proper nutrition of crops, correcting possible shortages and avoiding excess nutrients in order to provide high-quality productions while preserving soil, water and air quality;
  • Adopt appropriate fertilization techniques, taking into account the various factors involved in the dynamics of nitrogen and phosphorus in the soil, in order to favour its absorption by crops and to reduce its losses in runoff and/or infiltration waters, as well as in air emissions.

 

Progress analysis:

Over the past 17 years diverging trends have been identified with regard to the balance of nitrogen and phosphorus:

As regards the nitrogen balance, there was an increase of 5.8% between 2000 (144,969 tonnes) and 2017 (153,107 tonnes);

In what concerns the phosphorus balance, there was a significant decline of 35.0% between 2000 (36,573 tonnes) and 2017 (23,788 tonnes).

 

Nitrogen balance

Notas: p - Provisional data
Source: DGADR, 2018; INE, 2018

In 2017, the gross nitrogen balance decreased slightly by 3.6% (corresponding to 5,750 tonnes) compared to 2016, even though the trend in the last seven years has been towards stabilization. Nonetheless, there was an excess of 117 thousand tonnes, equivalent to 33 kg of nitrogen per hectare of Utilized Agricultural Area (UAA), against 34 kg in the previous year.

This evolution is justified by the decrease of 1.0% in the incorporation of this nutrient into the soil, compared to 2016, namely due to the reduction of inorganic fertilizers incorporated in the soil (-3.8%), even though the incorporation of manure in the soil increased 0.7%. On the other hand, the removal of nitrogen from the soil by agricultural crops, fodder and pastures increased by only 1.7%.

 

Phosphorus balance

Notas: p - Provisional data
Source: DGADR, 2018; INE, 2018

The phosphorus balance in 2017 had a surplus of about 25.4 thousand tonnes of this element, equivalent to 6.6 kg per hectare of UAA (7.0 kg per hectare in the previous year). These values represented a decline of 6.4% in the phosphorus balance compared to 2016.

Similarly to nitrogen, phosphorus uptake also decreased compared to 2016 (6.4%), due to the greater removal of this macronutrient by permanent crops. Still, the removal of phosphorus was below the incorporation of this nutrient into the soil, contributing to its surplus.

 

Last update: 
Thursday, 9 August, 2018
More information at: 

Statistics Portugal – www.ine.pt
Directorate-General for Agriculture and Rural Development – www.dgadr.mamaot.pt/