SEGH Articles

Enhancing Nutrient Use Efficiency: The Role of Specialty Fertilizers

13 March 2018
The International Fertilizer Association (IFA) held its Task Force and Strategic Forum Meeting in Zurich, Switzerland on Nov 13-15, 2017. The purpose of the meeting was to discuss and prepare the Fertilizer Industry for the challenges foreseen by 2030 along with a special focus on Enhancing Nutrient Use Efficiency: The Role of Specialty Fertilizers. Dr Munir Zia provides SEGH readers with a brief overview of this topic.

Nutrient Use Efficiency (NUE) is defined as yield per unit input. In agriculture this is usually related to the input of fertilizer, whereas in the scientific literature the NUE is often expressed as fresh weight or product yield per content of nutrient. Improvement of NUE is an essential pre-requisite for the expansion of crop production into marginal lands with low nutrient(s) availability. There are many forms of NUE. Four of them are commonly used (source: Hemantaranjan 2013):

1. Partial factor productivity -PFP (crop yield per unit of nutrient applied) tells us how productive the cropping system is in comparison to its nutrient input.

2. Partial nutrient budget –PNB (nutrient in harvested crop per unit of nutrient applied) tells us how much nutrient is taken out of the system in relation to the amount put in.

3. Agronomic efficiency –AE (yield increase per unit of nutrient applied) answers a more direct question: “How much productivity improvement was gained by the use of this nutrient?”

4. Recovery efficiency – RE (increase in above-ground crop uptake per unit of nutrient applied) tells us how much of the nutrient applied was taken up by the plant.

NUE in Pakistan: nitrogenous (N) and phosphatic (P) fertilizer use efficiency are only 30-60% and 15-20%, respectively. Pakistan is ranked lowest among neighboring countries for nitrogenous fertilizer use efficiency (Table 1):


Table 1: nitrogenous (N) fertilizers use efficiency



(million ha)


Mean Cereal Yield


Mean Nitrogen Rate



(kg grain/kg N)


(kg N grain/ kg fertilizer N)

















































Ref.: IPNI-2014

PFP = Partial Factor Productivity of nitrogenous fertilizer; PNB = Partial Nutrient Balance of nitrogenous fertilizer


Table 1 shows comparative nitrogenous fertilizer performance indicators. Pakistan has the lowest NUE computed as Partial Factor Productivity (PFP) - that is 21 kg of cereal grains/kg of N fertilizer. The second indicator (the Partial Nutrient Balance (PNB) - a ratio: kg N recovered/kg of N applied) is also the lowest (0.33%).

The N performance indicators for Pakistan are lowest among countries and even of world average, which suggests imbalanced application of nutrient N with special reference to phosphorus, potassium, and other micronutrient fertilizers. In case of phosphatic fertilizers, agronomic efficiency (AE) for wheat is about 9 kg /kg of applied phosphorus. Such low fertilizer use efficiencies are partially responsible for yield gaps in Pakistan.

Measures to Enhance NUE

i.        Specialty fertilizers – controlled release fertilizers

    ii.        Genetics and management practices assuring maximum economic yields

   iii.        Precision agriculture technologies to sense crop needs and improve application

   iv.        Increased use of on-farm measures evaluating nutrient use efficiency

    v.        Decision support tools applying science at the farm level


Specialty Fertilizers are customized and/or fortified fertilizers developed specifically to enhance NUE, e.g. granular fertilizer particles that help gradual release of fertilizer nutrients to match crop(s) requirements, usually over a few weeks/months (see Figure 1).

 Munir Fertilizer Granule

Figure. 1 Diffusion mechanism of controlled release of Nitrogen from fertilizer granule


Specialty fertilizers are intended to provide the following benefits:

  • INCREASE YIELD with same fertilizer dose
  • MAINTAIN YIELD with lower fertilizer dose
  • INCREASE YIELD with lower fertilizer dose


Specialty fertilizers can be grouped into three categories:

  • Slow and/or controlled release fertilizers (e.g. polymer coated urea)
  • Fortified secondary and micronutrients (e.g. chelated zinc)
  • Customized N-P-K grades; and fully water soluble grades etc. (e.g. N-P-K-S 15:15:15-10)


At present, major multinational fertilizer companies are focusing on development of controlled release fertilizers that can be subdivided into three categories:

  • Organic compounds (e.g., humate coated urea)
  • Water soluble fertilizers with a physical barrier to control the release of nutrients (e.g. polymer urea)
  • Inorganic low solubility compounds (e.g. partially acidulated rock phosphate)


Global Market of specialty fertilizers is projected to reach $20 billion by 2020. Major global players include:

Yara International (Norway)

Agrium Inc. (Canada)

The Mosaic Company (US)

Sinochem Group (China)

Sociedad Quimicay Minera S.A. (Chile)

Haifa Chemicals Ltd. (Israel)

In the US, a premium of 16-35% is charged over such specialty products. Below is a summary of coating materials used to produce Controlled Release Urea Fertilizer on a commercial scale. Until now, no breakthrough has been reported in the controlled release of phosphorus from MAP/DAP/TSP fertilizers.

Table 2: Commercial scale controlled release fertilizers and coating materials

Commercial name

Composition of coating material



Sulfur+wax + diatomaceous earth + coal tar

Tennessee Valley Authority, USA



Polyolefin + inorganic powder

Chisso Co. Kitakysya, Japan

LP30/LPS40/LPSS 100


Chisso-Asahi Fertilizer Corporation


Polymeric material

Agrium Inc. Canada


Polymeric material

Chisso-Asahi Fertilizer Corporation



Haifa Chemicals Ltd. Israel

Zn-coated urea

Zinc oxide

Indo-Gulf Fertilizers, India

Agrium PCU

Polymeric material

Agrium US Inc.

Kingenta PCU

Polymeric material

Shandong Kingenta Ecological Engineering Co. Ltd. China


In Pakistan other than Neem Coated Urea, only three commercial scale fertilizer products (Nurea - sulfur coated urea 36% N; calcium ammonium nitrate; and zinc-coated urea) fall under the category of specialty fertilizers.



Hemantaranjan. A, Physiology of Nutrition and Environmental Stresses on Crop Productivity, Scientific Publishers (2014).



Keep up to date

Submit Content

Members can keep in touch with their colleagues through short news and events articles of interest to the SEGH community.

Science in the News

Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

  • Arsenic exposure and perception of health risk due to groundwater contamination in Majuli (river island), Assam, India 2019-07-19


    Island populations are rarely studied for risk of arsenic (As) poisoning. As poisoning, multimetal contamination and people’s perceptions of health risks were assessed on India’s Majuli Island, the largest inhabited river island in the world. This holistic approach illustrated the association of groundwater contamination status with consequent health risk by measuring levels of inorganic arsenic (iAs) in groundwater, borehole sediment and biological samples (hair, nails and urine). Piper and Gibbs’s plots discerned the underlying hydrogeochemical processes in the aquifer. Demographic data and qualitative factors were evaluated to assess the risks and uncertainties of exposure. The results exhibited significant enrichment of groundwater with As, Mn and Fe along with significant body burden. Maximum Hazard Index values indicated severe non-carcinogenic health impacts as well as a significantly elevated risk of cancer for both adults and children. Most (99%) of the locally affected population did not know about the adverse health impacts of metal contamination, and only 15% understood bodily ailments and health issues. Various aspects of the island environment were used to elucidate the status of contamination and future risk of disease. A projection showed adverse health outcomes rising significantly, especially among the young population of Majuli, due to overexposure to not only As but also Ba, Mn and Fe.

  • The contents of the potentially harmful elements in the arable soils of southern Poland, with the assessment of ecological and health risks: a case study 2019-07-19


    Agricultural soil samples were collected from the areas where edible plants had been cultivated in southern Poland. The PHE content decreased in proportion to the median value specified in brackets (mg/kg d.m.) as follows: Zn (192) > Pb (47.1) > Cr (19.6) > Cu (18.8) > Ni (9.91) > As (5.73) > Co (4.63) > Sb (0.85) > Tl (0.04) > Cd (0.03) > Hg (0.001) > Se (< LOQ). No PHE concentrations exceeded the permissible levels defined in the Polish law. The PHE solubility (extracted with CaCl2) in the total concentration ranged in the following order: Fe (3.3%) > Cd (2.50%) > Ni (0.75%) > Zn (0.48%) > Cu (0.19%) > Pb (0.10%) > Cr (0.03%). The soil contamination indices revealed moderate contamination with Zn, ranging from uncontaminated to moderately contaminated with Pb, and, practically, no contamination with other PHEs was identified. The ecological risk indices revealed that soils ranged from uncontaminated to slightly contaminated with Zn, Pb, As, Cu, and Ni. The PCA indicated natural sources of origin of Co, Cu, Hg, Sb, Zn, Cr, and Pb, as well as anthropogenic sources of origin of Cd, Ni, As, and Tl. The human health risk assessment (HHRA) for adults and children decreased in the following order of exposure pathways: ingestion > dermal contact > inhalation of soil particles. The total carcinogenic risk values for both adults and children were at the acceptable level under residential (1.62E−05 and 6.39E−05) and recreational scenario (5.41E−06 and 2.46E−05), respectively, as well as for adults in agricultural scenario (1.45E−05). The total non-carcinogenic risk values for both adults and children under residential scenario (1.63E−01 and 4.55E−01, respectively), under recreational scenario (2.88E−01 and 6.69E−01, respectively) and for adults (1.03E−01) under agricultural scenario indicated that adverse health effects were not likely to be observed. Investigated soils were fully suitable for edible plant cultivation.

  • Using human hair and nails as biomarkers to assess exposure of potentially harmful elements to populations living near mine waste dumps 2019-07-17


    Potentially harmful elements (PHEs) manganese (Mn), cobalt (Co), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) were measured in human hair/nails, staple crops and drinking water to ascertain the level of exposure to dust transference via wind and rain erosion for members of the Mugala community living near a mine waste dump in the Zambian Copperbelt. The mean PHE concentrations of hair in decreasing order were Zn (137 ± 21 mg/kg), Cu (38 ± 7 mg/kg), Mn (16 ± 2 mg/kg), Pb (4.3 ± 1.9 mg/kg), Ni (1.3 ± 0.2 mg/kg) and Cr (1.2 ± 0.2 mg/kg), Co (0.9 ± 0.2 mg/kg) and Cd (0.30 ± 0.02 mg/kg). Whilst for toenails the decreasing order of mean concentrations was Zn (172 ± 27 mg/kg), Cu (30 ± 5 mg/kg), Mn (12 ± 2 mg/kg), Pb (4.8 ± 0.5 mg/kg), Ni (1.7 ± 0.14 mg/kg) and Co (1.0 ± 0.02 mg/kg), Cr (0.6 ± 0.1 mg/kg) and Cd (0.1 ± 0.002 mg/kg). The concentration of these potentially harmful elements (PHEs) varied greatly among different age groups. The results showed that Mn, Co, Pb, Cd and Zn were above the interval values (Biolab in Nutritional and environmental medicine, Hair Mineral Analysis, London, 2012) at 0.2–2.0 mg/kg for Mn, 0.01–0.20 mg/kg for Co, < 2.00 mg/kg for Pb, < 0.10 mg/kg for Cd and 0.2–2.00 mg/kg for Zn, whilst Ni, Cu and Cr concentrations were within the normal range concentrations of < 1.40 mg/kg, 10–100 mg/kg and 0.1–1.5 mg/kg, respectively. Dietary intake of PHEs was assessed from the ingestion of vegetables grown in Mugala village, with estimated PHE intakes expressed on a daily basis calculated for Mn (255), Pb (48), Ni (149) and Cd (33) µg/kg bw/day. For these metals, DI via vegetables was above the proposed limits of the provisional tolerable daily intakes (PTDIs) (WHO in Evaluation of certain food additive and contaminants, Seventy-third report of the Joint FAO/WHO Expert Committee on Food Additives, 2011) for Mn at 70 µg/kg bw/day, Pb at 3 µg/kg bw/day, Ni and Cd 5 µg/kg bw/day and 1 µg/kg bw/day, respectively. The rest of the PHEs listed were within the PTDIs limits. Therefore, Mugala inhabitants are at imminent health risk due to lead, nickel and cadmium ingestion of vegetables and drinking water at this location.