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

Country

Area

(million ha)

 

Mean Cereal Yield

(t/ha)

Mean Nitrogen Rate

(kg/ha)

PFP

(kg grain/kg N)

PNB

(kg N grain/ kg fertilizer N)

Bangladesh

11.18

4.02

93

44

0.69

China

83.14

5.48

172

32

0.50

Egypt

2.99

7.01

252

28

0.44

India

99.24

2.56

95

28

0.43

Pakistan

12.93

2.58

124

21

0.33

Turkey

13.04

2.68

68

39

0.62

USA     

52.86

6.69

144

47

0.74

World

679.08

3.43

81

43

0.67

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

Company

SCU

Sulfur+wax + diatomaceous earth + coal tar

Tennessee Valley Authority, USA

Meister

 

Polyolefin + inorganic powder

Chisso Co. Kitakysya, Japan

LP30/LPS40/LPSS 100

Polyolefin

Chisso-Asahi Fertilizer Corporation

CRU

Polymeric material

Agrium Inc. Canada

CU & CUS

Polymeric material

Chisso-Asahi Fertilizer Corporation

PCF

Polyurethane-like

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.

 

References:

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

 

 


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