3. Fertilizers
3.2 Efficiency and Sustainability Analysis
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sold under name “soil conditioners” rather than fertilizers. Using organic fertilizers make it difficult to “over” fertilize or harm plants and the overall risk is extremely low. Organic fertilizers are renewable, sustainable, biodegradable, and
environmentally friendly.
Disadvantages would be the limitation by seasonal usage, need of following natural rules, in other words, releasing nutrient takes some time, and information about nutrient ratios are unknown and overall lower than in chemical fertilizers.
However, by its usage, microorganisms obtain energy from decaying plant and animal matter; therefore, organic fertilizer provides a complete package of nutrients for soil.
Despite land degradation, agricultural yields continue to increase, mostly because of synthetic fertilizers and pesticides temporarily boost soil productivity.
Chemical fertilizer application can increase short term crop yields or improve aesthetic look of grass and flowers; in the same time, it comes with its share of
harming environmental and negative health effects. Plants’ stems are unable to absorb all of the fertilizer applied to the soil. In fact, it is estimated that about one half of every metric ton of fertilizer applied to fields never even reach the plants, but instead ends up evaporating or being washed into local waterways.
3.2 Efficiency and Sustainability Analysis
In following part, chemical fertilizers are elaborated in more detailed way than organic fertilizers since organic fertilizers are in accordance with sustainable agriculture methods and do not harm the environment. Typically, the most of
chemical fertilizers consist of three main macronutrients which are the primary major nutrients required for plant growth: nitrogen (N), phosphorus (P), and potassium (K).
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Nitrogen is used for leaf growth; phosphorus for roots developments, flowers, seeds and fruit; and potassium is used for strong stem growth, movement of water in plants, promotion of flowering and fruiting (Dittmar, 2009).
In general, consumption of fertilizers in East Asia is very high compared to other world regions through history, as is
presented in the work by Max Roser in Figure 5 “Fertilizer use by developing regions and type (nitrogen, phosphates, potassium in kg/ha) between 1961-1999”
(right) and in Figure 6 “Consumption of fertilizers by world regions from 1961 to 2002” (below). The same for waste generated by production of nitrogen and phosphorus which is more elaborated in the
Figure 6: Consumption of fertilizers by world regions from 1961 to 2002.
Source: Roser, 2016, based on FAO data (Fertilizer Archive).
Figure 5: Fertilizer use by developing regions and type (nitrogen, phosphates, potassium in kg/ha) between 1961-1999. Source: Roser, 2016, based on FAO data (Fertilizer Archive).
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last part of this part.
In Taiwan, in order to obtain high yields, amounts of N given to plants are often higher than required. In case of other three east Asian countries, China, Japan, South Korea, fertilizers are also overused (Lian, 1991; Ahmed, 1994). This significantly decreases the productive efficiency of N because of limited absorption and utilization.
The excess of applied nitrogen remains in the soil in the form of nitrate which, due to leaching and denitrification, are usually lost. Denitrification is typical case for wet soil with a lack of oxygen, for example, rice field. Timing of nitrogen application is also important to increase effectivity in increasing yield.
Over the four decades between 1950 and 1990, the fertilizer consumption in Taiwan was increasing and it is estimated that in 1991 farmers used about 1.3 million m.t. of fertilizer (0.4 million m.t. of nutrients) annually. In that time, the average rate for consumption of N-P-K in Taiwan was one of the highest in the world (at 269-78-112 kg/per hectare of arable land, or 188-55-79 kg/ha per crop). Compared to absorbed N by plant, the rate of N applied to vegetables is three to five times higher.
The main reason is the outcome which makes leafy vegetables to grow rapidly and with good quality, resulting in high prices in the market. Excessive usage of N is also in case of fruit trees, where chemical fertilizers and manure (organic fertilizers) are applied together, resulting in twelve times higher ratio of applied N then removed by harvested fruit. The N remain is far higher than needed also for other agriculture products, remaining as inorganic nitrogen. Due to leaching, losses of N are approximately from 13% to 102% (Lian, 1991; Ahmed, 1994).
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Over the last two decades from 1997 to 2015, consumption of fertilizers decreased approximately by 20% from 1,203,163 m.t. in 1997 to 959,623 m.t. in 2015. This is displayed in Figure 7 “Fertilizers in Taiwan from 1997 to 2015” (below) where is also evident that import of fertilizers remains near average 474,842 m.t. and export almost triples in 2015 compared to 18 years ago. Production of fertilizers is variable with slight decrease over time, with the highest amount of 1,678,511 m.t. in 1998 and lowest amount of 1,195,553 m.t. in 2015.
Figure 8, “Chemical Fertilizers Usage in Taiwan 2015” (next page) shows more details about types of used chemical fertilizers indicating that mostly are used combinations of chemical fertilizers then only single one. The total fertilizer production stood for 1,195,553 m.t., the total consumption of fertilizers in 2015 accounted 959,623 m.t., import and export were 503,852 m.t. and 355,728 m.t.
respectively; therefore, the surplus of inorganic fertilizers accounted 348,054 m.t. in
0 200000 400000 600000 800000 1000000 1200000 1400000 1600000 1800000
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
FIGURE 7: CHEMICAL FERTILIZERS IN TAIWAN FROM 1997 TO 2015 (UNIT: METRIC TONS)
Production Consumption Import Export
Data source: ASY, 2015 and 2008.
Data source: Ag. Statistical Yearboo
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2015.
According to the largest fertilizer company in Taiwan, Taiwan Fertilizer Co., Ltd., the ratio of N-P-K (N-P2O5-K) for Ammonium Sulphate is 21-0-0, for Urea is 46-0-0, for Calcium Superphosphate 0-18-0, and other artificial fertilizers are
Potassium Chloride with ratio 0-0-60 and Potassium Sulfate with 0-0-50. (TFC, 2014) N-P-K numbers represents the percentage by weight of the three major nutrients nitrogen-phosphorus-potassium.
Fertilizers also contain metals as cooper, iron, cobalt, aluminum, etc. However, these metals are not major three nutrients and their percentage do not have to be displayed on index of each product. Since there is no law to obligate fertilizers’
producers to inform users in details about products, no other information about content of fertilizers is given except the three major nutrients.
1,195,553 695,387 360,392 0 92,308 47,466
959,623 710,494 108,013 51,211 36,248 53,657
503,852 78,696 20,206 102,423 0 302,527
355,728 759 201,958 13 1 152,993
G R A N D T O T A L C O M B I N E D F E R T I L I Z E R S
A M M O N I U M S U L P H A T
U R E A C A L C I U M
S U P E R P H O S P H A T E
O T H E R S
FIGURE 8: CHEMICAL FERTILIZERS USAGE IN TAIWAN 2015 (UNIT: METRIC TON)
Production Consumption Import Export Data source: ASY, 2015.
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This is visible on Pictures 2 A-E and 3 A-C (above), particularly Pictures 2 E and 3 C show detail of two fertilizers’ composition where are specified only the three major nutrients. Fertilizer 1 on the Picture 2 E report only 29% of its compound and Fertilizer 2 on the Picture 3 C describe 35% of its
composition. For some reason the rest of compound remains mystery and customer has to rely on his/her trust to producer that the 50% of product are not heavy metals
Picture 2A. Fertilizer 1 Picture 2B. Fertilizer 1 Picture 2C. Fertilizer 1 Picture 2D. Fertilizer 1
Picture 2E. Fertilizer 1 detail on conposition
Picture 3A. Fertilizer 2 Picture 3B. Fertilizer 2
Picture 3C. Fertilizer 2 detail on composition Pictures 2A – 3C. Source: own pictures.
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nor any other chemicals which have negative impact on human health. The result of majority researches concerning fertilizers and pesticides conducted by the government are also not available for public. This topic is more elaborated in the next part about pesticides and Taiwan Agriculture Chemicals and Toxic Substances Research Institute, Council of Agriculture, Executive Yuan.
For computing the produced and consumed N-P-K in Taiwan for year 2015, ratios provided by Taiwan Fertilizer Company are used and as well as data about fertilizers from Agriculture Statistical Yearbook 2015. The result is presented in Table 1, “Three major fertilizer nutrients production and consumption in 2015” (below). In 2015, total nitrogen produced accounted 180,617 m.t., phosphorus 39,639 m.t., and potassium 62,270 m.t. while total consumed amount of these three fertilizers are 178,584 m.t., 24,890 m.t. and 112,847 m.t. respectively.
Source: own calculation using data from ASY, 2015; TFC, 2014.
These data in metric tons are converted into energy with Table 2 “World average of energy requirement for production, packaging, transportation, and application of inorganic fertilizers” (below) computed by Helsel (1992). Production and packaging parts are calculated with produced fertilizers while transportation and application are calculated with consumed amount of fertilizers. Fertilizers for import and export are omitted from this calculation since it is not clear what process is made with imported
Table 1: Three major fertilizer nutrients production and consumption in 2015 (UNIT: m.t.)
Nitrogen (N) Phosphorus (P) Potassium (K)
Produced 180,617 39,639 62,270
Consumed 178,584 24,890 112,947
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and exported fertilizers, for instance, whether they are already packed before import or packet after import. Therefore, the result of energy is the minimal energy
consumption in fertilizer’s life cycle.
Table 2: World average of energy requirement for production, packaging, transportation, and application of inorganic fertilizers (UNIT: kJ / kg)
Nitrogen (N) Phosphorus (P) Potassium (K)
Produce 69,530 7,700 6,400
Package 2,600 2,600 1,800
Transport 4,500 5,700 4,600
Apply 1,600 1,500 1,000
Total 78,230 17,500 13,800
Data source: Helsel, 1992.
The result is displayed in Table 3 “Total energy requirement for production, packaging, transportation, and application of inorganic fertilizers in Taiwan” (next page) about total energy consumption of nitrogen was 14,117,226 GJ7, phosphorus consumed 187,489.7 GJ, and potassium total energy consumption accounted 1,143,117 GJ. The grand total of energy consumption was 15,847,872.7 GJ, equivalent to 15.872 PJ8.
7 GJ (= gigajoule) is equal to one billion (109) joules. 6 GJ is about the amount of potential chemical energy in 160 L (approximately one US standard barrel) of oil, when combusted.
8 PJ (= petajoule) is equal to one quadrillion (1015) joules. 210 PJ is equivalent to about 50 megatons of TNT. This is the amount of energy released by the Tsar Bomba, the largest man-made nuclear
explosion ever.
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Table 3: Total energy requirement for production, packaging, transportation, and application of inorganic fertilizers in Taiwan 2015 (UNIT: GJ )
Nitrogen (N) Phosphorus (P) Potassium (K)
Produce 12,558,300 305,220 398,528
Package (produced) 469,604 103,061 112,086
Transport (consumed) 803,628 141,873 519,556
Apply (consumed) 285,734 37,335 112,947
Total 14,117,266 587,489.7 1,143,117
Grand total 15,847,872.7
Grand total in PJ 15.872
Source: own calculation based on Helsel’s (1992) world average data; ASY, 2015;
TFC, 2014.
The Figure 9 “Average price of fertilizers in Taiwan between 1994 and 2015”
(above) presents the changes in the average price of fertilizers over the last two decades from 1994 to 2015. In first part of observed period of time from 1994 to 2002, the average price of fertilizers remained quite stable, then after 2002 followed 3
5 5.2 5.2 5.2 5.2 5.2 5.3 5.3 5.4
FIGURE 9: AVERAGE PRICE OF FERTILIZERS IN TAIWAN BETWEEN 1994 AND 2015 (UNIT: NTD PER KG)
Price NTD/kg
Data source: ASY, 2015, 2007, and 2003.
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waves of increases in prices in 2003, 2007, and 2011. The recent average price from 2012 to 2015 was higher by 41% compare to first part of observed period of time from 1994 to 2002. The total consumption of fertilizers in 2015 accounted 959,623 m.t. equivalent to 959,623,000 kg with the total price of 8,540,644,700 NTD (8.9 NTD/kg). If the same amount of fertilizers would be consumed 16 years ago in year 1999, the total price would be only 4,990,039,600 NTD, making difference of
3,550,605,100 NTD in total. Thus, the overall increase in average price has significant impact on farmers who have to pay 41% higher expenditures for fertilizers within two decades.
In addition, all three chemicals N-P-K are energy intensive to produce creating vast amounts of waste, and contributing to greenhouse gas emissions. The production of nitric acid, the primary feedstock for synthetic commercial fertilizer, is also a source of nitrous oxide, a greenhouse gas 310 times more robust and influential than carbon dioxide. Nitrous oxide accounted for 15.9 Tg CO2E in 2005, the equivalent emissions of 2.9 million vehicles (EPA, 2016).
Producing one unit of N (nitrogen) requires 1.4 units of carbon and additional 3 units of carbon are required to manufacture, transport and apply 1 unit of phosphorus (P2O5 fertilizer). For every ton of phosphoric acid produced, additional five tons of phosphogypsum are generated. Over the past 50 years, more than 700 million m.t. of phosphogypsum have accumulated in U.S. in Florida alone. In 2005, huge stacks are covering there more than 300 hectares and more than 60 meters high with settling ponds that threaten local water sources (EPA, 2016). After recalculation of these information to production in Taiwan where was produced 180,617 m.t. of nitrogen, then we get 252,836.8 m.t. of carbon necessary to fulfill the nitrogen production in
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2015. And to manufacture, transport and apply 39,639 m.t. of phosphorus, there is generated 118,917 m.t. of carbon dioxide and also huge amount of wastewater by phosphogypsum accounting 198,195 m.t. in 2015 alone. It would be interesting to find out where is such a huge amount of waste is stored.
Nitrogen inorganic fertilization has both regional and global consequences.
Many research confirmed that excess of nitrate causes serious problems to the soil and the environment (Addiscott, 1991). In addition, experiments showed that lower rates of nitrogen fertilizer reduced the loss of nitrogen without affecting yield and grain quality, saving farmers money and reducing environmental impact (Matson et al., 1998). Long-term field observations for several decades often showed that metals contained in chemicals used in agricultural can remain in soil, even in nonacid soil when total metal concentration are below the proposed limits, and harm sensitive crops and microbes (McBride, 1994).
In contrast, the nitrogen concentration in compost, natural fertilizer, is found in stable compounds in the organic matter. The nitrogen compounds remain in the soil, available for uptake by the plant roots over a long period of time, greatly reducing the threat of water pollution and eutrophication. According to the European Commission, long-term application of compost will establish higher nitrogen levels in soils such that compost will completely displace synthetic fertilizers (Smith et al., 2001).
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