Mitigation of Climate Change by Nitrogen Managements in Agriculture

*Kazuyuki Inubushi and Miwa Yashima*

#### **Abstract**

Soil is one of the important sources of nitrous oxide (N2O), which is generally producing through soil microbial processes, such as nitrification and denitrification. Agricultural soils receive chemical and organic fertilizers to maintain or increase crop yield and soil fertility, but several factors are influencing N2O emissions, such as types and conditions of soil and fertilizer, and rate, form, and timing of application. Mitigation of N2O is a challenging topic for future earth by using inhibitors, controlled-release fertilizers, and other amendments, but the cost and side effects should be considered for feasibility.

**Keywords:** N2O, nitrification, denitrification, mitigation, soil type

#### **1. Introduction**

Global warming is significant and the impact of human activities is no doubt, such as mining of fossil fuels and deforestation, over-grazing, and constant increase of nitrogen fertilizer, resulting in atmospheric concentrations of CO2, methane (CH4) and nitrous oxide (N2O) keep increasing, respectively, as indicated by Intergovernmental Panel on Climate Change (**IPCC**), under the United National Framework Convention on Climate Change (**UNFCCC**) (**Figure 1**, [1]). CH4 and N2O are the main Short-Lived Climate Forcers (**SLCPs**) because these participate in air pollution chemistry (ozone production, the oxidizing capacity of the atmosphere) and have very high Global Warming Potential (**GWP**) to compare with CO2 = 1 as CH4 GWP = ~28; N2O GWP = ~298 (100 yr integration on per mole basis).

The Japanese government declared in 2020 that the year 2050 is the target of "Carbon Neutral Society", like other OECD countries. To achieve this target, we should reduce greenhouse gas emissions, not only CO2 but also CH4 and N2O, both strongly related to food production and agriculture sectors.

Soil is one of the important sources of N2O, which is generally producing through soil microbial processes, such as nitrification and denitrification. Agricultural soils receive chemical and organic fertilizers to maintain or increase crop yield and soil fertility. However, excess amount of chemical N fertilizer application may cause eutrophication and ground water pollution in the hydrosphere. Moreover, many factors are also influencing N2O emission in the atmosphere, such as types and conditions of soil and fertilizer, and rate, form, and timing of application. Mitigation of N2O emission to the atmosphere is a challenging topic in

**Figure 1.** *Total annual anthropogenic GHG emissions by gases 1970–2010 (source: [1]).*

sustainable agriculture, such as by using inhibitors, controlled-release fertilizers and other amendments, though the cost and side effects should be considered for feasibility. In this review, processes and influencing factors of N2O production in the soil is reviewing and some trials for mitigation are introduced.

## **2. Global N2O budget and production in soil**

Global Carbon Project (GCP) published a comprehensive quantification of global nitrous oxide sources and sinks [2]. This reports details of the global N2O budget in 21 natural and human sectors between 1980 and 2016 (**Figure 2**), indicating that

**5**

**Figure 3.**

*Mitigation of Climate Change by Nitrogen Managements in Agriculture*

natural and anthropogenic sources of N2O were 57% and 43%, or 9.3 and 7.3 TgN yr−1 (1 Tg = 1012 g or 1 million ton), respectively and total as 17.0 (minimum 12.2 to maximum 23.5 Tg), while 13.5 Tg sink by atmospheric chemical reactions, resulting 3.5 Tg increase annually. By continental or regional estimates, Africa releases most (3 Tg yr−1) due to large areas with tropical forests where high temperature and soil moisture, followed by Latin America and East Asia, where the agricultural contribution is largest. The annual increase of N2O emission is more than 1%, and the agricultural sector is largest, especially in Asia, followed by Latin America, Africa, and particularly in East Asia, the input of chemical fertilizer and manure plus direct emission is increasing as more than double in past three decades. National inventory of greenhouse gas emission in developing countries such as Indonesia (**Figure 3**) [3] contributions of agricultural sectors in N2O and CH4 are bigger than other sectors.

*National contribution of greenhouse gas emission by sector Indonesia source, [3].*

N2O is generally producing in the soil through microbial processes, mainly via nitrification and denitrification (**Figure 4**). Nitrification is carried out under aerobic conditions by two groups of autotrophic nitrifiers, namely ammonium oxidizers and nitrite oxidizers, both do not require organic matters, not only in bacteria group but also archaea group. Autotrophic nitrification is the dominant process in aerobic soil (less than 60% water-holding capacity), while heterotrophic nitrification is negligible [4]. N2O is producing as a byproduct during nitrite oxidation during nitrification. On the other hand, denitrification is carried out under wet and anaerobic conditions, such as in paddy soil and wetland soil, by heterotrophic denitrifiers, not only the bacteria but also fungi, both requires not only nitrate but also N-rich organic matter. N2O is producing as an intermediate product during denitrification between nitrite and N2. However, N2O emission from flooded paddy soil is generally low, probably due to the high solubility of N2O and complete denitrification to N2. Chemical denitrification was also negligible [4]. Microbial

**3. N2O production and its affecting factors**

*DOI: http://dx.doi.org/10.5772/intechopen.99972*

**Figure 2.** *Global N2O budget [2].*

*Mitigation of Climate Change by Nitrogen Managements in Agriculture DOI: http://dx.doi.org/10.5772/intechopen.99972*

**Figure 3.**

*Nitrogen in Agriculture - Physiological, Agricultural and Ecological Aspects*

sustainable agriculture, such as by using inhibitors, controlled-release fertilizers and other amendments, though the cost and side effects should be considered for feasibility. In this review, processes and influencing factors of N2O production in

Global Carbon Project (GCP) published a comprehensive quantification of global nitrous oxide sources and sinks [2]. This reports details of the global N2O budget in 21 natural and human sectors between 1980 and 2016 (**Figure 2**), indicating that

the soil is reviewing and some trials for mitigation are introduced.

*Total annual anthropogenic GHG emissions by gases 1970–2010 (source: [1]).*

**2. Global N2O budget and production in soil**

**4**

**Figure 2.**

**Figure 1.**

*Global N2O budget [2].*

*National contribution of greenhouse gas emission by sector Indonesia source, [3].*

natural and anthropogenic sources of N2O were 57% and 43%, or 9.3 and 7.3 TgN yr−1 (1 Tg = 1012 g or 1 million ton), respectively and total as 17.0 (minimum 12.2 to maximum 23.5 Tg), while 13.5 Tg sink by atmospheric chemical reactions, resulting 3.5 Tg increase annually. By continental or regional estimates, Africa releases most (3 Tg yr−1) due to large areas with tropical forests where high temperature and soil moisture, followed by Latin America and East Asia, where the agricultural contribution is largest. The annual increase of N2O emission is more than 1%, and the agricultural sector is largest, especially in Asia, followed by Latin America, Africa, and particularly in East Asia, the input of chemical fertilizer and manure plus direct emission is increasing as more than double in past three decades. National inventory of greenhouse gas emission in developing countries such as Indonesia (**Figure 3**) [3] contributions of agricultural sectors in N2O and CH4 are bigger than other sectors.

#### **3. N2O production and its affecting factors**

N2O is generally producing in the soil through microbial processes, mainly via nitrification and denitrification (**Figure 4**). Nitrification is carried out under aerobic conditions by two groups of autotrophic nitrifiers, namely ammonium oxidizers and nitrite oxidizers, both do not require organic matters, not only in bacteria group but also archaea group. Autotrophic nitrification is the dominant process in aerobic soil (less than 60% water-holding capacity), while heterotrophic nitrification is negligible [4]. N2O is producing as a byproduct during nitrite oxidation during nitrification. On the other hand, denitrification is carried out under wet and anaerobic conditions, such as in paddy soil and wetland soil, by heterotrophic denitrifiers, not only the bacteria but also fungi, both requires not only nitrate but also N-rich organic matter. N2O is producing as an intermediate product during denitrification between nitrite and N2. However, N2O emission from flooded paddy soil is generally low, probably due to the high solubility of N2O and complete denitrification to N2. Chemical denitrification was also negligible [4]. Microbial


#### **Figure 4.**

*Main processes of N2O production in soil.*

community structure was investigated also in tropical acid tea soil [5] and peat soil [6, 7]. Anaerobic ammonium oxidation (ANAMMOX) and dissimilatory nitrate reduction to ammonium (DNRA) are also focusing recently to see the possibility to relate N2O production and contribution in soil N dynamics [8, 9].

Based on above knowledges about N2O production processes, several mitigation technologies are proposed. To apply such mitigation technologies, it is important to understand factors affecting N2O production, which are (1) Soil type and amendments such as manure, compost, and biochar, (2) Soil management and mitigation technologies such as controlled-release chemical fertilizers and nitrification inhibitors, and (3) Trade-off effects with other greenhouse gas mitigation such as water management in paddy field to reduce CH4.

#### **4. Effect of soil types and amendment on N2O production and plant growth**

Generally, soil with a large amount of soil organic matter (SOM) tended to produce more N2O. However, in a case study using various soils in Japan and Hungary [10], Andosol, typical upland soil in Japan with higher SOM contents, produced less N2O than Chernozem with lower SOM contents, typical upland soil in Europe, under the same incubation conditions, especially amended with chemical N fertilizer and biochar (**Figure 5**). However sandy soils with fewer SOM contents, N2O production was small. Biochar is focused on soil C sequestration to build up C stock in soil, but also in Andosol, N2O tended not to be increased with biochar and N fertilizer. Leafy vegetable (Komatsuna; *Brassica rapa*) growth and yield were also enhanced by amendments of chemical N fertilizer and biochar.

Effects of amendments on N2O production were studied by many researchers, showing compost and N fertilizer generally increase N2O production [11–16]. Under field conditions, N2O emission to the atmosphere was much diversified in space and also soil depth [16, 17], and land-use [18]. Further study is needed for feasible soil and fertilizer management to meet sustainable developments.

#### **5. Soil and fertilizer managements and mitigation technologies**

To reduce N2O emission, controlled-release chemical fertilizers and nitrification inhibitors have been examined [19, 20], and meta-analysis of 113 field experiment

**7**

**Figure 6.**

regions [21].

**Figure 5.**

*Mitigation of Climate Change by Nitrogen Managements in Agriculture*

datasets showed that polymer-coated fertilizers significantly reduced N2O emissions (mean: −35%, 95% confidential interval: −58% to −14%) and nitrification inhibitors (−38%, −44% to −31%), respectively, depending on soil type and

*Effect of soil types and amendment on N2O production and plant growth (R: Rice husk biochar, 0, 1, 2:* 

Controlled-release coated urea (CRCU) is a type of polymer-coated fertilizer. CRCU was examined to compare with conventional chemical fertilizer in tropical oil palm plantations over 340–580 days, where vast areas have been converted from rainforest and other plantations. Sakata et al. [22] reported the effect of CRCU compare with conventional fertilizer on N2O emission and yield (**Figures 6** and **7**). In Tungal sandy loam soil, controlled-release nitrogen fertilizer (CRNF; M) showed lower N2O emission than conventional fertilizer (C), while in Simunjan sandy soil, N2O was low in both M and C. On the other hand in Tatau peat soil, both M and C emitted a similar amount of N2O, and much larger than other sites, and even from control (B; without fertilizer) (**Figure 7**). No significant effect on oil palm yield

*Field experimental sites in Sumatra, Indonesia and Sarawak, Malaysia [22], ① Tunggal, ② Simunjan, ③ Tatau.*

*DOI: http://dx.doi.org/10.5772/intechopen.99972*

*Application rate as 0, 1, 2%w/w, respectively, N: Urea).*

*Mitigation of Climate Change by Nitrogen Managements in Agriculture DOI: http://dx.doi.org/10.5772/intechopen.99972*

**Figure 5.**

*Nitrogen in Agriculture - Physiological, Agricultural and Ecological Aspects*

community structure was investigated also in tropical acid tea soil [5] and peat soil [6, 7]. Anaerobic ammonium oxidation (ANAMMOX) and dissimilatory nitrate reduction to ammonium (DNRA) are also focusing recently to see the possibility to

Based on above knowledges about N2O production processes, several mitigation technologies are proposed. To apply such mitigation technologies, it is important to understand factors affecting N2O production, which are (1) Soil type and amendments such as manure, compost, and biochar, (2) Soil management and mitigation technologies such as controlled-release chemical fertilizers and nitrification inhibitors, and (3) Trade-off effects with other greenhouse gas mitigation such as water

relate N2O production and contribution in soil N dynamics [8, 9].

**4. Effect of soil types and amendment on N2O production** 

enhanced by amendments of chemical N fertilizer and biochar.

and fertilizer management to meet sustainable developments.

**5. Soil and fertilizer managements and mitigation technologies**

Generally, soil with a large amount of soil organic matter (SOM) tended to produce more N2O. However, in a case study using various soils in Japan and Hungary [10], Andosol, typical upland soil in Japan with higher SOM contents, produced less N2O than Chernozem with lower SOM contents, typical upland soil in Europe, under the same incubation conditions, especially amended with chemical N fertilizer and biochar (**Figure 5**). However sandy soils with fewer SOM contents, N2O production was small. Biochar is focused on soil C sequestration to build up C stock in soil, but also in Andosol, N2O tended not to be increased with biochar and N fertilizer. Leafy vegetable (Komatsuna; *Brassica rapa*) growth and yield were also

Effects of amendments on N2O production were studied by many researchers, showing compost and N fertilizer generally increase N2O production [11–16]. Under field conditions, N2O emission to the atmosphere was much diversified in space and also soil depth [16, 17], and land-use [18]. Further study is needed for feasible soil

To reduce N2O emission, controlled-release chemical fertilizers and nitrification inhibitors have been examined [19, 20], and meta-analysis of 113 field experiment

management in paddy field to reduce CH4.

**and plant growth**

*Main processes of N2O production in soil.*

**Figure 4.**

**6**

*Effect of soil types and amendment on N2O production and plant growth (R: Rice husk biochar, 0, 1, 2: Application rate as 0, 1, 2%w/w, respectively, N: Urea).*

datasets showed that polymer-coated fertilizers significantly reduced N2O emissions (mean: −35%, 95% confidential interval: −58% to −14%) and nitrification inhibitors (−38%, −44% to −31%), respectively, depending on soil type and regions [21].

Controlled-release coated urea (CRCU) is a type of polymer-coated fertilizer. CRCU was examined to compare with conventional chemical fertilizer in tropical oil palm plantations over 340–580 days, where vast areas have been converted from rainforest and other plantations. Sakata et al. [22] reported the effect of CRCU compare with conventional fertilizer on N2O emission and yield (**Figures 6** and **7**). In Tungal sandy loam soil, controlled-release nitrogen fertilizer (CRNF; M) showed lower N2O emission than conventional fertilizer (C), while in Simunjan sandy soil, N2O was low in both M and C. On the other hand in Tatau peat soil, both M and C emitted a similar amount of N2O, and much larger than other sites, and even from control (B; without fertilizer) (**Figure 7**). No significant effect on oil palm yield

*Field experimental sites in Sumatra, Indonesia and Sarawak, Malaysia [22], ① Tunggal, ② Simunjan, ③ Tatau.*

**Figure 7.**

*N2O emission from field experiments with different soil and fertilizer [22].*

#### **Figure 8.**

*Nitrification inhibitors on N2O emission [29].*

was observed even N application rate of M was half of C. Tropical peat soil has been pointed out as a significant N2O emission source, even without fertilizer, strongly influenced by groundwater level [6, 7, 23–27]. Therefore CRCU has a significant impact even under tropical conditions to reduce N2O in certain mineral soils, but not in organic peat soil. Long-term evaluation and cost–benefit analysis are important with yield evaluation in various soil types under diverse climate conditions.

Another mitigation option, nitrification inhibitors to stop ammonium oxidation have been also examined, typically DCD (Dicyandiamide; [20]) which is biologically and temperature-dependently decomposed [28]. However, it caused contamination in exposed milk powder in New Zealand, so NZ banned DCD from 2013. Nitrapyrin and 3,4-dimethyl pyrazole phosphate (DMPP) are other chemicals of nitrification inhibitors, but less effective. Neem cake is derived from natural compounds, so less expensive, but also less effective to compare with chemical inhibitors [21]. Combined effects of a nitrification inhibitor, including DCD, neem, and clay mineral (zeolite) on N2O fluxes and corn growth were examined ([29]; **Figure 8**). Another biological nitrification inhibitor is also examined [30].

#### **6. Trade-off with other mitigation**

Mitigation options of other greenhouse gases, such as water management in the paddy field to reduce CH4, have been examined in Japan [31]. The controlling irrigation water level was also examined in Indonesia [32]. Groundwater level

**9**

**7. Conclusions**

*control CT [38].*

*Tamil Nadu Rice Research Institute*

**Table 1.**

*Mitigation of Climate Change by Nitrogen Managements in Agriculture*

control by alternate wet and drying (AWD) have established by IRRI and examined in Indonesia, the Philippines, Thailand, Vietnam [33–37] and India [38]. AWD has merit for saving labor and water. However, it may have a trade-off effect to increase N2O, because of the removal of flooded water to expose anaerobic soil directly to the atmosphere. To examine this trade-off, they measured not only CH4 but also N2O emissions in the same field experiments and found that N2O emission was mostly negligible without losing rice yield although CH4 was significantly reduced (**Table 1**). Such trade-off should be examined not only for water management but

*Effects of water management and crop establishments on N2O emission in field experimental site conducted at* 

**Varietyc Treatment CH4 (kg ha−1) N2O (kg ha−1) GWP (kg CO2-eq/ha) Reduction % ADT 43** SRI 59.97 a 1.94 a 2077.4 **28.8%**

CT 99.44 b 1.45 a 2918.1 **CO 51** SRI 51.73 a 2.09 a 1916.1 **27.1%**

CT 88.86 b 1.36 a 2626.8 *SRI as a type of AWD with reduce seedling numbers, and MSRI as modified SRI with seedling age to compare with* 

MSRI 45.11 a 2.69 a 1929.4 **33.9%**

MSRI 50.76 a 1.53 a 1724.9 **34.3%**

Nitrogen is one of the most critical elements for food production, local and global environments. Nitrous oxide (N2O) is an important greenhouse gas emitted from the soil via biological processes in N cycling. N2O emission keeps increasing to induce global warming, climate change, and stratospheric ozone layer depletion. N2O production in the soil is related to soil and fertilizer management and is influenced by many factors, such as soil conditions, chemical fertilizer, and organic manures. Mitigation is possible by appropriate soil and fertilizer management (controlled-release fertilizer and nitrification inhibitors), but exceptional soil such as peat soil should be careful. Feasibility is important to harmonize with yield and other factors (cost and economic merits, side effect, etc.). Under the COVID-19 pandemic, the balance of food production, human health, and environmental management become more and more crucial issues. Sustainable development goals

also other soil managements including biochar for soil C sequestration.

become more important view-points than before [39, 40].

*DOI: http://dx.doi.org/10.5772/intechopen.99972*

*Mitigation of Climate Change by Nitrogen Managements in Agriculture DOI: http://dx.doi.org/10.5772/intechopen.99972*


*SRI as a type of AWD with reduce seedling numbers, and MSRI as modified SRI with seedling age to compare with control CT [38].*

#### **Table 1.**

*Nitrogen in Agriculture - Physiological, Agricultural and Ecological Aspects*

*N2O emission from field experiments with different soil and fertilizer [22].*

was observed even N application rate of M was half of C. Tropical peat soil has been pointed out as a significant N2O emission source, even without fertilizer, strongly influenced by groundwater level [6, 7, 23–27]. Therefore CRCU has a significant impact even under tropical conditions to reduce N2O in certain mineral soils, but not in organic peat soil. Long-term evaluation and cost–benefit analysis are important with yield evaluation in various soil types under diverse climate conditions. Another mitigation option, nitrification inhibitors to stop ammonium oxidation have been also examined, typically DCD (Dicyandiamide; [20]) which is biologically and temperature-dependently decomposed [28]. However, it caused contamination in exposed milk powder in New Zealand, so NZ banned DCD from 2013. Nitrapyrin and 3,4-dimethyl pyrazole phosphate (DMPP) are other chemicals of nitrification inhibitors, but less effective. Neem cake is derived from natural compounds, so less expensive, but also less effective to compare with chemical inhibitors [21]. Combined effects of a nitrification inhibitor, including DCD, neem, and clay mineral (zeolite) on N2O fluxes and corn growth were examined ([29]; **Figure 8**). Another biological nitrification inhibitor is also examined [30].

Mitigation options of other greenhouse gases, such as water management in the paddy field to reduce CH4, have been examined in Japan [31]. The controlling irrigation water level was also examined in Indonesia [32]. Groundwater level

**8**

**Figure 7.**

**Figure 8.**

**6. Trade-off with other mitigation**

*Nitrification inhibitors on N2O emission [29].*

*Effects of water management and crop establishments on N2O emission in field experimental site conducted at Tamil Nadu Rice Research Institute*

control by alternate wet and drying (AWD) have established by IRRI and examined in Indonesia, the Philippines, Thailand, Vietnam [33–37] and India [38]. AWD has merit for saving labor and water. However, it may have a trade-off effect to increase N2O, because of the removal of flooded water to expose anaerobic soil directly to the atmosphere. To examine this trade-off, they measured not only CH4 but also N2O emissions in the same field experiments and found that N2O emission was mostly negligible without losing rice yield although CH4 was significantly reduced (**Table 1**). Such trade-off should be examined not only for water management but also other soil managements including biochar for soil C sequestration.

#### **7. Conclusions**

Nitrogen is one of the most critical elements for food production, local and global environments. Nitrous oxide (N2O) is an important greenhouse gas emitted from the soil via biological processes in N cycling. N2O emission keeps increasing to induce global warming, climate change, and stratospheric ozone layer depletion. N2O production in the soil is related to soil and fertilizer management and is influenced by many factors, such as soil conditions, chemical fertilizer, and organic manures. Mitigation is possible by appropriate soil and fertilizer management (controlled-release fertilizer and nitrification inhibitors), but exceptional soil such as peat soil should be careful. Feasibility is important to harmonize with yield and other factors (cost and economic merits, side effect, etc.). Under the COVID-19 pandemic, the balance of food production, human health, and environmental management become more and more crucial issues. Sustainable development goals become more important view-points than before [39, 40].

*Nitrogen in Agriculture - Physiological, Agricultural and Ecological Aspects*

#### **Author details**

Kazuyuki Inubushi\* and Miwa Yashima Chiba University, Matsudo, Chiba, Japan

\*Address all correspondence to: inubushi@faculty.chiba-u.jp

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**11**

(2), 79-86.

*Mitigation of Climate Change by Nitrogen Managements in Agriculture*

bacteria and their activity determine nitrogen retention or loss in agricultural soil, Soil Biology and Biochemistry,

[9] Sato, Y., Ohta, H., Yamagishi, T., Guo, Y., Nichizawa, T., Rahman, M.H.,

Yoshinaga, I., Inubushi, K., and Suwa, Y. 2012. Detection of anammox activity and 16S rRNA genes in ravine paddy field soil, Microbes and Environments,

Kuroda, H., Kato, T., Saito, M.,

[10] Saito, Y., Shiga, M., Sato, M., Bencsik, D., Kátai, J., Kovács, A.B., Tállai, M., Yashima, M.M., and

(ISBN 978-963-318-936-8).

Sciences, 2, 329-334.

35, 108-113.

2715-2727.

Inubushi, K. 2021, Effect of biochar and soil moisture on nitrogen dynamics, greenhouse gas emissions, and Komatsuna (*Brassica rapa*) growth in Japanese and Hungarian soils with different fertilities, Special volume for Prof Kátai, University of Debrecen

[11] Inubushi, K., Goyal, S., Sakamoto, K., Wada, Y., Yamakawa, K. and Arai, T., 2000. Influence of application of sewage sludge compost on N2O production in soils, Chemosphere-Global Change

[12] Li, Xinhui, Inubushi, K., and

Sakamoto, K., 2002a. N2O concentration in the Andisol profile and emissions to the atmosphere as influenced by the application of nitrogen fertilizers and manure, Biology and Fertility of Soils*,*

[13] Li, Xinhui, T. Nishio, Y. Uemiya, and K. Inubushi, 2002b. Gaseous losses of applied nitrogen from a corn field determined by 15N abundance of N2 and N2O, Communications in Soil Science and Plant Analysis, 33(15-18),

[14] Singla, A., Dubey, S.K., Iwasa, H., and Inubushi, K. 2013. Nitrous oxide

123, 97-104.

27(3), 316-319

*DOI: http://dx.doi.org/10.5772/intechopen.99972*

[1] IPCC, 2014. "AR5 Climate Change 2014: Mitigation of Climate Change." Working Group III to the Fifth Assessment Report of the Inter

governmental Panel on Climate Change.

[2] Tian, H., Xu, R., Canadell, J.G., Yao, Y., *et al.* 2020. A comprehensive quantification of global nitrous oxide sources and sinks, Nature, 586, 248-256

Cambridge, UK: Cambridge

[3] SNC 2010. Second National Communication of Indonesia to the

[4] Inubushi, K., Naganuma, H. and Kitahara, S. 1996. Contribution of denitrification, autotrophic and heterotrophic nitrification in nitrous oxide production in andosols. Biology and Fertility of Soils, 23(3), 292-298.

[5] Jumadi, O., Hala, Y., Anas, I., Ali, A., Sakamoto, K., Saigusa, M., Yagi, K., and

structure of ammonia oxidizing bacteria and their potential to produce nitrous oxide and carbon dioxide in acid tea soils, Geomicrobiology Journal, 25

Inubushi, K., 2008. Community

[6] Arai, H., Hadi, A., Darung, U., Limin, S.H., Takahashi, H., Hatano, R., and Inubushi, K. 2014. Land use change affects microbial biomass and fluxes of carbon, dioxide and nitrous oxide in tropical peatlands, Soil Science and Plant Nutrition, 60: 423-434

[7] Hadi, A., Haridi, M., Inubushi, K., Purnomo, E., Razie, F., and H. Tsuruta, 2001. Effect of land-use change in tropical peat soil on the microbial population and emission of greenhouse gases, Microbes and Environments, 16

[8] Martina, P., Schleusner P., Rütting, T., and Hallin, S. 2018. Relative abundance of denitrifying and DNRA

(7-8), 381-389

UNFCCC (SNC), Jakarta.

University Press.

**References**

*Mitigation of Climate Change by Nitrogen Managements in Agriculture DOI: http://dx.doi.org/10.5772/intechopen.99972*

#### **References**

*Nitrogen in Agriculture - Physiological, Agricultural and Ecological Aspects*

**10**

**Author details**

Kazuyuki Inubushi\* and Miwa Yashima Chiba University, Matsudo, Chiba, Japan

provided the original work is properly cited.

\*Address all correspondence to: inubushi@faculty.chiba-u.jp

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, [1] IPCC, 2014. "AR5 Climate Change 2014: Mitigation of Climate Change." Working Group III to the Fifth Assessment Report of the Inter governmental Panel on Climate Change. Cambridge, UK: Cambridge University Press.

[2] Tian, H., Xu, R., Canadell, J.G., Yao, Y., *et al.* 2020. A comprehensive quantification of global nitrous oxide sources and sinks, Nature, 586, 248-256

[3] SNC 2010. Second National Communication of Indonesia to the UNFCCC (SNC), Jakarta.

[4] Inubushi, K., Naganuma, H. and Kitahara, S. 1996. Contribution of denitrification, autotrophic and heterotrophic nitrification in nitrous oxide production in andosols. Biology and Fertility of Soils, 23(3), 292-298.

[5] Jumadi, O., Hala, Y., Anas, I., Ali, A., Sakamoto, K., Saigusa, M., Yagi, K., and Inubushi, K., 2008. Community structure of ammonia oxidizing bacteria and their potential to produce nitrous oxide and carbon dioxide in acid tea soils, Geomicrobiology Journal, 25 (7-8), 381-389

[6] Arai, H., Hadi, A., Darung, U., Limin, S.H., Takahashi, H., Hatano, R., and Inubushi, K. 2014. Land use change affects microbial biomass and fluxes of carbon, dioxide and nitrous oxide in tropical peatlands, Soil Science and Plant Nutrition, 60: 423-434

[7] Hadi, A., Haridi, M., Inubushi, K., Purnomo, E., Razie, F., and H. Tsuruta, 2001. Effect of land-use change in tropical peat soil on the microbial population and emission of greenhouse gases, Microbes and Environments, 16 (2), 79-86.

[8] Martina, P., Schleusner P., Rütting, T., and Hallin, S. 2018. Relative abundance of denitrifying and DNRA bacteria and their activity determine nitrogen retention or loss in agricultural soil, Soil Biology and Biochemistry, 123, 97-104.

[9] Sato, Y., Ohta, H., Yamagishi, T., Guo, Y., Nichizawa, T., Rahman, M.H., Kuroda, H., Kato, T., Saito, M., Yoshinaga, I., Inubushi, K., and Suwa, Y. 2012. Detection of anammox activity and 16S rRNA genes in ravine paddy field soil, Microbes and Environments, 27(3), 316-319

[10] Saito, Y., Shiga, M., Sato, M., Bencsik, D., Kátai, J., Kovács, A.B., Tállai, M., Yashima, M.M., and Inubushi, K. 2021, Effect of biochar and soil moisture on nitrogen dynamics, greenhouse gas emissions, and Komatsuna (*Brassica rapa*) growth in Japanese and Hungarian soils with different fertilities, Special volume for Prof Kátai, University of Debrecen (ISBN 978-963-318-936-8).

[11] Inubushi, K., Goyal, S., Sakamoto, K., Wada, Y., Yamakawa, K. and Arai, T., 2000. Influence of application of sewage sludge compost on N2O production in soils, Chemosphere-Global Change Sciences, 2, 329-334.

[12] Li, Xinhui, Inubushi, K., and Sakamoto, K., 2002a. N2O concentration in the Andisol profile and emissions to the atmosphere as influenced by the application of nitrogen fertilizers and manure, Biology and Fertility of Soils*,* 35, 108-113.

[13] Li, Xinhui, T. Nishio, Y. Uemiya, and K. Inubushi, 2002b. Gaseous losses of applied nitrogen from a corn field determined by 15N abundance of N2 and N2O, Communications in Soil Science and Plant Analysis, 33(15-18), 2715-2727.

[14] Singla, A., Dubey, S.K., Iwasa, H., and Inubushi, K. 2013. Nitrous oxide

flux from komatsuna (*Brassica rapa*) vegetated soil: a comparison between biogas digested liquid and chemical fertilizer, Biology and Fertility of Soils 49:971-976

[15] Zaman, M., Di, H.J., Sakamoto, K., Goto, S., Hayashi, H. and Inubushi, K. 2002. Effect of sewage sludge compost and chemical fertilizer applications on microbial biomass and N mineralization rates, Soil Science and Plant Nutrition, 48, 195-201.

[16] Zaman, M., Matsushima, M., Chang, S.X., Inubushi, K., Nguyen, L., Goto, S., Kaneko, F. and Yoneyama, T. 2004. Nitrogen mineralization, N2O production and soil microbiological properties as affected by long-term applications of sewage sludge composts, Biology and Fertility of Soils*,*40, 101-109.

[17] Yanai, J., Sawamoto, T., Oe, T., Kusa, K., Yamakawa, K., Sakamoto, K., Naganawa, T., Inubushi, K., Hatano, R. and Kosaki, T. 2003. Spatial variability of N2O emissions and their soil-related determining factors in an agricultural field. Journal of Environmental Quality, 32(6), 1965-1977.

[18] Kong, Y.H., Nagano, H., Kátai, J, Vágó, I., Oláh, Á.Z., Yashima, M. and Inubushi, K.: 2013. CO2, N2O and CH4 production/consumption potentials of soils under different land-use types in central Japan and eastern Hungary, Soil Science and Plant Nutrition, 59(3), 455-462

[19] Amkha, S., Inubushi, K., and Takagaki, M. 2007. Effects of controlledrelease nitrogen fertilizer application on nitrogen uptake of a leafy vegetable (*Brassica campestris* L.), nitrate leaching and N2O emission, *Japanese Journal of Tropical Agriculture*, 51(4), 152-159

[20] Hadi, A,, Jumadi, O., Inubushi, K., and Yagi, K., 2008. Mitigation options for N2O emission from a corn field in

Kalimantan, Indonesia: A case study, Soil Science and Plant Nutrition, 54 (4), 644-649

[21] Akiyama, H., Yan, X., and Yagi, K. 2010. Evaluation of effectiveness of enhanced-efficiency fertilizers as mitigation options for N2O and NO emissions from agricultural soils: metaanalysis, Global Change Biology, https:// doi.org/10.1111/j.1365-2486. 2009.02031.x

[22] Sakata R., Shimada S., Arai H., Yoshioka N., Yoshioka R., Aoki H., Kimoto N., Sakamoto A., Melling L., and Inubushi K. 2015. Effect of soil types and nitrogen fertilizer on nitrous oxide and carbon dioxide emissions in oil palm plantations, Soil Science and Plant Nutrition, 61: 48-60

[23] Furukawa, Y., Inubushi, K., Ali, M., Itang, AM. and Tsuruta, H. 2005. Effect of changing groundwater levels caused by land-use changes on greenhouse gas emissions from tropical peatlands, Nutrient Cycling in Agroecosystems, 71, 81-91

[24] Hadi, A., K. Inubushi, E. Purnomo, F. Razie, K. Yamakawa and H. Tsuruta, 2000. Effect of land-use changes on nitrous oxide (N2O) emission from tropical peatlands, Chemosphere-Global Change Sciences, 2, 347-358

[25] Hadi, A., Inubushi, K., Furukawa, Y., Purunomo, E., Rasmadi, M., and Tsuruta, H. 2005. Greenhouse gas emissions from tropical peatlands of Kalimantan, Indonesia, *Nutrient Cycling in Agroecosystems*, 71, 73-80.

[26] Inubushi, K., Furukawa, Y., Hadi, A., Purnomo, E., and Tsuruta, H. 2003. Seasonal changes of CO2, CH4 and N2O fluxes in relation to land-use change in tropical peatlands located in coastal area of south Kalimantan, Chemosphere, 52(3), 603-608.

[27] Susilawati, H.L., Setyanto, P., Ariani, M., Hervani A., and Inubushi, K., 2016, Influence of water depth and

**13**

8:319-324.

*Mitigation of Climate Change by Nitrogen Managements in Agriculture*

Evaluating the effects of Alternate Wetting and Drying (AWD) on methane and nitrous oxide emissions from a paddy field in Thailand. Soil Science and Plant Nutrition, 64

[34] Setyanto, P., A. Pramono, T. A. Adriany, H. L. Susilawati, T. Tokida, A. Tirol-Padre, and K. Minamikawa. 2018. "Alternate Wetting and Drying Reduces Methane Emission from a Rice Paddy in Central Java, Indonesia without Yield Loss." Soil Science and Plant Nutrition

[35] Sibayan, E. B., K. Samoy-Pascual, F. S. Grospe, M. E. D. Casil, T. Tokida, A. Tirol-Padre, and K. Minamikawa. 2018. Effects of Alternate Wetting and Drying technique on greenhouse gas emissions from irrigated rice paddy in Central Luzon, Philippines. Soil Science and

[36] Tirol-Padre, A., K. Minamikawa, T. Tokida, R. Wassmann, and K. Yagi. 2018. Site-specific feasibility of Alternate Wetting and Drying as a greenhouse gas mitigation option in irrigated rice fields in Southeast Asia: A Synthesis. Soil Science and Plant

[37] Tran, D. H., T. N. Hoang, T. Tokida, A. Tirol-Padre, and K. Minamikawa. 2018. Impacts of Alternate Wetting and Drying on greenhouse gas emission from paddy field in Central Vietnam. Soil Science and Plant Nutrition 64

[38] Oo, A.Z., Sudo, S., Inubushi, K., Mano, M., Yamamoto, A., Ono, K., Osawa, T., Hayashida, S., Patra, P.K., Terao, Y., Elayakumar, P., Vanitha, K., Umamageswari, C., Jothimani, P., and Ravi, V., 2018. Methane and nitrous oxide emissions from conventional and modified rice cultivation systems in South India, Agriculture, Ecosystems and Environment 252, 148-158.

Plant Nutrition 64(1): 39-46.

Nutrition 64 (1):2-13.

(1): 14-22.

(1): 31-38.

64 (1): 23-30.

*DOI: http://dx.doi.org/10.5772/intechopen.99972*

soil amelioration on greenhouse gas emissions from peat soil columns, Soil Science and Plant Nutrition, 62: 57-68

[28] Rajbanshi, S.S., Benckiser, G. and

concentration, incubation temperature,

degradation kinetics of dicyandiamide (DCD) in model experiments with a silt loam soil. Biology and Fertility of Soils **13,** 61-64. https://doi.org/10.1007/

[29] Jumadi, O., Hala, Y., Iriany, R.N., Makkulawu, A.T., Baba, J., Hartono, Hiola St.F., and Inubushi, K. 2020. Combined effects of nitrification inhibitor and zeolite on greenhouse gas fluxes and corn growth. Environmental Science and Pollution Research, 27,

[30] Subbarao, G.V., Nakahara, K., Hurtado, M.P., Ono, H., Moreta, D.E., Salcedo, A.F., Yoshihashi, A.T., Ishikawa, T., Ishitani, M., Ohnishi-Kameyama, M., Yoshida, M., Rondon, M., Rao, I.M., Lascano, C.E., Berry, W. L. O. Ito. 2009 Evidence for biological nitrification inhibition in *Brachiaria* pastures, Proceedings of the National Academy of Sciences 106 (41) 17302- 17307; DOI: 10.1073/pnas.0903694106

[31] Yagi, K., H. Tsuruta, K. Kanda, and K. Minami. 1996. Effect of water

management on methane emission from a Japanese rice paddy field: Automated

Biogeochemical Cycles 10 (2):255-267.

[33] Chidthaisong, A., N. Cha-un, B. Rossopa, C. Buddaboon, C. Kunuthai, P. Sriphirom, S. Towprayoon, T. Tokida, A.

Tirol, and K. Minamikawa. 2018.

[32] Hadi, A., Inubushi, K., and Yagi, K., 2010. Effect of water management on greenhouse gas emissions and microbial properties of paddy soils in Japan and Indonesia, Paddy Water Environment,

methane monitoring. Global

Ottow, J.C.G. 1992. Effects of

and repeated applications on

BF00337336

2087-2095.

*Mitigation of Climate Change by Nitrogen Managements in Agriculture DOI: http://dx.doi.org/10.5772/intechopen.99972*

soil amelioration on greenhouse gas emissions from peat soil columns, Soil Science and Plant Nutrition, 62: 57-68

*Nitrogen in Agriculture - Physiological, Agricultural and Ecological Aspects*

Kalimantan, Indonesia: A case study, Soil Science and Plant Nutrition, 54

[21] Akiyama, H., Yan, X., and Yagi, K. 2010. Evaluation of effectiveness of enhanced-efficiency fertilizers as mitigation options for N2O and NO emissions from agricultural soils: metaanalysis, Global Change Biology, https:// doi.org/10.1111/j.1365-2486. 2009.02031.x

[22] Sakata R., Shimada S., Arai H., Yoshioka N., Yoshioka R., Aoki H., Kimoto N., Sakamoto A., Melling L., and Inubushi K. 2015. Effect of soil types and nitrogen fertilizer on nitrous oxide and carbon dioxide emissions in oil palm plantations, Soil Science and

[23] Furukawa, Y., Inubushi, K., Ali, M., Itang, AM. and Tsuruta, H. 2005. Effect of changing groundwater levels caused by land-use changes on greenhouse gas emissions from tropical peatlands, Nutrient Cycling in Agroecosystems,

[24] Hadi, A., K. Inubushi, E. Purnomo, F. Razie, K. Yamakawa and H. Tsuruta, 2000. Effect of land-use changes on nitrous oxide (N2O) emission from tropical peatlands, Chemosphere-Global Change Sciences, 2, 347-358

[25] Hadi, A., Inubushi, K., Furukawa, Y., Purunomo, E., Rasmadi, M., and Tsuruta, H. 2005. Greenhouse gas emissions from tropical peatlands of Kalimantan, Indonesia, *Nutrient Cycling* 

[26] Inubushi, K., Furukawa, Y., Hadi, A., Purnomo, E., and Tsuruta, H. 2003. Seasonal changes of CO2, CH4 and N2O fluxes in relation to land-use change in tropical peatlands located in coastal area of south Kalimantan, Chemosphere,

[27] Susilawati, H.L., Setyanto, P., Ariani, M., Hervani A., and Inubushi, K., 2016, Influence of water depth and

*in Agroecosystems*, 71, 73-80.

52(3), 603-608.

Plant Nutrition, 61: 48-60

71, 81-91

(4), 644-649

flux from komatsuna (*Brassica rapa*) vegetated soil: a comparison between biogas digested liquid and chemical fertilizer, Biology and Fertility of Soils

[15] Zaman, M., Di, H.J., Sakamoto, K., Goto, S., Hayashi, H. and Inubushi, K. 2002. Effect of sewage sludge compost and chemical fertilizer applications on microbial biomass and N mineralization rates, Soil Science and Plant Nutrition,

[16] Zaman, M., Matsushima, M., Chang, S.X., Inubushi, K., Nguyen, L., Goto, S., Kaneko, F. and Yoneyama, T. 2004. Nitrogen mineralization, N2O production and soil microbiological properties as affected by long-term applications of sewage sludge composts,

Biology and Fertility of Soils*,*40,

K., Yamakawa, K., Sakamoto, K., Naganawa, T., Inubushi, K., Hatano, R. and Kosaki, T. 2003. Spatial variability of N2O emissions and their soil-related determining factors in an agricultural field. Journal of Environmental Quality,

[18] Kong, Y.H., Nagano, H., Kátai, J, Vágó, I., Oláh, Á.Z., Yashima, M. and Inubushi, K.: 2013. CO2, N2O and CH4 production/consumption potentials of soils under different land-use types in central Japan and eastern Hungary, Soil

Science and Plant Nutrition,

[19] Amkha, S., Inubushi, K., and Takagaki, M. 2007. Effects of controlledrelease nitrogen fertilizer application on nitrogen uptake of a leafy vegetable (*Brassica campestris* L.), nitrate leaching and N2O emission, *Japanese Journal of Tropical Agriculture*, 51(4), 152-159

[20] Hadi, A,, Jumadi, O., Inubushi, K., and Yagi, K., 2008. Mitigation options for N2O emission from a corn field in

[17] Yanai, J., Sawamoto, T., Oe, T., Kusa,

49:971-976

48, 195-201.

101-109.

32(6), 1965-1977.

59(3), 455-462

**12**

[28] Rajbanshi, S.S., Benckiser, G. and Ottow, J.C.G. 1992. Effects of concentration, incubation temperature, and repeated applications on degradation kinetics of dicyandiamide (DCD) in model experiments with a silt loam soil. Biology and Fertility of Soils **13,** 61-64. https://doi.org/10.1007/ BF00337336

[29] Jumadi, O., Hala, Y., Iriany, R.N., Makkulawu, A.T., Baba, J., Hartono, Hiola St.F., and Inubushi, K. 2020. Combined effects of nitrification inhibitor and zeolite on greenhouse gas fluxes and corn growth. Environmental Science and Pollution Research, 27, 2087-2095.

[30] Subbarao, G.V., Nakahara, K., Hurtado, M.P., Ono, H., Moreta, D.E., Salcedo, A.F., Yoshihashi, A.T., Ishikawa, T., Ishitani, M., Ohnishi-Kameyama, M., Yoshida, M., Rondon, M., Rao, I.M., Lascano, C.E., Berry, W. L. O. Ito. 2009 Evidence for biological nitrification inhibition in *Brachiaria* pastures, Proceedings of the National Academy of Sciences 106 (41) 17302- 17307; DOI: 10.1073/pnas.0903694106

[31] Yagi, K., H. Tsuruta, K. Kanda, and K. Minami. 1996. Effect of water management on methane emission from a Japanese rice paddy field: Automated methane monitoring. Global Biogeochemical Cycles 10 (2):255-267.

[32] Hadi, A., Inubushi, K., and Yagi, K., 2010. Effect of water management on greenhouse gas emissions and microbial properties of paddy soils in Japan and Indonesia, Paddy Water Environment, 8:319-324.

[33] Chidthaisong, A., N. Cha-un, B. Rossopa, C. Buddaboon, C. Kunuthai, P. Sriphirom, S. Towprayoon, T. Tokida, A. Tirol, and K. Minamikawa. 2018.

Evaluating the effects of Alternate Wetting and Drying (AWD) on methane and nitrous oxide emissions from a paddy field in Thailand. Soil Science and Plant Nutrition, 64 (1): 31-38.

[34] Setyanto, P., A. Pramono, T. A. Adriany, H. L. Susilawati, T. Tokida, A. Tirol-Padre, and K. Minamikawa. 2018. "Alternate Wetting and Drying Reduces Methane Emission from a Rice Paddy in Central Java, Indonesia without Yield Loss." Soil Science and Plant Nutrition 64 (1): 23-30.

[35] Sibayan, E. B., K. Samoy-Pascual, F. S. Grospe, M. E. D. Casil, T. Tokida, A. Tirol-Padre, and K. Minamikawa. 2018. Effects of Alternate Wetting and Drying technique on greenhouse gas emissions from irrigated rice paddy in Central Luzon, Philippines. Soil Science and Plant Nutrition 64(1): 39-46.

[36] Tirol-Padre, A., K. Minamikawa, T. Tokida, R. Wassmann, and K. Yagi. 2018. Site-specific feasibility of Alternate Wetting and Drying as a greenhouse gas mitigation option in irrigated rice fields in Southeast Asia: A Synthesis. Soil Science and Plant Nutrition 64 (1):2-13.

[37] Tran, D. H., T. N. Hoang, T. Tokida, A. Tirol-Padre, and K. Minamikawa. 2018. Impacts of Alternate Wetting and Drying on greenhouse gas emission from paddy field in Central Vietnam. Soil Science and Plant Nutrition 64 (1): 14-22.

[38] Oo, A.Z., Sudo, S., Inubushi, K., Mano, M., Yamamoto, A., Ono, K., Osawa, T., Hayashida, S., Patra, P.K., Terao, Y., Elayakumar, P., Vanitha, K., Umamageswari, C., Jothimani, P., and Ravi, V., 2018. Methane and nitrous oxide emissions from conventional and modified rice cultivation systems in South India, Agriculture, Ecosystems and Environment 252, 148-158.

[39] Inubushi, K., 2021. Sustainable soil management in East, South and Southeast Asia, Soil Science and Plant Nutrition, 67:1, 1-9.

[40] Lal, R., 2020. Soil Science beyond COVID-19, Journal of Soil and Water Conservation*,* 1-3.

**15**

**Chapter 2**

**Abstract**

*and Cândido Neto*

physiological system.

**1. Introduction**

ammonium (NH4

+

Influence of Heavy Metals on the

As an essential element, Nitrogen is needed in large quantities for being an important component of cellular constituents and for plant metabolism, and its deficiency is one of the most common limitations for plant development. The study of the toxic effects of metal in plants involves a complex system of reactions that can be better determined once having a large attention of the different backgrounds of occurence to determinate how to proceed. The objective of this review is to add scientific knowledge, addressing the main functionalities and characteristics of this relation heavy metals – nitrogen metabolism in plant. Increasing industrialization and urbanization had anthropogenic contribution of heavy metals in biosphere and had largest availability in ecosystems. This toxicity in plants varies with plant species, specific metal, concentration, soil composition, as many heavy metals are considered to be essential for plant growth. Were provided data and reviews regarding the effect of heavy metals on nitrogen metabolism of plants and the responses of plants and the cross-talk of heavy metals and various stressors factors. Is clear to understand the relation between metals amount and the benefit or harm caused on plants, determining then, which mechanism should be activated to protect your

**Keywords:** Plant physiology, human activities, industrialization, plant stress, toxicity

Nitrogen (N) is an essential nutrient required by all living organisms and often limits primary production in aquatic and terrestrial ecosystems. This element is needed in large quantities, as it is an essential component of proteins, nucleic acids and other cellular constituents. Proteins alone comprise 60% or more of the N of plants and microbial cells [1]. It is also an essential element for plant metabolism and its deficiency is one of the most common limitations for plant development [2]. The preference of plants for the source of N can vary according to the selective

) forms, the first being more abundant and better assimilated

− ) and

The most common and available forms in the soil are the nitrate (NO3

by plants [4], as a result of the nitrification process by bacteria. However, depending on soil conditions, the ammoniacal form may be the most abundant due to the

pressures and consequent physiological adaptations [3].

Nitrogen Metabolism in Plants

*Vitor Nascimento, Glauco Nogueira, Gabriel Monteiro,* 

*Waldemar Júnior, Joze Melissa Nunes de Freitas* 

#### **Chapter 2**

*Nitrogen in Agriculture - Physiological, Agricultural and Ecological Aspects*

[39] Inubushi, K., 2021. Sustainable soil management in East, South and Southeast Asia, Soil Science and Plant

[40] Lal, R., 2020. Soil Science beyond COVID-19, Journal of Soil and Water

Nutrition, 67:1, 1-9.

Conservation*,* 1-3.

**14**
