Scope and Strategies for Regulation of Nitrification in Agricultural Systems—Challenges and Opportunities

Subbarao, G. V.; Ito, Osamu; Sahrawat, K. L.; Berry, Wade L.; Nakahara, Kenji; Ishikawa, Takayuki; Watanabe, Takeshi; Suenaga, Kazuhiro; Rondón, Marco Antonio; Rao, Idupulapati M.

doi:10.1080/07352680600794232

Cited by 447 publications

(375 citation statements)

References 292 publications

(434 reference statements)

Supporting

Mentioning

347

Contrasting

Unclassified

Order By: Relevance

“…Fertilizer-N consumption is expected to reach 200 Tg⅐y Ϫ1 by 2025 from the present 150 Tg⅐y Ϫ1 (2,40,41). Environmental damage could result, given the pervasive inefficiencies in N use (Ͻ40% of applied N is recovered by most field crops) (2, 42), due largely to nitrification and its associated processes (1,13). The economic implications of this ''wasted N'' can be enormous; they are currently estimated as US$ 17 billion from cereal production systems alone (13,43).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Evidence for biological nitrification inhibition inBrachiariapastures

Subbarao

Nakahara²,

Hurtado³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

437

420

View full text Add to dashboard Cite

Nitrification, a key process in the global nitrogen cycle that generates nitrate through microbial activity, may enhance losses of fertilizer nitrogen by leaching and denitrification. Certain plants can suppress soil-nitrification by releasing inhibitors from roots, a phenomenon termed biological nitrification inhibition (BNI). Here, we report the discovery of an effective nitrification inhibitor in the root-exudates of the tropical forage grass Brachiaria humidicola (Rendle) Schweick. Named ''brachialactone,'' this inhibitor is a recently discovered cyclic diterpene with a unique 5-8-5-membered ring system and a ␥-lactone ring. It contributed 60 -90% of the inhibitory activity released from the roots of this tropical grass. Unlike nitrapyrin (a synthetic nitrification inhibitor), which affects only the ammonia monooxygenase (AMO) pathway, brachialactone appears to block both AMO and hydroxylamine oxidoreductase enzymatic pathways in Nitrosomonas. global warming ͉ nitrogen pollution ͉ nitrous oxide emissions ͉ root exudation ͉ climate change M ost modern agricultural systems are based on large inputs of inorganic nitrogen (N), with ammonium (NH 4 ϩ ) being the primary N source (1, 2). Also, current crop management practices result in the development of highly nitrifying soil environments (3, 4). Nitrification results in the transformation of the relatively immobile NH 4 ϩ to highly mobile nitrate (NO 3 Ϫ ), making inorganic N susceptible to losses through leaching of NO 3 Ϫ and/or gaseous N emissions, potentially initiating a cascade of environmental and health problems (1, 2, 5, 6). Nitrous oxide (N 2 O) is one of the three major biogenic greenhouse gases contributing to global warming, produced primarily from denitrification processes in agricultural systems (5, 7). Also, assimilation of NO 3 Ϫ by plants can result in further N 2 O emissions directly from plant canopies (8). The low agronomic N-use efficiency (NUE) found in many agricultural systems is largely the result of N losses associated with nitrification (i.e., N losses from NO 3 Ϫ leaching and denitrification) (9-11). Most plants have the ability to assimilate both NH 4 ϩ and NO 3 Ϫ (12); therefore, nitrification does not need to be a dominant process in the N cycle for efficient N use.Nitrification is low in some forest and grassland soils (13-17). Since the early 1960s, some tropical grasses have been suspected of having the capacity to inhibit nitrification (18-21). However, this concept remained controversial due to the lack of direct evidence showing such inhibitory effects or the identification of specific inhibitors (22).We adopted a very sensitive bioassay using a recombinant luminescent Nitrosomonas europaea to detect biological nitrification inhibition (BNI) in plant-soil systems with the inhibitory activity of roots expressed in allylthiourea units (ATU) (23). Using this methodology, we were able to show that certain plants release nitrification inhibitors from their roots (23-26). Such BNI capacity appears to be relatively widespread among...

show abstract

Section: Discussionmentioning

confidence: 99%

“…Nitrification is low in some forest and grassland soils (13)(14)(15)(16)(17). Since the early 1960s, some tropical grasses have been suspected of having the capacity to inhibit nitrification (18)(19)(20)(21).…”

mentioning

confidence: 99%

Evidence for biological nitrification inhibition inBrachiariapastures

Subbarao

Nakahara²,

Hurtado³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

437

420

View full text Add to dashboard Cite

show abstract

“…Interestingly, although leguminous crops fix N (so do not require additional N fertiliser) leguminous pastures can also give rise to N leaching, thus permitting N 2 O production (7) . Realistic targets for environmental improvement include an increased use of precision agricultural techniques for fertiliser application and increasing N use efficiency (the ability of plants to take up and sequester N) of crop plants (7) . A further opportunity is to exploit the natural presence of N-fixing endophytic bacteria on the roots of non-leguminous crop plants, including grasses (22)(23)(24) , the success of which will enable decreased requirement to add N fertilisers to land for forage production.…”

Section: Ruminants As a Source Of Environmental Pollutantsmentioning

confidence: 99%

Plant-based strategies towards minimising ‘livestock's long shadow’

et al. 2010

View full text Add to dashboard Cite

Ruminant farming is an important component of the human food chain. Ruminants can use offtake from land unsuitable for cereal crop cultivation via interaction with the diverse microbial population in their rumens. The rumen is a continuous flow fermenter for the digestion of ligno-cellulose, with microbial protein and fermentation end-products incorporated by the animal directly or during post-ruminal digestion. However, ruminal fermentation is inefficient in capturing the nutrient resource presented, resulting in environmental pollution and generation of greenhouse gases. Methane is generated as a consequence of ruminal fermentation and poor retention of ingested forage nitrogen causes nitrogenous pollution of water and land and contributes to the generation of nitrous oxide. One possible cause is the imbalanced provision of dietary substrates to the rumen micro-organisms. Deamination of amino acids by ammonia-producing bacteria liberates ammonia which can be assimilated by the rumen bacteria and used for microbial protein synthesis. However, when carbohydrate is limiting, microbial growth is slow, meaning low demand for ammonia for microbial protein synthesis and excretion of the excess. Protein utilisation can therefore be improved by increasing the availability of readily fermentable sugars in forage or by making protein unavailable for proteolysis through complexing with plant secondary products. Alternatively, realisation that grazing cattle ingest living cells has led to the discovery that plant cells undergo endogenous, stress-mediated protein degradation due to the exposure to rumen conditions. This presents the opportunity to decrease the environmental impact of livestock farming by using decreased proteolysis as a selection tool for the development of improved pasture grass varieties. Ruminant: Protein: Nitrogen: Methane: Grass: Clover: Forage Making assessments of the impact and value of livestock farming is complex. The rearing of domestic livestock is important in food production, although there are conflicts between the use of land for production of animal feed as opposed to producing grain for human consumption (1) . The livestock sector is economically valuable. Livestock contributes 1 . 4 % of global gross domestic product providing employment for 20% of the global population in both developed and developing countries (1) . Livestock products can provide an important addition to diet especially in the developing world, providing key vitamins and nutrients. Indeed, the consumption of meat has been linked to both physical and mental development in children (2) , but in the developed world over-consumption of meat has been linked to development of serious health problems (3) . Current projections estimate that the global demand for meat and milk will have doubled by 2050 compared with that at the onset of the 21st century (4) . This is being driven by demographic changes, (the emergence of a larger, but older population) and economic growth (1) . Increased demand for livestock products comes mostl...

show abstract

“…Controlling the process of nitrification through inhibition or suppression of nitrifiers in soil is perhaps one of the most effective strategies to reduce N losses by NO 3 -leaching and by gaseous N emissions that occur in nitrification (Rodgers 1986;Prasad and Power 1995;Subbarao et al 2006b). Field evaluations suggested that if nitrification rates are reduced in agricultural systems, plants have more time to take up available N, thereby improving N recovery and uptake and reducing NO 3 -leaching and associated off farm environmental impacts (Rodgers 1986;Subbarao et al 2006b).…”

Section: Introductionmentioning

confidence: 99%

“…Field evaluations suggested that if nitrification rates are reduced in agricultural systems, plants have more time to take up available N, thereby improving N recovery and uptake and reducing NO 3 -leaching and associated off farm environmental impacts (Rodgers 1986;Subbarao et al 2006b). …”

Section: Introductionmentioning

confidence: 99%

Effect of soil-applied calcium carbide and plant derivatives on nitrification inhibition and plant growth promotion

Abbasi

Manzoor

2013

Int. J. Environ. Sci. Technol.

View full text Add to dashboard Cite

The aim of this study was to evaluate the relative performance of three nitrification inhibitors (NIs) viz. calcium carbide (CaC 2 ), and plant derivatives of Pongamia glabra Vent. ? -N and NO 3 --N were examined during the study. A second experiment was conducted in a glasshouse using pots to evaluate the response of wheat to these amendments. Results indicated that more than 92 % of the NH 4? initially present had disappeared from the mineral N pool by the end of incubation. Application of NIs i.e., CaC 2 , karanjin, and M. azedarach resulted in a significant reduction in the extent of NH 4? disappearance by 49, 32, and 13 %, respectively. Accumulation of NO 3 --N was much higher in N amended soil 57 % compared to 11 % in N ? CaC 2 , 13 % in N ? karanjin, and 18 % in N ? M. azedarach. Application of NIs significantly increased growth, yield, and N uptake of wheat. The apparent N recovery in N-treated plants was 20 % that was significantly increased to 38, 34, and 37 % with N ? CaC 2 , N ? karanjin, and N ? M. azedarach, respectively. Among the three NIs tested, CaC 2 and karanjin proved highly effective in inhibiting nitrification and retaining NH 4? -N in the mineral pool for a longer period.

show abstract

Scope and Strategies for Regulation of Nitrification in Agricultural Systems—Challenges and Opportunities

Cited by 447 publications

References 292 publications

Evidence for biological nitrification inhibition inBrachiariapastures

Evidence for biological nitrification inhibition inBrachiariapastures

Plant-based strategies towards minimising ‘livestock's long shadow’

Effect of soil-applied calcium carbide and plant derivatives on nitrification inhibition and plant growth promotion

Contact Info

Product

Resources

About