Partial balance of nitrogen in a maize cropping system in humic nitisol of Central Kenya

Kimetu, J.M.; Mugendi, Daniel N.; Bationo, A.; Palm, Cheryl; Mutuo, Patrick K.; Kihara, Job; Nandwa, S.M.

doi:10.1007/s10705-005-6082-6

Cited by 22 publications

(10 citation statements)

References 26 publications

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“…Apparently, this was one of the very limited studies in Africa that looked into both wet and dry seasons and estimated annual N 2 O emissions of 1.54 kg N hm -2 from mineral fertilizer application and 0.97 kg N hm-2 from animal manure. However, similar urea broadcasting at 60 kg hm -2 by Kimetu et al (2006) only yielded up to T1 T2 T3 T4 T5 T6 T1 T2 T3 T4 T5 T6 T1 T2 T3 T4 T5 T6 Season I Season II Season III plant captured C (kg C hm -2 ) (e ) T1 T2 T3 T4 T5 T6 T1 T2 T3 T4 T5 T6 T1 T2 T3 T4 T5 (a, b), N-uptake (c, d) and C captured (e, f) by maize grown on experimental plots under six treatments at the UZ-Farm and DT-Centre 2.9 μg N 2 O-N and an annual total of 0.1 kg N 2 O-N hm -2 that is less than some of the N 2 O inventories from our study. There could therefore be a problem of heterogeneity in N inputs for area based measurements and in some parts of Europe some grazed pastures can have cattle urine patches that add 1000 kg N hm -2 , and yet many N 2 O measurements studies are carried out using randomly located chambers (Rees RM 2010, personal communication).…”

Section: Discussionmentioning

confidence: 80%

Effects of organic and mineral fertilizer nitrogen on greenhouse gas emissions and plant-captured carbon under maize cropping in Zimbabwe

Mapanda¹,

Wuta

Nyamangara³

et al. 2011

Plant Soil

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Optimizing a three-way pact comprising crop yields, fertility inputs and greenhouse gases may minimize the contribution of croplands to global warming. Fluxes of N 2 O, CO 2 and CH 4 from soil were measured under maize (Zea mays L.) grown using 0, 60 and 120 kg N hm -2 as NH 4 NO 3 -N and composted manure-N in three seasons on clay (Chromic luvisol) and sandy loam (Haplic lixisol) soils in Zimbabwe. The fluxes were measured using the static chamber methodology involving gas chromatography for ample air analysis. Over an average of 122 days we estimated emissions of 0.1 to 0.5 kg N 2 O-N hm −2 , 711 to 1574 kg CO 2 -C hm −2 and−2.6 to 5.8 kg CH 4 -C hm −2 from six treatments during season II with the highest fluxes. The posed hypothesis that composted manure-N may be better placed as a mitigation option against soil emissions of GHG than mineral fertilizer-N was largely supported by N 2 O fluxes during the wet period of the year, but with high level of uncertainty. Nitrogen addition might have stimulated both emissions and consumption of CH 4 but the sink or source strength depended highly on soil water content. We concluded that the application of mineral-N and manure input may play an important role with reference to global warming provided the season can support substantial crop productivity that may reduce the amount of N 2 O loss per unit yield. Confidence in fluxes response to agricultural management is still low due to sporadic measurements and limited observations from the southern African region.

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Section: Discussionmentioning

confidence: 80%

Effects of organic and mineral fertilizer nitrogen on greenhouse gas emissions and plant-captured carbon under maize cropping in Zimbabwe

Mapanda¹,

Wuta

Nyamangara³

et al. 2011

Plant Soil

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“…The Intergovernmental Panel on Climate Change (IPCC) guidelines for the calculation of national greenhouse gas inventories includes three tiers of approaches; the simplest, which is used widely for national inventories in SSA, assumes that 1% of applied fertilizer is lost as N 2 O in direct emissions annually [Intergovernmental Panel on Climate Change, 2006]. Among field studies that have been conducted in SSA, emission factors for a given cropping season or year are well below 1%, with an overwhelming majority under 0.75% [Chikowo et al, 2004;Baggs et al, 2006;Kimetu et al, 2006;Brümmer et al, 2008;Dick et al, 2008;Chapuis-Lardy et al, 2009;Mapanda et al, 2010Mapanda et al, , 2011Mapanda et al, , 2012b, except when fertilization rates exceeded 200 kg N ha À1 Baggs et al, 2006;Predotova et al, 2010;Lompo et al, 2012], though see two exceptions Dick et al, 2008] (Figure 4). The low-emission factors are also found in laboratory incubations Baggs, 2004, 2005;Gentile et al, 2008], although it should be emphasized that few field studies and no laboratory studies included measurements across an entire year.…”

Section: Discussionmentioning

confidence: 99%

A potential tipping point in tropical agriculture: Avoiding rapid increases in nitrous oxide fluxes from agricultural intensification in Kenya

Hickman

Tully

Groffman

et al. 2015

J. Geophys. Res. Biogeosci.

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There are national and regional efforts aimed at increasing fertilizer use in sub-Saharan Africa, where nitrogen (N) inputs must be increased by an order of magnitude or more to reach recommended rates. Fertilizer inputs increase N availability and cycling rates and subsequently emissions of nitrous oxide (N 2 O), a powerful greenhouse gas and the primary catalyst of stratospheric ozone depletion. We established experimental maize (Zea mays L.) plots in western Kenya to quantify the relationship between N inputs and N 2 O emissions. Mean N 2 O emissions were marginally, but not significantly, better described by an exponential model relating emissions to N input rate in 2011; in 2012, an exponential relationship provided the best fit compared to linear and other nonlinear models. Most N 2 O fluxes occurred during the 30 days following the second fertilizer application. Estimates of fertilizer N lost as N 2 O annually were well below the 1% Intergovernmental Panel on Climate Change default emission factor, ranging from 0.07% to 0.11% in 2011 and from 0.01% to 0.09% in 2012. In both years, the largest impact on annual N 2 O emissions occurred when inputs increased from 100 to 150 kg N ha

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“…In Tanzania, incorporation of maize straw and leaf residue into soil increased annual CO 2 fluxes substantially (emissions rose from 2.5 to 4.0 and 2.4 to 3.4 Mg C ha −1 yr −1 for clay and sand soils, respectively; Sugihara et al, 2012), although a study in Madagascar showed that incorporation of rice-straw residue resulted in larger fluxes of CO 2 but reduced N 2 O emissions due to N immobilization (Rabenarivo et al, 2014). In contrast, incorporation of Tithonia diversifolia (tithonia) leaves led to greater N 2 O emissions compared to urea application in maize fields in Kenya (Sommer et al, 2015;Kimetu et al, 2007). The higher N 2 O emissions after incorporation of Tithonia diversifolia were attributed to high levels of nitrate and available carbon in the soil caused by the application that subsequently enhanced denitrification rates.…”

Section: Croplandsmentioning

confidence: 99%

Greenhouse gas emissions from natural ecosystems and agricultural lands in sub-Saharan Africa: synthesis of available data and suggestions for further research

et al. 2016

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This paper summarizes currently available data on greenhouse gas (GHG) emissions from African natural ecosystems and agricultural lands. The available data are used to synthesize current understanding of the drivers of change in GHG emissions, outline the knowledge gaps, and suggest future directions and strategies for GHG emission research. GHG emission data were collected from 75 studies conducted in 22 countries (n = 244) in sub-Saharan Africa (SSA). Carbon dioxide (CO 2 ) emissions were by far the largest contributor to GHG emissions and global warming potential (GWP) in SSA natural terrestrial systems. CO 2 emissions ranged from 3.3 to 57.0 Mg CO 2 ha −1 yr −1 , methane (CH 4 ) emissions ranged from −4.8 to 3.5 kg ha −1 yr −1 (−0.16 to 0.12 Mg CO 2 equivalent (eq.) ha −1 yr −1 ), and nitrous oxide (N 2 O) emissions ranged from −0.1 to 13.7 kg ha −1 yr −1 (−0.03 to 4.1 Mg CO 2 eq. ha −1 yr −1 ). Soil physical and chemical properties, rewetting, vegetation type, forest management, and land-use changes were all found to be important factors affecting soil GHG emissions from natural terrestrial systems. In aquatic systems, CO 2 was the largest contributor to total GHG emissions, ranging from 5.7 to 232.0 Mg CO 2 ha −1 yr −1 , followed by −26.3 to 2741.9 kg CH 4 ha −1 yr −1 (−0.89 to 93.2 Mg CO 2 eq. ha −1 yr −1 ) and 0.2 to 3.5 kg N 2 O ha −1 yr −1 (0.06 to 1.0 Mg CO 2 eq. ha −1 yr −1 ). Rates of all GHG emissions from aquatic systems were affected by type, location, hydrological characteristics, and water quality. In croplands, soil GHG emissions were also dominated by CO 2 , ranging from 1.7 to 141.2 Mg CO 2 ha −1 yr −1 , with −1.3 to 66.7 kg CH 4 ha −1 yr −1 (−0.04 to 2.3 Mg CO 2 eq. ha −1 yr −1 ) and 0.05 to 112.0 kg N 2 O ha −1 yr −1 (0.015 to 33.4 Mg CO 2 eq. ha −1 yr −1 ). N 2 O emission factors (EFs) ranged from 0.01 to 4.1 %. Incorporation of crop residues or manure with inorganic fertilizers invariably resulted in significant changes in GHG emissions, but results were inconsistent as the magnitude and direction of changes were differed by gas. Soil GHG emissions from vegetable gardens ranged from 73.3 to 132.0 Mg CO 2 ha −1 yr −1 and 53.4 to 177.6 kg N 2 O ha −1 yr −1 (15.9 to 52.9 Mg CO 2 eq. ha −1 yr −1 ) and N 2 O EFs ranged from 3 to 4 %. Soil CO 2 and N 2 O emissions from agroforestry were 38.6 Mg CO 2 ha −1 yr −1 and 0.2 to 26.7 kg N 2 O ha −1 yr −1 (0.06 to 8.0 Mg CO 2 eq. ha −1 yr −1 ), respectively. Improving fallow with nitrogen (N)-fixing trees led to increased CO 2 and N 2 O emissions compared to conventional croplands. The type and quality of plant residue in the fallow is an important control on how CO 2 and N 2 O emissions are affected. Throughout agricultural lands, N 2 O emissions slowly increased with N inputs below 150 kg N ha −1 yr −1 and increased exponentially with N application rates up to 300 kg N ha −1 yr −1 . The lowest yield-scaled N 2 O emissions were reported with N application rates ranging between 100 and 150 kg N ha −1 . Overall, total CO 2 eq. emissions Published by Cop...

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Partial balance of nitrogen in a maize cropping system in humic nitisol of Central Kenya

Cited by 22 publications

References 26 publications

Effects of organic and mineral fertilizer nitrogen on greenhouse gas emissions and plant-captured carbon under maize cropping in Zimbabwe

Effects of organic and mineral fertilizer nitrogen on greenhouse gas emissions and plant-captured carbon under maize cropping in Zimbabwe

A potential tipping point in tropical agriculture: Avoiding rapid increases in nitrous oxide fluxes from agricultural intensification in Kenya

Greenhouse gas emissions from natural ecosystems and agricultural lands in sub-Saharan Africa: synthesis of available data and suggestions for further research

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