Cycling of fixed N in tropical cropping systems.

Giller, K.E.

doi:10.1079/9780851994178.0093

Cited by 156 publications

(290 citation statements)

References 0 publications

Supporting

Mentioning

280

Contrasting

Unclassified

Order By: Relevance

“…Chalk 1985;Shearer and Kohl 1986;Witty and Minchin 1988;Peoples and Herridge 1990;Hardarson and Danso 1993;Danso et al 1993;Vessey 1994;Unkovich and Pate 2000;Giller 2001;Peoples et al 2002;Unkovich et al 2008), and associative and freeliving N 2 -fixing agents (Boddey 1987;Chalk 1991;Boddey et al 2001;Giller 2001;Giller and Merckx 2003;Unkovich et al 2008). The N balance and N difference methods provide estimates of N 2 fixation on an area basis, i.e.…”

Section: Measurement Of N 2 Fixationmentioning

confidence: 93%

“…The %Ndfa values for the crop legume symbioses in Table 2 were sourced from Peoples et al (2008) in which data from a number of reviews and experimental papers were summarised (Peoples and Craswell 1992;Herridge and Danso 1995;Peoples et al 1995;Wani et al 1995;Jensen 1997;Unkovich et al 1997;Schulz et al 1999;Unkovich and Pate 2000;Giller 2001;Rochester et al 2001;Turpin et al 2002;Aslam et al 2003;Shah et al 2003). Additional information on N 2 fixation of common bean was sourced from Rennie and Kemp (1982a, b) and .…”

Section: Crop Legumes-rhizobiamentioning

confidence: 99%

See 1 more Smart Citation

Global inputs of biological nitrogen fixation in agricultural systems

2008

View full text Add to dashboard Cite

Biological dinitrogen (N 2 ) fixation is a natural process of significant importance in world agriculture. The demand for accurate determinations of global inputs of biologically-fixed nitrogen (N) is strong and will continue to be fuelled by the need to understand and effectively manage the global N cycle. In this paper we review and update long-standing and more recent estimates of biological N 2 fixation for the different agricultural systems, including the extensive, uncultivated tropical savannas used for grazing. Our methodology was to combine data on the areas and yields of legumes and cereals from the Food and Agriculture Organization (FAO) database on world agricultural production (FAOSTAT) with published and unpublished data on N 2 fixation. As the FAO lists grain legumes only, and not forage, fodder and green manure legumes, other literature was accessed to obtain approximate estimates in these cases. Below-ground plant N was factored into the estimations. The most important N 2 -fixing agents in agricultural systems are the symbiotic associations between crop and forage/fodder legumes and rhizobia. Annual inputs of fixed N are calculated to be 2.95 Tg for the pulses and 18.5 Tg for the oilseed legumes. Soybean (Glycine max) is the dominant crop legume, representing 50% of the global crop legume area and 68% of global production. We calculate soybean to fix 16.4 Tg N annually, representing 77% of the N fixed by the crop legumes. Annual N 2 fixation by soybean in the U.S., Brazil and Argentina is calculated at 5.7, 4.6 and 3.4 Tg, respectively. Accurately estimating global N 2 fixation for the symbioses of the forage and fodder legumes is challenging because statistics on the areas and productivity of these legumes are almost impossible to obtain. The uncertainty increases as we move to the other agricultural-production systems-rice (Oryza sativa), sugar cane (Saccharum spp.), cereal and oilseed (non-legume) crop lands and extensive, grazed savannas. Nonetheless, the estimates of annual N 2 fixation inputs are 12-25 Tg (pasture and fodder legumes), 5 Tg (rice), 0.5 Tg (sugar cane), <4 Tg (nonlegume crop lands) and <14 Tg (extensive savannas). Aggregating these individual estimates provides an overall estimate of 50-70 Tg N fixed biologically in agricultural systems. The uncertainty of this range Plant Soil (would be reduced with the publication of more accurate statistics on areas and productivity of forage and fodder legumes and the publication of many more estimates of N 2 fixation, particularly in the cereal, oilseed and non-legume crop lands and extensive tropical savannas used for grazing.

show abstract

Section: Measurement Of N 2 Fixationmentioning

confidence: 93%

Section: Crop Legumes-rhizobiamentioning

confidence: 99%

Global inputs of biological nitrogen fixation in agricultural systems

2008

View full text Add to dashboard Cite

show abstract

“…However, there was no consistent relationship between field estimates of P atm and relative growth rates at either 15 or 25°C in liquid medium (Lynch and Smith 1993). Based on an examination of the literature, Giller (2001) concluded that there was little likelihood that the results of laboratory screening of strains for a single stress would have much relevance to field performance. Temperature can also affect the response to inoculation through an effect on competitive performance (Montanez et al 1995).…”

Section: Temperaturementioning

confidence: 98%

“…Fixed N was significantly higher for all strains at 25°C than at 15 or 35°C (Table 2). Giller (2001) concluded that the optimum temperatures for growth and N 2 -fixation vary widely between legume species and reflect their environmental adaptation. This is illustrated by the data of Sangakkara et al (1996a) where the cool-season legume fababean (Vicia faba) failed to nodulate and fix N 2 under a day / night temperature regime of 30 / 23°C, whereas the symbiosis functioned well at 23 / 18°C (Table 3).…”

Section: Temperaturementioning

confidence: 98%

Integrated effects of abiotic stresses on inoculant performance, legume growth and symbiotic dependence estimated by 15N dilution

et al. 2009

View full text Add to dashboard Cite

Temperature, water, salinity, sodicity, acidity and nutrient disorders are major abiotic stresses that can affect legume growth or the establishment and function of the legume-Rhizobium symbiosis. We have examined the literature where the application of the 15 N isotope dilution methodology permits the effect of individual abiotic stresses to be independently and quantitatively separated into plant growth-mediated and BNF (biological N 2 fixation)-mediated components. The response of the symbiosis to a particular stress depends on a host of factors, including legume genotype, cultivar, Rhizobium inoculant, climatic conditions, and the duration, timing and severity of the stress. Published data are analysed in terms of the above variables and their interactions. As a general rule, severe stress inhibits both legume dry matter (DM) and the proportional dependence of the legume on BNF as a source of N. The symbiosis is resilient to low to moderate stress, but there may still be a penalty on legume DM. Gaps in knowledge are identified, and general guidelines on the identification and amelioration of abiotic stresses are provided.

show abstract

“…cover crops have also been highlighted in earlier studies (Lal et al 1979;Akobundu 1980;Dovonou 1994;Becker and Johnson 1998;Galiba et al 1998). The cover crops manifest this effect through their ability to climb up and shade out weeds within their vicinity (Giller and Wilson 1991). These studies have however been conducted on-station (Tonye et al 1997) and concentrated in West Africa, particularly in Southern Nigeria, where first experiments date back to about four decades for cover cropping and two decades for alley cropping.…”

Section: Introductionmentioning

confidence: 97%

Weed biomass dynamics in planted fallow systems in the humid forest zone of southern Cameroon

et al. 2007

View full text Add to dashboard Cite

Interest in planted fallow systems has focused on soil fertility improvement, neglecting other potential benefits of such systems. It is important to quantify other processes responsible for crop yield increases under planted fallows, such as weed control. The suppressive potential on weeds of Flemingia macrophylla [(Willd.) Merrill] and Pueraria phaseoloides (Roxb.) Benth, planted fallows was evaluated in field trials in three villages in southern Cameroon. In each village, experiments were set up in 4-5 year-old bush fallow dominated by Chromolaena odorata (L.) R. M. King & H. Rob. and 20 year-old secondary forest. Total aboveground biomass production of P. phaseoloides was 7.45 Mg ha À1 , 4.2 times higher than F. macrophylla (1.78 Mg ha À1 ; P < 0.05). The high biomass of P. phaseoloides resulted in a significantly greater reduction in total weed biomass compared to Flemingia macrophylla in both wet and dry seasons. In the wet season (11 and 18 MAP), there were significant fallow system · land use and fallow system · village interactions for total weeds and broadleaf weeds. P. phaseoloides in bush (0.55 Mg ha À1 ), and P. phaseoloides at Ngoumou (0.09 Mg ha À1 ) had the lowest total weeds in the wet seasons. After the dry season, the lowest total weed mass was consistently recorded in P. phaseoloides while the highest was in the natural regrowth. The population of grasses was always higher in the F. macrophylla system than in P. phaseoloides system throughout the wet and dry seasons. Grass biomass in the P. phaseoloides-forest LUS was the least (0.01 Mg ha À1 ), 58 times lower than in F. macrophylla-bush (0.58 Mg ha À1 ). Biomass production of P. phaseoloides was highly significantly correlated with total weed biomass (r = À0.64; P = 0.004) while no relationship was found between biomass production of F. macrophylla and total weed biomass (r = À0.08, P = 0.747). It was concluded that P. phaseoloides was a suitable leguminous species for weed control. But for F. macrophylla, its low biomass production coupled with a compact plant architecture compromised it as an appropriate species for weed control in a planted fallow system.

show abstract

Cycling of fixed N in tropical cropping systems.

Cited by 156 publications

References 0 publications

Global inputs of biological nitrogen fixation in agricultural systems

Global inputs of biological nitrogen fixation in agricultural systems

Integrated effects of abiotic stresses on inoculant performance, legume growth and symbiotic dependence estimated by 15N dilution

Weed biomass dynamics in planted fallow systems in the humid forest zone of southern Cameroon

Contact Info

Product

Resources

About