Nodulation and yield of groundnut (Arachis hypogaea L.) due to phosphorus on an Alfisol at Minjibir, Sudan savannah, Nigeria

A.I. Gabasawa*1, A.A. Yusuf1, E.N.O. Iwuafor1 and C.A. Echekwu2

1Department of Soil Science, Faculty of Agriculture/Institute for Agricultural Research, Ahmadu Bello University, P.M.B. 1044, Samaru, Zaria, Kaduna State, Nigeria.
2Department of Plant Science, Faculty of Agriculture/Institute for Agricultural Research, Ahmadu Bello University, P.M.B. 1044, Zaria, Kaduna State, Nigeria.

*Corresponding Author: E-mail:


Photosynthesis and biological nitrogen fixation are two vital biochemical processes for the growth, development and yield of a leguminous crop. The plants can require large amounts of P for effective fixation. Under deficient conditions, P fertilization will result in improved nodulation and enhanced N2-fixation. A field trial was conducted in 2015 cropping season in the Institute for Agricultural Research experimental field, Ahmadu Bello University, Zaria, Nigeria. The study was aimed at determining the symbiotic nitrogen fixation potential of groundnut genotypes grown on an Alfisol. The treatments consisted of 16 groundnut genotypes and 3 P sources. The P sourced was in the main plot with genotype in the sub-plot of a split plot design that was replicated four times. More chlorophyll content (CC) was recorded by ICGV-IS 07815, and together with ARRORS ICGX 000201/5/P4/P10 and SAMNUT 21 the highest haulm yield. The lowest content was recorded by ICIAR 7B. Genotypes ICIAR 6AT, ICIAR 7B, Kwankwaso and SAMNUT 10 recorded the lowest haulm yield. All the genotypes were at par in terms of number of nodules, but they were statistically different in their nodule weights. Two (RP and SSP) of the P sources contributed, to nodule weight and haulm yield, statistically better than the other (0) source. There was, however, no statistical difference between all the P sources in terms of nodule number. Further studies at multi-locations level and attempting to understand the P use mechanisms involved will allow for a better understanding of the genotypic potentials.


From field to factory: shifting regulatory focus to reduce nitrogen pollution

David R. Kanter1,2, Jeffrey D. Sachs3

1 Department of Environmental Studies, New York University, 285 Mercer Street, New York, NY, 10003, USA

2 Agriculture and Food Security Center, Columbia University, 61 Route 9w, Palisades, NY, 10964, USA

3 The Earth Institute, Columbia University, Hogan Hall, 2910 Broadway, New York, NY, 10025, USA


Nitrogen pollution is one of the most important environmental issues of the 21st century, contributing to air and water pollution, biodiversity loss, climate change and stratospheric ozone depletion. While the planetary boundary for nitrogen is one of two that humanity has exceeded, it has yet to garner the attention from the policy community that it deserves. Moreover, emerging calls for a coordinated international response to nitrogen pollution need to be reconciled with the reality that solutions, particularly in the agricultural sector, are often locally specific. This is the goal of the new “Pathways to Nitrogen’s Planetary Boundary” project (PNPB): disaggregating nitrogen’s planetary boundary into several regional boundaries, and developing pathways to reach these boundaries using regionally-tailored nitrogen use efficiency strategies. This new form of regional integrated assessment aims to provide a roadmap for policy-makers to better address nitrogen pollution. It also adopts a form of scenario development seldom used in environmental modeling: “backcasting” technical pathways to achieve a future goal (nitrogen’s planetary boundary), instead of forecasting multiple futures from a common present. The regional teams (East Asia, South Asia, East Africa, Eastern Europe, Latin America and North America) have already been formed as part of the International Nitrogen Management System initiative. Their focus on improving understanding of regional nitrogen flows is a crucial first step for developing the regional boundaries and pathways. PNPB would provide a forum for sharing methods, tools, data, and results among the teams, and ultimately aggregate the pathways to determine the extent to which they meet nitrogen’s planetary boundary.

Impacts of dietary changes on global scale nitrogen losses to air and water

Wim de Vries1,2, Jia Wei1, Hans Kros1, David Windhorst3 and Lutz Breuer3

1Alterra, Wageningen University and Research Centre (WUR), PO Box 47, 6700 AA Wageningen, The Netherlands

2Environmental Systems Analysis Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands

3Justus-Liebig University of Giessen, Heinrich-Buff-Ring 26, 35392 Gießen, Germany


A simple fast calculation approach has been developed that gives insight in the overall effects of dietary changes on nitrogen (N) emission to air and water by 2050 for ten identified world regions. The impact of dietary change on N fertilizer and N manure applications and related emissions was based on the consumption of crop and animal commodities, making use of the FAO data from 1961 to 2005 and extrapolating the data towards 2050 in response to five dietary change scenarios. Scenarios included a ‘North American Diet’ (NAD), a ‘Same Diet’ (SD), a ‘Business-as-Usual’ (BAU) diet; a ‘Demitarian Diet’ (DD) and a ‘Vegan Diet’ (VD).  The calculated N2O and NH3 emissions and N leaching/runoff for the reference year (i.e. 2005) showed good agreement with various literature estimates. N2O was the most persistent problem, even increasing under the VD scenario, due to the increased use of N fertilizer to cultivate food crops and the assumed high contribution of N fertilizer to N2O emission. NH3 emissions increased three times in the NAD scenario, while it decreased by 13% in the VD scenario. This happens because NH3 emissions mainly follow the N manure trends. In the VD scenario, N leaching/runoff remains equal to 2005, while it increases by 145% in the NAD scenario. Overall, results show that dietary change affects most strongly NH3 emissions, followed by N leaching/runoff and then N2O emissions. Only a severe reduction in meat consumption can substantially reduce N losses with the exception of N2O emissions.

A comparison of disaggregated nitrogen budgets for Danish agriculture using Europe-wide and national approaches

Johannes Kros1, Nicholas Hutchings2, Inge Toft Kristensen2, Ib Sillebak Kristensen2, Christen Duus Børgesen2, Jan Cees Voogd1, Tommy Dalgaard and Wim de Vries1,3

1 Alterra Wageningen University and Research Centre, PO Box 47, 6700 AA Wageningen, the Netherlands,,

2 Department of Agroecology, Aarhus University, Blichers Allé 20, DK-8830 Tjele, Denmark

3 Environmental Systems Analysis Group, Wageningen University, PO Box 47, 6700 AA Wageningen, the Netherlands


Spatially detailed information on nitrogen (N) budgets is relevant for the identification of regions N pollution needs to be reduced. However, the availability of consistent reliable data is generally lacking. Therefore most models applied in Europe use national or even European scale data as model input. To gain insight in the reduction in uncertainty that could be achieved by using higher resolution input data, spatially disaggregated agricultural N budgets for Denmark for the period 2000-2010 were generated by the European scale model Integrator, being fed with high spatial resolution national data for Denmark (Integrator-DK) and compared with results obtained by using the default data (Integrator-EU). Here we focus on the year 2010, for which the quality of the regional Danish input data was considered best. Results show that clear differences exists for the national budgets calculated by both versions of the model but comparison with an independently derived Danish national budget appeared to be better with Integrator-EU results. However, the spatial distribution of manure distribution and N losses from Integrator-DK are closer to the observed distributions than those from Integrator-EU.

Urban Nitrogen Metabolism in Xiamen City, China

Wei Huang1, Shenghui Cui1, Yang Yu1, Bing Gao1, Xuemei Bai2

1 Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimi Road, Xiamen, China, 361021,
2 Fenner School of Environment and Society, College of Medicine, Biology and Environment, Australian National University, Canberra, Australia, 0200,


Urban settlements, as highly concentrated areas for human production and consumption activities, have become important components in the alteration of regional and even global nitrogen (N) cycle. This study, by using substance flow analysis (SFA), establishes an urban N metabolism model and quantifies a detailed N mass balance for Xiamen, a rapidly urbanizing city in China, in 2008. The results show that the total N input into Xiamen was 103.2 kt in 2008, including 64% through products and 36% from the environment. The total N output was 99.6 kt, with 12% as products exported to other regions and 88% released to the environment. Fossil fuels ranked first of the N inputs, contributing 78% of N to the atmosphere. About 50% of N inputs were retained within the urban ecosystem. N use efficiency in the food chain was only 11%. Several interventions are suggested to improve N efficiency and reduce N environmental impacts, including municipal solid waste composting, reduced fossil fuel consumption, fuel N removal and integrated watershed management.

Improving Nitrogen Use Efficiency in the Chinese Food Chain to Reduce Air and Water Pollution

Mengru Wanga,b, Lin Mab, Maryna Strokala,c, Yanan Chuc, Ang Lia,b, Carolien Kroezea

a Water Systems and Global Change Group, Wageningen University, Droevendaalsesteeg 3, 6708 PB Wageningen, The Netherlands,,

b Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang 050021, China

c Environmental Systems Analysis Group, Wageningen University, Droevendaalsesteeg 4, 6708 PB Wageningen, The Netherlands


Nitrogen (N) use efficiency is low in Chinese agriculture. This results in large N losses to air and water. We aim to explore effective nutrient management options to increase N use efficiencies in the food chain, and thus to reduce N losses to the environment for 2020 and 2050 in China by scenario analysis. Three scenarios were developed and implemented assuming Business As Usual (BAU) trends, Zero Fertilizer (ZF) growth from 2020, and Improved Nutrient Management (INM). N use efficiencies in agriculture, and N losses were quantified using the NUFER (NUtrient flows in Food chains, Environment and Resources use) model. Results show that N use efficiency in 2013 is low at about 20%. Thus the losses to air (14 Tg of N) and water (12 Tg of N) are high in 2013. The N use efficiencies will likely remain at their low 2013 levels in 2020 and 2050 under BAU, resulting in large increase in N losses to air and water between 2013 and 2050. INM is projected to increase N use efficiency to 33% in 2050. N losses to water in 2050 are almost half of that in 2013, and to air are 20% lower. Scenario ZF incorporates recent Chinese policies aiming at a zero growth in synthetic fertilizer use from the year 2020 onwards. ZF is projected to be much less effective than INM. We conclude that nutrient management that simultaneously reduces fertilization, improves manure management, and reduces nutrient excretion in animal manure, is needed for Chinese agriculture.