Fates of applied nitrogen fertilizer after harvesting wheat on dryland soil

Jianbin Zhou1, Bin Liang1,2, Wei Zhao1, 3, Mengjie Xia1, Xueyun Yang1

1College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China;

Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China

2College of Resources and Environmental Sciences, Qingdao Agriculture University, Qingdao, Shandong 266109, China

3Weinan Agricultural Technology Extension Service Center, Weinan, Shaanxi 714000, China


About one third of nitrogen (N) fertilizer is retained in the soil after crop harvest. Understanding the fate of this residual fertilizer N in soil is important for evaluating its overall use efficiency and environmental effects. In this study, the 15N-labelled fertilizer was applied to winter-wheat growing in three different fertilizedsoils (No-F, no fertilizer; NPK, inorganic NPK fertilization; and MNPK, manure plus inorganic NPK fertilization) from a long-term trial (19-year) on the south edge of the Loess Plateau, China. The fate of residual 15N in soils over summer fallow and the second winter-wheat growing season was followed. The amount of the residual N in the No-F soil was significantly higher than that in the NPK and MNPK soils after harvesting the first wheat crop. The forms of the residual N in the No-F soil was mainly in mineral form; and for the NPK and MNPK soils, they were mainly in organic form. The loss of 15N in No-F soil over the summer fallow was as high as 33%, and significantly higher than that in the NPK soil (8%) and MNPK soil (5%). The residual 15N use efficiency by the winter-wheat in the second cropping were equivalent to 9.0%, 2.0% and 2.2% of the originally applied 15N. A high proportion of the residual 15N was lost during the summer fallow in dryland farming. Better management of the residual N in soil during the summer fallow is required, its contribution to subsequent cropsis also deserved consideration when makingN fertilizer recommendation.

N-acetylcysteine increased nitrogen-induced rice yield

Sarwar, MJ1, Mohd Nozulaidi1, Mohd Khairi1

1Faculty of Bioresources and Food Industry, Universiti Sultan Zainal Abidin, 22200, Besut, Terengganu, Malaysia


N-acetylcysteine (NAC) biosynthesized reduced glutathione (GSH) which maintains redox homeostasis in plants under normal and stressful conditions. To justify the effects of NAC on rice production, we measured yield parameters, chlorophyll (Chl) content, minimum Chl fluorescences (Fo), maximum Chl fluorescences (Fm), quantum yield (Fv/Fm), net photosynthesis rate (Pn), photosynthetically active radiation (PAR) and relative water content (RWC). Four treatments, namely, N1G0 {nitrogen (N) with no NAC}, N1G1 (N with NAC}, N0G0 (no N and no NAC) and N0G1 (no N but with NAC) were arranged as completely randomized design with five replications. Nitrogen significantly increased yield and yield parameters of rice plants. Moreover, NAC treatment increased panicle numbers, filled grains per panicle and yield of rice plants. Nitrogen significantly increased Chl content, Chl fluorescence parameters (Fm, Fv/Fm ratio) and Pn in leaves of the rice plant regardless of N treatments. NAC significantly increased RWC in leaves of N-untreated rice plant. In conclusion, this study suggests that NAC might enhance rice yield through modulating physiological functions of rice plants.

The effect of ‘Double High Agriculture’ on nitrogen losses from crop production to coastal water in China

Ang Li1, Maryna Strokal1, Carolien Kroeze1,2, Zhaohai Bai3, Lin Ma3

1 Environmental Systems Analysis Group, Wageningen University, Droevendaalsesteeg 3, Wageningen, The Netherlands, 6708 PB, ang.li@wur.nl
2 Water Systems and Global Change Group, Wageningen University, Droevendaalsesteeg 3, Wageningen, The Netherlands,  6708 PB

3 Key Laboratory of Agricultural Water Resource, Center for Agricultural Resources Research, Institute of Genetic and Developmental Biology, Chinese Academy of Sciences, Huaizhong Road 286, Shijiazhuang, Hebei 050021, China.


‘Double High Agricultural’ (DHA) is a nutrient management strategy focusing on increasing nitrogen (N) and phosphorus (P) use efficiencies, while also increasing crop yields. DHA may thus reduce losses of nutrients to the environment. We quantified the impact of DHA on N inputs to rivers and coastal seas in the year 2050. To this end, we applied the Global NEWS (Nutrient Export from WaterSheds) model. Two scenarios were developed based on two different agricultural practice of DHA: 1) The Integrated Soil-crop Systems Management (ISSM) scenario which assumes a 30% lower synthetic fertilizer application and 30% higher crop yields; 2) The ISSM-MR scenario, which is as ISSM, but assumes increased Manure Recycling in crop production, leading to lower synthetic fertilizer use. The results indicate that river export of dissolved inorganic N (DIN) and dissolved organic N (DON) in the ISSM scenario are about 10% lower than in the reference scenario. In ISSM-MR river export of DIN is about 30% lower than in the reference scenario.

Closing the nitrogen supply and demand gap using legume residue combined with fertiliser nitrogen input

Pilar Muschietti-Piana1,2, Therese McBeath1,2, Ann M. McNeill1, Pablo A. Cipriotti3 and Vadakattu Gupta2,

1 School of Agriculture, Food & Wine, The University of Adelaide, SA5005, E mail: pilar.muschiettipiana@csiro.au

2 CSIRO Agriculture & Food, CSIRO Agricultural Systems, Waite Campus, PB 2, Glen Osmond, Adelaide SA, 5064

3 School of Agriculture, University of Buenos Aires, Av. San Martin 4453, Ciudad Autónoma de Buenos Aires, C1417DSE


In low-rainfall wheat cropping systems, low crop uptake of nitrogen (N) has been linked to asynchrony in soil-N supply through mineralisation. This is especially true on sandy soils of SE Australia which have a low-N supply capacity. When N released from soil and residues is insufficient, and/or the timing of biological supply is not well matched with crop demand, manipulating N supply using fertiliser applications becomes vital to achieve yield potential. The aim of this study was to measure the timing of N supply with crop N uptake for wheat following wheat-residues and wheat following lupin-residues under two N fertiliser rates in a low-rainfall sandy soil environment. In each residue-type site, plants and deep soil samples to rooting depth were collected at sowing and at 5 key wheat growth stages. Plants were analysed for N content, above-ground biomass and grain yield at maturity. All soil samples were analysed for gravimetric water content and mineral-N. The combination of lupin residues with a high fertiliser N rate increased soil mineral-N at the time of high demand, promoted plant growth and wheat N uptake. In a dry season, the additional N supplied as fertiliser at early stages was a key input to support an increase in wheat yield potential. Responses in N uptake throughout the growing season indicate that there remains a demand for fertiliser N following legume-N residue in this environment, but fertiliser N inputs remain risky as indicated by the lack of significant yield increase in a low rainfall growing season.

The effects of intensification on Nitrogen Dynamics and Losses on Diversified Organic Vegetable Farms

Debendra Shrestha1, Krista Jacobsen2, Ole Wendroth3

1University of Kentucky, Ag. Science Bldg. N 308, Lexington, KY, 40546-0091, dsh243@uky.edu 

2 University of Kentucky, Ag. Science Bldg. N 308, Lexington, KY, 40546-0091

3 University of Kentucky, Ag. Science Bldg. N 1100, Lexington, KY 40546-0091


Nitrogen (N) is the main limiting nutrient, and is both a great driver of yield as well as agriculture’s impact on the environment. Organic farming systems are subject to N losses and have less predictable N dynamics than conventional systems. The objective of this study is to compare the N dynamics and key loss pathways in three farming systems, including two organic systems, representing a gradient of intensification (characterized by quantity of inputs, and the frequency of tillage and fallow periods) in Kentucky, USA. We have grown spring planted table beet (Beta vulgaris), summer planted green pepper (Capsicum anuum), and fall planted collard green (Brassica oleracea var. medullosa). Soils were sampled monthly for soil mineral N (NH4+ and NO3) at 0-15 cm, 15-30, and 30-50 cm depths. Trace gas fluxes (N2O and CO2) were measured weekly using a FTIR-based field gas analyzer. The results of this study showed the higher N2O and CO2 fluxes at the time of fertilizer application and tillage, at the beginning of the crop season.

Moringa Oleifera leaves and fertiplus affect nitrogen status and garden egg yield in Nigeria Savanna and rainforest soils.

A. Kekong1*, A. Ali2, T. O. Ojikpong1 and N. B. Ibrahim2

1-Cross River University of Technology, Obubra Campus

2- University of Agriculture, Makurdi, Benue State

*Corresponding author; email:matikekong@gmail.com


The dynamics of Nitrogen in manures has remained a challenge in the environment.  A field study was conducted at a rainforest and savannah locations in Nigeria during the 2009 and 2010 cropping seasons to evaluate effects of Moringa oleifera leaves and Fertiplus manure on soil total N and  yield of garden egg. A  factorial combination of two garden egg varieties (Gilo and Kumba) and Moringa( 5, 10, 20 t ha-1); Fertiplus( 1,2,3 t ha-1 ) with a     control   giving 14 treatments,within 3 replicates.  Results show that the manures increased soil total N from 30-90 days, with the highest increase from Moringa leaf 20 t ha-1 while the control showed a decline in total N. All manure rates significantly (P < 0. 05) increased yield of Solanum aethiopicum  varieties over the control. Moringa 20 t ha-1 produced highest fruit yield (7.22 t ha-1 and 6.68t ha-1 ) in 2009 and 10.37 t ha-1  and 9.17 t ha-1) in 2010 for Makurdi and Obubra respectively. The yields were significantly (t <0.05) higher in Makurdi than Obubra in both years.  Moringa leaf (20 t ha-1 ) is a good source of N for sustainable production of garden egg in Nigeria Rainforest and   savannah soils.

Nitrogen use efficiency for green onion (Allium fistulosum) in sands of South Central Coastal Vietnam using 15N-labelling

Truc T T Do1, Richard W Bell2, Nga P N Doan3, Surender Mann2

1 The Institute of Agricultural Sciences for southern Vietnam, 121 Nguyen Binh Khiem St., district 1, Ho Chi Minh city, 70000, Vietnam. http://iasvn.org. truc.dtt@iasvn.org

2 School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch, 6150, Western Australia, Australia.

3 Center for Nuclear Techniques, Ho Chi Minh city, Vietnam.


The recovery of nitrogen (N) from N fertilizer is generally poor. Increasing N use efficiency (NUE) on sands is particularly challenging due to low nutrient storage and high percolation rate of water through the root zone.  The objectives of the experiment were to assess the change in fertilizer NUE for onion with clay or sugarcane residue amendments, and using 15N labelled urea to determine the recovery of N in the plant-soil system in a deep sand. The experiments were carried out in Ninh Thuan province, Vietnam  under flood or sprinkler irrigation. The 15N-labelled urea was applied to 0.72 m2 mini-plots at 134 kg N/ha and 10.16 % N atom excess. Clay-rich soil or bentonite were applied to raise clay content to 25 g/kg  and sugarcane residues were applied at 30 t/ha.

Fertilizer supplied 47.5 to 50.5 % the onion N demand, however, this represented only 3.8 to 19 % of fertilizer N applied. Sugarcane residue was more effective than clay and bentonite additions while sprinkler irrigation increased NUE compared to flood irrigation. After harvesting onion, 19 to 24 % of fertiliser N was found in 0-20 cm top soil. Despite the increases in NUE with sugarcane residue, clay-rich soil or bentonite, 63 to 73 % of fertiliser N was lost from the soil-plant system. In addition to using sprinkler irrigation on sands, we suggest that adding clay and organic materials in combination with postponed application of N fertiliser or fertigation may be needed to further increase soil N retention and fertilizer NUE.

Mineral nitrogen and rice production in Myanmar

Soe Soe Thein1, Deli Chen2, Robert Farquharson2, and Ian Willett2

1Yezin Agricultural University, soesoethein1@gmail.com

2Faculty of Veterinary and Agricultural Sciences, The University of Melbourne


Myanmar, like other countries in Asia, has made great efforts to intensify the production of rice (Oryza sativa L.) to feed a rapidly growing population. Most of these efforts concentrated on lowland paddy fields with irrigated double rice cropping systems. Nitrogen (N) rates applied by Myanmar farmers are generally low and do not consider economic aspects.  Mineral nutrient management is crucial to boost rice production as N is the most limiting nutrient. There is substantial potential to raise rice production by increased use of N fertiliser, which will increase regional demand for fertilisers and the supply of rice in the international market in the near future.  At this pivotal time in Myanmar’s development it is timely to elucidate the biophysical and socio-economic factors that lead to financially and environmentally viable intensification of rice production based largely on N fertilisation.

Sheep grazing on crop residues increase soil mineral N and grain N uptake in subsequent wheat crops

James R Hunt1,3, Antony D Swan1, Paul D Breust2,4, Mark B Peoples1, John A Kirkegaard1

1CSIRO Agriculture & Food, PO Box 1600 Canberra ACT 2601 Australia

2FarmLink Research, PO Box 240 Junee NSW 2663 Australia

3Present address: Department of Animal, Plant and Soil Sciences, AgriBio Centre for AgriBiosciences, 5 Ring Rd, La Trobe University, Bundoora 3086, Australia j.hunt@latrobe.edu.au

4Present address: Southern Farming Systems, 23 High Street, Inverleigh VIC 3321


In southern Australia, the majority of farms combine a sheep enterprise with cropping to form a mixed farming business. Crops are grown in sequence with pastures, and sheep graze crop stubble residues after harvest. Recently, growers practicing no-till, controlled traffic cropping, became concerned that grazing livestock would damage soil and reduce soil water capture, crop yield and profitability. Sheep grazing on stubbles remove residue cover and compact surface soil, but there is little published research on potential impacts on subsequent crop performance. A long-term experiment was established in 2009 to quantify trade-offs between grazing stubbles, resource capture and subsequent crop performance. Here we report effects on soil mineral nitrogen (N) accumulation and grain N uptake due to stubble grazing in the seven phase years of the experiment in which wheat crops were grown. Grazing wheat and canola stubbles on average increased mineral N prior to sowing of the subsequent wheat crop by 19 kg/ha, and grain N uptake by 7 kg/ha N. This could have arisen from 1) rapid mineralisation of N in livestock excreta, and/or 2) the reduction in stubble carbon inputs to soil due to grazing lowering rates of N immobilisation. Further research is necessary to confirm the relative importance of these processes, and to explore how they could be exploited to greater advantage to manage soil N availability in mixed farming systems.

Nitrogen cycling enhanced by conservation agriculture in a rice-based cropping system of the Eastern Indo-Gangetic Plain

M.A.Islam1 &2, R.W.Bell2, C. Johansen3, M. Jahiruddin4, M.E.Haque2&5

1 Pulses Research Center, Bangladesh Agricultural Research Institute, Ishurdi, Pabna, 6620 Bangladesh, Email: arifbau06@gmail.com
2 School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch WA 6150 Australia, Email: R.Bell@murdoch.edu.au
3Agricultural Consultant, Leeming, Australia, Email: cjo41802@bigpond.net.au
4Bangladesh Agricultural University, Mymensingh, Bangladesh, Email: m_jahiruddin@yahoo.com
5Conservation Agriculture Project, 2nd Floor, House 4C, Road 7B, Sector 9, Uttara, Dhaka 1230, Bangladesh, Email:  e.haque@murdoch.edu.au


Changes in soil tillage and residue retention after introducing conservation agriculture practices in intensive rice-based cropping systems in Bangladesh may alter nitrogen (N) cycling and N fertilizer requirements. An experiment was established on a farmer’s field, with a legume dominated-rotation (lentil-mungbean-monsoon rice), two types of tillage – strip planting (SP) and conventional tillage (CT); and two levels of residue retention – high residue (HR) and low residue (LR). A total seven crops were studied in the 2.5 year periods (2010-13). Soil total N concentration (TN), soil N-stocks after Crop 7 and the annual N accumulation rates at 0-15 cm soil depth for 2010-13 are presented. At the end of Crop 7 (after 2.5 years), SP treatment increased the TN concentrations and N-stocks by 11 % compared to CT at 0-15 cm soil depth. The annual soil N accumulation rates were 66 kg/ha with SP while N losses were 20 kg/ha under CT during 2010-13. The N accumulation rate was 3.3 times higher with HR than LR. From 2010 to 2013, the N balance calculation indicated an estimated N gain of 51 kg/ha in SPHR but a loss in CT which ranged from 9 kg/ha in CTHR to 319 kg/ha in CTLR at 0-15 cm soil depth. The N uptake was also 14 % higher from grain and straw under SP than CT. Both SP and HR increased TN, N-stocks and N accumulation by contrast with N loss under CT. However, the turnover of TN in SPHR needs longer investigation because of likely effects on N fertiliser requirements.