Hangs, R.D.

Schoenau, J.J.

English

eCommons@USASK

Impact of biochar and manure additions on canola growth and fate of applied nitrogen fertilizer in a Humic Vertisol and Brown Chernozem after four years

University of Saskatchewan Research Archive

Impact of Biochar and Manure Additions on Canola Growth and Fate of Applied NitrogenFertilizer in a Humic Vertisol and Brown Chernozem After Four YearsRyan Hangs, Jeff Schoenau, and J. Diane KnightDepartment of Soil Science, University of Saskatchewan, Saskatoon, SKMATERIALS & METHODS• A two-factor (biochar and manure soil amendments) field study was set up in2013, using a split-plot experimental design, with four replicates. The soilamendments and 15N-labelled fertilizer were applied only in year one (2013).• The study was established on two contrasting fields: Orthic Humic Vertisol(Class 1; Melfort) and Orthic Brown Chernozem (Class 4; Central Butte).• Whole plots: 100 kg N/ha as solid cattle manure (SCM) or liquid hog manure(LHM); split-plots: 8 Mg C/ha as willow (Salix spp.) ‘chunky’ or ‘powder’biochar produced using slow- and fast-pyrolysis, respectively.• After each year of the four-year cereal-oilseed crop rotation (barley-canola-wheat-canola), the recovery of broadcast applied double-labelled 15NH415NO3fertilizer was measured from the biochar-only treated plots.• Variables measured: crop yield (only the fourth year canola data is presentedhere); accumulation of fertilizer N in the above- and below-ground croptissues; and the distribution of fertilizer N within the soil profile.OBJECTIVE• Examine the effect of two biochar amendments with, and without, the additionof different animal manures on canola growth, along with the fate of 15N-labelled fertilizer four years after application in two contrasting soil types.• The ability of biochar to improve numerous soil physical, chemical, andbiological properties (e.g., bulk density, cation-exchange capacity, pH,microbial community activity, etc.) is well established.• Previous research has concentrated on tropical soils (i.e., old and highly-weathered, acidic pH, low organic matter content, and poor fertility). However,the influence of biochar application on the relatively young and fertile soils ofSaskatchewan is largely unknown.• The potential value of biochar soil amendments to improve plant utilization ofnitrogen (N) fertilizer is not well understood.INTRODUCTIONCONCLUSION• Biochar alone, or in combination with manure, had occasional impact oncanola yield four years after application, which indicates the potential for long-term residual effects.• Crop uptake of fertilizer N primarily occurred in the year of application, withdecreasing utilization in subsequent years, due to immobilization in soil.• Thanks to the Saskatchewan Agriculture Development Fund and NSERC for funding; D. Leach and K. Strukoff(AAFC) for their field support; E. Powell (SRC) for the biochars; and , R. Avila, B. Barlow, R. de Freitas, B. Ewen,C. Fatteicher, K. Gudkova, E. Hildebrand, R. and R. Hangs, N. Howse, G. and R. Kar, T. King, M. Miheguli, L.Schoenau, W. Soomro, W. Stock, M. Stocki, B. Swerhone, R. Urton, and J. Wiens for their logistical support.ACKNOWLEDGEMENTSRESULTS & DISCUSSION• Regardless of treatment, the Class 1 Melfort soil supported greater canolayield compared to the poorer quality Class 4 Central Butte soil (Fig. 1).• Biochar with, or without manure, had a limited and variable effect on canolagrowth relative to the control (i.e., no biochar or manure added) four yearsafter application. At Melfort, powder biochar alone reduced canola grain yieldby 29%, while the combination of chunky biochar + SCM increased yield by39% (Fig. 1). At Central Butte, the combination of powder biochar + LHMincreased yield by 56%. These contrasting effects are interesting and may bedue to the relative predominance of organic and inorganic N fractions in thesemanures (SCM and LHM, respectively).• Biochar reduced the plant recovery of 15N-labelled fertilizer, with acorresponding increase in the upper 30 cm of soil (Fig. 2). The upper 15 cmrepresented 53% of the soil fertilizer 15N pool (data not shown); suggestingsorption of inorganic N by the biochar amendments.• The majority (70%) of the plant recovered 15N-labelled fertilizer was taken upby the initial barley crop, with decreasing recovery by subsequent crops (datanot shown), which is likely due to fertilizer N immobilization into recalcitrantsoil organic N pools resistant to mineralization.• The unrecovered 15N-labelled fertilizer is presumably lost from the plant-soilsystem due to leaching, denitrification, and/or volatilization.Figure 2. Mean (n = 8) fate of broadcast 15N-labelled fertilizer with, and without, willow ‘chunky’ and ‘powder’biochar additions (8 Mg C/ha), after a barley-canola-wheat-canola rotation (Note: Melfort and Central Butteresults are averaged). For each corresponding fertilizer 15N sink (e.g., comparing the grain 15N recovery amongthe biochar treatments), values with the same letter are not significantly different (P >0.05) using LSD.Figure 1. Mean (n = 4) canola yield four years after willow ‘chunky’ and ‘powder’ biochar additions (8 Mg C/ha)with, and without, added animal manure (100 kg N/ha; urea equivalent applied in non-manured plots), to OrthicHumic Vertisol (Melfort) and Orthic Brown Chernozem (Central Butte) soils. For each plant component (e.g.,grain), columns with the same letter are not significantly different (P >0.05) using LSD.Fate of Broadcast 15NH415NO3 Fertilizer (Both Sites Averaged)Powder BiocharOverall Recovery: 86% aStraw6% bGrain20% b38% a10% a5% a0Depth (cm)306075Crowns1% aRoots5% bStubble1% aChunky BiocharOverall Recovery: 86% aStraw5% bGrain22% b35% a14% a3% a0Depth (cm)306075Crowns1% aRoots5% bStubble1% aNo BiocharOverall Recovery: 88% aStraw8% aGrain30% a30% b8% a4% a0Depth (cm)306075Crowns1% aRoots5% bStubble2% a

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Impact of biochar and manure additions on canola growth and fate of applied nitrogen fertilizer in a Humic Vertisol and Brown Chernozem after four years

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