Léon E. Parent

Mineralization of Nitrogen and Carbon in Soils Amended with Composted Manure

ABSTRACT A study was conducted under laboratory conditions to determine the quantity of N mineralized from four composted manures incorporated into 2.7 kg of St-Jude sand or Tilly silty loam at rates of 0.05%, 0.10% and 0.20% of total N. With one exception (a hog slurry-sawdust based compost), net cumulative mineralization of N (Nm) during successive incubation periods increased with incubation time and with the rate of addition. After four months of incubation, Nm values varied from 0 to 14% of total added N. A significant third order interaction on Nm values was obtained with compost type, application rate and soil type. Net immobilization of N was apparent at all incorporation rates of hog slurry compost in the two soils. To evaluate C mineralization, composts were applied at the highest N rate and CO2 production measured periodically. One to 8.2% of total added C from manure composts was mineralized after 28 days of incubation. For each compost type, C mineralization was higher with the sandy than wit...

Phosphorus transformations in acid light-textured soils treated with dry swine manure

Organic matter can sorb P in acid soils through metal-organic matter-phosphate complexes. The pyrophosphate extractable Al and Fe and soil C contents were hypothetized to influence P partitioning in Ferro-Humic Podzols. Reaction of added P may be mitigated by adding lime or organic matter as dry swine manure (DSM) together with mineral P fertilizers. Three soils had 40 to 50 g kg-1 of soil organic matter (SOM) content, and 76 to 140 mmol (Al + Fe)pyro kg-1. A peaty soil phase had 200 g SOM kg-1, and 58 mmol (Al + Fe)pyro kg-1. Rates of monoammonium phosphate were 0, 27, 69, and 144 kg P ha-1 in a simulated fertilizer band. Rates of DSM and lime were 800 and 185–369 mg per 35 mL of soil, respectively. After 6 wk of incubation, soil P was fractionated sequentially into aluminium bound P (Al-P), iron bound P (Fe-P), and loosely bound P. Total P, desorbed P and organic P were determined in separate subsamples. A proportion of 79–92% of added P was recovered as Al-P and Fe-P in the three low SOM soils, compare...

Changes in phosphorus fractions of a Humic Gleysol as influenced by cropping systems and nutrient sources

Information about the dynamics of soil P fractions is useful to predict their bioavailability and risk of P transfer from soils to surface waters. The objective of this study was to assess the effects of cropping systems and nutrient sources on P fractions in a Labarre silty clay (Humic Gleysol). Soil samples (0-15 cm) were collected in 1989, 1994 and 1997 from a field with four cropping systems, combining two crop rotations, barley (Hordeum vulgare L.) monoculture and 3-yr barley-forage rotation, with two tillage operations (chisel and moldboard plowing) as main plots, and two nutrient sources (mineral fertilizer and liquid dairy manure) as subplots. A modified Hedley sequential fractionation scheme was used. The inorganic P (Pi) fractions (resin-P, NaHCO3-Pi, and NaOH-Pi) increase with time in all cropping system and nutrient source combinations. Organic (Po) fraction (NaHCO3-Po and NaOH-Po) changes were related to C inputs and total soil C contents. The barley monoculture combined with mineral fertiliz...

Potential of Sphagnum peat for improving soil organic matter, water holding capacity, bulk density and potato yield in a sandy soil

Low soil organic matter content and limited soil water holding are the major natural constraint of dryland cropping on sandy soils in the Quebec boreal regions. We conducted a 3-yr (1994–1996) study in a boreal sandy soil, Ferro-Humic Podzol (Spodosols), to determine the potential of Sphagnum peat for improving soil organic matter (SOM), water holding capacity, bulk density (BD), plant leaf nutrient status, and potato and barley yields. The cropping was a rotation of 2-yr potato (Solanum tuberosum L. ‘Superior’) and 1-yr barley (Hordeum vulgare L. ‘Chapais’). The treatments consisted of Sphagnum peat at rates of 0, 29, 48, and 68 Mg ha−1 3-yr−1 on a dry weight basis, and granular N-P-K fertilizers (12-7.5-7) at rates of 1.4, 1.6, and 1.8 Mg ha−1 yr−1, respectively, arranged in a split-block design. The peat-amended soils were higher in water content (SWC), SOM and total porosity but lower in BD and N than neighboring non-peat soils (P < 0.05). Effects of peat and fertilizer treatments and their interaction were significant on potato leaf N, Ca, Mg, and P, tuber yield, dry weight, harvested N and tuber specific gravity (P < 0.05), depending on year. Potato tuber yield and N increased simultaneously up to 30% (compared to the control), and were significantly correlated with SWC, SOM, BD, and NO3-N (−0.52 ≤r ≤ 0.80). In the 3rd year, the linear effect of peat treatments was significant on barley grain yield. In 1995 there was a decline of 4.5−7.3% of SOM of the previous year level. It is suggested that Sphagnum peat at a rate of 48 Mg ha−1 had the potential for improving sandy soil productivity. A longer-term investigation of soil water, N, SOM pool and crop yield changes is necessary to better understand the physical, chemical and biological processes of peat in cropping systems and to maximize the benefits of peat applications.

Efficiency of soil and fertilizer nitrogen of a sod-potato system in the humid, acid and cool environment

It was hypothesized that soil N variability, and fertilization and cropping management affect potato (Solanum tuberosum L.) growth and fertilizer N efficiency. Following a 20-year sod breakup on a loamy soil in eastern Quebec, Canada (46°37′ N, 71°47′ W), we conducted a 3-year (1993–1995) study to investigate the effects of soil pool N and fertilizer N management on non-irrigated potato (cv. Superior) tuber yield, fertilizer N recovery (NRE), and residual N distribution in soils under humid, cool and acid pedoclimatic conditions. The fertilizer N treatments consisted of a control, side-dress at rates of 70, 105 and 140 kg ha−1, and split applications (at seeding and bloom) at rates of 70+70, 105+70 and 140+70 kg ha−1, respectively. Soil acidity was corrected with limestone following the plow down of the sod. Years of cropping, main effect of N treatment, and year and fertilizer N interaction were significant on total and marketable tuber yields and N uptake, which were significantly related to soil N, and root growth. Apparent NRE ranged between 29 and 70%, depending on years and N rates. Total tuber yield, N uptake, soil N use and NRE were significantly higher in the first (sod–potato) year, but decreased by 41.8, 22.7, 21.4 and 14.7%, respectively, in the third (sod–potato–potato–potato) year. Initial soil N pool was declined by 75% following the 3-year cropping. In 2–3 years, the side-dress N (140 kg ha−1) increased significantly tuber yields (11.4–19.8%) compared to the split N (70+70 kg ha−1). Higher split N had no effect on tuber yield and N uptake but increased residual N at harvest. Unused fertilizer N was strongly linked (R2=0.98) to fertilizer N rates. Time factor and N treatment had significant effects (P<0.0001) on loss of N to below the root zone. Smaller scale rate and timing of split N need to be further determined. Increasing fertilizer N use efficiency could be expected with sod breakup and 75% of regional recommendation rate under humid, cool and acid pedoclimatic conditions.

Soil organic carbon sequestration potential for Canadian agricultural ecoregions calculated using the Introductory Carbon Balance Model

The potential for storage of atmospheric CO2-C as soil organic C (SOC) in agroecosystems depends largely on soil biological activity and the quantity and quality of annual C inputs to soil. In this study we used the Introductory Carbon Balance Model (ICBM) approach driven by daily standard weather station data, specific soil properties and crop characteristics at the scale of Canadian agricultural ecoregions. The objectives were to calculate a climate-dependent soil biological activity parameter representative for annual agricultural crop production systems (re_crop) and to estimate the effect of fallow (re_fallow). These parameters are based on the daily product of soil temperature and stored water that influence biological activity in the arable layer, and are used to adjust the decomposition rates of the ICBM SOC pools. We also tested re_crop and re_fallow on SOC stock change data for different site and treatment combinations from long-term field experiments located in some of the ecoregions. An re_cro...

Effect of NH4+:NO3- ratios on growth and nitrogen uptake by onions

The modelling of ion uptake by plants requires the measurement of kinetic and growth parameters under specific conditions. The objective of this study was to evaluate the effect of nine NHinf4sup+:NOinf3sup−ratios on onions (Allium cepa L.). Twenty-eight to 84 day-old onion plants were treated with NHinf4sup+:NOf3/sup− ratios ranging from 0 to 100% of each ionic species in one mM solutions in a growth chamber. Maximum N influx (Imax) was assessed using the N depletion method. Except at an early stage, ionic species did not influence significantly Imax, the Michaelis constant (Km) and the minimum concentration for net uptake (Cmin). Imax for ammonium decreased from 101 to 59 pmole cm-2 s-1 while Imax for nitrate increased from 26 to 54 pmole cm-2 s-1 as the plant matured. On average, Km and Cmin values were 14.29 μM, and 5.06 μM for ammonium, and 11.90 μM and 4.54 μM for nitrate, respectively. In general, the effect of NH4+:NO3- ratios on root weight, shoot weight and total weight depended on plant age. At an early stage, maximum plant growth and N uptake were obtained with ammonium as the sole source of N. At later stages, maximum plant growth and N uptake were obtained as the proportion of nitrate increased in the nutrient solution. The was no apparent nutrient deficiency whatever NH4+:NO3- ratio was applied, although ammonium reduced the uptake of cations and increased the uptake of phosphorus.

Forms of phosphorus in composts and in compost- amended soils following incubation

Gagnon, B., Demers, I., Ziadi, N., Chantigny, M. H., Parent, L.-É., Forge, T. A., Larney, F. J. and Buckley, K. E. 2012. Forms of phosphorus in composts and in compost-amended soils following incubation. Can. J. Soil Sci. 92: 711-721. Information on the forms and bioavailability of P from composts applied to horticultural crops under organic production are required to promote soil quality and plant growth while protecting the environment. Seven composts were selected and characterized for their chemical composition. The composts were mostly mature and the total P contained 73 to 96% as inorganic P (Pi), although the total P concentration and P fractions varied amongst the materials selected for this study. These composts along with an inorganic P (KH2PO4) alone were added to three soils with contrasting chemical properties at a rate equivalent to 65 kg P ha-1 and incubated in the dark at 25°C. An unfertilized control was included to estimate soil P contribution. The amount and relative solubility of P from these compost-soil mixtures were evaluated by a modified Hedley fractionation after 2 and 16 wk of incubation. Results indicated that P added with composts was preferentially found in the Pi portion of soil labile pools after 2 and 16 wk. Except for the dairy cattle manure compost, all composts resulted in the same amounts of labile P (51-58%) and total Pi (61-98%) in soils, which were significantly lower than the labile P (82%) and close to the total Pi (108%) from inorganic KH2PO4 alone. Unlike the other composts, the potato residue compost produced a significant increase in the organic P fraction (Po) extractable with NaHCO3. This study indicated that Pi was the most important form of P in these composts and in the compost-amended soils. Nevertheless, it remains difficult to predict the availability of compost P following its application to soil.

Ammonia volatilization following application of pig slurry increases with slurry interception by grass foliage

Efficient liquid manure application systems that minimize ammonia volatilization are required for use on perennial forage grasses. Ammonia volatilization was monitored using wind tunnels for 10 d after three pig slurry applications using four boom-mounted applicators: a broadcast splash-plate system, a trailing-shoe system and a drag-hose system with and without previous soil aeration. Average losses of 32, 20 and 15% of the total ammonia-N (TAN) applied to plots were observed for the splash-plate, the trailing-shoe and the drag-hose systems, respectively. The grass canopy intercepted, on average, 14% of pig slurry TAN using the splash-plate system compared with 4% for the trailing-shoe and 5% for the drag-hose systems. Reductions in canopy interception explained 58% of differences in volatilization rates among the application systems. On two of three application dates, NH3 volatilization was lower using the drag-hose than the trailing-shoe system. This was attributed to the sealing of the soil surface by...

Multinutrient diagnosis of nitrogen status in plants

Abstract The nitrogen (N) status of conifer seedlings, onion, and potato was diagnosed using the Critical Value Approach and the Compositional Nutrient Diagnosis (CND). The multinutrient CND N indices (In) accounted for the phosphorus (P) and potassium (K) concentrations in tissues. For conifer seedlings, a linear‐plateau relationship with well defined deficiency and excess zones was shown between dry matter yields and In, while the yield‐N response curve was distorted. The yield‐In relationship for onion and potato was improved as compared to the yield‐N curve. Correlation coefficients with yields were higher for In values than for raw concentration values. Critical In values were ‐1.8 for conifers, ‐0.8 for potato, and ‐0.7 for onion.