Field Pea Residues Research Articles

Combined effect of cover crops and bio-fertilizer on sustainable popcorn maize production.

Cover crops play an important role in low-input cropping systems, increasing the use of agro-ecosystem services. Due to the lack of information about the impact of cover crops and bio-fertilizers on popcorn maize (Zea mays everta Sturt.) growth and yield quality, especially the popping volume and nutritive quality, such as concentrations of protein and mineral elements, this research aimed to provide essential information. The interrelation between popcorn maize productivity and quality with important groups of soil microorganisms presents additional novelty. The results demonstrated that field pea is a beneficial cover crop, especially when combined with a bio-fertilizer, supporting the accumulation of maize biomass, chlorophyll, yield potential, and the concentrations of protein, Ca, Mg, Fe, and Zn. In addition, field pea residues promoted N-fixing bacteria, and the number of total microorganisms, especially actinomycetes and decomposing bacteria, which could promote nutrient uptake and grain quality. Residues of cover crop mixtures, common vetch + winter oats and field pea + winter oats, promoted the total number of microorganisms in the soil, and up to the end of vegetation, a greater number of decomposition and ammonification microorganisms were found, especially when the bio-fertilizer was applied, which consequently could support greater maize biomass. Popping volume, as a main trait of popcorn maize, had the highest value in the common vetch + winter oats variant, supporting again the statement that quality traits could be enhanced in sustainable production. Unlike living cover crops, mulch mainly affected soil microbial communities and promoted the development of actinomycetes and cellulolytic microorganisms during the growing season. The results of this research could contribute to the development of sustainable popcorn maize production for improved grain quality. They could also serve as a basis for isolating beneficial soil microorganisms to develop new bio-fertilizers that could improve maize production in synergy with cover crops.

Overwinter survival and alternative crop hosts of fungi and oomycetes present in field pea residue on the Canadian prairies

Root rot is an important disease of field pea (Pisum sativum L.) on the Canadian Prairies. The composition and alternative crop hosts of fungal and oomycete communities colonizing pea residues from Alberta and Manitoba were studied in field trials over two years. Standing pea residues were sampled from diseased and asymptomatic patches of 17 commercial fields in 2013 and 2014 after harvest and again in early spring the following year prior to seeding. The pea residue was ground to a powder and mixed with sterile Cornell potting mix. Plants of pea, wheat, and canola were grown in this mixture under controlled conditions. The root rot severity on each plant was evaluated and sections from diseased roots were plated on agar medium. Fungal and oomycete communities isolated from symptomatic roots were identified based on culture morphology and PCR analysis. About 3000 fungal isolates, belonging to some 50 species, were identified. Canola was less susceptible to infection than pea or wheat. Fusarium avenaceum (Fr.) Sacc. was the most abundant species infecting the three hosts; F. culmorum (Wm.G.Sm.) Sacc. and Bipolaris sorokiana (Sacc.) Shoemaker were more frequently isolated from wheat, and F. solani (Mart.) Sacc., F. oxysporum Schlecht. and Aphanomyces euteiches Drechsler were more frequently isolated from pea. Pathogen communities from asymptomatic and diseased patches of fields were similar. Overall, composition of the fungal community changed over winter, but the most abundant species did not change. The results show that multiple pathogens, and particularly Fusarium spp., can survive overwinter on pea residue.

Elevated CO2 alters the rhizosphere effect on crop residue decomposition

Elevated atmospheric CO2 (eCO2) can affect microbial decomposition of native soil organic carbon (SOC) via enhanced root exudation and rhizosphere activity. Few studies have examined the effect of eCO2 on the decomposition of newly-added crop residues, which are important to understand below-ground C changes. A soil microcosm experiment was conducted to examine whether eCO2 would enhance the rhizosphere effects on the decomposition of crop residues. White lupin (Lupinus albus L. cv. Kiev) was grown for 34 or 62 days under ambient CO2 (aCO2, 400 μmol mol−1) or eCO2 (800 μmol mol−1) in a low-C (2.0 mg g−1) soil which was amended with or without dual 13C and 15N labelled wheat, field pea or canola crop residues. An isotopic tracing technique was adopted to partition residue-derived CO2 from total below-ground CO2 efflux. Two independent groups of data were analysed statistically at either Day 34 or 62. The presence of white lupin increased the decomposition of all residues at Day 34. This positive rhizosphere effect on residue decomposition decreased and was even reversed at Day 62, probably due to depletion of labile C, or microbial N limitation, or rhizosphere acidification. The eCO2-induced decomposition depended on residue type at Day 34. Specifically, when compared to aCO2, eCO2 did not affect the decomposition of canola residue, increased that of field pea residue by 13.5% but decreased wheat straw decomposition by 7.4%. However, residue decomposition was, on average, 13% higher under eCO2 at Day 62, which was correlated positively with the increase in rhizosphere extractable C (P < 0.01). Elevated CO2 generally increased residue decomposition in the rhizosphere, but this effect was mediated by residue type at Day 34. Enhanced residue decomposition under legumes at eCO2 may favour C turnover and the release of residue N.

Residue addition and liming history interactively enhance mineralization of native organic carbon in acid soils

Lime application is the most common method to improve crop production in acid soils and has been shown to change soil organic C content. However, the impact of liming history on the priming effect on soil organic C is not well understood. This study examined the effect of liming history on C priming in response to the addition of crop residues of different qualities. Soils with pH ranging from 4.7 to 7.4 were collected from two adjacent field experiments whereby lime was applied at different rates, 6 and 35 years ago. A 90-day incubation study was conducted by applying 13C-labelled wheat (C/N 42) and field-pea (C/N 29) residues at a rate of 5 g kg−1 soil. Residue application to soils yielded the positive priming effect in all pH levels with the magnitude of C priming being the greatest at initial soil pH 6.6. In comparison, the optimal pH for residue decomposition (7.3) was higher than that for priming. The overall priming effect was about 17% greater with field-pea than wheat residue. However, cumulative decomposition of added field-pea residue was 15% lower than that of wheat residue. Furthermore, C priming was greater in soils from the 35-year-old than the 6-year-old limed plots, indicating that a longer history of liming did not enhance the protection of indigenous C from mineralization. The results suggest that increases in soil pH by liming enhanced native C priming through greater microbial biomass and activity and that the magnitude and dynamics of the priming effect largely depended on residue quality and its consequent nutrient supply to decomposer organisms. The study implies that over-liming would likely have negative impacts on the long-term C sequestration.

Elevated CO2 induced rhizosphere effects on the decomposition and N recovery from crop residues

Elevated atmospheric CO2 (eCO2) can affect soil-plant systems via stimulating plant growth, rhizosphere activity and the decomposition of added (crop residues) or existing (priming) soil organic carbon (C). Increases in C inputs via root exudation, rhizodeposition and root turnover are likely to alter the decomposition of crop residues but will ultimately depend on the N content of the residues and the soil. Two soil column experiments were conducted under ambient CO2 (aCO2, 390 ppm) and eCO2 (700 ppm) in a glasshouse using dual-labelled (13C/15N) residues of wheat (Triticum aestivum cv. Yitpi) and field pea (Pisum sativum L. cv. PBA Twilight). The effects of eCO2 and soil N status on wheat rhizosphere activity and residue decomposition and also N recovery from crop residues with different N status (C/N ratio 19.4–115.4) by different plant treatments (wheat, wheat + 25 mg N kg−1 and field pea). Total belowground CO2 efflux was enhanced under eCO2 despite no increases in root biomass. Plants decreased residue decomposition, indicating a negative rhizosphere effect. For wheat, eCO2 reduced the negative rhizosphere effect, resulting in greater rates of decomposition and recovery of N from field pea residues, but only when N fertiliser was added. For field pea, eCO2 enhanced the negative rhizosphere effect resulting in lower decomposition rates and N recovery from field pea residue. The effect of eCO2 on N utilisation varied with the type of residue, enhancing N utilisation of wheat but repressing that of field pea residues, which in turn could alter the amount of N supplied to subsequent crops. Furthermore, reduced decomposition of residues under eCO2 may slow the formation of new soil C and have implications for long-term soil fertility.

Increased microbial activity under elevated [CO2] does not enhance residue decomposition in a semi-arid cropping system in Australia

The association between the responses of microbial activity and residue decomposition to elevated atmospheric [CO2] under field conditions in Australian cropping systems is unknown. We measured soil CO2 emission and decomposition of wheat and field pea residues in a wheat cropping system in the field using the Australian Grains Free-Air CO2 Enrichment (AGFACE) facility in Horsham, Victoria. Elevated [CO2] (550 μmol mol−1) increased soil CO2 emission by 41%, but did not affect the percentage of the original mass or C remaining for either type of residue throughout the experimental period. Our findings suggest that the rates of residue decomposition and residue C mineralization in this semi-arid wheat cropping system were not affected by elevated [CO2] despite higher microbial activity. This has major implication for the C sequestration potential of semi-arid cropping systems under future CO2 climates.

The effect of elevated atmospheric carbon dioxide concentration on the contribution of residual legume and fertilizer nitrogen to a subsequent wheat crop

This study investigated the residual contribution of legume and fertilizer nitrogen (N) to a subsequent crop under the effect of elevated carbon dioxide concentration ([CO2]). Field pea (Pisum sativum L.) was labeled in situ with 15N (by absorption of a 15N-labeled urea solution through cut tendrils) under ambient and elevated (700 μmol mol–1) [CO2] in controlled environment glasshouse chambers. Barley (Hordeum vulgare L.) and its soil were also labeled under the same conditions by addition of 15N-enriched urea to the soil. Wheat (Triticum aestivum L.) was subsequently grown to physiological maturity on the soil containing either 15N-labeled field pea residues (including 15N-labeled rhizodeposits) or 15N-labeled barley plus fertilizer 15N residues. Elevated [CO2] increased the total biomass of field pea (21 %) and N-fertilized barley (23 %), but did not significantly affect the biomass of unfertilized barley. Elevated [CO2] increased the C:N ratio of residues of field pea (18 %) and N-fertilized barley (19 %), but had no significant effect on that of unfertilized barley. Elevated [CO2] increased total biomass (11 %) and grain yield (40 %) of subsequent wheat crop regardless of rotation type in the first phase. Irrespective of [CO2], the grain yield and total N uptake by wheat following field pea were 24 % and 11 %, respectively, higher than those of the wheat following N-fertilized barley. The residual N contribution from field pea to wheat was 20 % under ambient [CO2], but dropped to 11 % under elevated [CO2], while that from fertilizer did not differ significantly between ambient [CO2] (4 %) and elevated [CO2] (5 %). The relative value of legume derived N to subsequent cereals may be reduced under elevated [CO2]. However, compared to N fertilizer application, legume incorporation will be more beneficial to grain yield and N supply to subsequent cereals under future (elevated [CO2]) climates.

Effect of crop residue, nitrogen rate and fungicide application on malting barley productivity, quality, and foliar disease severity

Turkington, T. K., O'Donovan, J. T., Edney, M. J., Juskiw, P. E., McKenzie, R. H., Harker, K. N., Clayton, G. W., Xi, K., Lafond, G. P., Irvine, R. B., Brandt, S., Johnson, E. N., May, W. E. and Smith, E. 2012. Effect of crop residue, nitrogen rate and fungicide application on malting barley productivity, quality, and foliar disease severity. Can. J. Plant Sci. 92: 577–588. The productivity and quality of the malting barley cultivar AC Metcalfe and leaf disease severity were evaluated under three residue types [barley (Hordeum vulgare L.), canola (Brassica napus L.), field pea (Pisum sativum L.)], two nitrogen (N) fertilizer rates (50 or 100% of soil test recommendation for N), and two fungicide treatments (no fungicide or fungicide applied) at seven sites across western Canada from 2006 to 2009. Residue type had a significant effect on leaf disease severity, which was increased when barley was the previous crop compared with canola and field peas. In general, emergence, head counts, grain yield, kernel weight, test weight, kernel plumpness were lowest for barley grown on barley residue compared with canola and field pea residue. Fungicide application reduced leaf disease severity and increased yield, kernel weight, test weight, and kernel plumpness, while decreasing dockage and thins. However, the magnitude of the impact of fungicide on one or more of these parameters was lower compared with planting barley on field pea or canola residue. Overall, increasing the N rate from 50 to 100% had no effect on leaf disease levels and only increased yields slightly compared with not planting barley on barley residue. However, the 100% rate of N did significantly increase grain protein levels. In contrast, planting barley on field pea residue did not result in a consistent increase in grain protein.

Nitrogen release from field pea residues and soil inorganic N in a pea-wheat crop rotation in northwestern Canada

Pea (Pisum sativum L.) varieties can differ in morphology, N2 fixation and straw N content. A study was conducted over 3 site-years to evaluate the influence of pea variety and inoculation with Rhizobium on N release from decomposing pea residues. The litterbag technique was used to measure N release over a 52-wk period starting from the time of pea harvest in one season through part of the following season when wheat was grown. Experimental treatments comprised factorial combinations of three pea varieties and either inoculation with 5 kg ha-1 of a granular inoculant or none, arranged in a randomized complete block design. Neither pea variety nor inoculation affected amounts or patterns of N released. Patterns of N release over time showed mostly net N mineralization in two of 3 site-years, and some net N immobilization in one site-year. The percentages (up to 19 to 24% over time) and amounts (up to 2.3 to 7.5 kg N ha-1) of N released were low, probably due to the combination of low N concentrations (mostly &lt; 1%) in the residues and below-normal rainfall in all 3 site-years. Soil NO3-N and NH4-N (0- to 80-cm depth) in the fall after pea harvest (20 to 39 and 27 to 55 kg N ha-1, respectively) and in spring before wheat seeding (23 to 51 and 16 to 40 kg N ha-1, respectively) were not affected by pea variety or inoculation. However, soil NO3-N was mostly higher after peas than after barley (the control). There is need to measure patterns of N release over several subsequent crops to check if more N is released in the long term. Key words: Crop residue, N mineralization, Rhizobium inoculation, soil inorganic N

Isotopic tracing of phosphorus uptake in corn from 33P labelled legume residues and 32P labelled fertilisers applied to a sandy loam soil

In low input (e.g. organic) farming systems where soil phosphorus (P) fertilisers such as superphosphate are not used, maintaining sufficient available soil P for plant growth can be a major challenge. The use of P accumulating cover crops may increase P availability for subsequent crops. We hypothesised that P release from organic residues of legumes (faba bean (Vicia faba) and field peas (Pisum sativum)) could supply adequate P to meet the needs of a subsequent crop in a low P soil. A pot experiment was conducted to determine the contribution of P by legume green manure to subsequent corn using 33P labelled legume residues and 32P labelled inorganic fertiliser (KH2PO4). The treatments included two rates of P application, (a) 10 kg P ha−1 as legume root and shoot residues or as inorganic fertiliser with and without a C source, and (b) 38 kg P ha−1as a combination of legume shoot and root residues or a combination of root and inorganic fertiliser and inorganic fertiliser alone. An absolute control (zero P) was also used. Shoot dry matter, P uptake and P source (residues or fertilisers) of total P in corn were measured at harvest. Faba bean and field pea residues alone or in combination with fertilisers contributed up to 10% and 5% of the total P uptake by corn respectively, compared with up to 54% by inorganic fertilisers. Incorporation of field pea and faba bean residues with P concentrations higher than those observed under field conditions, may not always lead to adequate net P release to supply the early growth phase of subsequent crops.

N-utilization by maize (Zea mays L.) as influenced by crop rotation and field pea (Pisum sativum L.) residue management

Abstract. A five year field experiment was conducted to assess the influence of crop rotation and field pea residue incorporation into the soil on maize yield. The data indicated a 30% increase in maize yield grown in rotation with field pea compared to when it was grown after wheat and a further increase of 35% when field pea residues were incorporated into the soil. The effect of field pea and residue incorporation was greater in the presence of fertilizer nitrogen indicating the enhanced capacity of the crop to utilize N from the residue. Legume residue management in sub-tropical regions of the world, having coarse textured soils low in organic matter, could help to increase the yield of cereals besides saving some of the expensive fertilizer input.

Tillage and N source influence soil-emitted nitrous oxide in the Alberta Parkland region

Zero tillage systems are receiving attention as possible strategies for sequestering atmospheric carbon. This benefit may be offset by increased N2O emissions, which have been reported for soils under zero tillage (ZT) compared to those under more intensive tillage (IT). Comparisons of N2O emissions from the two systems have been restricted to the growing season, but substantial losses of N2O have been reported during spring thaw events in many regions. Inorganic and organic additions of nitrogen and fallowing have also been shown to increase levels of soil-emitted N2O. The objectives for this study were: (i) to confirm that losses of N2O are higher under ZT than under IT in Alberta Parkland agroecosystems; (ii) to compare the relative influence of urea fertilizer (56 or 100 kg N ha−1), field pea residue (dry matter at 5 Mg ha−1), sheep manure (dry matter at 40 Mg ha−1) additions, and fallow on total N2O losses; and (iii) to investigate possible interactions between fertility and tillage treatments. Gas samples were collected using vented soil covers at three sites near Edmonton, Alberta during 1993, 1994, and 1995. Gas samples were analyzed using a gas chromatograph equipped with a 63Ni electron capture detector. Estimated annual N2O loss ranged from 0.1 to 4.0 kg N ha−1. Emissions during summer were slightly higher, similar, or lower on ZT compared to those under IT, but were consistently lower on ZT plots during spring thaw. Combined estimates (spring plus summer) of N2O loss under ZT were equal to or lower than those under IT. Highest overall losses were observed on fallow plots, followed by fertilizer, pea residue, and then either manure or control plots. We conclude that ZT management systems have potential for reducing agricultural greenhouse gas emissions in the Alberta Parkland region. Key words: Nitrous oxide, thawing soil, tillage, nitrogen fertilizer, manure, fallow

Leaching in Small Lysimeters of Nitrate Derived from Nitrogen-15-Labeled Field Pea Residues.

Field pea (Pisum sativum L.) crop residues labeled with 15 N were incorporated during September in small monolith lysimeters of a sandy loam soil. The leaching of 15 N-labeled and nonlabeled NO3 to below 45 cm was studied during the subsequent 2 to 3 yr comparing (i) planted vs. unplanted soil and (ii) with and without pea residue incorporation. The peak flux of labeled NO3 -N from uncropped soil occurred in December. During the first leaching period (September-April), 15 and 7% of the residue N was recovered as NO3 in the percolate in the two experiments, corresponding to 18 and 13% of total NO3 -N in the percolates, respectively. The difference observed in leaching of labeled N in the two experiments was mainly due to a much higher drainage volume in the first experiment. The different residue particle sizes, 10 mm or <3 mm, used in the two experiments may have influenced the immobilization-mineralization of N in the soil differently and consequently the potential for NO3 leaching. Pea residue N constituted 10 to 15% and 5% of total NO3 -N leached from unplanted soil in the second and third leaching periods, respectively. Incorporating the ground pea residues reduced the total amount of NO3 leached by 15% during the first leaching period, indicating that the pea residue may be an important factor in controlling leaching losses. Ryegrass (Lolium perenne L.) established on lysimeters at the time of residue incorporation reduced the total leaching of N in the first leaching period by 15%, but in the second and third leaching period grass eliminated NO3 leaching completely.