Fran Walley

Nitrogen and phosphorus fertility management for desi and kabuli chickpea

Chickpea (Cicer arietinum L.) is a relatively new crop in Saskatchewan and acreage has undergone a rapid expansion during the past decade. However, uncertainty remains regarding growth and yield responses of this grain legume to N and P fertilization under the semiarid environment of Saskatchewan. Field experiments were conducted at various locations in Saskatchewan to investigate chick pea response to starter N (0, 15, 30, and 45 kg N ha-1) and P (0, 20 and 40 kg P2O5 ha-1) using desi cv. Myles and kabuli cv. Sanford. Starter N was side banded (2.5 cm to the side and 4 cm below the seed) and the P was placed in the seed row or side banded. Starter N promoted early vegetative growth of both desi and kabuli chickpea, but kabuli seed yield was unaffected by N application. Application of 30 or 45 kg N ha-1 enhanced desi yield by as much as 221 kg ha-1. Starter N reduced N2 fixation by kabuli chickpea whereas N2 fixation by desi apparently was not as sensitive to inorganic N. Phosphorus (40 kg P2O5 ha-1) enha...

Calibration method at the N K-edge using interstitial nitrogen gas in solid-state nitrogen-containing inorganic compounds

The standard method of soft X-ray beamline calibration at the N K-edge uses the nu = 0 peak transition of gas-phase N(2). Interstitial N(2) gas trapped or formed within widely available solid-state ammonium- and amine-containing salts can be used for this purpose, bypassing gas-phase measurements. Evidence from non-nitrogen-containing compounds (KH(2)PO(4)) and from He-purged ammonium salts suggest that production of N(2) gas is through beam-induced decomposition. Compounds with nitrate or nitrite as anions produce coincident features and are not suitable for this calibration method.

Spring wheat (Triticum aestivum) yield and grain protein responses to N fertilizer in topographically defined landscape positions

A 3-yr field study was initiated in 1996 to examine the different grain yield and grain protein responses of wheat to varied N fertilizer rates in a typical glacial till landscape in Saskatchewan, Canada. Our objective was to assess the agronomic and economic feasibility of variable rate fertilizer (VRF) N application for wheat. Results suggest that spring soil water status largely determined the yield and the protein content of wheat both within different years of the study and between different landscape positions within a given year. Although grain yield was strongly related to spring soil water and was predictable on that basis, the grain yield response of wheat to fertilizer N additions was highly variable due, in part, to the dual role that N played in determining both grain yield and grain protein content. As a consequence of the unpredictable nature of the varied response of wheat to N fertilizer additions, there was little economic rationale for using VRF strategies in the 3 yr of this study. How...

Response of four common bean cultivars to granular inoculant in a short-season dryland production system

Common bean (Phaseolus vulgaris L.) is considered to be a poor N fixer relative to other legumes. However, considerable genotypic variability between cultivars is known to exist. Determining the importance of the host genotype to the symbiotic process will assist breeders in developing bean cultivars with improved N2 fixing capacity. Field experiments were conducted at two locations in Saskatchewan for two seasons to assess the N2 fixation rates of four common bean cultivars differing in growth habit and maturity. Beans were inoculated using a granular inoculant applied in the seedrow or in a sideband, or not inoculated at all. Inoculation resulted in greater nodule dry mass, shoot dry mass, seed yield and amount of N derived from atmosphere as compared with the uninoculated control. The response to inoculant application was cultivar specific, with N derived from the atmosphere ranging from a low of 51% (CDC Camino) to a high of 78% (CDC Pinnacle). The cultivars responded similarly to inoculant placement....

Nitrogen speciation in fine and coarse clay fractions of a Cryoboroll - new evidence from pyrolysis-mass spectrometry and nitrogen K-edge XANES

Soil clay fractions are usually enriched in nitrogen (N), but the chemical identity of this N is largely unknown. Therefore, we investigated organic N in fine and coarse clay of a clay-rich Cryoboroll by Curie-point pyrolysis-gas chromatography/mass spectrometry (Cp Py-GC/MS), Pyrolysis-field ionization mass spectroscopy (Py-FIMS) and synchrotron-based nitrogen K-edge X-ray absorption near edge structure (N-XANES) spectroscopy. The Cp Py-GC-MS revealed 30 structurally different N-containing compounds, such as substituted pyridines, pyrroles; pyrazines, pyrazoles, imidazoles, quinolines, side-chain N-containing benzenes, and single compounds of substituted benzotriazole, purine and indole. These accounted for about 10% of peak area in the Py-GC chromatograms. The Py-FIMS and N-XANES spectra indicated interlayer-NH4+ and revealed pyridinic and nitrilic N compounds, but disagreed in the proportions of pyrroles. All three complementary methods confirmed to different extents previous wet-chemical data on N-fra...

Response of Determinate and Indeterminate Common Bean Genotypes to Rhizobium Inoculant in a Short Season Rainfed Production System in the Canadian Prairie

ABSTRACT Common bean (Phaseolus vulgaris L.) has been shown to be a poor di-nitrogen (N2) fixer and nitrogen (N) fertilizers are usually recommended in bean production. Recent research results suggest that the success of the bean/Rhizobium symbiosis may depend, in part, on the specific bean genotype. Twelve dry bean genotypes differing in growth habit, commercial class, and maturity were evaluated for N2 fixation in field experiments. Response to inoculant application was highly influenced by environmental conditions. Genotypes differed in nodule dry mass, seed yield, seed N yield, and in amount of N2 fixed. Growth habit alone was not adequate in classifying bean genotypes for N2 fixation. The actual amount of N2 fixed was low ranging from 16 kg ha−1 to 27 kg ha−1, suggesting that the symbiotic process alone may not provide adequate N for optimum seed yield in dry environments.

Performance of Rhizobial Inoculant Formulations in the Field

Regardless of the formulation, the goal is maximum Rhizobium bacteria near emerging roots. Research evidence from western Canada suggests that the granular formulations typically are as good as and often better than peat or liquid formulations. However, convenience, expense, equipment requirements, and farmer experience and preference are all important considerations when deciding which formulation is best for any commercial operation.

Chapter 9 – Nitrogen Compounds in Dissolved and Solid Environmental Samples

The chapter describes the state of the art in Nitrogen K-edge X-ray absorption near-edge structure (N-XANES) spectroscopy applied to environmental problems. Technical details of beamline optimization are given as well as advice for sample preparation and spectral evaluation. The thorough overview of reference compounds includes mineral N-compounds, amino acids, amides, nitriles, and a wide range of heterocyclic compounds. We show new evidence of radiation damage on N-XANES spectra of proteinaceous N-reference compounds and soil-related materials, and propose approaches to minimize it. Calculated N-XANES spectra using density functional theory showed excellent agreement with measurements that resolved pyridinic and pyrrolic N in the same molecule. Using environmental samples, we demonstrate that measurements of soil solutions indicate a large contribution of mineral N (NO3−, NH4+). In particle-size fractions and bulk soil samples, differences in the proportions of various N functions may originate from clay-organic matter interactions, rhizosphere processes, and soil management practices. In conclusion, N-XANES is a valuable component in the multimethod approach toward the study of inorganic and organic N in environmental samples.

Single and Multistrain Rhizobial Inocula for Pinto and Black Bean Cultivars

ABSTRACT Common bean (Phaseolus vulgaris L.) is relatively poor in dinitrogen (N2) fixation, so selecting compatible host cultivar and Rhizobium strain combinations may offer an improvement. The effectiveness of six rhizobial strains was evaluated using five bean cultivars of bean (three pinto and two black bean) in a growth-room experiment. We subsequently selected the three best strains to assess whether multi-strain inoculation had advantages over single-strain inoculation in growth-room and field experiments. In the first-growth-room experiment, Rhizobium strains UMR 1899, RCR 3618, and USDA 2676 were selected for high nodulation, plant dry weight, shoot nitrogen (N), and N2 fixation. In a second growth-room experiment, the individual strains and a mixture of the three strains generally did not differ in the parameters evaluated. Total shoot N accumulated ranged from 172.9 to 162.8 mg plant−1, of which 32.1% to 33.6% (equivalent to 54.0 to 59.2 mg plant− 1) was fixed. In field experiments, plant biomass and seed N2 fixed did not differ among the inoculants at any site. These results suggest that the three strains were equally effective and that the multi-strain inoculant offered no consistent advantage over the single-strain inoculants.

Genetic and phenotypic diversity of rhizobia nodulating Chickpea (Cicer arietinum L.) in soils from southern and central Ethiopia

Forty-two chickpea-nodulating rhizobia were isolated from soil samples collected from diverse agro-ecological locations of Ethiopia and were characterized on the basis of 76 phenotypic traits. Furthermore, 18 representative strains were selected and characterized using multilocus sequence analyses of core and symbiotic gene loci. Numerical analysis of the phenotypic characteristics grouped the 42 strains into 4 distinct clusters. The analysis of the 16S rRNA gene of the 18 strains showed that they belong to the Mesorhizobium genus. On the basis of the phylogenetic tree constructed from the combined genes sequences (recA, atpD, glnII, and gyrB), the test strains were distributed into 4 genospecies (designated as genospecies I-IV). Genospecies I, II, and III could be classified with Mesorhizobium ciceri, Mesorhizobium abyssinicae, and Mesorhizobium shonense, respectively, while genospecies IV might represent an unnamed Mesorhizobium genospecies. Phylogenetic reconstruction based on the symbiosis-related (nifH and nodA) genes supported a single cluster together with a previously described symbiont of chickpea (M. ciceri and Mesorhizobium mediterraneum). Overall, our results corroborate earlier findings that Ethiopian soils harbor phylogenetically diverse Mesorhizobium species, justifying further explorative studies. The observed differences in symbiotic effectiveness indicated the potential to select effective strains for use as inoculants and to improve the productivity of chickpea in the country.