Nitrogenase Activity and Nodule Biomass of Cowpea (Vigna unguiculataL. Walp.) Decrease in Cover Crop Mixtures

Myrica gale L. populations growing in central Massachusetts were observed throughout the ice-free season. Nitrogenase activity appeared in mid-May shortly after budbreak, was at its maximum between late June and mid-August, and disappeared in late October after all leaves had fallen. Growth of overwintering nodules began in early May and was largely complete by mid-July. Most nodules (88%) lived for 3 years or less and 61% of the nodule biomass present in autumn was produced during the current season.Colonizing hyphae of the Frankia sp. endophyte were seen throughout the year in partially expanded cortical cells near the nodule lobe apex. Vesicles first appeared in mature cortical cells coincident with the onset of nitrogenase activity in mid-May, occupied the bulk of the infected tissue during the summer, and disappeared as nitrogenase activity ceased in late October. Evidence is presented that the vesicles are the site of nitrogenase activity and are newly produced each season in freshly formed nodule lobe tissue. Sporangia frequently formed in mature infected cells in nodules at one site but were rare at another. The processes described here in M. gale are probably typical of winter-deciduous actinorhizal plants.

Download Full-text

Dinitrogen fixation by a mature Ceanothus velutinus (Dougl.) stand in the Western Oregon Cascades

Canadian Journal of Microbiology ◽

10.1139/m83-159 ◽

1983 ◽

Vol 29 (8) ◽

pp. 1014-1021 ◽

Cited By ~ 20

Author(s):

D. H. McNabb ◽

K. Cromack Jr.

Keyword(s):

Nitrogenase Activity ◽

Dinitrogen Fixation ◽

Total Biomass ◽

Fixation Rate ◽

Xylem Pressure ◽

Nodule Biomass ◽

Oregon Cascades ◽

Mature Stands ◽

Large Nodule ◽

Precipitation Events

Dinitrogen fixation was measured in a 17-year-old snowbrush, Ceanothus velutinus var. velutinus (Dougl.), stand in the Western Oregon Cascades. Diurnal and seasonal rates of nitrogenase activity were measured in the field using the C2H2 reduction technique. Snowbrush had a total biomass, estimated with equations developed, of 42 680 kg∙ha−1, including 750 kg∙ha−1 of nodule biomass. Snowbrush fixed N2 for approximately 240 days annually. Except during precipitation events or periods of low xylem pressure potentials, C2H2 reduction rates in the summer and fall were significantly correlated with soil temperature (R2 = 0.93**, n = 6). A diurnal variation in nitrogenase activity also was measured. The annual N2 fixation rate was estimated at approximately 101 kg N∙ha−1 (C2H2). Sustained periods of precipitation suppressed nitrogenase activity and reduced the estimate by about 19%. The annual N2 fixation rate is higher than previously reported for other mature stands and primarily is attributed to the maintenance of a large nodule biomass.

Download Full-text

Pertumbuhan Mucuna bracteata DC. pada Berbagai Waktu Inokulasi dan Dosis Inokulan

Jurnal Agronomi Indonesia (Indonesian Journal of Agronomy) ◽

10.24831/jai.v44i1.12510 ◽

2016 ◽

Vol 44 (1) ◽

pp. 104 ◽

Cited By ~ 2

Author(s):

Purwanti Budi Laksono ◽

Ade Wachjar ◽

Dan Supijatno

Keyword(s):

Cover Crop ◽

Nitrogenase Activity ◽

Block Design ◽

Dry Weight ◽

Nutrient Content ◽

Leaf Nitrogen ◽

Leaf Nitrogen Content ◽

Shoot Dry Weight ◽

Legume Cover Crop ◽

Rhizobium Population

ABSTRACT<br /><br />Mucuna bracteata DC. is a legume cover crop to prevent erosion and to suppress weed growth. M. bracteata can fix N2 from the air with the help of Rhizobium. M. bracteata get benefit from the symbiosis in the form of increased nodule weight, shoot dry weight, and leaf nitrogen content when the Rhizobium population in the soil is optimal. Application of inoculant is one method to increase the Rhizobium population in the soil. This study aimed to analyze the effects of inoculation times and inoculant rates on M. bracteata growth. The research was conducted in Boyolali, Central Jawa, from February to August 2014. The inoculant contained Bradyrhizobium japonicum and Aeromonas punctata. This experiment was arranged in a randomized block design with two factors and three replications. The first factor was two inoculation times, i.e at the nursery when the seedlings were 2 weeks old and in the field when the seedlings reached 5 weeks old. The second factor was 5 inoculant rates (0, 2, 4, 6, and 8 g per plant). The results showed that inoculation on 5-week-old seedlings was the best result compared to the 2-week-old seedlings. The recommended inoculant rate for Mucuna bracteata was 6.43 g per plant. <br /><br />Keywords: legume cover crop, nitrogenase activity, nodule, nutrient content, runner

Download Full-text

FEATURES OF SALTS MIGRATION IN DELTAIC ECOSYSTEMS

Vestnik of the Russian agricultural science ◽

10.30850/vrsn/2018/6/28-29 ◽

1970 ◽

pp. 28-29

Author(s):

М. I. Dzhalalova ◽

P. А. Abdurashidova ◽

R. М. Zagidova

Keyword(s):

Cover Crop ◽

Groundwater Salinity ◽

Salt Composition ◽

Material Resource ◽

Aboveground Phytomass ◽

Soil Layers ◽

Material Energy ◽

Theoretical Foundations ◽

Pasture Plants ◽

Salinity Seawater

The coastal strip of the northwestern Caspian is characterized by hydromorphism and salinization processes which depending on the Caspian piled-up water, groundwater salinity, seawater, and salt composition of the underlying rocks. The migrational salts capability in deltoic ecosystem components in dynamic over the main representatives of pasture plants occurring in the Western Caspian and playing an important role in developing the theoretical foundations of a system of measures to increase the productivity of cover crop have studied. Salts migration from soil layers into plants which taking place in synthesis of material-energy and material resource of environment is one of the chains of bio-substrat links. The research results confirm the data that the ash elements stock in the ephemeral-absinthial group varies from 21.5 to 64.5 kg per 1 ha. The organogens prevail in them – 944 kg / ha, K is dominant, then Ca and Mg. The amount of halogens is 7.05 kg / ha, of which Cl portion includes 3.31 and Na – 2.80 kg / ha. In the ephemeral-absinthial group cenoses rather high values of aboveground phytomass are up to 50 centners / ha and the supply of ash elements (halogens 32.14 and organogens 36.18 mg-eq) is much higher compared to their content in soil (7.05 and 6, 31 mg-eq). In roots difference in quantity of organogens and halogens is insignificant – 2.03 and 2.04 mg-eq. We associate such differences with a greater proportion of absinthial in the aboveground phytomass composition

Download Full-text