Carbon storage and sequestration potential in aboveground biomass of bamboos in North East India

The Northeastern hilly states of India harbor nearly 90 species of bamboos, 41 of which are endemic to the region. Estimation of C-storage and C-sequestration in aboveground biomass of two common bamboo species namely Bambusa tulda and Dendrocalamus longispathus was carried out in Mizoram-one of the eight states of Northeastern India. Recording of density of culms was done by quadrate method and harvesting of culms was done to estimate the aboveground biomass. C-storage in different components of the culms was found out for three age classes namely 1, 2 and ≥ 3 year old culms. Aboveground biomass ranged from 73.58 to 127 Mg/ha in Bambusa tulda and 115 to 150 Mg/ha in Dendrocalamus longispathus. Culm density and aboveground biomass were maximum in the ≥ 3 year age class in both the species. C-storage ranged from 36.34 to 64.00 Mg/ha in Bambusa tulda and 50.11 to 65.16 Mg/ha in Dendrocalamus longispathus. Although having lower aboveground biomass the rate of C-sequestration was higher in Bambusa tulda with 27.79 Mg/ha/year than Dendrocalamus longispathus which have 15.36 Mg/ha/year. The reason was attributed to higher increment of culm density and DBH of the older age class in the second year study period in Bambusa tulda.

Morphological Responses Explain Tolerance of the Bamboo Yushania microphylla to Grazing

Mechanisms of tolerance of the bamboo Y. microphylla to ungulate herbivory were investigated by measuring above- and belowground morphogenetic traits and biomass allocation patterns of the bamboo Y. microphylla under grazed and ungrazed conditions in a Himalayan mixed conifer forest. Data were collected from 5 populations consisting of 10 ramets each in adjacent grazed and ungrazed plots. Compared with ungrazed ramets, the aboveground morphological modifications of grazed ramets were higher culm density, shorter and thinner culms, shorter internode, and shorter top leaf. The belowground morphological modifications for the grazed ramets were thinner rhizomes, lower rhizome biomass and dry matter, more nodes, and shorter internodes. Despite the lower biomass and dry matter, the root-to-shoot ratio was higher for grazed ramets. Results suggest that Y. microphylla subjected to herbivory shows aboveground overcompensation in terms of densification at the cost of belowground biomass, but at the same time maintains a higher proportion of belowground reserves, as compared to ungrazed conditions. These responses provide adequate evidence to conclude that Y. microphylla tolerates ungulate herbivory through above- and belowground morphological modifications.

Effects of plant cover on the macrofauna of Spartina marshes in northern Brazil

Data on macrofauna density and diversity, and the height and density of Spartina brasiliensis, were obtained from salt marsh beds of a tropical estuary in northern Brazil. Sampling was carried out at four distinct times of the year, during the wet and dry seasons and in the transition periods between these. Sampling was also carried out in salt marshes of three size classes, small, medium and large. Variables were analyzed in relation to time of year and salt marsh size class. Overall, 46 taxa were found, with polychaetes, isopods and the gastropod Neritina virginea dominating the fauna. Macrofauna density and diversity were positively correlated with culm density, indicating a possible role in protection from predation. All the three variables were higher during the transitional periods between the wet and dry seasons and seasonal changes in rainfall, salinity and light availability may influence mortality, food availability and settlement of the macrofauna. There was no effect of salt marsh size on either the macrofauna or the vegetation.

Morphotypic Differentiation in the South-Western Australian Restiad Lyginia barbata R.Br (Restionaceae)

Study of Lyginia barbata across its distribution range in south-western Australia identified five distinctive morphotypes, viz. a tall-culmed, densely tufted fire-sensitive obligate seeder (S morphotype), a tall densely tufted fire-resistant resprouter (R1), a short flexuose-culmed, tufted resprouter (R2), a weakly clonal, semi-tufted resprouter (R3) and a short-culmed, widely spreading clonal form (R4). There was little variation within a morphotype between habitat locations and no evidence of intergrading of cohabiting morphotypes. Morphotype-specific differences were observed in culm height, rhizome morphology, culm density and spikelet morphology. Differences in reproductive biology related to the time of first reproduction in juvenile recruits, spikelet number per male and female culm, ovule number per female culm and seed : ovule ratio. Differences of a physiological nature were observed in seedling growth rates and proportional biomass (dry matter) allocations to culms, rhizomes, spikelets and seeds. Comparative quantitative scorings of the above features according to concepts of r- and K-selection rated the S form strongly r-selected, the R4 form equally strongly K-selected and the other forms (R1, R2 and R3) intermediate and with the R1 form possibly more r-selected than the others. It is suggested that the data provide a basis on which future taxonomic decisions regarding the taxon might be made.

CONTROL OF QUACKGRASS IN FALLOW FROM SEVERAL GLYPHOSATE PLUS TILLAGE TREATMENTS AND ITS EFFECT ON THE SUBSEQUENT YIELD OF BARLEY

The control of quackgrass (Agropyron repens (L.) Beauv.) using glyphosate applied with either a conventional sprayer or a rope wick applicator, each followed by several levels of tillage, was studied in 1983, 1984 and 1985. With the conventional sprayer, glyphosate was either applied alone or with ammonium sulfate (3.4 kg ha−1) and the surfactant, nonylphenoxy polyethoxy ethanol (0.5% vol/vol of spray volume). Applications made with the sprayer were more effective in reducing quackgrass culm density than those made with the rope wick applicator. The density of quackgrass culms declined as the number of tillage operations increased from one, performed at 115 or more days after herbicide application (DAT), to three performed at 5–8, 39–60 and 115 or more DAT. Doubling the rate of sprayer-applied glyphosate, from 0.8 to 1.7 kg acid equivalent ha−1, did not result in a reduction in the density of quackgrass culms. However, in 1 of the 2 years in which comparisons were made, both of these treatments reduced the density of quackgrass culms more than a similar application of glyphosate alone at 0.5 kg ha−1. The addition of ammonium sulfate and surfactant to glyphosate enhanced quackgrass control only at the 0.5 kg ha−1 rate and only in 1 of 2 yr at that rate. Glyphosate, applied at 0.5 kg ha−1 with the sprayer, and followed by three tillage operations consistently reduced the density of quackgrass culms by 95% or more. Both the herbicide and the tillage treatments resulted in increases in the yield of barley seeded the following year. In 2 of the 3 years, barley yields, averaged across tillage treatments, were greater in the plots where the sprayer had been used to apply the glyphosate treatments than in the plots where the rope wick applicator had been used. Barley yields decreased as the quackgrass culm density increased, although other factors seemed to have influenced the yields in one of the years.Key words: Glyphosate, tillage, barley, quackgrass, fallow

Red Rice (Oryza sativa) Control in Drill-Seeded Rice (O. sativa)

Field experiments were conducted to investigate methods of controlling red rice (Oryza sativaL. ♯ ORYSA) in drill-seeded rice (O. sativa). Treatments included the rice cultivar ‘Mars', coated with calcium peroxide (CaO2) at 40% (w/w) and a crop protectant, R-33865 (O,O-diethyl-O-phenyl phosphorothioate) at 0.5 and 1% (v/w). Molinate (S-ethyl hexahydro-1H-azepine-1-carbothioate) at 6.7 kg ai/ha was applied preplant incorporated (ppi). The land was flooded (2.5 to 5 cm deep) after seeding with rice (100 kg/ha, 2.5 cm deep), and the water was maintained throughout the growing season. CaO2, with or without molinate, increased rice grain yield 50% and increased rice culm density fivefold above untreated rice. Molinate applied ppi controlled 96% of the red rice. Rice seed coated with only CaO2or with CaO2plus R-33865 at 0.5%, each combined with ppi molinate, produced 5690 and 6030 kg/ha of grain, respectively. These high yields were associated with red rice control by molinate and good stands of rice provided by O2supplied by CaO2. R-33865 applied to rice seed at 1% (v/w) injured rice by reducing rice culm densities 41%, compared with rice without protectant.

Growth and Development of Johnsongrass Ecotypes

Studies were conducted on the growth and development of 55 morphologically distinct vegetative types of johnsongrass (Sorghum halepense(L.) Pers.) collected throughout the United States and from several foreign countries. Observations were made also on the growth of sorghum almum (Sorghum almumParodi) from three foreign countries. Mature leaf-blades of the different johnsongrass ecotypes varied in length from 31 to 59 cm and in width from 1.7 to 3.4 cm. Plant height and culm density varied 2 to 4-fold for the different ecotypes. Floret production varied from 87 to 352 sessile spikelets for representative panicles of the different ecotypes. The number and arrangement of branchlets within panicles also varied as did the size of various spikelet components. Sorghum almum produced much taller plants than did johnsongrass although culm density and lateral growth were less than that of johnsongrass.

Analysis of growth, development and yield in a spacing experiment with winter rye (Secale cereals L.).

It was concluded from an experiment with Petkus winter rye sown at 7 seed rates in the range 5-180 kg/ha that: (1) crop analysis facilitated the interpretation of yield analysis; (2) crop analysis can be confined to the counting of plants at tillering, of ears during heading and of florets per ear after anthesis, and to determinations of either dry weight or of N or chlorophyll contents per unit soil area, per plant or per organ; (3) tillering was able to compensate for lower plant densities until 1.5 dm2 of space per plant was reached; (4) at decreasing seed rates, the rate of development decreased, while the number of florets per ear, floret fertility and rate and duration of grain filling increased; (5) the number of florets per ear, their fertility and grain filling depended on the nutritive conditions during tillering and shooting, at about the time of anthesis, and during ripening, respectively; (6) there were close correlations between the amount of N and of chlorophyll in the aerial parts and the logarithm of plant or culm space, indicating that the relative space per plant or per culm rather than the absolute space per plant or per culm was the determining factor; (7) grain weight and total weight per culm increased proportionally with logarithm of culm space and, hence, yield per unit area showed an optimum value at a culm density of about 2.7 x 106 culms per ha; (8) dry-matter distribution in the culms was largely independent of the size and the nutritive conditions of the culms, grain weight always being about 30% of total weight.-A.G.G.H. (Abstract retrieved from CAB Abstracts by CABI’s permission)