Plant Pathology Commons^™

Studies On Nitrogen Fixation Of Forage Grasses In Taiwan, K C. Lee

IGC Proceedings (1977-2023)

Experiments were conducted to determine the nitrogen(N)-fixing activities of the tropical forage grasses in Taiwan, the relationship between N-fixing activity and soil fertility and the morphological and the physiological properties of the associated bacteria. Hybrid napier grass (Pennisetum americanum X P. purpureum) cv.A7005 was the most effective in N fixation among 13 species of forage grasses,with 97 nmoles C2H4 per gram dry roots per hour. A negative correlation was found between N activity and total N content in soil. However, no relationship was observed between N-fixing activity and pH value, organic matter, and available P and K in …

Studies On Leucaena-Rhizobium Symbiosis On Northeast Thailand, J Homchan

IGC Proceedings (1977-2023)

A few studies on the symbiosis between Rhizobium and Leucaena leucocephala under soil and environmental conditions of Northeast Thailand are presented. The results obtained so far indicated that the response of high yielding introduced cultivars of L.leucocephala varied with the sources of inoculant used. The finding that some local Rhizobium isolates showed superior symbiotic performance compared with the introduced recommended strain implies that local strains may be of great potential especially for local use. Further study on the ecology of leucaena rhizobia will be useful in an attempt to increase the herbage yield of L.leucocephala through biological nitrogen fixation.

A Tentative For Appreciation Of The Nitrogen Nutrition Status In Grasses- Red Clover Mixtures Compared To Pure Stands, Noelle Amarger, A Mariotti, J Picard

IGC Proceedings (1977-2023)

In our country it is commonly accepted at the level of extension services that growing forage grasses and legumes mixtures can offer to the farmers a good opportunity to achieve high dry matter yield and good quality feed at a lower rate of input than growing pure grass stands. This is supposed to be so due to combination of the chief advan­tages coming from each component as far as their chemical composition and feeding value, the influence of their root system on soil structure, their mineral nutrition character­istics, ... are concerned. A number of experiments have been done, the results …

Effect Of Early Season Nitrogen On Nitrogen Fixation In A Ryegrass/ White Clover Pasture, P M. Murphy, P. Roger Ball

IGC Proceedings (1977-2023)

The effect of rate and time of nitrogen fertilizer application on nitrogen fixation by white clover (Trifolium repens) in a ryegrass sward was studied under field conditions in two consecutive years. Very different weather conditions prevailed over the two years resulting in contrasting seasonal patterns of nitrogen fixation. In 1983 only 30% of the total annual fixation rate was achieved by rate June and this pattern was reversed in 1984. Nitrogen fertilizer affected nitrogen fixation more than clover growth in 1983 but in 1984 a combination of fertilizer and drought reduced both clover growth and nitrogen fixation. At the highest …

Competition Effects On Nitrogen Fixation And Mineral N Uptake In Trifolium Repens L.- Lolium Perenne L. Associations, C P. West, K W. Steele, E A. Halligan

IGC Proceedings (1977-2023)

Improved While clover (Trifolium re pens L.) cul ti vars can potentially increase the input of nitrogen (N) from symbiotic fixation into clover-grass pastures and maintain elevated N2 fixation rates in the presence of nitrogenous fertilizers. The objective of this study was to determine the effects of interspecific competition on N2 fixation and mineral N uptake in white cover-perennial ryegrass (Lolium perenne L.) associations with either a medium-small ('Grasslands Huia') or large leaved ('G18') cultivar. The clover and grass were grown in a controlled environment room in pots that were partitioned to allow either no interspecific competition for shoots and …

Interspecific Differences In Sodium Nutrition Among Tropical Grasses, T Ando, Y Masaoka, K Matsumoto

IGC Proceedings (1977-2023)

In order to clarify interspecific differences in sodium (Na) accumulation and requirement, the following grasses were grown in the nutrient solution with 0-40 ppm Na for 4 weeks; Panicum coloratum (Coloured guineagrass: abbr. as CG, Kabulabula grass: KB and Makarikari grass: MK), P.maximum (green panic: GP and Guineagrass: GG), P. dichotomiflorum (fall panic: FP), Chloris gayana (Rhodes grass: RG), Echinochloa care-galli (Jananese millet: JM), Eleusine coracana ( African millet: AM) and Sorghum vulgare (Sorghum: SG). The ability to accumulate Na in shoots was ranked in the following order; KB and RG: high, GP and MK: intermediate, CG, GG, JM, …

Effect Of The K Fertilization On The N-Mineralization In A Grassland Soil And On The N-Uptake By Italian Ryegrass, I Campino

IGC Proceedings (1977-2023)

In a pot experiment with a hydromorph grassland soil enriched with organic matter containing tagged N and sown with Italian ryegrass N-mineralization and uptake with increasmg K fertilization were investigated. The N-mineralization and the mtnficatlon were promoted with increasing K fertilization. Because the K content of the plant was high enough to guarantee a healthy growth, the higher N uptake, a��d especi��lly the m��reased uptake of mineralized N from the + added organic matter, was attnbuted to the higher content of mmeral N m the sod and to a synergic interaction between K and NO3

Effect Of Invertebrates On Nitrogen Fixation In Temperate Pastures, K W. Steele, R N. Watson, P M. Bonish, R A. Littler, G W. Yeates

IGC Proceedings (1977-2023)

Annual nitrogen fixation in New Zealand pastures is well below its potential. The research reported is part of a programme directed towards identifying limitations to nitrogen fixation by the Trifolium repens-Rhizobium trifolii symbiosis. Sixteen field trials were conducted with tretments designed to provide selective control of various invertebrate pests of Trifolium repens. Measurements included herbage production, botanical composition, nitrogen fixation and root dissections. Application of pesticides significantly increased legume production, the number of nodules/g of Trifolium repens root and nitrogen fixation. Total N uptake in pasture herbage was increased by up to 118 kg N/ha/yr. The increase in nitrogen fixation …

Study Of Nitrogen Transfer From Alfalfa To Associated Timothy Under Field Conditions, M A. Faris, T C. Ta

IGC Proceedings (1977-2023)

In a forage cropping system (legume-grass), some of the nitrogen (N) which is fixed symbiotically by legumes is used by the associated grass. However, very few measurements of such transfer have been conducted under field conditions. The objective of this work was to estimate N transfer from alfalfa to associated timothy under field conditions, by using the 15N dilution technique. There was no significant difference in total N (T-N) content in timothy grown alone or in mixture at cut one. However, the effects of associated alfalfa became apparent at cuts two and three where T-N% increased by 15 to 38% …

The Fate Of Fertilizer Nitrogen Applied To Grass Sward In Japan- Influence Of Sward Age And Season Of The Year, T Kimura, K Kurashima

IGC Proceedings (1977-2023)

The seasonal uEtake of fertilizer nitrogen (N) and the annual fertilizer-N balance in cut orchard grass swards were studied by using the field SN-tracer method under humid temperate condition in Japan. 1) Fertilizer-N applied in early spring (for the first cut) and early summer (for the third cut) was readily absorbed by grass, but N applied in autumn (for the fifth cut) was slowly absorbed, the fact is considered to reflect on the efficiency of fertilizer-N. Much more fertilizer-N was recovered in grass (the total of top and root) of the first and third cut than in grass of the …

Maintenance Of Lolium Perenne L. In Mixture, K Sato, R Meguro, T Nomoto, M Nashiki

IGC Proceedings (1977-2023)

Lolium perenne L. (PRG) is one of the promising species in the northern Japan. However, this species is utilized less widely due to short persistency. The study was conducted to clarify the proper conditions for maintenance of this species in the context of defoliation treatments. The grasslands mixed with Dactylis glomerata L. (OG), Festuca arundinacea Schreb. (TF), Poa pratensis L. (KBG) and PRG were established and botanical composition of this mixture were measured in terms of Summed Dominance Ratio (SDR) under grazing (3 Japanese Black Cattle per ha) and cutting (3 times a year) conditions. PRG were maintained well …

Growth Analysis In The Regrowth Of Italian Ryegrass As Affected By Fertilization Level, K Watanabe, Y Sato, H Shirakawa, S Abe

IGC Proceedings (1977-2023)

Growth analysis was conducted to clarify the process of the regrowth, and the relation between LAI and plant height, percentage light penetration, CGR or NAR in the 2nd crops of Italian ryegrass (Lolium multiflorum) given 3 rates of fertilizer (20kg N + 10kg P205 + 17.5kg K20 ha-1, twice and 4 times). For the analysis, cubic regrassion curves were used, as they were fitted significantly by the changes of plant height, LAI, percentage light penetration and dry weight of whole plant with the regrowth. CGR (dt/dw) was obtained by the differentiation of cubic regression equation in the dry weight (w); …

Conditions For Raising The Yield Of Orchardgrass, S Kawashima

IGC Proceedings (1977-2023)

Up to the present, studies have been done on cutting height and plant length at the time of cutting. Concern with planting density, on the other hand, has been slight, with the result that reports which consider all three factors are almost non existent. Our field experiment considered these three aspects to determine the conditions for raising the yield of orchardgrass. Our perspective in the research was ecological.

The following points were recognized:

1) Long plants at cutting time are preferable to short ones.

2) Planting density should be high rather than low.

3) Cutting height must be low.

Cold Acclimation Of Alfalfa Cells In Suspension Culture, S Shibata

IGC Proceedings (1977-2023)

Effects of 2,4-D and kinetin on the growth of cells derived from alfalfa and their capacity to induce cold acclimation were investigated for the breeding of the cold hardy alfalfa using suspension culture. The yield was the highest in the modified Schnek and Hildebrandt medium containing 1 ppm 2,4-D and 0.5 ppm kinetin. Cells proliferated 12-fold in this medium at 26°C in the dark in ten days. Cells ceased growing during the cold acclimation and the pH in the medium kept unchanged. The cold hardiness of cells incubated at 1 °C in the dark increased during the first 20 days …

Grass Species Selection For Meadows Establishment, J V. Chlevickas, S J. Mikutenas

IGC Proceedings (1977-2023)

Observations have shown that due to better moisture supply perennial grasses grown on bog soils produce higher yields as compared with grass species grown on mineral soils. Nevertheless, at higher levels of N fertilization a number of grasses show poor winter hardiness, therefore, most of productive meadows must be reseeded, which requires high inputs and leads to significant yield losses in the year of reseeding. Furthermore, soil loosening causes peat mineralization, which is quite undesirable. In 1977-1980, at the Radviliskis Experimental Station a series of trials was carried out with the aim to determine grass species most suitable for meadows …

Effects Of High Temperature Stress On Growth And Digestible Dry Matter Content Of Timothy Cultivars, M Furuya, T Masutani, S Tsutsui

IGC Proceedings (1977-2023)

As part of a study on the adaptability of timothy cultivars to environmental conditions, the effects of high temperature stress on growth and digestible dry matter content were examined using the following cultivars: Kunpii (extremely early maturing), Senpoku (early), Nosappu (early), Erecta R. v. P. (medium), and Hokushu (late). Three levels of temperature treatment employed in this study were 23/18 (Tl), 31/26 (TI), and 31/31°C (T3) (day/night) for 10 days. High temperature treatment for 10 days resulted in an obvious decrease in dry weight and RGR at TI, which might be mainly caused by the decrease in NAR. These values …

Relationship Between Productivity And Canopy Structure During Reproductive Growth Stage In Dactylis Glomerata, Festuca Pratensis And F. Arundinacea, S Sagiyama, A Kusutani, N Takahashi, K Gotoh

IGC Proceedings (1977-2023)

The relationship between productivity and canopy structure during reproductive growth stage was examined in swards of three temperate grass species, Dactylis glomerata, Festuca pratensis and F. arundinacea. The relationship between extinction coefficient(K) and culm length depended on species, and the relation was positive in short-culmed species but negative in Jong-cul med one. The relationship between productivity and K during this stage was also inconsistent among three species. The relation was negative in D. glomerata, but positive in F. pratensis. And there was no clear relation in F. arundinacea. These relations were discussed in terms of the arrangement of leaves …

Physiological Characteristics Of Green Needlegrass (Stipa Viridula Trin.), Edward F. Redentre, Timothy E. Fulbright

IGC Proceedings (1977-2023)

Green needlegrass is commonly used in range seedings in the northern Great Plains in the United States (U.S.). Because of its potential as a revegetation species a series of experiments were conducted to determine 1) germination requirements; 2) capacity of seedlings for emergence and root growth following dehydration; and 3) influence of planting depth, seed source and temperature on seedling emergence and morphology. A variety of sources of green needle grass seed were used in growth chamber experiments following standard procedures. The results indicated that optimum temperatures for green needlegrass germination were 20°C (constant) and 20-15°C (16 hour-8 hour alteration) …

Relationship Between Soil Physics And Grass Roots Elongation, T Sugiura, H Kobatashi

IGC Proceedings (1977-2023)

Differences in soil strength and pore configuration between natural structure soil and compacted structure soil composed of volcanic ash soil and brown forest soil were compared, and their effects on the elongation of grass roots were examined. It was found that the soil strength and pore configuration of natural and compacted soils differed despite equal bulk density. Soil strength of natural soil was greater than that of compacted soil because the structure of natural soil was stable. On the other hand, compacted soil had continuous pores. Root growth in these soils of different structures was not hampered by soil containing …

Physiology Of Regrowth In Sorghum Bicolor Moench: Studies On The Sequential Action Of Hormones And Reserves, H Oizumi, Y Takasaki, H Nojima, Y Isono

IGC Proceedings (1977-2023)

As a hypothesis on the mechanism of the regrowth of sorghum plants, the sequential action of phytohormones and reserves was proposed.By application of cytokinin and sucrose to sorghum plants it was clarified that cytokinin was essential as a trigger for the growth of the lateral buds after cutting and the supply of sucrose to the buds was indispensable for the growth of buds afterwards. The cytokinin level of the stubble of sorghum plants was highest on the 1st day after cutting (Nojima et al., 1985) and that of buds was the highest on the second day after cutting. The detached …