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Associative Nitrogen Fixation in Lowland Rice / Raj K. Shrestha in Nepal Agriculture Research Journal, Vol. 6 (2005)
[article]
Title : Associative Nitrogen Fixation in Lowland Rice Material Type: printed text Authors: Raj K. Shrestha, Author ; Maskey, S.L., Author Publication Date: 2005 Article on page: 112-121 p General note: Review paper Languages : English (eng) Keywords: Key words: Fertilizer, fixation, nitrogen, rice Abstract: Nitrogen (N), a most limiting nutrient, is the input required in the largest quantity for lowland
rice production. The concerns on N economy and efficiency and its impact on environment have
renewed interest in exploring alternative or supplementary N source for sustainable agriculture.
Several studies have indicated the existence of significant rice genotypic differences in N2
fixation stimulating traits (NFS). Rice genotypes with high NFS are desirable because they add N to
the soil-water-plant system without additional farm inputs and reduce dependence on fertilizer.
Large genotypic differences in percent N derived from air (% Ndfa) like 1.5% in Abang Basur, medium
maturing genotype, to 21% in Oking Seroni, late maturing genotype, indicates potential of isolating
genotypes with high NFS for sustainable agriculture. The exogenous supply of nitrogenous fertilizer
to lowland rice significantly inhibited N fixation but improved plant growth. Where as phosphorous
fertilizer did not affect atom % 15N excess and % Ndfa significantly but slight decrease in atom %
15N excess and increase in N2 fixation was observed. Inhibitory effect of exogenous supply of N
fertilizer indicates limited potential of associative N2 fixation to significantly benefit
agriculture. Farmers would have to withhold N fertilizer from their rice crop in order to increase
biological N2-fixation associated with rice. If they do such practice the plants will be N
deficient and might have a lower yield. However, the development of N fixation in response to a
deficiency of available N may well be an integral part of the N cycle of natural ecosystem and low
input farming system there by maintaining a N balance in the environment.Link for e-copy: http://elibrary.narc.gov.np/?r=70
in Nepal Agriculture Research Journal > Vol. 6 (2005) . - 112-121 p[article] Associative Nitrogen Fixation in Lowland Rice [printed text] / Raj K. Shrestha, Author ; Maskey, S.L., Author . - 2005 . - 112-121 p.
Review paper
Languages : English (eng)
in Nepal Agriculture Research Journal > Vol. 6 (2005) . - 112-121 p
Keywords: Key words: Fertilizer, fixation, nitrogen, rice Abstract: Nitrogen (N), a most limiting nutrient, is the input required in the largest quantity for lowland
rice production. The concerns on N economy and efficiency and its impact on environment have
renewed interest in exploring alternative or supplementary N source for sustainable agriculture.
Several studies have indicated the existence of significant rice genotypic differences in N2
fixation stimulating traits (NFS). Rice genotypes with high NFS are desirable because they add N to
the soil-water-plant system without additional farm inputs and reduce dependence on fertilizer.
Large genotypic differences in percent N derived from air (% Ndfa) like 1.5% in Abang Basur, medium
maturing genotype, to 21% in Oking Seroni, late maturing genotype, indicates potential of isolating
genotypes with high NFS for sustainable agriculture. The exogenous supply of nitrogenous fertilizer
to lowland rice significantly inhibited N fixation but improved plant growth. Where as phosphorous
fertilizer did not affect atom % 15N excess and % Ndfa significantly but slight decrease in atom %
15N excess and increase in N2 fixation was observed. Inhibitory effect of exogenous supply of N
fertilizer indicates limited potential of associative N2 fixation to significantly benefit
agriculture. Farmers would have to withhold N fertilizer from their rice crop in order to increase
biological N2-fixation associated with rice. If they do such practice the plants will be N
deficient and might have a lower yield. However, the development of N fixation in response to a
deficiency of available N may well be an integral part of the N cycle of natural ecosystem and low
input farming system there by maintaining a N balance in the environment.Link for e-copy: http://elibrary.narc.gov.np/?r=70 Characteristics of Ralstonia Solanacearum Strains of Potato Wilt Disease from Nepal and Thailand / Dhital, S.P. in Nepal Agriculture Research Journal, Vol. 4 (2000/2001)
[article]
Title : Characteristics of Ralstonia Solanacearum Strains of Potato Wilt Disease from Nepal and Thailand Material Type: printed text Authors: Dhital, S.P., Author ; N. Thaveechai, Author ; Sundar K. Shrestha, Author Publication Date: 2000 Article on page: 42-47 p Languages : English (eng) Keywords: Key words: Bacterial wilt, potato, Pseudomonas solanacearum, Ralstonia solanacearum Abstract: Characterization of strains of Ralstonia solanacearum, the causal agent of potato bacterial wilt
disease from Nepal and Thailand was performed based on pathogenicity,
biochemical/physiological and serological tests. Fifteen R. solanacearum strains isolated from wilt
infected potato plants and tubers grown in Nepal were characterized as race 3, biovar II based on
the pathogenicity on different host plants, hypersensitive reaction on tobacco leaf and utilization of
some sugars. Results of pathogenicity test show that all strains from Nepal had limited host range.
Degree of virulence of all strains varied from high to medium in potato and tomato and medium to
low in eggplant. They did not cause wilting in tobacco, pepper and peanut plants. Six strains from
Thailand were characterized as biovar II and III. Additionally, comparisons on the physiological,
biological and serological characters of seven strains from Nepal and six from Thailand revealed
similar characters. Race 3 and biovar II of the pathogen was widely spread over potato growing
areas of mid and high hills of Nepal. Both biovars II and III were prevalent in the potato growing
areas of Thailand but biovar III was the most dominating one.Link for e-copy: http://elibrary.narc.gov.np/?r=92
in Nepal Agriculture Research Journal > Vol. 4 (2000/2001) . - 42-47 p[article] Characteristics of Ralstonia Solanacearum Strains of Potato Wilt Disease from Nepal and Thailand [printed text] / Dhital, S.P., Author ; N. Thaveechai, Author ; Sundar K. Shrestha, Author . - 2000 . - 42-47 p.
Languages : English (eng)
in Nepal Agriculture Research Journal > Vol. 4 (2000/2001) . - 42-47 p
Keywords: Key words: Bacterial wilt, potato, Pseudomonas solanacearum, Ralstonia solanacearum Abstract: Characterization of strains of Ralstonia solanacearum, the causal agent of potato bacterial wilt
disease from Nepal and Thailand was performed based on pathogenicity,
biochemical/physiological and serological tests. Fifteen R. solanacearum strains isolated from wilt
infected potato plants and tubers grown in Nepal were characterized as race 3, biovar II based on
the pathogenicity on different host plants, hypersensitive reaction on tobacco leaf and utilization of
some sugars. Results of pathogenicity test show that all strains from Nepal had limited host range.
Degree of virulence of all strains varied from high to medium in potato and tomato and medium to
low in eggplant. They did not cause wilting in tobacco, pepper and peanut plants. Six strains from
Thailand were characterized as biovar II and III. Additionally, comparisons on the physiological,
biological and serological characters of seven strains from Nepal and six from Thailand revealed
similar characters. Race 3 and biovar II of the pathogen was widely spread over potato growing
areas of mid and high hills of Nepal. Both biovars II and III were prevalent in the potato growing
areas of Thailand but biovar III was the most dominating one.Link for e-copy: http://elibrary.narc.gov.np/?r=92 Management of Botrytis Gray Mold (Botrytis cinerea Pers. Ex. Fr.) of Chickpea at Tarahara, Nepal / Prem C.P. Chaurasia in Nepal Agriculture Research Journal, Vol. 4 (2000/2001)
[article]
Title : Management of Botrytis Gray Mold (Botrytis cinerea Pers. Ex. Fr.) of Chickpea at Tarahara, Nepal Material Type: printed text Authors: Prem C.P. Chaurasia, Author ; Sharada Joshi, Author Publication Date: 2000 Article on page: 37-41 p Languages : English (eng) Keywords: Key words: Botrytis gray mold, chickpea, Trichoderma Abstract: An experiment was conducted in randomized complete block design with six treatments and four
replications at loamy soil of Regional Agriculture Research Station, Tarahara, Nepal during
1997/98 and1998/99 seasons to find out the effect of bioagent Trichoderma viride as compared to
fungicide Bavistin (carbendazim) for management of Botrytis gray mold (Botrytis cinerea) of
chickpea (Cicer arietinum). Treatments were use of water spray (check), three sprays of T. viride
(10 7-108 spores/ml of water), three sprays of Bavistin @ 0.2%, three sprays of Bavistin @ 0.1%
+ T. viride, two sprays of Bavistin @ 0.2% and two sprays of T.viride. The area under the disease
progress curve (AUDPC) was the least (193.6) with three sprays of Bavistin (0.2%) followed by
two sprays of Bavistin (0.2%) and three sprays of Bavistin + T. viride (216.9). The highest mean
grain yield of 267.3 kg ha-1 was produced by three sprays of Bavistin + T. viride followed by
three sprays of Bavistin. Three sprays of T. viride was inferior to three and two sprays of Bavistin
but it was at par with two sprays of T. viride with respect to grain yield production and reduction
of Botrytis gray mold severity. When AUDPC was regressed against grain yield, a negative
correlation was obtained between the disease and the grain yield. The correlation coefficients for
the disease and yields during1997/98 and 1998/99 respectively were -0.583, and - 0.490.Link for e-copy: http://elibrary.narc.gov.np/?r=91
in Nepal Agriculture Research Journal > Vol. 4 (2000/2001) . - 37-41 p[article] Management of Botrytis Gray Mold (Botrytis cinerea Pers. Ex. Fr.) of Chickpea at Tarahara, Nepal [printed text] / Prem C.P. Chaurasia, Author ; Sharada Joshi, Author . - 2000 . - 37-41 p.
Languages : English (eng)
in Nepal Agriculture Research Journal > Vol. 4 (2000/2001) . - 37-41 p
Keywords: Key words: Botrytis gray mold, chickpea, Trichoderma Abstract: An experiment was conducted in randomized complete block design with six treatments and four
replications at loamy soil of Regional Agriculture Research Station, Tarahara, Nepal during
1997/98 and1998/99 seasons to find out the effect of bioagent Trichoderma viride as compared to
fungicide Bavistin (carbendazim) for management of Botrytis gray mold (Botrytis cinerea) of
chickpea (Cicer arietinum). Treatments were use of water spray (check), three sprays of T. viride
(10 7-108 spores/ml of water), three sprays of Bavistin @ 0.2%, three sprays of Bavistin @ 0.1%
+ T. viride, two sprays of Bavistin @ 0.2% and two sprays of T.viride. The area under the disease
progress curve (AUDPC) was the least (193.6) with three sprays of Bavistin (0.2%) followed by
two sprays of Bavistin (0.2%) and three sprays of Bavistin + T. viride (216.9). The highest mean
grain yield of 267.3 kg ha-1 was produced by three sprays of Bavistin + T. viride followed by
three sprays of Bavistin. Three sprays of T. viride was inferior to three and two sprays of Bavistin
but it was at par with two sprays of T. viride with respect to grain yield production and reduction
of Botrytis gray mold severity. When AUDPC was regressed against grain yield, a negative
correlation was obtained between the disease and the grain yield. The correlation coefficients for
the disease and yields during1997/98 and 1998/99 respectively were -0.583, and - 0.490.Link for e-copy: http://elibrary.narc.gov.np/?r=91 Socio-economic Study on Current Farmer's Practices on Wheat and Mustard Production Systems in Surkhet, Salyan and Doti Districts / Thakur, Naresh Singh in Nepal Agriculture Research Journal, Vol. 5 (2004)
[article]
Title : Socio-economic Study on Current Farmer's Practices on Wheat and Mustard Production Systems in Surkhet, Salyan and Doti Districts Material Type: printed text Authors: Thakur, Naresh Singh, Author ; Khadka, Ramji, Author Publication Date: 2004 Article on page: 49-55 p Languages : English (eng) Keywords: Key words: Farmer's practice, impact evaluation, mixed crops, socio-economic study Abstract: Wheat is one of the major cereal crops grown as a mono crop or mixed with mustard/lentil or pea
in the Mid and Far Western Development Regions. The main objective of the study was to explore
the existing cropping practices of wheat and mustard production systems and to establish a
benchmark for further impact evaluation. Three representative districts Surkhet, Salyan and Doti
were selected for the socio-economic study in wheat and mustard production system. A total of 92
households were surveyed (using two stage purposive random sampling method) in the districts
and information was also collected through RRA techniques. The total population of the surveyed
households was 744 with an average family size of 7.8, 8.3 and 8.3 persons in Surkhet, Salyan and
Doti, respectively. Brahmin/Chhetri (66%) and Gurung/Newar (1%) were the major and minor
groups, respectively. The total area of the surveyed households was 79.96 hectares with an
average farm size of 0.91, 1.02 and 0.60 hectare for Surkhet, Salyan and Doti respectively.
Recommendation was made to identify the technology on mixed cropping of wheat and mustard
for appropriate time of planting to maximize productivity of wheat and mustard crops without
disturbing the existing farmer's practices.Link for e-copy: http://elibrary.narc.gov.np/?r=79
in Nepal Agriculture Research Journal > Vol. 5 (2004) . - 49-55 p[article] Socio-economic Study on Current Farmer's Practices on Wheat and Mustard Production Systems in Surkhet, Salyan and Doti Districts [printed text] / Thakur, Naresh Singh, Author ; Khadka, Ramji, Author . - 2004 . - 49-55 p.
Languages : English (eng)
in Nepal Agriculture Research Journal > Vol. 5 (2004) . - 49-55 p
Keywords: Key words: Farmer's practice, impact evaluation, mixed crops, socio-economic study Abstract: Wheat is one of the major cereal crops grown as a mono crop or mixed with mustard/lentil or pea
in the Mid and Far Western Development Regions. The main objective of the study was to explore
the existing cropping practices of wheat and mustard production systems and to establish a
benchmark for further impact evaluation. Three representative districts Surkhet, Salyan and Doti
were selected for the socio-economic study in wheat and mustard production system. A total of 92
households were surveyed (using two stage purposive random sampling method) in the districts
and information was also collected through RRA techniques. The total population of the surveyed
households was 744 with an average family size of 7.8, 8.3 and 8.3 persons in Surkhet, Salyan and
Doti, respectively. Brahmin/Chhetri (66%) and Gurung/Newar (1%) were the major and minor
groups, respectively. The total area of the surveyed households was 79.96 hectares with an
average farm size of 0.91, 1.02 and 0.60 hectare for Surkhet, Salyan and Doti respectively.
Recommendation was made to identify the technology on mixed cropping of wheat and mustard
for appropriate time of planting to maximize productivity of wheat and mustard crops without
disturbing the existing farmer's practices.Link for e-copy: http://elibrary.narc.gov.np/?r=79 Sustaining Wheat Productivity and Maintaining Soil Fertility in Maize- Wheat System / Tripathi, B.P. in Nepal Agriculture Research Journal, Vol. 4 (2000/2001)
[article]
Title : Sustaining Wheat Productivity and Maintaining Soil Fertility in Maize- Wheat System Material Type: printed text Authors: Tripathi, B.P., Author ; Tuladhar, J.K., Author Publication Date: 2000 Article on page: 31-36 p Languages : English (eng) Keywords: Key words: Maize-wheat system, organic materials, soil fertility, sustainability Abstract: Field experiments on maize-wheat system were carried out in rainfed upland (bari) at Agricultural
Research Station, Lumle for three years (1994/95-1996/97) to determine the effect of different
quality organic materials on maize and wheat yields and soil properties. Wheat grain yield
significantly differed over years and the highest mean grain yield (1.98 t ha-1) was recorded in the
treatment of mixture of low and high quality organic materials (maize + leaf litter, farmyard
manure). Maize and wheat grain as well as straw yield significantly differed over years. In all the
three years, the mixture of low and high quality organic materials produced the highest grain yield
of maize plus wheat ranging from 6.72 to 2.20 t ha-1 with mean yield of 4.43 t ha-1. Mean N uptake
by wheat grain and straw ranged from 32.2 to 40.4 kg ha-1 and 13.8 to 16.0 kg ha-1, respectively in
different treatments. Similarly, mean P uptake by wheat grain was the highest (25.4 kg ha-1) in the
mixture treatment while mean P uptake by wheat straw was the highest (26.5 kg ha-1) in low
quality organic materials. Mean soil pH after wheat harvest was the lowest (5.1) in the low quality
organic material. Organic carbon and available P ranged from 3.4 to 3.7% and from 329 to 370
ppm, respectively in different treatments while total N and exchangeable K increased to 0.31%
and 0.2 me/100g, respectively with the application of low quality organic material. The three years
result showed that semi-decomposed organic materials were more efficient in improving and
stabilizing production of wheat and maize yields in maize-wheat system as well as in maintaining
N fertility than high quality organic materials.Link for e-copy: http://elibrary.narc.gov.np/?r=90
in Nepal Agriculture Research Journal > Vol. 4 (2000/2001) . - 31-36 p[article] Sustaining Wheat Productivity and Maintaining Soil Fertility in Maize- Wheat System [printed text] / Tripathi, B.P., Author ; Tuladhar, J.K., Author . - 2000 . - 31-36 p.
Languages : English (eng)
in Nepal Agriculture Research Journal > Vol. 4 (2000/2001) . - 31-36 p
Keywords: Key words: Maize-wheat system, organic materials, soil fertility, sustainability Abstract: Field experiments on maize-wheat system were carried out in rainfed upland (bari) at Agricultural
Research Station, Lumle for three years (1994/95-1996/97) to determine the effect of different
quality organic materials on maize and wheat yields and soil properties. Wheat grain yield
significantly differed over years and the highest mean grain yield (1.98 t ha-1) was recorded in the
treatment of mixture of low and high quality organic materials (maize + leaf litter, farmyard
manure). Maize and wheat grain as well as straw yield significantly differed over years. In all the
three years, the mixture of low and high quality organic materials produced the highest grain yield
of maize plus wheat ranging from 6.72 to 2.20 t ha-1 with mean yield of 4.43 t ha-1. Mean N uptake
by wheat grain and straw ranged from 32.2 to 40.4 kg ha-1 and 13.8 to 16.0 kg ha-1, respectively in
different treatments. Similarly, mean P uptake by wheat grain was the highest (25.4 kg ha-1) in the
mixture treatment while mean P uptake by wheat straw was the highest (26.5 kg ha-1) in low
quality organic materials. Mean soil pH after wheat harvest was the lowest (5.1) in the low quality
organic material. Organic carbon and available P ranged from 3.4 to 3.7% and from 329 to 370
ppm, respectively in different treatments while total N and exchangeable K increased to 0.31%
and 0.2 me/100g, respectively with the application of low quality organic material. The three years
result showed that semi-decomposed organic materials were more efficient in improving and
stabilizing production of wheat and maize yields in maize-wheat system as well as in maintaining
N fertility than high quality organic materials.Link for e-copy: http://elibrary.narc.gov.np/?r=90