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Dr. Roshan Babu Ojha
Nepal Agricultural Research Council

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Research Keywords & Expertise

0 Pedology
0 Soil carbon dynamic (modeling, stable isotopes)
0 Soil fertility and nutrient management
0 Soil carbon and nutrient cycling
0 Soil science ecology

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Soil carbon and nutrient cycling
Soil fertility and nutrient management

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Journal article
Published: 30 May 2021 in Sustainability
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Mustang valley in the central Himalaya of Nepal is a unique landscape formed by massive soil mass during a glacial period, which is attributed to a mix of vegetations and long agricultural history. Soil nutrients and their sourcing is highly important to understand the vegetation assemblage and land productivity in this arid zone. Twenty soil samples (from 0 to 20 cm depth) were collected from three landscape positions in Mustang district: valley, ridge, and midslope. We explored nutrient sourcing using natural abundance carbon (δ13C) and nitrogen isotope (δ15N) employing isotope ratio mass spectrophotometry. The results showed that the total soil carbon (TC) and total nitrogen (TN) ranged from 0.3 to 10.5% and 0.3 to 0.7%, respectively. Similarly, the CN ratio ranged from 0.75 to 15.6, whereas soil pH ranged from 6.5 to 7.5. Valley soil showed higher values of TN, CN, and soil pH than the ridge and midslope soils. The valleys had more positive δ15N signatures than ridge and midslope, which indicates higher inorganic and organic N fertilizer inputs in the valley bottom than in the midslope and ridge. This suggests that a higher nutrient content in the valley bottom likely results from agro-inputs management and the transport of nutrients from the ridge and midslope. Soil pH and CN ratio were a non-limiting factor of nutrient availability in the study regions. These findings are crucial in understanding the nutrient dynamics and management in relation to vegetation and agricultural farming in this unique topography of the Trans-Himalayan zone of Mustang in central Nepal.

ACS Style

Roshan Ojha; Sujata Manandhar; Avishesh Neupane; Dinesh Panday; Achyut Tiwari. Carbon and Nitrogen Sourcing in High Elevation Landscapes of Mustang in Central Nepal. Sustainability 2021, 13, 6171 .

AMA Style

Roshan Ojha, Sujata Manandhar, Avishesh Neupane, Dinesh Panday, Achyut Tiwari. Carbon and Nitrogen Sourcing in High Elevation Landscapes of Mustang in Central Nepal. Sustainability. 2021; 13 (11):6171.

Chicago/Turabian Style

Roshan Ojha; Sujata Manandhar; Avishesh Neupane; Dinesh Panday; Achyut Tiwari. 2021. "Carbon and Nitrogen Sourcing in High Elevation Landscapes of Mustang in Central Nepal." Sustainability 13, no. 11: 6171.

Research article
Published: 18 March 2021 in PLOS ONE
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Most of the soils of Nepal had a higher potassium (K, expressed as K2O) level inherently. Later in 1976, the Government of Nepal has recommended K fertilizer rate at 30 kg K2O ha-1 in rice-wheat cropping systems. However, those crops began showing K deficiency symptoms in recent decades, which could be due to a large portion of soils with depleted K level or the insufficient input of K fertilizer for crop production. This study explored a limitation of K nutrient in the crops by establishing field trials from 2009–2014 at three agro-ecozones i.e., inner-Terai (2009–2010), high-Hills (2011–2012), and Terai (2012–2014) in Nepal. Seven rates of K fertilizer at 0, 15, 30, 45, 60, 75, and 90 kg K2O ha-1 were replicated four times in a randomized complete block design, where crop yields and yield-attributing parameters of rice-wheat cropping system were recorded. Results revealed that an increase in K rates from 45 to 75 kg K2O ha-1 under inner-Terai and Terai conditions and 45 to 60 kg ha-1 under high-Hills conditions produced significantly higher grain yields compared to the recommended K dose. Economically, the optimum rate of K fertilizer should not exceed 68 kg K2O ha-1 for rice in all agro-ecozones, or 73 kg K2O ha-1 for wheat in inner-Terai and 60 kg K2O ha-1 for wheat in high-Hills and Terai. Our findings suggest to increase potassium application in between 1.5 to 2.5 times of the current K fertilizer rate in rice-wheat cropping system of Nepal that need to be tested further in different locations and crop varieties.

ACS Style

Roshan Babu Ojha; Shova Shrestha; Yajna Gajadhar Khadka; Dinesh Panday. Potassium nutrient response in the rice-wheat cropping system in different agro-ecozones of Nepal. PLOS ONE 2021, 16, e0248837 .

AMA Style

Roshan Babu Ojha, Shova Shrestha, Yajna Gajadhar Khadka, Dinesh Panday. Potassium nutrient response in the rice-wheat cropping system in different agro-ecozones of Nepal. PLOS ONE. 2021; 16 (3):e0248837.

Chicago/Turabian Style

Roshan Babu Ojha; Shova Shrestha; Yajna Gajadhar Khadka; Dinesh Panday. 2021. "Potassium nutrient response in the rice-wheat cropping system in different agro-ecozones of Nepal." PLOS ONE 16, no. 3: e0248837.

Article
Published: 17 March 2021 in Environmental Management
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Despite widely reported trends of agricultural land abandonment across many parts of the globe, this land use change phenomenon is relatively new in the context of Nepal. In recent years, rural farming communities in the hill region are gradually reducing the intensity of farming, leading to underutilisation and abandonment of agricultural lands. Adopting a mixed methods research approach, this study investigated the extent of agricultural land abandonment, its underlying causal drivers and perceived impacts in the hill agro-ecological region of Nepal. A structured survey of 374 households and six focus group discussions were carried out in three districts. The study revealed that around 40% of agricultural lands in the hill agro-ecological region have been abandoned and 60% of farmers have left at least one parcel of agricultural land abandoned. It was found that biophysical drivers (distance from homestead to parcel, slope of the parcel, land fragmentation, land quality and irrigation availability) and socio-demographic drivers (family size, higher education of the household members, domestic migration and out-migration) were responsible for agricultural land abandonment. Negative impacts of land abandonment were observed on the rural landscape, human-made farm structures, socio-economic systems, local food production and food security. In line with global studies, this research suggest that marginal land quality, demographic changes and rising alternative economic opportunities elsewhere contribute to farmland abandonment. This study also discusses land management approaches and policy implications to address the issue of agricultural land abandonment.

ACS Style

Yuba Raj Subedi; Paul Kristiansen; Oscar Cacho; Roshan Babu Ojha. Agricultural Land Abandonment in the Hill Agro-ecological Region of Nepal: Analysis of Extent, Drivers and Impact of Change. Environmental Management 2021, 67, 1100 -1118.

AMA Style

Yuba Raj Subedi, Paul Kristiansen, Oscar Cacho, Roshan Babu Ojha. Agricultural Land Abandonment in the Hill Agro-ecological Region of Nepal: Analysis of Extent, Drivers and Impact of Change. Environmental Management. 2021; 67 (6):1100-1118.

Chicago/Turabian Style

Yuba Raj Subedi; Paul Kristiansen; Oscar Cacho; Roshan Babu Ojha. 2021. "Agricultural Land Abandonment in the Hill Agro-ecological Region of Nepal: Analysis of Extent, Drivers and Impact of Change." Environmental Management 67, no. 6: 1100-1118.

Journal article
Published: 26 March 2019 in International Journal of Applied Sciences and Biotechnology
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A field experiment was conducted in an Inceptisols with sandy loam soil of the research farm of Agriculture and Forestry University, Rampur, Chitwan, Nepal from October 2016 to January 2017 to evaluate the effects of different sources of organic manure in growth and yield of radish. The experiment was carried out in a Randomized Complete Block Design with six treatments (Poultry manure, goat manure, FYM, biogas byproduct, recommended dose of fertilizer and control) and was replicated four times. Pyuthane Red variety (released on 1994) of radish was used as a test crop. After analysis of primary nutrients of the organic manures, the amount was fixed on the basis of recommended nitrogen (100 kg N per hectare) as a reference value. The application of organic manures significantly increased the plant height, number of leaves, leaf breadth, root length, root diameter and biomass yield. The highest biomass yield (75.16 Mg/ha) and highest root yield (49.41 Mg/ha) was obtained from poultry manure application which was similar with recommended rate of fertilizer. The study suggested that application of poultry was found more beneficial and significantly improved growth and yield of radish. Int. J. Appl. Sci. Biotechnol. Vol 7(1): 39-42

ACS Style

Keshar Bahadur Khatri; Roshan Babu Ojha; Keshab Raj Pande; Babu Ram Khanal. The Effects of Different Sources of Organic Manures in Growth and Yield of radish (Raphanus sativus L.). International Journal of Applied Sciences and Biotechnology 2019, 7, 39 -42.

AMA Style

Keshar Bahadur Khatri, Roshan Babu Ojha, Keshab Raj Pande, Babu Ram Khanal. The Effects of Different Sources of Organic Manures in Growth and Yield of radish (Raphanus sativus L.). International Journal of Applied Sciences and Biotechnology. 2019; 7 (1):39-42.

Chicago/Turabian Style

Keshar Bahadur Khatri; Roshan Babu Ojha; Keshab Raj Pande; Babu Ram Khanal. 2019. "The Effects of Different Sources of Organic Manures in Growth and Yield of radish (Raphanus sativus L.)." International Journal of Applied Sciences and Biotechnology 7, no. 1: 39-42.

Journal article
Published: 01 January 2019 in Cogent Food & Agriculture
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ACS Style

Dinesh Panday; Roshan Babu Ojha; Devraj Chalise; Saurav Das; Bikesh Twanabasu. Spatial variability of soil properties under different land use in the Dang district of Nepal. Cogent Food & Agriculture 2019, 5, 1 .

AMA Style

Dinesh Panday, Roshan Babu Ojha, Devraj Chalise, Saurav Das, Bikesh Twanabasu. Spatial variability of soil properties under different land use in the Dang district of Nepal. Cogent Food & Agriculture. 2019; 5 (1):1.

Chicago/Turabian Style

Dinesh Panday; Roshan Babu Ojha; Devraj Chalise; Saurav Das; Bikesh Twanabasu. 2019. "Spatial variability of soil properties under different land use in the Dang district of Nepal." Cogent Food & Agriculture 5, no. 1: 1.

Journal article
Published: 10 August 2018 in Journal of the Institute of Agriculture and Animal Science
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Vermicompost production technology uses half decomposed organic wastes to feed earthworms which produces nutrient enriched compost. Vermicompost production supports both organic waste management as well as organic farming. A research was conducted with the aim to assess the production and marketing aspect of vermicompost in Chitwan district during the year 2013. Interview schedule was used to collect information from all the 32 vermicompost producers within the study area and 32 adjacent non-producers were selected through snowball sampling. The total respondents' size was 64. The non-producers were farmers with few of them vermicompost users. Training on vermicompost production, group membership and type of farming were the significant factors affecting adoption of vermicompost production technology whereas the volume of earthworm reared and labor use were the significant factors affecting total income from vermicompost production. Resource use efficiency revealed that volume of earthworm reared and material cost were being over utilized but the labor use was underutilized. The volume of earthworm reared and labor use was to be increased by 300 % and 1.48 % respectively to obtain optimum economic advantage.Journal of the Institute of Agriculture and Animal Science. Vol. 33-34, 2015, page:19-26

ACS Style

D. Devkota; S. C. Dhakal; D. D. Dhakal; Roshan Babu Ojha. Assessment on factors affecting adoption and total income from vermicompost production in Chitwan, Nepal. Journal of the Institute of Agriculture and Animal Science 2018, 33, 19 -26.

AMA Style

D. Devkota, S. C. Dhakal, D. D. Dhakal, Roshan Babu Ojha. Assessment on factors affecting adoption and total income from vermicompost production in Chitwan, Nepal. Journal of the Institute of Agriculture and Animal Science. 2018; 33 ():19-26.

Chicago/Turabian Style

D. Devkota; S. C. Dhakal; D. D. Dhakal; Roshan Babu Ojha. 2018. "Assessment on factors affecting adoption and total income from vermicompost production in Chitwan, Nepal." Journal of the Institute of Agriculture and Animal Science 33, no. : 19-26.

Journal article
Published: 23 July 2018 in Advances in Plants & Agriculture Research
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ACS Style

Roshan Babu Ojha; Bikram Basyal; Baburam Khanal; Kesab Raj P. Nitrogen-Sulphur use economics in rapeseed productivity at Rampur, Chitwan, Nepal. Advances in Plants & Agriculture Research 2018, 8, 1 .

AMA Style

Roshan Babu Ojha, Bikram Basyal, Baburam Khanal, Kesab Raj P. Nitrogen-Sulphur use economics in rapeseed productivity at Rampur, Chitwan, Nepal. Advances in Plants & Agriculture Research. 2018; 8 (4):1.

Chicago/Turabian Style

Roshan Babu Ojha; Bikram Basyal; Baburam Khanal; Kesab Raj P. 2018. "Nitrogen-Sulphur use economics in rapeseed productivity at Rampur, Chitwan, Nepal." Advances in Plants & Agriculture Research 8, no. 4: 1.

Journal article
Published: 06 May 2018 in Journal of Nepal Agricultural Research Council
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Tomato is one of the most demanded vegetable with increasing trend of commercial cultivation in Nepal. As it is the heavy feeder crop thus soil nutrient management has been always challenging. Since, in modern world organic production has been favored by consumers for many reasons thus we aimed to compare the efficacy of various compost, mineral fertilizers and their combinations in tomato production and soil productivity. For the purpose a field experiment in plastic tunnel was carried out in Horticulture Research Division, Khumaltar in two consecutive years (2014 and 2015). Srijana, a popular tomato hybrid among commercial producers, was purposively selected. Eight treatments (control, recommended doses of chemical fertilizers, compost 15 t ha-1 + cattle urine, compost 10 t ha-1 + cattle urine, compost 12.5 t ha-1 + cattle urine, compost 15 t ha-1 + 1/4 recommended dose of chemical fertilizers, compost 10 t ha-1 + ¾ recommended dose of chemical fertilizer and compost 12.5 t ha-1 + 1/2 recommended dose of chemical fertilizer) were laid out in randomized complete block design and replicated thrice. The result showed significant (p < 0.05) positive correlation between the plant height and yield of tomato. The treatment with compost dose of 12.5 t ha-1 with half dose of recommended dose of chemical fertilizers produced the highest incremental yield (85% increment) over other treatments followed by compost 15 t ha-1 with cattle urine. Addition of soil organic carbon, soil nitrogen, soil potassium by the increasing level of compost though not significant, but increment in carbon content, nitrogen content and potassium content of soil observed in successive years. For commercial producer at plastic tunnel, compost at the rate 12.5 t ha-1 with half dose of recommended level of chemical fertilizer (100:90:40 kg N:P:K ha-1) is recommended to apply in field, while for organic producer, application of 15 tha-1 compost with fermented cattle urine is recommended.

ACS Style

Shova Shrestha; Roshan Babu Ojha; Navin Gopal Pradhan; Bishnu Dash Joshi. Performance of Tomato with Organic Manures in Plastic Tunnel. Journal of Nepal Agricultural Research Council 2018, 4, 1 -6.

AMA Style

Shova Shrestha, Roshan Babu Ojha, Navin Gopal Pradhan, Bishnu Dash Joshi. Performance of Tomato with Organic Manures in Plastic Tunnel. Journal of Nepal Agricultural Research Council. 2018; 4 (1):1-6.

Chicago/Turabian Style

Shova Shrestha; Roshan Babu Ojha; Navin Gopal Pradhan; Bishnu Dash Joshi. 2018. "Performance of Tomato with Organic Manures in Plastic Tunnel." Journal of Nepal Agricultural Research Council 4, no. 1: 1-6.

Journal article
Published: 01 December 2014 in International Journal of Scientific Research in Agricultural Sciences
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ACS Style

Roshan Babu Ojha; Shree Chandra Shah; Keshab Raj Pande; Durga Datta Dhakal. Residual Effects of Farm Yard Manure on Soil Properties in Spring Season, Chitwan, Nepal. International Journal of Scientific Research in Agricultural Sciences 2014, 1, 165 -171.

AMA Style

Roshan Babu Ojha, Shree Chandra Shah, Keshab Raj Pande, Durga Datta Dhakal. Residual Effects of Farm Yard Manure on Soil Properties in Spring Season, Chitwan, Nepal. International Journal of Scientific Research in Agricultural Sciences. 2014; 1 (8):165-171.

Chicago/Turabian Style

Roshan Babu Ojha; Shree Chandra Shah; Keshab Raj Pande; Durga Datta Dhakal. 2014. "Residual Effects of Farm Yard Manure on Soil Properties in Spring Season, Chitwan, Nepal." International Journal of Scientific Research in Agricultural Sciences 1, no. 8: 165-171.

Journal article
Published: 25 June 2014 in International Journal of Applied Sciences and Biotechnology
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Two experiments were carried out in a Randomized Complete Block Design with six treatments (0, 10, 20, 30, 40, 50 Mg FYM ha-1) replicated four times at the horticultural farm, IAAS, Rampur, Chitwan, Nepal in winter (Oct-Jan) and spring (Feb-May) seasons to quantify optimum dose of organic manure (FYM) to maintain earthworm population and enhance soil properties. In each treatment 100 earthworms (Eisenia fetida) were inoculated within one square meter of each plot. Porosity in the first season was significantly higher than the control treatment (0 Mg FYM ha-1). In the second season it remained unaffected but in increasing trend. In the second season the highest porosity (40.75 ± 1.57%) was obtained from 50 Mg FYM ha-1. The highest bulk density (1.553 ± 0.017 Mg m-3) in the second season was observed from the control treatment but it was in decreasing trend with increasing doses of FYM. There was no significant effect of FYM on pH in the either season. The highest OM (3.87 ± 0.22%) was observed from 50 Mg FYM ha-1 which was similar to 30 and 40 Mg FYM ha-1 in first season. Similarly, in the second season, increasing doses of FYM increased the OM and the highest OM (3.83 ± 0.19%) was from 50 Mg FYM ha-1 which did not differ from 40 Mg FYM ha-1. As anticipated, the lowest OM 2.425 ± 0.224% and 2.275 ± 0.1968% were from control treatments of the first and second seasons, respectively. As the doses of FYM were increased, earthworm populations were also increased significantly in the both seasons. Earthworm numbers from 50 Mg FYM ha-1 were significantly higher than the 20, 30 and 40 Mg FYM ha-1 in both seasons. The highest numbers 887 ± 12.84 and 976 ± 20.30 of earthworm per square meter were recorded from 50 Mg FYM ha-1 in the both seasons, respectively. Thus, the application of 30 Mg FYM ha-1 is optimum for both the seasons to improve soil properties and to maintain earthworm population in the agricultural field. Also, this research indicated a possibility for earthworm inoculation in the field to enhance soil fertility for sustainable agriculture in the western Chitwan, Nepal. DOI: http://dx.doi.org/10.3126/ijasbt.v2i2.10474Int J Appl Sci Biotechnol, Vol. 2(2): 193-198

ACS Style

Roshan Babu Ojha; Shree Chand Shah; Keshab Raj Pande; Durga Datta Dhakal. Soil Properties and Earthworm Population Dynamics Influenced by Organic Manure in Winter and Spring Seasons at Rampur, Chitwan, Nepal. International Journal of Applied Sciences and Biotechnology 2014, 2, 193 -198.

AMA Style

Roshan Babu Ojha, Shree Chand Shah, Keshab Raj Pande, Durga Datta Dhakal. Soil Properties and Earthworm Population Dynamics Influenced by Organic Manure in Winter and Spring Seasons at Rampur, Chitwan, Nepal. International Journal of Applied Sciences and Biotechnology. 2014; 2 (2):193-198.

Chicago/Turabian Style

Roshan Babu Ojha; Shree Chand Shah; Keshab Raj Pande; Durga Datta Dhakal. 2014. "Soil Properties and Earthworm Population Dynamics Influenced by Organic Manure in Winter and Spring Seasons at Rampur, Chitwan, Nepal." International Journal of Applied Sciences and Biotechnology 2, no. 2: 193-198.

Review
Published: 01 January 2014 in World Journal of Agricultural Research
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Earthworms can alter the soil environment by changing soil properties. They have great potentiality to enhance soil physical properties like bulk density, infiltrability, hydraulic conductivity, porosity, aggregate stability. Due to this ability they are only species which plays significant role in pedoturbation. Similarly, their role in nutrient cycling and organic matter breakdown is of unique interest. Earthworm cast fortified with the microbial population. Increasing microbial activity in soil, increases the nutrient mineralization and release. Earthworm activity enhances root distribution so that immobile macro nutrients like phosphorous and other micronutrients, which are absorbed by plant through root interception, are easily available to the plants. Hence, earthworms play important role in bioturbation, they are considered as 'soil engineer.' However, their activity differs with the agroecosystems. Their population density is more in reduced tillage system than conventional tillage system, aerobic condition than anaerobic conditions, grasslands than forest. Low population of earthworm was found in dry land agroecosystems. But earthworm presence in extreme environment is not studied well yet. So, this paper was reviewed to explore the role of earthworm as soil and ecosystem engineer. This was already established fact but main aim of this paper is to collect the related information and conclude the future research prospects to strengthen the earthworm role as soil and ecosystem engineer.

ACS Style

Roshan Babu Ojha; Deepa Devkota. Earthworms: 'Soil and Ecosystem Engineers' – a Review. World Journal of Agricultural Research 2014, 2, 257 -260.

AMA Style

Roshan Babu Ojha, Deepa Devkota. Earthworms: 'Soil and Ecosystem Engineers' – a Review. World Journal of Agricultural Research. 2014; 2 (6):257-260.

Chicago/Turabian Style

Roshan Babu Ojha; Deepa Devkota. 2014. "Earthworms: 'Soil and Ecosystem Engineers' – a Review." World Journal of Agricultural Research 2, no. 6: 257-260.