Papers by Jagadish Timsina
Sustaining rice (Oryza sativa L.) productivity at high level is a great challenge, particularly i... more Sustaining rice (Oryza sativa L.) productivity at high level is a great challenge, particularly in areas where rice productivity declines in spite of following recommended nutrient management practices. Nutrient management by integrating organic manures, inorganic fertilizers and biofertilizers may play an important role in improving and sustaining rice productivity. In this study, the authors tried to evaluate the suitable proportion of organic manures and inorganic fertilizers along with biofertilizer to maximize growth and productivity of hybrid rice on sandy-loam lateritic soils of West Bengal, India. The crop having 50% recommended dose of fertilizer (RDF) + 50% recommended dose of nitrogen (RDN) through mustard oil cake (MOC) and 75% RDF + 25% RDN through MOC + biofertilizer significantly increased plant height, number of tillers/m 2 , leaf area index (LAI), dry matter accumulation (DMA) and crop growth rate (CGR) at initial and vital period of grain growth over those of 25% RDF + 75% RDN through MOC and 100% RDN through MOC. The former two treatments also increased number of panicles/m 2 and number of grains/panicle over those of only organic manuring (100% RDN) or only chemical fertilization (100% RDF) or 25% RDF + 75% RDN through MOC. Crop with 75% RDF + 25% RDN through MOC + biofertilizer or 50% RDF + 50% RDN through MOC produced 20.2%-33.8% higher grain yield and 11.0%-33.3% greater straw yield, and paid higher gross and net returns over other treatments. This study suggests growing hybrid rice with 75% RDF + 25% RDN through MOC + biofertilizer or 50% RDF + 50% RDN through MOC for better growth, higher productivity and greater profit.
Farmers need to increase irrigation water productivity to remain viable in the face of the increa... more Farmers need to increase irrigation water productivity to remain viable in the face of the increasing costs and decreasing availability of water. Wheat is the predominant winter cereal in the irrigated areas of the southern Murray-Darling Basin (SMDB). We used the model CSM-Wheat V4.0 to evaluate management options for increasing the water productivity of wheat. CSMwheat is derived from CERES-Wheat and CROPSIM-Wheat and embedded within the Decision Support System for Agro-technology Transfer (DSSAT V4.0).
Advances in Agronomy, 2005
Journal of the Institute of Agriculture and Animal Science, 2007
Soil Science Society of America Journal, 1997
Nitrogen dynamics and balances in intensive and diversified lowland rice (Oryza sativa L.)-based ... more Nitrogen dynamics and balances in intensive and diversified lowland rice (Oryza sativa L.)-based cropping systems that receive heavy fertilization, tillage, and irrigation have not been explored. Such information is essential to improve the efficiency of N fertilizer, an input based on a nonrenewable energy resource and whose oxidized products pose hazards to human health and the environment. Field experiments at an experimental farm on an Inceptisol and in two farmers' fields, one with an Inceptisol and one with a Vertisol soil, quantified (i) NO 3~-N and NtU-N in different soil layers in relation to waterfilled pore spaces (WFPS), (ii) N balance, and (iii) systems-level N efficiencies in several cropping patterns. Nitrate-N and NHJ-N were quantified monthly from July 1993 to June 1994. The WFPS remained <0.80 mL mL ' in the beginning of the wet season and throughout the dry season that enhanced nitrification. Ammonium-N in the 100cm layer was 20 to 40 kg ha" 1 in the wet season and 10 kg ha ' in the dry season. Nitrate-N, however, ranged from 27 to 54 and from 67 to 195 kg ha ' in the two seasons; it was higher in farmers' fields (192-195 kg ha" 1 ) than in the experimental farm (67-112 kg ha" 1 ). Total N loss was 34 to 549 kg ha" 1 across sites, with the largest in rice-sweetpepper (Capsicum annuum L. var. annuum) and ricetomato (Lycopersicon esculentum Miller). Despite a lack of a consistent trend in N efficiency among the different cropping systems, it was higher with tobacco (Nicotiana tabacum L.) and garlic (Alliiim sativum L.). There appears an opportunity to grow a NO^ catch crop during the dry-wet transition in rice-sweetpepper and rice-tomato systems to capture and recycle soil NOf-N.
Plant Production Science, 2005
Water shortage is a major constraint to sustaining and increasing the productivity of rice-wheat ... more Water shortage is a major constraint to sustaining and increasing the productivity of rice-wheat systems. Saving water can be elusive in that reducing seepage, percolation and runoff losses from fields does not necessarily save water if it can be recaptured at some other temporal or spatial scale, for example by groundwater pumping. Many technologies appear to save substantial amounts of water through reducing irrigation water requirement, but whether these are true water savings is uncertain as components of the water balance have not been quantified. Such technologies include laser levelling, direct drilling, raised beds, non-ponded rice culture and irrigation scheduling. It is questionable whether puddling saves water. Reducing non-beneficial evaporation losses is a true water saving, and optimal planting time of rice to avoid the period of highest evaporative demand and changing to non-ponded rice culture can save significant amounts of water. However, moving away from puddled, ponded to more aerobic rice culture sometimes brings new production problems. Furthermore, farmers faced with unreliable water supplies need to store water on their fields as insurance, and puddling assists retention of water during the rice crop. Rehabilitation and improvement of canal and power systems in Asia, funded by charging according to use, are required to facilitate adoption of many water saving technologies. Australian farmers pay fixed plus volumetric charges for water to cover the cost of infrastructure and operation of irrigation systems, which are continuously being improved to provide water on demand and minimise losses. They are able to plan their plantings based on knowledge of the likely amount of irrigation water available each season and crop water use requirement, and thus avoid wasting water and financial loss by overplanting and crop failure. Such approaches have the potential to increase production and water productivity in Asia, however the challenge would be to apply them in an equitable way that benefits many millions of subsistence farmers.
Field Crops Research, 2009
Raised beds are widely used in agriculture in developed countries and have proven to be an excell... more Raised beds are widely used in agriculture in developed countries and have proven to be an excellent option for wheat. Permanent raised beds may also offer benefits for rice-wheat (RW) systems in South Asia, in terms of both production and the possibility that furrow-irrigation may be more efficient than flood irrigation. The performance of a RW system on permanent raised beds (37 cm wide, 15 cm high, furrow width 30 cm) was compared with conventional cultivation on the flat on sandy loam and loam soils in replicated experiments in central Punjab, India. The experiments commenced with wheat sown in November 2002, and were continued for 8 crops.
Field Crops Research, 1994
Field Crops Research, 1994
Field Crops Research, 2001
Rice (Oryza sativa L.) and wheat (Triticum aestivum L.) are often grown in sequences under a rang... more Rice (Oryza sativa L.) and wheat (Triticum aestivum L.) are often grown in sequences under a range of nitrogen (N), water (W), and planting date in South Asia. Field experiments were conducted from 1994±1995 to 1996±1997 to de®ne the effects of two W and three N regimes on growth and productivity, N uptake and N-use ef®ciencies, and N balance for rice±wheat systems of northern Bangladesh. Mean grain yields of rice and wheat were greatest (4.9 and 3.1 t ha À1 , respectively) during the ®rst and smallest (2.2 and 2.4 t ha À1 , respectively) during the third year. The cultivars of rice and wheat responded to irrigation and to N, with greater response to irrigation in rice, but to N in wheat. Delayed wheat seeding reduced wheat yields in all years. Agronomic N-use ef®ciency (kg grain yield per kg N applied), physiological ef®ciency (kg grain yield per kg N absorbed), and fertilizer N-recovery ef®ciency (kg N absorbed per kg N applied, expressed as %) for rice across treatments ranged from 2.8 to 10.8, 5.2 to 27.5, and 33 to 61, respectively, and all were greater for N application at 90 compared with 135 kg N ha À1 . For wheat, those values ranged from 15 to 27, 33 to 51, and 45 to 63, respectively, and were greater at 120 compared with 180 kg N ha À1 , and under irrigation than rainfed. All those parameters had greater values under irrigation than rainfed. Total soil N increased slightly after 3 years of cropping, while organic carbon and pH decreased slightly in all treatments. There was a net increase of soil ammonium N (80 kg ha À1 ) and a zero balance of N after the ®rst year of cropping under irrigation with high N (135 and 180 kg ha À1 for rice and wheat, respectively), but without N there was a decrease of soil mineral N (70 kg ha À1 ) with a balance of 16 kg ha À1 . Biological N ®xation accounted for N balance in N-omitted as well as N-applied treatments. The results emphasize the need for regular monitoring of weather, crop performance, irrigation water, and soil and plant mineral N for further understanding the growth, productivity, N-use ef®ciencies, and balance in rice±wheat systems. #
Field Crops Research, 2006
Both intensification and diversification of cropping systems may allow improving the productivity... more Both intensification and diversification of cropping systems may allow improving the productivity and sustainability of agricultural production in the Indo-Gangetic Plain (IGP), but the choices to be made require integrated assessment of various cropping systems. A field experiment was conducted from 1999 to 2002 on a sandy clay loam (Inceptisol) to evaluate nine predominant cropping systems in West Bengal, India. Productivity, energy use efficiency, and nutrient uptake generally increased with increasing cropping intensity. Positive residual effects of potato and jute on yield and energy output of subsequently grown crops were observed as well as maintenance or improvement of soil properties such as soil organic matter, available P, and available K. The P balance was positive for most systems, except for jute-containing systems. However, negative K balances occurred due to almost complete removal of crop biomass in all systems, suggesting that recommended rates of applied K fertilizer were to low for sustaining soil K supply over the longer term. Cropping systems containing potato had the highest levels of yield, net return, benefit to cost ratio and energy productivity, but energy use efficiency was reduced due to higher energy consumption in these systems. Jute-wheat and jute-rapeseed-rice systems showed high energy use efficiency along with moderate cost and return. Based on economic considerations alone, jute-potato-rice, rice-potato-rice and rice-potato-sesame can be recommended as cropping systems for resource-rich growers in the eastern part of the IGP. Systems such as jute-wheat, rice-wheat and juterapeseed-rice appear to be most suitable for small and marginal farmers that cannot afford the large production costs associated with crops such as potato. #
European Journal of Agronomy, 2012
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.
European Journal of Agronomy, 2012
Photosynthetic aquatic biomass (PAB -algae and other floodwater flora) is a significant source of... more Photosynthetic aquatic biomass (PAB -algae and other floodwater flora) is a significant source of organic carbon (C) in rice-based cropping systems. A portion of PAB is capable of fixing nitrogen (N), and is hence also a source of N for crop nutrition. To account for this phenomenon in long term simulation studies of rice-based cropping systems, the APSIM modelling framework was modified to include new descriptions of biological and chemical processes responsible for loss and gain of C and N in rice floodwater. We used well-tested algorithms from CERES-Rice, together with new conceptualizations for algal dynamics, in modelling the contribution of PAB to maintenance of soil organic C and soil N-supplying capacity in ricebased cropping systems. We demonstrate how our new conceptualization of PAB growth, turnover, and soil incorporation in flooded rice systems facilitates successful simulation of long-term soil fertility trials, such as the IRRI Long Term Continuous Cropping Experiment (35+ years), from the perspectives of both soil organic carbon levels and yield maintenance. Previous models have been unable to account for the observed maintenance of soil organic C in these systems, primarily due to ignoring inputs from PAB as a source of C. The performance of long-term rice cropping system simulations, with and without inclusion of these inputs, is shown to be radically different. Details of our modifications to APSIM are presented, together with evidence that the model is now a useful tool to investigate sustainability issues associated with management change in rice-based cropping systems.
… International Symposium on …, 2001
To increase crop and soil productivity in rice-wheat cropping systems of Bangladesh, short durati... more To increase crop and soil productivity in rice-wheat cropping systems of Bangladesh, short duration mungbean crops are being considered for the wheat to rice transition period. Due to uncertainties in onset, frequency, and amount of pre-monsoon rainfall, these crops are often damaged by waterlogging, with its incidence and severity exacerbated by the presence of shallow watertables (SWT). This study examined the potential benefits of shallow sub-surface drainage on mungbean performance using the SWAGMAN Destiny simulation model. The model, validated for grain and biomass yields for a site in northern Bangladesh, was used to examine various planting dates and water table scenarios for irrigated mungbean crops. With drainage (at 50 cm depth), yields were greater under a SWT (50 cm), but without drainage, they were greater under a deep watertable (DWT, 500 cm) for all planting dates. In drained fields, the yields were greater for 30 April planting, but when undrained, they were greater for 15 March planting for both watertable scenarios. When crops were rainfed, yields were also greater when shallow drainage was provided. Smaller yields in all scenarios were associated with either high water deficit stress or waterlogging stress. Results indicate that mungbean productivity in rice-wheat systems in Bangladesh could be increased by managing water tables and selecting optimum planting time.
Final Report, ACIAR …, 2002
Page 1. Performance and application of CERES and SWAGMAN ® Destiny models for rice-wheat cropping... more Page 1. Performance and application of CERES and SWAGMAN ® Destiny models for rice-wheat cropping systems in Asia and Australia: a review J. Timsina and E. Humphreys May 2003 CSIRO Land and Water Technical Report 16/03 Page 2. ii ...
Australian Journal of Experimental Agriculture, 2006
Agronomy Journal, 2007
Insect feeding on leaves, pods, and seeds causes significant yield loss in soybean [Glycine max (... more Insect feeding on leaves, pods, and seeds causes significant yield loss in soybean [Glycine max (L.) Merr.]. Robust soybean growth models would be helpful to simulate the effect of defoliation or depodding on soybean growth and yield. The objective of this study was to evaluate the CROPGRO-Soybean model for its ability to predict the impacts of insect defoliation and depodding. Growth data were used to calibrate the model for two cultivars in Griffith, NSW, Australia. The model was evaluated against independent data from defoliation and depodding experiments at Griffith and at Gainesville, FL. The work tested the sensitivity of the model to defoliation and depodding at various growth stages, by comparison to data on manual defoliation of 30 and 60% in Australia and 30 and 70% in the USA, and depodding of 50 and 100% in Australia. The model predicted small yield reductions (4-11%) from 30% defoliation and greater reductions (17-49%) from 60 to 70% defoliation. The model illustrated well the pattern of sensitivity to defoliation: low during vegetative growth, increasing until beginning seed growth, and decreasing thereafter. The model overpredicted yield loss for severe defoliation but predictions improved after model modification to include photosynthetic contribution of green area of stems, petioles, and pods. Depodding predictions were generally accurate, but showed the need to evaluate model ability to add late pods after depodding. We conclude that the CROPGRO-Soybean model has adequate capabilities for use as a tool to predict the effects of timing and intensity of defoliation and depodding.
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Papers by Jagadish Timsina