Papers by Dibakar Mahanta
Journal of Plant Nutrition, 2015
ABSTRACT Carbon sequestration potential (CSP) and sustainability of gardenpea-french bean croppin... more ABSTRACT Carbon sequestration potential (CSP) and sustainability of gardenpea-french bean cropping system was assessed with farmyard manure (FYM) application vis-à-vis mineral fertilization as recommended NPK (NPK) and integrated nutrient management practices (INM) after six years’ cropping in Indian Himalayas. Application of 20 tons FYM ha−1 provided highest CSP (0.527 Mg C ha−1 year−1) in soil and sustainability index. With the help of quadratic equation, it was estimated that maximum profit (optimum yield) and turn over of invested money could be achieved with application of 20.0 and 15.6 t FYM ha−1, respectively. Application of 5.9 and 8.9 tons FYM ha−1 would substitute NPK and INM, respectively. Pod number plant−1 was the most important yield contributing attribute as found from principal component analysis. Pod yield could be modelled through multiple linear equation with help of yield attributes.
Field Crops Research, 2014
Phosphorus inflow rate Root cation exchange capacity Root length density Soybean VAM Wheat A B S ... more Phosphorus inflow rate Root cation exchange capacity Root length density Soybean VAM Wheat A B S T R A C T Alteration of crop root morphology is a new innovative approach to provide food security. Phosphorus is the most important nutrient to influence root properties. Efficient use of P fertilizers has become an important issue of agriculture all over the world due to limited availability of rock phosphate and its nonrenewable nature. Hence, root properties and grain yield of soybean-wheat cropping system were evaluated by inoculation of phosphate solubilizing bacteria (PSB) and vesicular arbuscular microorganism (VAM) with 50% recommended P (0.5 P + PSB + VAM) against 100% P (1.0 P), 50% P and control in a Typic Ustochrepts of the Indo-Gangetic plains. The root cation exchange capacity (CEC) of soybean and wheat treated with 0.5 P + PSB + VAM were 3.6 and 4.6% higher than 1.0 P, respectively. The same treatment produced 2.3 and 2.6% higher root length density (RLD) in soybean and wheat, respectively in comparison to 1.0 P. The P inflow rate under 0.5 P + PSB + VAM was 9.2 and 4.6% higher than 1.0 P in soybean and wheat, respectively indicating higher acquisition of P through VAM, although higher rhizospheric P availability was recorded in 1.0 P. The root CEC, RLD and P inflow rate were closely related to P concentration and content in root, shoot and nodule, specific root length, root diameter and internal P requirement. The better root property observed in 0.5 P + PSB + VAM enhanced 4.1 and 4.9% grain yield of soybean and wheat, respectively as compared to 1.0 P. Inoculation of PSB and VAM could substitute 50% P of soybean-wheat cropping system with better root property and higher grain yield in semi-arid sub tropics of the Indo-Gangetic plains.
Indian Journal of Weed Science, 2003
The study on system productivity, energy-use efficiency and economics of pigeonpea [Cajanus cajan... more The study on system productivity, energy-use efficiency and economics of pigeonpea [Cajanus cajan (L.) Mill
sp.]–based cropping systems, viz., pigeonpea–wheat {Triticum aestivum (L.) emend. Fiori & Paol.}, pigeonpea–
barley (Hordeum vulgare L.), pigeonpea–lentil {Lens culinaris (L.) Medicus, pigeonpea–field pea {Pisum sativum
(L.), sensu lato} and pigeonpea–toria {Brassica rapa (L.) var. toria} with comparise to rice (Oryza sativa L.)–wheat
cropping system was carried out at the Hawalbagh experimental farm of Vivekananda Parvatiya Krishi
Anusandhan Sansthan, Almora, Uttarakhand during 2007–2009, under rainfed conditions. Results showed that all
the pigeonpea–based cropping systems were superior to traditional rice–wheat cropping system in terms of system
productivity, net returns, benefit:cost ratio and net energy returns. Pigeonpea–lentil cropping system proved
superior in terms of system net returns ( 63,616/ha), benefit:cost ratio (1.64) and energy ratio (1.94) to
pigeonpea–wheat, pigeonpea–barley, pigeonpea–field pea and pigeonpea–toria cropping systems. Rice–wheat
cropping system recorded the lowest pigeonpea–equivalent yield (1.32 t/ha), net returns ( 2,750/ha) and
benefit:cost ratio (0.06). Nutrient status of the soil improved significantly due to pigeonpea–lentil cropping system
over other cropping systems. Pigeonpea–lentil cropping system proved to be the best in terms of monetary returns,
net energy return and soil productivity and hence, could be adopted in the north-west Himalayas under
rainfed conditions.
A field experiment was conducted during winter (rabi) seasons of 2008-09 and 2009-10 at Hawalbagh... more A field experiment was conducted during winter (rabi) seasons of 2008-09 and 2009-10 at Hawalbagh to evaluate the performance of lentil (Lens culinaris Medikus) and toria (Brassica campestris L. var. toria) intercropping with wheat (Triticum aestivum L. emend. Fiori & Paol.). Wheat + lentil in 2:1 and 1:1 row ratios were superior to sole wheat and wheat + toria intercropping. Lentil yield was higher in 1:1 (0.45 tonne/ha) than in 2:1 (0.31 tonne/ha). Similarly, toria recorded higher yield in 1:1 (0.41 tonne/ha) than in 2:1 (0.30 tonne/ha) ratio. The highest wheat-equivalent yield (5.24 tonnes/ha), net returns (Rs 36 770/ha), benefit: cost ratio (1.81), monetary advantage index (Rs 7 207) and land-equivalent ratio (1.19) were obtained with wheat + lentil under 2:1 row ratio followed by 1:1 ratio. Negative values of aggressivity under intercrop indicated that wheat was dominant, and lentil and toria were the dominated crops. Competitive ratio and relative crowding coefficient of wheat was higher under intercropping of wheat with lentil under 1:1 and 2:1 ratios, respectively. Relative crowding coefficient of the system was highest for wheat + lentil under 2:1 ratio intercropping (5.90). Similarly, water use efficiency (27.6 kg/ha-mm) was highest with wheat + lentil under 2:1 ratio.
This study examines the energy requirement and energy inputeoutput relationship of colocasia-base... more This study examines the energy requirement and energy inputeoutput relationship of colocasia-based cropping systems viz., Colocasiaeonionefrenchbean, colocasiaegardenpeaefrenchbean, colocasiae wheateokra, colocasiaeradishepotato, colocasiaecabbageefrenchbean, colocasiaecorianderecauliflowere frenchbean, colocasiaecorinderetomato and riceewheat in the Indian Himalayas. Results revealed that potato consumed the highest total input energy (25084 MJ/ha) and the least was in coriander (5108 MJ/ha). System productivity in terms of colocasia equivalent yield was highest with colocasiae onionefrenchbean system (52.38 t/ha). Mineral fertilizers (50e62%), seed (8e26%) and irrigation water (11e17%) consumed the bulk of the input energy for all cropping systems. The total input energy was highest under colocasiaeradishepotato (59919 MJ/ha) and the lowest in riceewheat (38244 MJ/ha). Colocasiaeonionefrenchbean, with the highest system productivity, produced the highest energy productivity (1.203 kg/MJ). Colocasiaecorianderetomato, with the highest system biomass, produced higher energy ratio (30.4), human energy profitability (2813.4) and energy profitability (29.43). Colocasiaewheateokra (1362928 MJ/ha) recorded the highest total energy output. Human energy profitability was highest under colocasiaecorianderetomato (2813.4) indicating that it was the most labor energy efficient cropping system. Hence, the colocasiaecorinderetomato and colocasiae onionefrenchbean cropping systems are more suitable in the Indian Himalayas for their higher energy use efficiency and energy productivity, respectively, and are advised for wide adoption.
A field experiment was carried out during 2000–01 to 2002–03, at Kendrapara, to study the effect ... more A field experiment was carried out during 2000–01 to 2002–03, at Kendrapara, to study the effect of nutrient
management on yield, nutrient uptake and economics of white jute (Corchorus capsularis L.)–rice (Oryza sativa
L.) cropping system in rainfed medium land. Application of 60 kg N, 30 kg P2O5 and 30 kg K2O/ha (recommended
dose for white jute) along with MgSO4. 7H2O @ 10 kg/ha + lime (0.5 lime requirement ) to jute crop recorded the
highest fibre yield (2.28 tonnes/ha), and maximum grain yield (3.89 tonnes/ha) of succeeding rice crop were obtained
with a fertilizer dose of 60 kg N, 30 kg P2O5 and 30 kg K2O/ha in the system. This resulted in an increased
yield of 26.7% in jute fibre and 10.2% of rice grain over the recommended fertilizer dose in both the crops. The
nutrient uptake (N,P,K, Ca, Mg and S) of individual crop and the system increased owing to NPK + 10 kg MgSO4.
7 H2O + lime (0.5 lime requirement) in jute, followed by rice with only recommended fertilizer dose in comparison
to other treatments. The maximum net returns (Rs 22,628/ha) and the highest benefit : cost ratio (1.71) were recorded
with the recommended NPK to both crops along with MgSO4 and lime to jute only in jute-rice cropping
system under rainfed condition
Carbon retention is a critical issue in arable farming of the Indian Himalayas. This study, condu... more Carbon retention is a critical issue in arable farming of the Indian Himalayas. This study, conducted from 2001 through 2010 on a sandy clay loam soil, evaluated the effect of tillage alterations (conventional tillage [CT] and zero tillage [ZT]) and selected irrigation treatments (I1: pre-sowing, I2: pre-sowing + active tillering or crown root initiation, I3: pre-sowing + active tillering or crown root initiation + panicle initiation or flowering, and I4: pre-sowing + active tillering or crown root initiation + panicle initiation or flowering + grain filling), applied at the critical growth stages to rice (Oryza sativa L.) and wheat (Triticum aestivum L.) on soil organic C (SOC) retention and its pools, soil aggregation, and aggregate-associated C contents in the 0-to 30-cm soil layer. Results indicate that the plots under ZT had nearly 17 and 14% higher total SOC and particulate organic C contents compared with CT (~9.8 and 3.6 g kg -1 soil) in the 0-to 5-cm soil layer after 9 yr of cropping, despite similar mean aboveground biomass yields of both crops on both CT and ZT plots. Tillage had no effect on C pools in the subsurface layers. Irrigation had positive impact on SOC content in the 0-to 5-and 5-to 15-cm layers. Although the labile pools of SOC were positively affected by ZT, the recalcitrant pool was not. Plots under ZT and I4 also had higher large and small macroaggregates and macroaggregate-associated SOC. Thus, adoption of ZT is the better management option for soil C improvement than CT, and irrigation generally enhances the positive impacts.
Sustainability of agricultural systems has become an important issue all over the world. Hence, s... more Sustainability of agricultural systems has become an important issue all over the world. Hence, sustainability and climate resilience of gardenpea-french bean cropping system was evaluated by yield trends, C sequestration and emission reduction and soil properties as affected by four application rates of farmyard manure (FYM) (5-20 t ha −1 ) vis-à-vis mineral fertilization, integrated nutrient management (INM) practices as 50% recommended NPK + FYM at 5 t ha −1 and un-amended control after six years of cropping in the Indian Himalayas. The highest sustainable yield index of 0.606 was achieved with the application of 20 t FYM ha −1 (FYM 20 ). The carbon sequestration potential of FYM 20 plots was about 459 and 193% more than NPK and INM plots, respectively. The same plots reduced 53 and 24% carbon equivalent emission with comparison to NPK and INM application, respectively. The soil cation exchange capacity (CEC) under FYM 20 plots was 22 and 11% higher than NPK and INM plots. The soil cracking volume under FYM 20 plots (57 cm 3 m −2 area) was very less compared to NPK (324 cm 3 m −2 area) and INM (154 cm 3 m −2 area) plots. The morning soil temperature (0-15 cm depth) in coldest week of last year experimentation under FYM 20 plots was moderated by 0.60 and 0.47 • C than NPK and INM plots, respectively. Successive increase of FYM level improved soil organic C, microbial colony formation unit, dehydrogenase activity, bulk density and soil cracking surface area and the best values for all soil properties were recorded under FYM 20 plots. Application of 20 t FYM ha −1 produced 54 and 29% higher gardenpea equivalent pod yield of the system than mineral fertilization and INM, respectively. The principal component analysis revealed that soil CEC was the most important property (among the selected soil parameters) contributing to the pod yield. Soil organic carbon markedly improved other soil properties as evident from correlations. Organic production system with FYM 20 t ha −1 could be recommended for climate resilient sustainable yield and better soil property of gardenpea-french bean cropping system than mineral fertilization and INM in the Indian Himalayan regions.
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Papers by Dibakar Mahanta
sp.]–based cropping systems, viz., pigeonpea–wheat {Triticum aestivum (L.) emend. Fiori & Paol.}, pigeonpea–
barley (Hordeum vulgare L.), pigeonpea–lentil {Lens culinaris (L.) Medicus, pigeonpea–field pea {Pisum sativum
(L.), sensu lato} and pigeonpea–toria {Brassica rapa (L.) var. toria} with comparise to rice (Oryza sativa L.)–wheat
cropping system was carried out at the Hawalbagh experimental farm of Vivekananda Parvatiya Krishi
Anusandhan Sansthan, Almora, Uttarakhand during 2007–2009, under rainfed conditions. Results showed that all
the pigeonpea–based cropping systems were superior to traditional rice–wheat cropping system in terms of system
productivity, net returns, benefit:cost ratio and net energy returns. Pigeonpea–lentil cropping system proved
superior in terms of system net returns ( 63,616/ha), benefit:cost ratio (1.64) and energy ratio (1.94) to
pigeonpea–wheat, pigeonpea–barley, pigeonpea–field pea and pigeonpea–toria cropping systems. Rice–wheat
cropping system recorded the lowest pigeonpea–equivalent yield (1.32 t/ha), net returns ( 2,750/ha) and
benefit:cost ratio (0.06). Nutrient status of the soil improved significantly due to pigeonpea–lentil cropping system
over other cropping systems. Pigeonpea–lentil cropping system proved to be the best in terms of monetary returns,
net energy return and soil productivity and hence, could be adopted in the north-west Himalayas under
rainfed conditions.
management on yield, nutrient uptake and economics of white jute (Corchorus capsularis L.)–rice (Oryza sativa
L.) cropping system in rainfed medium land. Application of 60 kg N, 30 kg P2O5 and 30 kg K2O/ha (recommended
dose for white jute) along with MgSO4. 7H2O @ 10 kg/ha + lime (0.5 lime requirement ) to jute crop recorded the
highest fibre yield (2.28 tonnes/ha), and maximum grain yield (3.89 tonnes/ha) of succeeding rice crop were obtained
with a fertilizer dose of 60 kg N, 30 kg P2O5 and 30 kg K2O/ha in the system. This resulted in an increased
yield of 26.7% in jute fibre and 10.2% of rice grain over the recommended fertilizer dose in both the crops. The
nutrient uptake (N,P,K, Ca, Mg and S) of individual crop and the system increased owing to NPK + 10 kg MgSO4.
7 H2O + lime (0.5 lime requirement) in jute, followed by rice with only recommended fertilizer dose in comparison
to other treatments. The maximum net returns (Rs 22,628/ha) and the highest benefit : cost ratio (1.71) were recorded
with the recommended NPK to both crops along with MgSO4 and lime to jute only in jute-rice cropping
system under rainfed condition
sp.]–based cropping systems, viz., pigeonpea–wheat {Triticum aestivum (L.) emend. Fiori & Paol.}, pigeonpea–
barley (Hordeum vulgare L.), pigeonpea–lentil {Lens culinaris (L.) Medicus, pigeonpea–field pea {Pisum sativum
(L.), sensu lato} and pigeonpea–toria {Brassica rapa (L.) var. toria} with comparise to rice (Oryza sativa L.)–wheat
cropping system was carried out at the Hawalbagh experimental farm of Vivekananda Parvatiya Krishi
Anusandhan Sansthan, Almora, Uttarakhand during 2007–2009, under rainfed conditions. Results showed that all
the pigeonpea–based cropping systems were superior to traditional rice–wheat cropping system in terms of system
productivity, net returns, benefit:cost ratio and net energy returns. Pigeonpea–lentil cropping system proved
superior in terms of system net returns ( 63,616/ha), benefit:cost ratio (1.64) and energy ratio (1.94) to
pigeonpea–wheat, pigeonpea–barley, pigeonpea–field pea and pigeonpea–toria cropping systems. Rice–wheat
cropping system recorded the lowest pigeonpea–equivalent yield (1.32 t/ha), net returns ( 2,750/ha) and
benefit:cost ratio (0.06). Nutrient status of the soil improved significantly due to pigeonpea–lentil cropping system
over other cropping systems. Pigeonpea–lentil cropping system proved to be the best in terms of monetary returns,
net energy return and soil productivity and hence, could be adopted in the north-west Himalayas under
rainfed conditions.
management on yield, nutrient uptake and economics of white jute (Corchorus capsularis L.)–rice (Oryza sativa
L.) cropping system in rainfed medium land. Application of 60 kg N, 30 kg P2O5 and 30 kg K2O/ha (recommended
dose for white jute) along with MgSO4. 7H2O @ 10 kg/ha + lime (0.5 lime requirement ) to jute crop recorded the
highest fibre yield (2.28 tonnes/ha), and maximum grain yield (3.89 tonnes/ha) of succeeding rice crop were obtained
with a fertilizer dose of 60 kg N, 30 kg P2O5 and 30 kg K2O/ha in the system. This resulted in an increased
yield of 26.7% in jute fibre and 10.2% of rice grain over the recommended fertilizer dose in both the crops. The
nutrient uptake (N,P,K, Ca, Mg and S) of individual crop and the system increased owing to NPK + 10 kg MgSO4.
7 H2O + lime (0.5 lime requirement) in jute, followed by rice with only recommended fertilizer dose in comparison
to other treatments. The maximum net returns (Rs 22,628/ha) and the highest benefit : cost ratio (1.71) were recorded
with the recommended NPK to both crops along with MgSO4 and lime to jute only in jute-rice cropping
system under rainfed condition