Bihar Agricultural University, Sabour

Bihar Agricultural University, Sabour established on 5th August, 2010 is a basic and strategic institution supporting more than 500 researchers and educationist towards imparting education at graduate and post graduate level, conducting basic, strategic, applied and adaptive research activities, ensuring effective transfer of technologies and capacity building of farmers and extension personnel. The university has 6 colleges (5 Agriculture and 1 Horticulture) and 12 research stations spread in 3 agro-ecological zones of Bihar. The University also has 21 KVKS established in 20 of the 25 districts falling under the jurisdiction of the University. The degree programmes of the university and its colleges have been accredited by ICAR in 2015-16. The university is also an ISO 9000:2008 certified organisation with International standard operating protocols for maintaining highest standards in teaching, research, extension and training.VisionThe Bihar Agricultural University was established with the objective of improving quality of life of people of state especially famers constituting more than two third of the population. Having set ultimate goal of benefitting society at large, the university intends to achieve it by imparting word-class need based agricultural education, research, extension and public service.

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Open Access
Soil Resources Mapping of Sabour Block of Bhagalpur District, Bihar
(Department of Soil Science (Agril. Chemistry), BAU, Sabour, 2020) Bagoria, Neeraj; Vimal, B. K.
The present study entitled “Soil Resources Mapping of Sabour block of Bhagalpur district, Bihar” represented the soil fertility status and Land Capability Classification. Soil profiles viz. P1, P2, P3 and P4 predominantly were taxonomically observed in three orders namely, Entisols, Inceptisols and Vertisols under investigation and varied from sandy loam in Diara land to clay in Tal land. However, textural class as clay loam was found in agricultural land followed by silt loam under horticultural land. In context of soil fertility, the soil pH of the study area ranged from 6.5 to 8.53 (mean value of 7.52) and 90 per cent of the soil samples categorized under neutral range. The electrical conductivity (EC) varied from 0.10 to 0.160 dSm-1 which comes under almost non saline in nature. The calcium carbonate content in soil ranged from non- calcareous (0.5-1.0 %) to calcareous (>10 %). The range of organic carbon was observed medium (2.05), available nitrogen was low (1.09), available phosphorus was medium (2.11) and available potassium was high (2.70). However, The DTPA Iron content of the study area was very high and sufficient in Copper and Manganese content. But, Zinc deficiency was observed in all Panchayats. In this context, the availability of Copper, Iron, Manganese and Zinc were seen to be decreased with growing pH values. In context of land capability class, the study was placed under class IIIw in Tal and Diara lands which are assessed under flood and water logging during monsoon. However, agricultural land and horticultural lands put under class III followed by class IV. The present investigation helped how to trace out the actual agricultural land out of the total geographical area under RS-GIS domain that dealt the actual mapping for soil fertility status up to block and panchayat level which may be helpful for the management of agricultural land under cereals, pulses, oilseeds and vegetables crops. In view of analyzed facts, maps over soil fertility status may be also helpful towards refinement of the supply chain of the nitrogenous fertilizers.
Open Access
Fractionation of inorganic Arsenic and determination of its safe limit in irrigation water in rice
(Department of Soil Science and Agricultural Chemistry, BAU, Sabour, 2020) : Kumari, Preety Bala; Singh, Y. K.
A pot experiment was conducted with two soil types (alluvial and red) using ten levels (of contaminated irrigation water (0, 0.25, 0.5, 0.75, 1.0, 1.25, 1.50, 1.75, 2.0, 2.25 mg L-1), irrigated for 5 times using rice (Variety: Sushak Samrat) as a test crop to determine the safe limit for irrigation water contaminated with As. The increase in the level of contamination in the irrigation water significantly affected the yield attributing characters and yield in both the soils. The results reveal that the different fractions of arsenic, water soluble arsenic (F1), Aluminium bound arsenic (F2), amorphous iron bound arsenic (F3), crystalline iron bound arsenic (F4) and Calcium bound arsenic (F5)in terms of its profusion followed the order F4 > F2 > F5 > F3 > F1 and F4 > F3 > F2 > F5 > F1across all the doses of As for alluvial soil and red soil respectively. The safe limit of irrigation water in terms of risk assessment expressed as Hazard Quotient (HQ) was 0.75 mg L-1 and the solubility FIAM can effectively predict the As content in rice grain in both the soils. The Tobit Regression Model, which is a censored model served as an effective tool in predicting the safe limit of irrigation water based on the inherent soil As content. In alluvial soil the safe limit for As in irrigation water is from 1.20 to 0.10 mg L-1 and for red soil, the range is from 0.10 to 0.40 mg L-1 based on the available soil As and provided that the As content in rice grain is < 0.4 mg Kg-1. This can be used as an effective protocol for estimation of safe limits for irrigation water which will vary for diverse soils having varied physio-chemical properties acting as a sink and plays the role for water-soil-food transfer of the contaminant.
Open Access
Adsorption-Desorption behaviour of sulphur under conservation agriculture
(Department of Soil Science and Agricultural Chemistry, BAU, Sabour, 2020) Kumari, Kirti; Shambhavi, Shweta
Sulphur is the essential secondary macronutrient element required for optimum growth, metabolism and development of all plants and is rightly called as fourth major plant nutrient. It is essential for synthesis of amino acid like methionine, cystine and cysteine and resembles Nitrogen for many functions in plant and synergistic to N fixation and nodule development in legume. In soil S mostly remains in organic combination, constituting more than 95 % of total sulfur. Sulphate sulfur is the form plant prefers to uptake and its availability depends upon the mineralization of organic sulfur in soil. Soil tillage is the basic and key to reducing soil-related constraints in crop production. It has a long-term effect on soil properties and crop growth. CA systems are currently being practiced on a wide range of soil types, environments and numerous crops and cropping systems. Because of the possibilities to increase productivity and improve soil health, CA becomes a crucial part of the national polices for an agricultural production system. Adsorption desorption characteristics are useful for describing, studying and managing the sulfur status of soils.The concentration of sulphate in soil solution, as predicted by sulphate sorption-desorption curve provides a valuable information on sulfur availability to crop plants. The experimental soil was sandy loam in texture, neutral in reaction, low in N, medium in organic carbon and K and high in available P. As per taxonomic classification the soil falls under the order “Inceptisols”. The soil samples from the depth of 0-20 cm was collected from the field experiment on conservation agriculture with six maize based cropping systems and three tillage practices laid out in split plot design with tillage practices being main plot and cropping system in sub-plots replicated thrice. The samples were collected before Maize in Kharif 2019 and analysed for various soil physico-chemical properties, available N, P and K, total N, free Fe and Al oxides as well as different forms of sulphur and adsorption and desorption behaviour of sulphur in soil. Continuous practice of reduced tillage and different cropping systems led to improvement in soil physico-chemical properties such as soil pH, OC, available N, P, K, S, total N, and free iron and aluminum oxide. Among the different forms of sulphur studied it was found that all the forms were higher under zero tillage and soybean-maize cropping system except adsorbed sulphur which was higher under conventional and maize-maize cropping system. Available Sulphur, Water soluble sulphur (WSS), Heat Soluble Sulphur (HSS), Adsorbed Sulphur (AdS) and Organic sulphur (OS) was on an average 3.99, 3.57, 11.38, 3.67 and 64.06 %, respectively of Total Sulphur. Amongst all the forms studied, Organic Sulphur was the most dominant form of Sulphur. Maize yield and uptake was found to have positive and significant correlation with all the forms of S except adsorbed as it’s not a bioavailable form. The adsorption data was best fitted in Langmuir equation as per the R2 values are concerned. The adsorption maxima followed the order CT>PRB>ZT under tillage system and for cropping system the highest adsorption was in maize-wheat system. The adsorption data also fitted well in Freundlich isotherm having higher R2 values. The extent of adsorption followed similar order as observed as that in case of adsorption maximum under Langmuir isotherm. In terms of adsorption maxima (Langmuir) and the extent of adsorption (Freundlich) the tillage practices followed the order CT>PRB>ZT while cropping systems were in the order of C2>C5>C3>C4>C1> C6.While, desorption of S was observed to be minimum under CT followed by PRB followed by ZT. While in terms of cropping system, the minimum was in maize-maize while maximum under soybean-maize across all tillage systems. It can be concluded that zero tillage and soybean-maize cropping system performed better in increasing the sulphur status of soil and the linear plot of the adsorption data were good fitted in both Langmuir and Freundlich equation with best fit in Langmuir equation.
Open Access
Revisiting the nutrient composition of composts prepared with prevailing practices in Bhagalpur
(Department of Soil Science and Agricultural Chemistry, BAU, Sabour, 2017-07) Yadav, Rajeev Ranjan; Dwivedi, M. K.
Soil fertility maintenance is very essential in achieving and maintaining high crop yields. Decline in soil fertility is becoming increasingly critical to secure sustainable soil productivity. Compost prepared from farm waste is an important input that contributes to soil fertility. Compost samples were collected as prepared by the farmers through prevailing practices in 6 blocks of Bhagalpur namely Goradih, Sanhaula, Kahalgaon, Rangra, Kharik and Naugachhia and were analysed for their nutrient status. Among the selected blocks, some farmers of Rangra block have used bedding material of maize stalk for composting. However, many farmers of the Rangra block wanted to use it for fodder. The C:N ratio of composts prepared at Rangra block were minimum as compared to rest of the blocks. Farmers of other blocks also used bedding materials, but the materials were not suitable for the same. The objective of some of the farmers was to get rid of farm waste rather than using it for composting to take benefit from it. The type of materials available for different farmers was different. Some of them were very cautious about the nutrient value of the compost and wanted to replace chemical fertilisers with it. However, they knew that using only compost in their farms could not supply the required amount of nutrients to the crop but they were keen to make beneficial use of farm waste in the form of compost. The farmers’ composts in selected blocks of Bhagalpur were not free from chemical fertilizers, plastics, metals, glasses and dry cells. Care must be taken to avoid any contamination from heavy metals, plastics etc.
Open Access
Soil properties and nutrient uptake by rice under different fertigation regimes in rice based cropping systems
(Department of Soil Science & Agricultural Chemistry, BAU, Sabour, 2017-07) Basak, Piu; Kohli, Anshuman
Nutrient and water management are important for diversifying and intensifying the rainfed rice based cropping systems. A fertigation experiment in split plot design was laid out at the farm of BAC, Sabour in 2014 with three levels of fertigation in main plots (nitrogen levels as fertigation @ 20, 40, and 60 kg ha-1 in rice and irrigation levels @ 200, 300 and 400 mm in post rice crops) and four rice based cropping systems as sub plot treatments (rice followed by either durum wheat, barley, lentil or chickpea). The third year rice crop in the system was used for taking observations on growth and yield, soil physical and chemical parameters and nutrient uptake in terms of N, P and K using standard methods. Fertigation levels and cropping systems can be significant determinants of crop yields. They also have distinct influences on soil conditions and nutrient relations. Most of the significant influences are cyclic, being observable only during a part of the year. Rice grain yield was significantly greater under higher fertigation regimes. Steady state infiltration rate was found higher under rice-legume cropping systems in comparison to any of the rice-cereal cropping systems (i.e. rice-durum wheat and rice-barley) but no influences of fertigation and cropping systems on bulk density were observable. Fertigation regimes and cropping systems can influence the profile penetration resistance. Maximum water holding capacity of surface soil after the harvest of rabi season crops was significantly greater under the higher fertigation regimes. Soil organic carbon was reduced in rice legume cropping systems, likely because of greater rate of organic matter decomposition under higher nitrogen fixation as well as due to the effect of heterotrophic Rhizobia colonising the legume roots. Nitrogen availability at the start of the rice growing season aka. left over available nitrogen by the rabi season crops in the sub-soil layers was significantly greater in treatments receiving less irrigation during the rabi season. Cropping systems influenced the availability of nitrogen in the soil after rice harvest as a result of differential nitrogen applications and contributions of the preceding crops and followed the trend rice-chickpea < rice - durum wheat < rice-barley = rice-lentil cropping systems. The available nitrogen content in the 15-30 cm and 30-45 cm soil layer was also significantly lower in rice-chickpea cropping system in comparison to other cropping systems. Before rice crop establishment, the average P availability in the surface soil and at the depth of 15-30 cm in the soil followed the trend rice-lentil > rice-chickpea > rice-durum wheat = rice-barley cropping systems. At the depth of 30-45 cm, rice barley cropping system exhibited statistically lower availability of P in comparison to other cropping systems. This again shows the probable effect of heterotrophic Rhizobia, which act as phosphate solubilizers while consuming soil available nitrogen in decomposing organic matter. Available K was found to be statistically similar across various fertigation regimes and cropping systems. N fertigation @ 60 kg ha-1 and 40 kg ha-1 demonstrated significantly greater nitrogen uptake by rice grains in comparison to 20 kg ha-1, which is due to significantly greater rice grain yield under these treatments. P content in rice straw was found to be lower with 40 kg ha-1 and 60 kg ha-1 N fertigation compared to 20 kg ha-1 N fertigation because of the dilution effect under greater N application. P uptake by rice grains was significantly greater in rice-lentil and rice-durum wheat cropping systems in comparison to rice-chickpea and rice-barley cropping systems which probably is the result varying rates of P addition and extraction resulting in greater P availability in certain treatments at the start of the season. K content in rice straw was found to be significantly more in rice- durum wheat cropping system compared to rest three cropping systems. This resulted in low K availability after harvesting of rice in rice -durum wheat cropping system than other cropping systems. K content in rice straw was greater in rice-durum wheat cropping system because of greater application of potassic fertilizer (MOP) cumulated over both rabi and kharif seasons. A significant effect of cropping systems on the internal nutrient use efficiency of P was observed as rice-barley cropping system had significantly greater internal phosphorus use efficiency than the other three cropping systems. The partial factor productivity of applied nutrients was significantly affected by fertigation regimes in case of N, P and K as N fertigation had a negative relation with the partial factor productivity of applied nitrogen but a positive relationship with the partial factor productivity of applied P and K. The phosphorus harvest index was significantly greater when N fertigation was given @ 40 kg ha-1 in comparison to when N fertigation rates were 20 and 60 kg ha-1. Phosphorus harvest index was significantly lower for rice-durum wheat and significantly greater for rice-lentil cropping system in comparison to other systems. The physiological phosphorus and potassium use efficiencies of rice were significantly higher under higher levels of N fertigation. An analysis of the salient findings and reasoning based on pre-existing literature lead us to the conclusion that fertigation and cropping systems do have significant influences on productivity of rice based cropping systems along with soil physical conditions and nutrient relations in soils and plants. These influences might have resulted from the interactive effects of diverse microbial communities acting under the differential nutrient additions and removals as well as soil profile moisture conditions influencing the root growth, exudation, and decomposition created by the imposed treatments. Most of the influences are not long lasting but their ephemeral nature can be an indicator of the direction of changes expected in the long term. Hence, the decision of fertigation in rainfed rice based ecologies should not only take into consideration the objectives of efficient water and nutrient delivery but also the ecosystem characteristics on a cropping systems basis.
Open Access
Characterization of Paddy growing soils of Supaul district after Kosi devastation 2008 in Bihar
(Department of Soil Science & Agricultural Chemistry, BAU, Sabour, 2017-07) Prakash, Kumar Jay; Kumar, Rajkishore
In the present study, characterization of paddy growing soils of Supaul district after Kosi devastation 2008 in Bihar, was done with surface and sub-surface samples, soil constraints and soil site suitability for important paddy crop of pedons 1, 2, 3, 4 and 5. The paddy crop production related constraints were also identified with appropriate land use and management technologies. The soils of the study area as per the criteria of taxonomic classification predominantly come under Entisols. All the physical and chemical parameters were estimated by following standard procedures. The bulk density of profile 1 to 5 varied from 1.42-1.71 g/cc and the maximum water holding capacity of pedons varied from 24.15-38.48 %. The pH, EC, ESP, CEC, CaCO3, SOC, available N, P2O5, K2O, DTPA-Fe, Mn, Zn, and Cu of surface soil irrespective of profiles varied from 6.46-7.14, 0.08-0.83 dSm-1, 0.42-2.51 %, 4.14-12.10 meq/100g, 1.29-3.70 %, 0.14-0.40 %, 21.48-163.07 kg ha-1, 11.14-47.62 kg ha-1, 85.93-344.06 kg ha-1, 17.19-60.26 mg kg-1, 4.38-20.79 mg kg-1, 0.08-4.75 mg kg-1 and 0.31-6.83 mg kg-1 respectively. The surface and sub-surface samples of paddy growing soils in respect of soil pH varied from 6.25-8.49 and 6.56-8.83, respectively. Similarly, EC in paddy growing soil varies from 0.04-0.46 and 0.04-0.45 dSm-1 respectively. Similarly, ESP in paddy growing soil varied from 0.27-4.89 % and 0.27-4.98%, respectively. Similarly, CaCO3 in paddy growing soils varied from 1.00-6.54 % and 0.78-5.10 %, respectively. The organic carbon of surface and sub-surface samples of paddy growing soil varies from 0.06-0.54 % and 0.06-0.59%, respectively. The available nitrogen of surface and sub-surface samples of paddy growing soil varies from 37.72-175 kg ha⁻1and 33.34-154.7 kg ha⁻1, respectively. The available P2O5 of surface and sub-surface samples of paddy growing soil varies from 6.89-32 kg ha⁻1and 5.95-27.64 kg ha⁻1, respectively. The available K2O of surface and sub-surface samples of paddy growing soil varies from 173.65-282 kg ha⁻1and 151.77-246.46 kg ha⁻1, respectively. The DTPA-Fe, Mn, Zn, Cu and available boron of surface and sub-surface samples of paddy growing soil varies from 12.05-59.65 mg kg-1 and 10.29-50.94 mg kg-1, 7.04-19.25 mg kg-1 and 5.94-16.25 mg kg-1, 0.50-3.38 mg kg-1 and 0.41-2.79 mg kg-1, 1.22-4.82 mg kg-1and 1.21-4.07 mg kg-1, 0.06-1.54 mg kg-1 and 0.05-1.27 mg kg-1, respectively. Considering the soil-site suitability criteria, Supaul (PN1), Triveniganj (PN2), Kishanpur (PN3) and Pratapganj (PN5) were identified as moderate suitable (S2) block and Raghopur (PN4) was categorized in marginal suitable class (S3) for paddy cultivation (local variety), whereas, based on Naidu et al. (2006) and slight modification of local situation, Supaul (PN1), Triveniganj (PN2) and Kishanpur (PN3) and Pratapganj (PN5) were identified as highly suitable (S1) block and the Raghopur (PN4), was categorized in moderate suitable class (S2) for Garma Dhan (Boro rice). From the above facts, it can be concluded that model of Naidu et. al. (2006) with slight modification of location situation, fitted better to NBSSLUP, Nagpur (2000) under different bocks of paddy growing soils in Supaul district.
Open Access
Effect of Co-inoculation of Arbuscular Mycorrhizal Fungi and Plant Growth Promoting Rhizobacteria on Soil Zinc Dynamics
(Department of Soil Science & Agricultural Chemistry, BAU, Sabour, 2017-07) Bharti, Kumari Priyanka; Pradhan, Amit Kumar
Maize is an important cereal crop of Bihar and it is the third largest maize producing state (after Andhra Pradesh and Karnataka) contributing around 10 percent to national production. Phosphorus (P) and zinc (Zn) are the major nutrients limiting plant growth and their bioavailability to nutrient-exhaustive plants like maize is a major concern. Arbuscular mycorrhizal fungi (AMF) inoculation has been proved to improve plant growth along with P and Zn nutrition. On the other hand, certain species of Plant Growth Promoting Rhizobacteria (PGPR) release low molecular weight organic acids (esp., Gluconic and keto-gluconic acid) which dissolve minerals and help to bring the poorly soluble nutrients into the soil solution. Co-inoculation of AMF with PGPR further helps to increase plant performance, and enhance their efficacy and reliability. Keeping these points in view, the present investigation was carried out with objectives to study the effect of co-inoculation of AMF and PGPR on i) soil Zn fractions; ii) Zn and P interaction in soil; and iii) Zn and P uptake. To achieve the objectives, a field experiment was conducted in Randomized Block Design with 9 treatments, each replicated thrice. The treatments were: T1-control; T2-100%RDF; T3-AMF@10kg/ha + 75%P; T4-AMF@10kg/ha + PSB @20g/kg seed + 75%P; T5- AMF@10kg/ha + ZSB @20g/kg seed + 75%P; T6- AMF@10kg/ha + ZSB @20g/kg seed + PSB@20 g/kg seed + 75%P); T7-AMF@10kg/ha + PSB @20g/kg seed + 50%P; T8- AMF@10kg/ha + ZSB @20g/kg seed + 50%P; and T9-(AMF@10kg/ha + ZSB @20g/kg seed + PSB@20g/kg seed + 50%P). Analysis of experimental soil for Zn fractions, plant-available Zn and P, microbial population and enzymatic activities was done at 2 stages, viz., flowering and after harvesting. Results from the experiment obtained at both the stages show that the highest values for DTPA Zn (1.38 and 0.89 mg kg-1), available phosphorus (21.8 and 21.14 kg ha-1), grain Zn content (52.58 mg kg-1) and its uptake (0.390 kg ha-1); grain P content (0.313%) and uptake (23.18 kg ha-1) were recorded to be significantly higher under the T6 (AMF@10kg/ha + ZSB @20g/kg seed + PSB@20 g/kg seed + 75%P) in both the stages in comparison to the other treatments. Also, the enzymatic activity and microbial population were highest under the same treatment. While the maximum biological yield of 207.89 q ha-1 was recorded under the T2 i.e. 100% RDF, the yield obtained under T6 (206.45 q ha-1) was observed to be statistically at par with T2. Residual fraction of Zn comprised of more than 80 % of total soil Zn while water soluble-exchangeable Zn accounted for the least (about 1%). The co-inoculation treatments, specifically T6 had a significant effect on the water solubles-exchangeable and organically bound Zn, while the oxide-bound Zn fractions had higher values in the non-organic treatments i.e.,Control (13.4 mg kg-1) and 100% RDF (13.02 mg kg-1). It may thus be concluded that, although the results for co-inoculation effects have to be revalidated over a longer period of time, they can be considered as positive signs and possible strategies towards improved P and Zn nutrition and sustainable soil quality as a whole.
Open Access
Comparative Effect of Prilled Urea and Neem-coated Urea on Plant-available Forms of Nitrogen in Rice (Oryza sativa L.)
(Department of Soil Science & Agricultural Chemistry, BAU, Sabour, 2017-07) Yadav, Abhineet; Ghanshyam
Rice (Oryza sativa L.) is one of important cereal crop grown in India. Our country has the largest area under rice cultivation. Rice is the basic food crop and being a tropical plant, it flourishes in humid climate. Among 17 nutrients which are essentially required by crop plants for their normal growth and reproduction, nitrogen (N) is generally required by them in the largest amount. Urea is one of the most widely used source of N fertilizer in the world. It also has a high nitrogen content (46%), in comparison to other popular nitrogen sources. When applied to soil, urea is first transformed into ammonical (NH4+) form after its hydrolysis and then to nitrite (NO2-), followed by to nitrate (NO3-) forms by the process of nitrification. Addition of urea in soil, by virtue of its hydrolysis, increases soil pH thereby causes tremendous ammonia volatilization losses. Use of slow-release fertilizers and nitrification inhibitors and puddling of the rice fields are also ways of reducing leaching losses. The present investigation on “Comparative effect of prilled urea and neem-coated urea on plant available forms of nitrogen in rice (Oryza sativa L.) was undertaken to elucidate the relative influence of nitrogen dose, nitrogen source and nitrogen split on rice crop. Soil analysed for basic characteristics of experimental site was alkaline in reaction, deficient in available nitrogen, medium in organic carbon content and sandy loam in texture. Long duration rice cv. Rajendra Mahsuri was taken as a test crop. Graded doses of nitrogen i.e 100 kg, 120 kg and 140 kg nitrogen ha-1 were applied through prilled and neem-coated urea in splitting manner. The balance sheet of nitrogen in post harvest soil checked and results indicate that the maximum available-N, ammonical-N and nitrate-N were 207.8 kg ha-1, 97.7 kg ha-1 and 52.3 kg ha-1 respectively at 140 kg ha-1. In case of nitrogen sources neem-coated urea build up more nitrogen in soil by 8.12 % and 4.42 % for available-N and ammonical-N respectively over prilled urea. No conclusive impact of nitrogen split was found. Highest grain yield (66.9 q ha-1) of rice was found at 140 kg ha-1 nitrogen applied through neem-coated urea and statistically significant over the yields 60.2 q ha -1 and 66.7 obtained respectively at 100 and 120 kg ha-1 nitrogen. No significant effect of source and split of nitrogen was found on grain yield. Maximum 1.47 % nitrogen content in rice grain and 0.64% in straw was noticed at 140 kg N ha-1 respectively that was significantly superior over the content obtained at 100 kg ha-1 and 120 kg ha-1 nitrogen level. Neem coated urea registered significant difference in nitrogen content in rice grain and straw over prilled urea. Total nitrogen uptake (152.8 kg ha-1) as biological yield of rice crop was estimated at 140 kg ha-1 applied nitrogen dose and was statistically superior over both level of nitrogen. Neem coated urea responded more uptake of nitrogen than prilled urea. To assess the release pattern of nitrogen, soil treated with neem-coated urea and prilled urea adding 50 mg N kg-1, 60 mg N kg-1 and 70 mg N kg-1 of soil had been taken for incubation study upto 90 days. In initial soil available-N, ammonical-N and nitrate-N were 70 mg kg-1, 28 mg kg-1 and 7 mg kg-1 respectively. The results of incubation study showed that neem-coated urea registered 11.94 %, 12.38 % and 13.32 % slow release of nitrogen over prilled urea at 15 days after incubation (D.A.I) for available-N at 50 mg kg-1, 60 mg kg-1 and 70 mg kg-1 nitrogen doses respectively. Almost similar trend was observed in case of ammonical-N. At 45 D.A.I, nitrogen release pattern of both neem-coated and prilled urea have showed less changing in nitrogen mineralization. Onward 60 to 90 D.A.I, nitrogen mineralization pattern had been changed and neem-coated urea released about 10 % more nitrogen over prilled urea as available-N at 50 mg kg-1 nitrogen dose. It might be due to slow and steady release nature of neem-coated urea. Almost similar trend was observed for ammonical-N forms of nitrogen and the trend of nitrogen mineralization for nitrate-N at all D.A.I at different nitrogen doses and nitrogen sources was observed in indiscriminate manner.
Open Access
Effect of Tillage and Cropping System on Phosphorus Fractions in soil Aggregates
(Department of Soil Science and Agricultural Chemistry, BAU, Sabour, 2017-07) Priyadarshi, Rashmi; Choudhary, C. D.
Phosphorus (P) is a crucial fertilizer element for sustaining crop productivity. Increasing global demand and declining of reserves of mineable phosphate rock put forward a threat to future availability of phosphorus in fertilizer form. The amount of P fertilizer needed depends not only on the crop P requirement, but also on the amount of extractable soil P and the P fixing capacity of the soil. For phosphorus requirement plants depend on inorganic form of phosphorus like Al-P, Fe-P, R-P and Ca-P and relative proportion of these inorganic fractions depends upon various factor. Management practices may help to improve use efficiencies of the said nutrient so that the fertilizer P can be better managed in agricultural system, continuous ploughing and other tillage operation stimulate organic matter losses by increasing aeration, changing temperature and moisture conditions and thus favouring microbial decomposition. Conservation tillage systems, with proper residue management, are expected to maintain or increase SOM by maintaining relatively slow decomposition rate of surface residues. Cropping system affects phosphorus dynamics by rapid decomposition of the P in the soil coarse fraction with an increase of inorganic P in the fine fractions. Keeping these points in view, the present investigation was carried out with objectives to study the Effect of Tillage and Cropping System on i) the aggregates associated with phosphorus and ii) distribution of phosphorus fractions in soil aggregates. To achieve the objectives, a field experiment was conducted in factorial randomized block design with 9 treatments, each replicated thrice at two depths i.e., 0-15&15-30 cm. Three treatments in main plot for Tillage practices were: Zero tillage (ZT), Permanent Bed (PB) and Conventional tillage (CT) and three treatments in sub plot for cropping system were Rice-Wheat (R-W), Maize-Wheat(M-W) and Maize-Maize (M-M). Result revealed that soil aggregates significantly influences the phosphorus concentration within the size fraction. Macro-aggregate (>2.0 mm) contributed higher phosphorus concentration than micro aggregate. Within the aggregate size fractions, large macro-aggregate attributed to highest phosphorus concentration followed by small macro-aggregates and microaggregates and least at silt + Clay fraction irrespective of tillage and cropping system upto 30 cm soil depth. In zero tillage system, soluble and exchangeable Phosphorus was found maximum compared to other tillage practices. Similarly, Rice-Wheat cropping system and it’s interaction with zero tillage had maximum soluble and exchangeable P at both depths that is 0-15 cm and 15-30 cm. Same trend were observed in all other fractions. Thus it may be concluded that zero tillage practices improves the each fraction of soil phosphorus. Aggregation improves the phosphorus retention. Larger aggregates contributed higher phosphorus density than smaller aggregates. Zero tillage in rice-wheat cropping system enhances total phosphorus in soil whereas maize-wheat cropping system improves aggregate associated phosphorus. This infers that zero tillage with crop diversification with C3 and C4 crops will holistically improves the phosphorus reserve and protects it from fixation, hence improves phosphorus use efficiency.

Bihar Agricultural University, Sabour

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