Neem Coated Urea Research Articles

Effect of slow release nitrogenous fertilizers and biochar on growth, physiology, yield, and nitrogen use efficiency of sunflower under arid climate

Sunflower plants need nitrogen consistently and in higher amount for optimum growth and development. However, nitrogen use efficiency (NUE) of sunflower crop is low due to various nitrogen (N) losses. Therefore, it is necessary to evaluate the advanced strategies to minimize N losses and also improve sunflower productivity under arid climatic conditions. A field trial was conducted with four slow release nitrogenous fertilizers [SRNF (bacterial, neem, and sulfur-coated urea and N loaded biochar)] and three N levels (100% = 148 kg N ha−1, 80% = 118 kg N ha−1, and 60% = 89 kg N ha−1) of recommended application (100%) for sunflower crop under arid climatic conditions. Results showed that neem-coated urea at 148 kg N ha−1 significantly enhanced crop growth rate (CGR) (19.16 g m−2 d−1) at 60–75 days after sowing (DAS); leaf area index (2.12, 3.62, 5.97, and 3.00) at 45, 60, 75, and 90 DAS; and total dry matter (14.27, 26.29, 122.67, 410, and 604.33 g m−2) at 30, 45, 60, 75, and 90 DAS. Furthermore, higher values of net leaf photosynthetic rate (25.2 µmol m−2 s−1), transpiration rate (3.66 mmol s−1), and leaf stomatal conductance (0.39 mol m−2 s−1) were recorded for the same treatment. Similarly, neem-coated urea produced maximum achene yield (2322 kg ha−1), biological yield (9000 kg ha−1), and harvest index (25.8%) of the sunflower crop. Among various N fertilizers, neem-coated urea showed maximum NUE (20.20 kg achene yield kg−1 N applied) in comparison to other slow release N fertilizers. Similarly, nitrogen increment N60 showed maximum NUE (22.40 kg grain yield kg−1 N applied) in comparison to N80 and N100. In conclusion, neem-coated urea with 100% and 80% of recommended N would be recommended for farmers to get better sunflower productivity with sustainable production and to reduce the environmental nitrogen losses.

CONTROLLED RELEASE OF UREA USING MESOPOROUS SILICA

Mesoporous silica has many applications due to its porous and morphological characteristics. This study used mesoporous silica as a carrier of fertilizer for controlled release. Mesoporous silica was synthesized by using cetyltrimethylammonium bromide (CTAB) as a template. Urea was taken as a model fertilizer to study the control release behaviour of mesoporous silica. For loading of urea on silica simple immersion technique was used. The high concentration of urea was taken for loading. In vitro release studies of urea loaded on porous silica in water indicate a fast release of urea within 12 hours, attributed to urea adsorbed on the external surface of porous silica. Then slow and sustained release for the next 4 days, ascribed to urea entrapped in the pores of silica. The release profile of urea loaded in silica synthesized without CTAB was also observed. The release profile of urea loaded on silica gel shows the full urea release within two days. The release profile of Neem-coated urea, commercially used in India as fertilizer, was also studied, in which maximum urea was released within one day. The great potential of developing a fertilizer carrier system based on mesoporous silica was revealed. The nanostructured delivery system for fertilizer could minimize losses of nutrients and consequently reduce the amount applied.

Mitigation of nitrous oxide emission through fertigation and ‘N’ inhibitors – A sustainable climatic crop cultivation in tomato

The impact of nitrous oxide (N2O) released from the fertilized agro-ecosystems are of increasing concern. Governing fertilizer requirements and utilizing nitrification inhibitors (NI) are effective methodologies to increase nitrogen retention and reduce N2O emissions from soil. Therefore, the effect of potassium thiosulfate (KTS) and neem-coated urea (NCU) on N2O efflux under irrigated tomato cultivation was assessed. Soil Test Crop Response (STCR) based recommendation of NPK with normal Urea and KTS at 1% of applied N (183:160:125 kg ha−1) (STCR-U + KTS) recorded the least N2O emission and high efficiency in suppressing the nitrate reductase activity. STCR-NCU was on par with STCR-U + KTS, reporting a higher reduction of N2O (21.1, 31.2, and 34.4% during the basal application, 1st and 2nd top dressing, respectively) compared to the blanket recommendation of nutrients. Similarly, STCR-U + KTS recorded the highest reduction (26.2, 25.6, and 30.9% during the basal application, 1st and 2nd top dressing, respectively) after fertilizer application. Besides, the yield of tomatoes is increased in the STCR-NCU (14.08%) and STCR-U + KTS (12.48%) with good quality fruit along (AA, Lycopene, and TSS contents) with low N2O emissions. The DeNitrification-DeComposition (DNDC) model further revealed that the simulated data and assessed findings were in good accord, proving the model's reliability and use as a tool for predicting the efficiency of fertilizer application.

Biochar and slow-releasing nitrogen fertilizers improved growth, nitrogen use, yield, and fiber quality of cotton under arid climatic conditions

The efficiency of nitrogenous fertilizers in South Asia is on a declining trajectory due to increased losses. Biochar (BC) and slow-releasing nitrogen fertilizers (SRNF) have been found to improve nitrogen use efficiency (NUE) in certain cases. However, field-scale studies to explore the potential of BC and SRNF in south Asian arid climate are lacking. Here we conducted a field experiment in the arid environment to demonstrate the response of BC and SRNF on cotton growth and yield quality. The treatments were comprised of two factors, (A) nitrogen sources, (i) simple urea, (ii)neem-coated urea, (iii)sulfur-coated urea, (iv) bacterial coated urea, and cotton stalks biochar impregnated with simple urea, and (B) nitrogen application rates, N1=160 kg ha-1, N2 = 120 kg ha-1, and N3 = 80 kg ha-1. Different SRNF differentially affected cotton growth, morphological and physiological attributes, and seed cotton yield (SCY). The bacterial coated urea at the highest rate of N application (160 kg ha-1) resulted in a higher net leaf photosynthetic rate (32.8 μmol m-2 s-1), leaf transpiration rate (8.10 mmol s-1), and stomatal conductance (0.502 mol m-2 s-1), while leaf area index (LAI), crop growth rate (CGR), and seed cotton yield (4513 kg ha-1) were increased by bacterial coated urea at 120 kg ha-1 than simple urea. However, low rate N application (80 kg ha-1) of bacterial coated urea showed higher nitrogen use efficiency (39.6 kg SCY kg-1 N). The fiber quality (fiber length, fiber strength, ginning outturn, fiber index, and seed index) was also increased with the high N application rates than N2 and N3 application. To summarize, the bacterial coated urea with recommended N (160 kg ha-1) and 75% of recommended N application (120 kg ha-1) may be recommended for farmers in the arid climatic conditions of Punjab to enhance the seed cotton yield, thereby reducing nitrogen losses.

Conservation agricultural practices for minimizing ammonia volatilization and maximizing wheat productivity.

A large amount of ammonia volatilization from the agricultural system causes environmental problems and increases production costs. Conservation agriculture has emerged as an alternate and sustainable crop production system. Therefore, in the present study, ammonia losses from different agricultural practices were evaluated for the wheat crop under different tillage practices. The results of the present study showed that the cumulative emission of ammonia flux from the wheat field varied from 6.23 to 24.00 kg ha-1 (P ≤ 0.05) in conservation tillage (CA) and 7.03 to 26.58 kg ha-1 (P ≤ 0.05) in conventional tillage (CT) among different treatments. Application of basal 80% nitrogen resulted in the highest ammonia flux in conventional and conservation tillage practices. The ammonia volatilization followed the following trend: urea super granules with band placement > neem-coated urea with band placement > neem-coated urea with broadcast before irrigation > neem-coated urea with broadcast after irrigation > slow-release N fertilizer (urea stabilized with DCD and N(n-butyl)thiophosphoric triamide) with band placement. The conservation agricultural practices involving conservation tillage appear to be a sustainable approach for minimizing ammonia volatilization and improving wheat productivity.

Nitrogen Challenges and Opportunities for Agricultural and Environmental Science in India

In the last six decades, the consumption of reactive nitrogen (Nr) in the form of fertilizer in India has been growing rapidly, whilst the nitrogen use efficiency (NUE) of cropping systems has been decreasing. These trends have led to increasing environmental losses of Nr, threatening the quality of air, soils, and fresh waters, and thereby endangering climate-stability, ecosystems, and human-health. Since it has been suggested that the fertilizer consumption of India may double by 2050, there is an urgent need for scientific research to support better nitrogen management in Indian agriculture. In order to share knowledge and to develop a joint vision, experts from the UK and India came together for a conference and workshop on “Challenges and Opportunities for Agricultural Nitrogen Science in India.” The meeting concluded with three core messages: (1) Soil stewardship is essential and legumes need to be planted in rotation with cereals to increase nitrogen fixation in areas of limited Nr availability. Synthetic symbioses and plastidic nitrogen fixation are possibly disruptive technologies, but their potential and implications must be considered. (2) Genetic diversity of crops and new technologies need to be shared and exploited to reduce N losses and support productive, sustainable agriculture livelihoods. (3) The use of leaf color sensing shows great potential to reduce nitrogen fertilizer use (by 10–15%). This, together with the usage of urease inhibitors in neem-coated urea, and better management of manure, urine, and crop residues, could result in a 20–25% improvement in NUE of India by 2030.

Real-time application of neem-coated urea for enhancing N-use efficiency and minimizing the yield gap between aerobic direct-seeded and puddled transplanted rice

Abstract An appropriate nitrogen (N) management strategy is required for minimizing the yield loss incurred in aerobic direct-seeded rice (ADR) due to moisture stress. Field experiments for two consecutive years were conducted to evaluate comparative performance of real-time application of neem-coated urea (NCU) and prilled urea (PU) using a customized leaf color chart (CLCC) on growth, yield and N use efficiency of both ADR and puddled transplanted rice (PTR). Six treatments were tested with cultivar ‘Apo’:0 N (T1) as control, 100 kg N ha−1 as prilled urea (PU) applied conventionally (T2), 100 kg N ha−1 as NCU applied conventionally (T3), 100 kg N ha−1 as PU applied on the basis of CLCC recommendation (T4), 100 kg N ha−1 as NCU applied on the basis of CLCC recommendation (T5), and 50 kg N ha−1 as PU and 50 kg N ha−1 as farm yard manure (FYM) (T6). Results of the field experiments showed significant effects (p ≤ 0.05) of both cultivation method and N management on yield. The ADR produced 22.5–46.0% less yield as compared to PTR mainly due to substantial reductions in leaf area, biomass and sink size. As compared to PU, the conventional application of NCU increased yields by 7.1–13.4 % and 6.8–10.0 %,in ADR and PTR, respectively and the differences were significant (p ≤ 0.05). But when applied using CLCC, yield enhancements from PU increased to 21.2–22.9 % and 14.6–15.9 %, respectively. The NCU resulted in 6.6–8.9 and 6.2–6.5 % higher N recovery efficiency as compared to PU, which was further increased to 16.3–18.0 and 11.4–14.6 % in ADR and PTR, respectively when applied using CLCC. Hence, our results indicate that optimization of N application combining both a real-time N management tool (CLCC) and enhanced efficiency N fertilizer (NCU) could help minimize yield losses, which was more visible under ADR by improving growth and yield parameters. The findings of the present study can be proposed as a suitable alternative to the existing N-fertilizer management for rice farmers of both aerobic dry-seeded and puddled transplanted conditions, while more yield advantage was realized in the former.

Neem Coated Urea (NCU), An Efficient Nitrogen Source for Paddy Cultivation: A Review

Green revolution dramatically change the nitrogen application in paddy cultivation and day by day its demand increased but excessive and imbalanced use of nitrogen fertilizer has raised certain global concerns, also its low nitrogen use efficiency. Nitrogen is required in huge amounts for rice and supply of N in the right amount, at the right rate and at right time throughout the growing season is most important to increase the yield. Approximately 90% of the N-fertilizer applied worldwide is in the NH4+ form, which is rapidly oxidized to NO3- by soil nitrifier bacteria. Whereas, NCU temporarily delays the bacterial oxidation of the ammonium-nitrogen by depressing over a certain period of time the activity of Nitrosomonas bacteria in the soil. So far more than 75 studies have been conducted to study the performance of NCU in increasing the yield of rice and several other crops. In rice more than 30% of the urea consumed in India is applied, the mean increase in grain yield by replacing urea with NCU is 5 to 6%. NCU has been observed to improve nitrogen use efficiency and subsequently grain yield of rice. Possibly, applying NCU following the site-specific nutrient management principles will lead to paddy production of higher levels as observed with ordinary urea but with lower fertilizer application rates.

From South Asia to the world: embracing the challenge of global sustainable nitrogen management

From South Asia to the world: embracing the challenge of global sustainable nitrogen management

Effect of different mitigation options on growth, productivity and economics of wheat (Triticum aestivum)

Wheat (Triticum aestivum L.) is second most important food grain after rice and is consumed in different forms. The production of wheat in India is currently facing new challenges due to increasing population and adverse impacts of climate change. The production of wheat has increased significantly after the introduction of high yielding varieties. Modern wheat cultivars require adequate amount of nitrogen (N) fertilizer and several irrigations for economical production. The amount and type of nitrogen fertilizers not only affect the production of wheat but also has impact on climate change due to emission of nitrous oxide. A field experiment was conducted in 2016-17 to study the impact of water management (3 and 5 irrigations) and nitrogen fertilizer (urea, neem coated urea (NCU), urea with thiourea, and leaf colour chart (LCC) based N application) on wheat production and profitability. The nitrogen-management practices and irrigation practices significantly influenced the yield parameters, cost of cultivation, net returns and benefit to cost ratio of wheat crop. Grain yield was increased by 15.89% (p ≥ 0.05) in 5 irrigations compared to 3 irrigations. The grain yield increased by 3.0%, 3.4% and 5.9% in treatments where N was applied using NCU, LCC based N application and urea + thiourea respectively, over urea treatment. Grain yield per kg of N applied was highest in LCC based N application treatment followed by thiourea + urea, NCU and urea N treatments. Highest gross returns was from thiourea treatment however the net returns and B: C ratio were highest in LCC based urea N application due to higher biological yield and saving of 20 kg nitrogen per ha. The study revealed that the economic performance of greenhouse gas mitigation technologies where N was applied based on the plant requirement using leaf colour chart and 5 irrigations was the best followed by application of nitrification inhibitor thiourea with urea and 5 irrigations.

Effect of neem coated urea on yield attributes, yield, nutrient uptake and economics of rice (Oryza sativa L.)

A field experiment was carried out during the Kharif, 2017 at Rice Research Centre, Agricultural Research Institute, Rajendranagar, Hyderabad (TS), India to study the “Effect of Neem coated urea on yield attributes, yield, nutrient uptake and economics of rice (Oryza sativa L)”. The experiment was laid out in Randomized complete block design with three replications and eight treatments viz., T1- RDF 120-60-40 N through Prilled urea (PU), T2- RDF 120-60-40 N through Neem coated urea (NCU), T3- 95% Recommended dose of nitrogen (RDN) through NCU + Recommended dose of Phosphorus and Potassium (RDP and K), T4- 90% Recommended dose of nitrogen (RDN) through NCU + Recommended dose of Phosphorus and Potassium(RDP and K), T5- 85% Recommended dose of nitrogen (RDN) through NCU + Recommended dose of Phosphorus and Potassium(RDP and K), T6-80% Recommended dose of nitrogen (RDN) through NCU + Recommended dose of Phosphorus and Potassium(RDP and K), T7- 75% Recommended dose of nitrogen (RDN) through NCU + Recommended dose of Phosphorus and Potassium(RDP and K) andT8- 0 Nitrogen + Recommended dose of Phosphorus and Potassium(RDP and K) (Control). The results showed that T2- RDF 120-60-40 N through Neem coated urea (NCU) produced higher grain, straw yields and BC ratio whereas, T3- 95% Recommended dose of nitrogen (RDN) through NCU + Recommended dose of Phosphorus and Potassium (RDP and K) with 5% reduction in recommended nitrogen in NCU form produced the similar yields of grain and straw, BC ratio which were obtained in T2- RDF 120-60-40 N through Neem coated urea (NCU). Hence, T3- 95% Recommended dose of nitrogen (RDN) through NCU + Recommended dose of Phosphorus and Potassium (RDP and K) with 5% saving in recommended nitrogen in NCU form proved to be better for higher productivity and profitability of rice.

Relative competency of urea in augmenting physiological and agronomic traits of baby corn (Zea mays)

Nitrogen is indispensable for aggrandizing productivity of crop but the losses associated due to swift transformation and release pattern are subjected to various losses leading to pitiful amount left for crop uptake, pollution and resource wastage. Present study was conducted to evaluate the efficacy of coated urea and nitrogen rates on baby corn growth, yield and NUE. The experiment comprised varieties PHM-1 and HM-4, coated urea (NCU, ZCU, SCU and PU) and nitrogen levels @180, 150, 120 kg N/ha along with the control. The study revealed that PHM-1 obtained significantly higher plant height, no. of cobs and weight of dehusked cob that led to significant increase of 18.47 and 19.67 % higher husked and dehusked cob yields over HM-4 which attained 12.6% higher fodder yield over latter. The baby corn cob yield and fodder yield were significantly higher in coated urea over prilled urea. The husked and dehusked yield of baby corn was higher in neem-coated urea over prilled urea by 14.81 and 14.37% respectively. H o w e v e r , a reduction of 59.9% in total fodder yield was recorded in control when compared to 180 kg N ha. Also, NPK uptake was higher then PHM-1 and uptake by coated urea was higher then prilled urea along with high uptake for 180 kg N/ha, further the AE and higher PE of baby corn cob was found highest in variety PHM-1 although for fodder, the higher AE was recorded in HM-4, whereas ANR was higher in PHM-1.

Fertilizer management through coated urea to mitigate greenhouse gas (N2O) emission and improve soil quality in agroclimatic zone of Northeast India.

Agricultural soils are an important source of greenhouse gas nitrous oxide (N2O) emission. The comprehensive effects of nitrogen fertilizer management on N2O emission from paddy fields of India have not been evaluated under field conditions. A 2-year field study was conducted to evaluate the effect of different nitrogen fertilizers, namely, conventional fertilizer (NPK), starch-coated urea (SCU), neem-coated urea (NCU), and normal urea alone (NUA) on soil quality, grain yield, and N2O emission from rice field. Gas samples were collected from the field at weekly intervals by static chamber technique and analyzed in a gas chromatograph. During the crop-growing season, the application of NPK resulted in the highest cumulative N2O emission (2.49kg N2O-Nha-1) followed by NUA (2.34kg N2O-Nha-1), NCU (2.20kg N2O-Nha-1), and SCU (1.97kg N2O-Nha-1). As against the application of conventional fertilizer (NPK), the application of SCU and NCU reduced the total N2O emission by 21% and 12%, respectively (p < 0.05), during the rice-growing period. The results indicate a good correlation of N2O emissions with soil organic carbon, soil mineral nitrogen, and urease activity (p < 0.05) at different stages of crop growth. Application of SCU significantly increased the rice grain productivity by 12%, 10%, and 3% over NPK (control), NCU, and NUA respectively without affecting the soil quality and nutrient status. The use of SCU improved the nitrogen use efficiency (NUE) and was the effective substitute for conventional fertilizer in terms of reducing N2O emissions from tropical rice paddy.

Effectiveness of neem coated urea in increasing productivity of okra (Abelmoschus esculentus (L.) Moench)

An experiment was carried out to evaluate effectiveness of neem coated urea (NCU) as N source either alone or along with organic manures in increasing productivity of okra during summer seasons of year 2016 and 2017 at Pantnagar, Uttarakhand (India). Experiment with 14 treatments and replicated thrice was laid out in randomized complete block design. Among different treatments, 75% recommended dose of N (RDN) as NCU + 25% N as vermicompost proved to be best in terms of improvement in various growth parameters, green pod yield and higher N uptake and N use efficiency. The combined application of NCU (75% RDN) and vermicompost (25% RDN) by the farmers will increase the production of okra and N use efficiency.

Polycoated urea performance in wheat under semi-arid tropics

Field experiments were conducted using wheat cultivar HD-2967 during Rabi 2016-17 for evaluating efficiency of polycoated urea (PCU) (42% N) viz. neem coated urea (NCU) (46% N) under semi-arid tropical conditions in Tarn Taran district of Punjab, India. Treatments comprised of T1 100% N through NCU (3-Splits), T2 100% N through PCU (3-Splits), T3 100% N through PCU (1-Split), T4 75% N through PCU (1-Split). Results revealed that T3 treatment had highest grain as well as straw yields followed by T1, T2 and T4 (for grain yields) while T4, T1 and T2 (for straw yields) though in a non-significant mode. Crop biomass reported to be significantly higher in T3 in January while become at par during February and March, 2017. Among yield attributes viz. spike length, grains spike−1 and 1000 grain weight reported to be highest in T3 while tillers reported to be highest in the T2 treatment. Nitrogen concentration (%) in plant biomass reported to be highest in T3 followed by T1, T4 and T2, respectively. Among, nutrient efficiency parameters viz. agronomic efficiency (kg N ha−1) and physiological efficiency (kg N ha−1) T3 (100% PCU (1 splits) reported to have highest values than T1 and T2, where as recovery efficiency (%) found to be highest in T4 followed by T3, T2 and T1, respectively. Hence, being a slow release fertilizer 100% PCU (42% N) (1-Split) will serve the purpose for sustainable wheat production in semi-arid tropics.

Dynamics and temperature sensitivity of soil organic carbon mineralization under medium-term conservation agriculture as affected by residue and nitrogen management options

In the scenario of global climate change, the enhancement and stabilization of soil organic carbon holds prime importance. In this context, conservation agriculture (CA) based practices i.e., diversified cropping systems and permanent bed (PB) holds great potential. In this article, we have compared the dynamics of soil organic carbon under mustard and wheat based systems [MMuMb, maize-mustard-mungbean and MWMb, maize-wheat-mungbean)] planted on PB, with and without residue (PB + R and PB - R) along with four nitrogen (N) management options [Un-fertilized, N through prilled urea (PU), N through sulphur coated urea (SCU), and N through neem coated urea (NCU)]. After 5-years of experimentation, to assess the medium-term impact of full CA (PB + R) in comparison to partial CA (PB-R) on SOC dynamics under mustard and wheat based systems with diverse N sources, we had conducted an incubation study at three temperature levels (27, 32 and 37 °C) in a sandy loam soil (Typic Haplustept) of north-western Indo- Gangetic Plains (IGP) of India. Wheat-based cropping system (MWMb) resulted in higher values of less labile, non-labile as well as total SOC, as compared with mustard-based system (MMuMb). On the other hand, MMuMb registered higher amount of very labile and labile SOC, with enhanced decay rate. The cumulative C mineralization (Ct) was 11–17% higher under MMuMb compared with MWMb, from all the soil depths at 27 °C. Retention of crop residue in PB increased total SOC by 11.5 to 19.5% compared with PB-R, across the soil depths. The Ct were significantly higher under full CA plots with lower decay rate (Kc), as compared to plots under partial CA. Application of N fertilizers registered a significant hike in total SOC compared to un-fertilized control plots. At the same time, the coated N sources i.e., SCU and NCU failed to cause any significant improvements in total SOC as compared with uncoated PU plots. On the other hand, coated urea treated plots registered significantly higher C mineralization compared with uncoated PU plots. Between the two coated urea products, the NCU application registered significantly higher C mineralization compared with SCU across the sampling events and temperature regimes from all the soils layers. Cropping system or residue addition/removal did not affect temperature sensitivity of SOC mineralisation. At the same time, addition of N-fertilizers, irrespective of sources lowered the Q10 compared with no-N fertilization.

Differential response from nitrogen sources with and without residue management under conservation agriculture on crop yields, water-use and economics in maize-based rotations

Under the present scenario of resource degradation, shortage of water & labour, growing production cost, falling water tables as well as farm profitability and climate-change; the sustainability of traditional rice-wheat (RW) system became a major challenge in Indo-Gangetic Plains (IGP). Therefore, to address these issues in India’s, north-western IGP, RW system need to be diversified with conservation agriculture (CA) based profitable and sustainable systems. Full CA based crop production technologies may furnish more yield, reduce water need and enhance farm profitability, without hampering the sustainability of natural resources. So in an established on-going long term study (since 2012), we assessed the medium term-impact of four different nitrogen management practices [Un-fertilized, N through Prilled urea (PU), N through Sulphur coated urea (SCU) and N through Neem coated urea (NCU)] in residue retained permanent bed (PB + R) vs. residue removed permanent bed (PB-R) plots under maize-mustard-mungbean (MMuMb) and maize-wheat-mungbean (MWMb) crop rotations. Results showed that, the maize, wheat and mustard yields were statistically similar in first year of study irrespective of residue retention or removal, whereas during subsequent years, yields of maize, wheat and mustard were significantly (P < 0.05) higher by 10.1–16.7%, 9.3–23.6% and 13.6–21.9% under residue retained plots (full CA) than residue removed plots (partial CA), respectively. However, the mungbean yield was significantly (P < 0.05) greater by 12.4–24.3% in residue retained plots right from first year onwards. In permanent bed plots, residue retention reduced the water requirement by 50–55 ha-mm, and improved water productivity by 9.4–27.6%, 17.7–30.4%, 21.7–42.6% and 33–57.2% in maize, wheat, mustard and mungbean, respectively compared to no residue plots. Economic profit for MMuMb (from 2nd year onward) and MWMb rotations (in all the 5-years) was significantly (P < 0.05) higher by 220–464 and 165–474 US$/ha/year, respectively in residue retained plots compared to residue removed plots. Among N management practices, application of neem and sulphur coated urea significantly improved the individual crops yield, water productivity and system profitability compared to un-fertilized both under residue retained and removed plots. However, across the cropping systems the effectiveness of different N sources varied with residue management, as the annual increment in system productivity of SCU treated and residue retained plots under MMuMb system was about thrice than the residue removed plots. Whereas, in MWMb system the annual increment in system productivity was double in NCU treated and residue retained plots as compared to residue removed plots. Effectiveness of PU was not increased with residue retention in maize and mustard, whereas in wheat both the coated and uncoated urea application increased the annual yield by manifolds. Findings of this study support differential opportunity of residue management and suggest that a combination of full CA-based MMuMb/MWMb system with use of proper N sources [like slow release coated fertilizers (NCU/SCU)] could augment the system productivity, resource-use efficiency, farm profitability, while sustaining the natural resources in Western IGP in India and other similar agro-ecologies.

Dynamics of dry matter and nitrogen distribution in transplanted rice on mollisols

We studied the dynamics of dry matter (DM) and nitrogen (N) distribution in different plant parts (leaf, stem, and panicle) and grain yield of transplanted rice due to N management practices through neem coated urea (NCU). The results indicated that application of NCU at 125% recommended dose of N (RDN) with 50:25:25 split schedule at basal (B), active tillering (AT), and panicle initiation (PI) stages resulted in higher DM and N distribution to leaf, stem, and panicle at 60 and 90 days after transplanting and harvest than the application of prilled urea at 100% RDN with the same split schedule (existing practice). Further, the increment in grain yield was 10.95% than the existing practice. Hence, we suggest the application of NCU at 125% RDN with 50:25:25 split schedule at B, AT, and PI stages for achieving higher DM and grain yield on Mollisols.

Energy auditing and carbon footprint under long-term conservation agriculture-based intensive maize systems with diverse inorganic nitrogen management options

A greater energy grant in diesel-fed machinery driven farming substantiate the higher GHGs emission along with improper input (fertilizer, pesticide and irrigation) use and intensive soil management. Practicing conservation tillage, residue retention and diversified crop rotations were advocated because of their multiple benefits. Hence we explored the energy requirement and carbon footprint of conservation agriculture (CA) based maize production systems. Coated N fertilizer [sulphur coated urea (SCU) and neem coated urea (NCU)] were compared with unfertilized and uncoated prilled urea (PU) in the scenario of with and without residue retention on permanent beds (PB) under diversified maize systems [MMuMb, maize-mustard-mungbean and MWMb, maize-wheat-mungbean] in search of a sustainable and energy efficient production system with lesser C-footprint. Results of the 4-year study showed that crops planted on permanent bed with crop residue (PB+R) registered 11.7% increase in system productivity compared to PB without residue (PB−R). N management through Neem coated urea (NCU) recorded 2.3 and 10.9% higher system productivity compared with non-coated prilled urea plot under PB−R and PB+R, respectively. MMuMb was marginally superior than MWMb system in terms of cropping sequence yield, profitability, and energy and carbon use efficiency. Crop residue retention in zero tilled PB increased cost of cultivation by 125 and 147 USD/ha in MMuMb and MWMb systems, respectively. The quantified carbon footprint value was higher in MWMb system. In CA-based practices, crop residues management contributed the highest energy input (61.5–68.4%) followed by fertilizer application (17–20%). Among N management practices, neem coated urea (NCU) significantly improved system productivity and profitability in all the residue applied plots compared to un-fertilized and prilled urea (PU) applied plots. Similarly, higher energy output was also observed in NCU treated plots. However, carbon footprint value was higher in PU (268–285 CO2-e kg/Mg) plots than NCU (259–264 CO2-e kg/Mg) treated plots. Thus, the study supports and recommends that the CA-based MMuMb system with efficient N management through NCU is an environmentally safe, clean and energy efficient one, hence can reduce carbon footprint, will ensure food security and will mitigate climate change.

Effect of graded doses of neem coated urea on productivity of low land rice

A field experiment was conducted in the Research field of Regional Research and Technology Transfer Station, Coastal Zone, OUAT to study the efficiency of neem coated urea (NCU) on yield and yield attributing characteristics of low land rice. Results revealed that application of 80 kg N ha -1 as NCU was effective over application of 100 kg N ha-1 as prilled urea (PU). The highest plant height (109.8 cm) panicle length (24 cm) and effective tiller (11.5) was observed with T5 (100 kg N ha-1 as PU) whereas lowest value of 84.5 cm, 20.6 cm and 9.1 cm for plant height, panicle length and effective tillers per hill respectively were recorded with T 1 (control). The highest grain yield of 47.3 q ha -1 was observed in T8 (80 kg N ha-1 as NCU) where as lowest value - of 32.7 q ha-1 was observed in T1 (control). The grain yield of rice under T5 (100 kgN ha-1 as PU) was 47.0 q ha1 which was statistically at par with T8 (80 kg N ha-1 as NCU) indicating the higher efficiency of NCU than that of PU. With the doses at 80 kg N ha-1 the yield advantages was due to application of NCU which had a 5.1% more yield advantages than that of PU. The straw and harvest index followed the same trend as that of grain yield of rice. The highest B: C ratio of 1.44 was observed with application of 80 kg N ha -1 as NCU where as the B: C value of 1.42 was observed with application of 100 kg N ha -1 as PU indicating the efficiency of NCU than that of PU application.