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The shifting cultivation practice is the predominant land use system of Nagaland, India, and Wokha district in particular. In general, there are four different forms of land use: forest, shifting cultivation, cultivated fallow, and wet terrace rice cultivation. In the Wokha district, a study was conducted in the year 2015 to evaluate the variability in soil characteristics among four different land use systems and to map their spatial distribution. A total of 381 soil samples were collected and tested for six soil fertility parameters; clay, pH, soil organic carbon, available nitrogen (N), phosphorus (P) and potassium (K). The results showed that all of the soils were very acidic in nature; however the mean value of soil pH was substantially higher in the shifting cultivation system. Soil organic carbon concentrations ranged from high to very high across all land use systems. Average soil organic carbon content was highest in the forest, followed by cultivated fallow, shifting, and wet terrace rice cultivation (WTRC) systems, whereas available N content was very low to low. The P concentration of the soil was very low in the WTRC system and low in the other systems. Soil K concentration was high in shifting (361.95 kg/ha), cultivated fallow (312.4 kg/ha), forest (309.73 kg/ha), and low in WTRC (166.975 kg/ha) land use systems. Available N, P and K deficiency was found in 93.8%, 72.2%, and 32.9% of soil samples, respectively. Soil organic carbon correlated positively with K and significantly positively with N. Soil pH correlated negatively with clay content and positively but non-significantly with P. The generated maps might be used to assist farmers in identifying the expected nutrient levels in their areas and encourage them to change their crop management practices to improve crop yield and profitability. Due to soil acidity, higher SOC, lower N and P, and higher potassium content, suitable acid loving crops, higher N and phosphorus fertilization, and some commercially advantageous potassium responsive crops may be encouraged in farming practices.

Rice (Oryza sativa L.) is one of the major crop of India and the lifeline of the Eastern states. The challenges however are to produce more food for the increasing population by utilizing limited resources and maintain it under climate change conditions. This can be achieved by devising appropriate agro-techniques. We calibrated and evaluated CERES-Rice model of Decision Support System for Agro-Technology Transfer (DSSAT) for different resource conserving technologies (RCTs) to assess their effects on yield of transplanted rice under projected climate change scenarios. Yields were projected for 2030, 2050 and 2070 using data downloaded from MarkSim® DSSAT weather file generator for RCP 4.5 climate change scenario. The simulated result indicated that the productivity of transplanted rice under resource conserving technologies is likely to increase by 11.6-14.9% in 2030, 18.6-22.3% in 2050 and 17.6-20.2% in 2070 compared to the present yield levels (2015) with current management practices. Yield can further be enhanced through adoption of appropriate resource conservation technologies (RCTs). The DSSAT model predicted the effects of RCTs in transplanted rice very well and can be a useful tool for evaluating the effects of climate change on rice under these managements.

Wet direct seeding is proved as a viable alternate to conventional transplanting method of rice. Maintenance of optimum population by adopting an appropriate sowing method followed by judicious weed control practices ensures profitability of wet direct seeded rice (W-DSR). A field experiment was carried out to find out a suitable sowing technique and weed control options for enhancing productivity and economics of W-DSR. The W-DSR was infested with twelve numbers of weed species comprising of eight families under different sowing methods. The composition of sedges, broadleaved (BLW) and grassy weeds was 83.07, 11.0 and 5.93%, respectively. Irrespective of sowing methods, weeds such as, Echinochloa glabrescens and Leptochloa chinensis among grasses, Cyperus difformis and Scirpus juncoides among sedges and Lindernia anagallis among BLW were dominant. Drum seeding recorded 6.9 and 12.7% higher gross and net return, respectively than broadcasting, but it was at par with spot seeding. Highest B: C ratio of 2.07 was recorded with drum seeding, whereas spot seeding recorded lowest B: C ratio (1.99). Crop-weed competition caused 31.7% reduction in grain yield with W-DSR. Application of early post-emergent herbicide bensulfuron-methyl + pretilachlor @ 60+600 g/ha at 10 DAS, azimsulfuron @ 35 g/ha at 20 DAS, and bispyribac sodium @ 30 g/ha at 20 DAS recorded increase in grain yield 40.3, 40.1 and 39.8%, respectively over the weedy check. Ready mix bensulfuron-methyl + pretilachlor @ 60+600 g/ha at 10 DAS registered highest B: C ratio (2.16) but it did not vary significantly with bispyribac sodium @ 30 g/ha and azimsulfuron @ 35 g/ha.

Methane (CH4) and nitrous oxide (N2O) emissions coupled with climate change are issues which are of great concern for modern rice cultivation. It is very difficult and costly affair to quantify the CH4 and N2O emissions at regional and national scales due to large scale spatial and temporal variability in soil and crop management practices. In this study, the denitrification and decomposition (DNDC) model was used for simulating the CH4 and N2O gas emissions from rice fields in Eastern India. For simulating the gaseous emission, the maps of pH, bulk density, soil organic carbon and clay content were prepared using geostatistics and ordinary kriging with study area divided into 1178 grids with an area of 32 ha for each grid. The maps along with other datasets used for running the DNDC model were compiled as model input parameter. The model was then applied for simulation of methane and nitrous oxide emissions from rice fields with various management practices. Simulated CH4 emission in the study area ranged from 9.38 to 110.63 kg C ha−1 and N2O emissions ranged from 0.01 to 1.82 kg N ha−1 as simulated by the DNDC for the crop growing season. Simulated CH4 emission ranged from 0.07 to 1.15 kgC/ha/day, whereas N2O reached upto 8.96 g N ha−1 day−1. The study suggested that the DNDC model can be used for estimating the CH4 and N2O emissions by capturing the information about the different crop management practices from rice fields.

Accurate measurements of actual evapotranspiration (ETa) and crop coefficients (Kc) are essential to know crop water requirements and to improve irrigation scheduling. The eddy covariance (EC) technique is increasingly being used to do so. Precise information on Kc for lowland rice is essential for local- and regional-scale irrigation planning but it is lacking for tropical humid climates such as those found in eastern India. We used the EC technique to measure ETa and Kc—the ratio of ETa to reference potential evapotranspiration (ET0)—of tropical lowland rice in eastern India over 2 years. ET0 was estimated by four different approaches—the Food and Agriculture Organization-Penman–Monteith (FAO-PM) method, the Hargreaves and Samani (HS) method, the Mahringer (MG) method, and pan evaporation (Epan) measurements. Measurements were taken when rice was grown in the dry season (January–May) and wet season (July–November) and in between growing seasons when the field was kept fallow. The magnitude of average ETa during dry seasons (2.86 and 3.32 mm d−1 in 2015 and 2016, respectively) was higher than that of the wet seasons (2.3 and 2.2 mm d−1) in both the study years. Of the four methods tested for ET0 estimation, the FAO-PM method best-represented ET0 in this region of India. The energy balance was found to be more closed in the dry seasons (75–84%) and dry fallow periods (73–81%) as compared to the wet season (42–48%) and wet fallow (33–69%) periods of both years of study, suggesting that lateral heat transport was an important term in the energy balance. The estimated Kc values for lowland rice in dry seasons by the FAO-PM method at the four crop growth stages, namely, initial, crop development, reproductive, and late-season, were 0.23, 0.42, 0.64, and 0.90, respectively, in 2015 and 0.32, 0.52, 0.76, and 0.88, respectively, in 2016. The FAO-PM, HS, and MG methods produced reliable estimates of Kc values in the dry seasons, whereas Epan performed better in wet seasons. The actual Kc values derived for tropical lowland rice in eastern India are different from those suggested by the FAO implying revision of Kc values for regional-scale irrigation scheduling.

Integrated farming system (IFS) based shifting cultivation reduces soil erosion and outperform in terms of productivity and income generation in North-Eastern Hills of India. To address this hypoth...

Maximum and minimum temperatures play an important role in determining yield of rice crop. Yield anomaly of rice under different nutrient management practices was analyzed in a long-term rice–rice system with respect to maximum and minimum temperatures. The treatments included applications of inorganic sources of nutrients (NPK), organic sources of nutrients, i.e., farmyard manure (FYM), combinations of inorganic and organic sources of nutrient (NPK + FYM) and a no nutrient (control). An increase in mean + 1 °C for both the maximum and minimum temperatures during the vegetative stage had positive effect on yield, but when the increase was during the reproductive and ripening stages, the effect on the yield was negative effect on yield. The increase in minimum temperature during the vegetative stage, however, had greater positive effect on yield as compared to increase in maximum temperature. Magnitudes of negative yield anomaly due to increase in temperature during reproductive and ripening stages were less in the NPK + FYM treatment (− 0.77% and − 0.74%, respectively) than in the control treatment (− 4.52% and − 5.31%, respectively). Negative effect of increased temperature during the reproductive and ripening stages on yield anomaly of dry season rice can be minimized by early planting and application of recommended dose of NPK and FYM.

Climate change is widely recognized as one of the most pressing issues confronting humanity today. It is considered to be a direct threat to our food production system including rice. Climate change affects rice production in various ways. The variability in temperature and precipitation increases, predictability of seasonal weather patterns reduces and the frequency and intensity of extreme weather events such as droughts, floods and cyclones increases. In India, the effect of natural disasters on agriculture, including disasters caused by climate change has been gradually growing. It is believed that during the mid and end century India's future rice production is projected to reduced by 2.5 to 5% from the current level. As there is less scope for rice area to grow in the future, any growth in rice production will have to come only from productivity gains. Since climate change is a continuous process, the rice production system requires specific adaptation strategies to prevent rice yield losses and its variability. Therefore, it's critical to understand how climate change affects rice crop and to follow better production practises including crop establishment methods, water management, weed management, nutrient management and microbial resources utilization that make cropping systems more resilient to extreme weather events. The spread of climate resilient production technologies would benefit rice production systems' resilience.

A study was conducted to examine the interrelationships among socioeconomic factors, household consumption patterns, calorie intake and greenhouse gas emissions factors in rural eastern India based on household survey data. Findings indicated that higher monthly per capita incomes (12.1–80.1$) were associated with greater average calorie intakes (2021–2525 kcal d−1). As estimated by the FEEDME model, in total 17.2% of the population was calorie malnourished with a regional disparity of 29.4–18.2% malnourishment. Greenhouse gas (GHG) emissions were calculated only on the basis of crop and livestock production and consumption. Rice accounted for the highest share of total GHG emissions, on average 82.6% on a production basis, which varied from 58.1% to 94.9% in regional basis. Rice contributed the greatest share (~ 65% and 66.2%) in terms of both calories and GHG emissions (CO2 eq y−1), respectively, on a consumption basis. We conclude that extensive rice farming and increasing animal product consumption are dominant factors in the higher carbon footprint in this region and are likely to further increase with increase in per capita income. This study provides useful information to help for better crop planning and for fine-tuning food access policy, to reduce carbon footprint and calorie malnutrition.

We propose a parasitic BJT-based zero capacitor random access memory (Z-RAM) cell suitable for stand-alone memory applications. In this Z-RAM cell, high-bandgap TiO $$_2$$ is used as the source/drain material and silicon as the channel of an n-channel fully depleted silicon-on-insulator MOSFET. Using well-calibrated TCAD simulations, we demonstrate the programming of the proposed Z-RAM cell at low drain voltages, which is a major advantage from an application perspective. At low drain voltage, hole storage is initiated by band-to-band tunnelling, which is subsequently taken over by impact ionization. Large valence band offset between TiO $$_2$$ and Si ( $$\varDelta { E }_\mathrm{V }\approx$$ 2 eV) is utilized for storing larger number of excess holes inside the body for a longer time. This leads to the improvement of both sense margin and retention time compared to an all-silicon Z-RAM cell. We predict a retention time of 2 s and 70 ms at $$T=300$$ K and 358 K, respectively, for device gate length of 30 nm. We have optimized the device design to obtain a write ‘0’ time of 6 $$\upmu$$ s. Multiple non-destructive reading operation for the proposed Z-RAM cell is also demonstrated.

Net ecosystem exchange of CO2 (NEE) measurement was carried out in tropical lowland paddy at ICAR-National Rice Research Institute, Cuttack, Odisha, India, in 2015 using eddy covariance technique with the objective to assess the variation of NEE of CO2 in lowland paddy and to find out the most suitable model for better partitioning of net ecosystem exchange of CO2 in tropical lowland paddy. Paddy is grown twice (dry and wet season) a year in this region in the lowland, and the field is kept fallow during the remainder of the year. Two different flux partitioning models (FPMs)—the rectangular hyperbola (RH) and the Q10, were evaluated to assess NEE of CO2, and its partitioning components—gross primary production (GPP) and ecosystem respiration (RE), and the resulting flux estimates were compared. The RH method assessed the effects of photosynthetically active radiation on the NEE, whereas the Q10 method utilized the relationship between ecosystem respiration and temperature in lowland paddy. The average NEE during the dry season and wet season was − 1.62 and − 1.83 g C m−2 d−1, respectively, whereas it varied from − 5.71 to 2.29 g C m−2 d−1 during the observation period covering both the cropping seasons and the fallow period. The mean difference between modeled GPP and RE from two FPMs was found significant in both the seasons. The maximum correlation for GPP estimation was found between two FPMs at the panicle initiation stage during both the dry season (R2 = 0.767) and wet season (R2 = 0.321). It was evident from the study that the Q10 method reliably produced the most realistic carbon flux estimates over the RH method, for the lowland paddy. The Q10 model which used nighttime flux and temperature data to estimate RE produced estimates that had lower prediction error (RMSE) as compared to the RH model. It can be concluded that in lowland paddy, the Q10 predicted better estimates of RE and GPP values than the RH method, suggesting that the Q10 model can be used for partitioning of NEE in tropical lowland paddy.

Background: The various presentations of carcinoma of the colon are well known. Abscess formation occurs in 0.3 to 0.4% and is the second most common complication of perforated lesions. Perforation and penetration of adjacent organs with intra-abdominal abscess formation as the initial presentation is uncommon. It is difcult to make an accurate diagnosis of abscess formation as the rst evidence of colonic carcinoma preoperatively. A 68 yrs old female who presented to the ED with acute onset of left lower abdominal f Case presentation: ullness, pain and local redness for 15 days. She denied any history of vomiting, fever, anorexia but history of altered bowel habit. Clinically she had a palpable lump (20 x15) cm in left lumber region .The lump was parietal with local raise of temperature , redness and tenderness can be elicited . So our initial impression was parietal wall abscess and we underwent emergency drainage of abscess. She had uneventful recovery and discharged after 2 weeks. She was admitted with similar presentation in previous location 30 days after discharge. Now we investigate thoroughly, a CECT scan of whole abdomen which conrms radio-logically as carcinoma of descending colon with abscess extending into the parietal wall .We underwent an exploratory laparotomy and HPE proven as adenocarcinoma of the colon. Post op she developed SSI which was managed with regular dressing and she was discharged in post-op day 20. We report this case because of an unusual Conclusion: presentation of left sided colonic Ca. The accurate preoperative diagnosis of these conditions extremely complicated because of the fuzzy clinical presentation. The CT scan can diagnose malignancy pre-operatively, even if the denitive diagnosis of colonic perforated neoplasia may be evident only during surgery. So early diagnosis and prompted intervention can save the patient to developed sepsis and to reduce signicantly the morbidity and mortality. The importance is to focus on the differential diagnosis and keep in mind that a colon carcinoma can present with abdominal abscess. Surgeons should be aware of this differential because it is easily ignored pre-operatively.

Consecutive five-year long eddy covariance measurements in a lowland tropical rice-rice system were used to investigate the impacts of gross primary productivity (GPP), climate drivers and ecosystem responses (i.e. ecosystem respiration, RE) on the inter-annual variability (IAV) of the net ecosystem exchange (NEE), which is directly related to the agricultural productivity and climate change. The IAV of carbon dioxide fluxes in two crop growing phases i.e. dry and wet season along with fallow period were analysed. The respiratory fluxes build up during the non-growing season were lower by net uptake in growing season. Annual cumulative value of NEE was negative (sink) in both the crop growing season. The variability of climate drivers and changes in the ecosystem responses to drivers revealed a large intra-annual as well as inter-annual variability of net ecosystem fluxes. NEE was found to be strongly correlated with GPP and RE and also with other metrological variables such as photosynthetically active radiation (PAR), precipitation, air temperature and soil temperature. The anomalies of NEE, GPP and RE were observed to be less in 2017 and 2018 which may be due to lower temperature anomalies recorded in these years. Further understanding of biological mechanisms is needed which is involved in the variation of climatological variables to improve our ability to predict future IAV of NEE.

The fundamental building block of an artificial spiking neural network (SNN) is an element which can effectively mimic a biological neuron. There are several electronic and spintronic devices which have been demonstrated as a neuron. But the main concern here is the energy consumption and large area of those artificial neurons. In this letter, we propose and demonstrate a highly scalable and CMOS compatible bulk FinFET with an ${n}^{+}$ buried layer for ultra low energy artificial neuron using well calibrated TCAD simulations. The proposed device shows the signature spiking frequency versus input voltage curve of a biological neuron. The energy per spike of the integrate block of the proposed leaky integrate and fire (LIF) neuron is ${6.3}~\textit {fJ}$ /spike which is the minimum reported till date.

Human interventions in the environment leading to higher green house gas emissions which are degrading the soil and environment quality. Traditional/conventional tillage systems following since inception and residue burning are accelerating the degradation of soil and environment leading to food insecurity. The present study was executed to evaluate energy budgeting, carbon foot prints, gaseous emission and soil health under conservation tillage with residue retention for identifying cleaner production technology in rice-maize system. The novelty of the study is that it examines the integrated effect of tillage, residue retention through mulching on GHG emission along with soil health, energy consumption and carbon footprints together as conservation effective measure for sustainable and clean agricultural production. Zero tillage reduced the energy consumption by 56% and carbon footprints by 39% and besides that N2O emission was 20% lower than conventional tillage. Apart from clean environment, soil health was also improved by adoption of zero tillage in terms of NPK status, labile pool of carbon and enzymatic activities; the population of all the microbiota was increased, which was around 21.3, 51.2 and 27.6% higher in bacteria, fungi and actinomycetes. Crop residue retention as residue mulching (rice straw) significantly improved the crop productivity, microbial biota and enzymatic activities of soil, but it increased the energy consumption and carbon footprints by around 10%. N2O emission was also enhanced by residue mulching, and higher the quantity of residue used as mulch, more was emission. Although in initial years some yield penalty (10–15%) was recorded but in long run zero tillage can be a step towards sustainability as it can be a valuable approach for resilient soil health and cleaner production of maize in rice–maize system.

Shifting cultivation is the primary source of livelihood for farmers in the hilly tracts of North East India. The jhumias’ (farmers involved in shifting cultivation) livelihoods are at stake due to low productivity and low profit due to detrimental effects of soil erosion, loss of soil nutrients and biodiversity. An action research was planned and executed in Wokha, Nagaland for agricultural intensification and diversification through integrated farming system (IFS) models, rainwater harvesting (RWH) structures and secondary agricultural options. Purposively the research work was carried out in three distinct altitudes at Yanthamo (26°3.753′N, 94°18.195′E, 973 m), Longsa (26°04.029′N, 94°14.936′E, 1174 m) and Riphyim (26°12.282′N, 94°15.748′E, 563 m). The overall impacts of the interventions were quantified in terms of crop productivity, farm-based livelihood diversity, improvement in soil health and jhumias’ livelihood conditions. The results were quite encouraging as it clearly indicated yield enhancement in IFS for cereals (29%), oilseeds (40.7%), pulses (15%), fruits (9.9%), vegetables (298%) and spices (53.6%). On-farm fodder cultivation supplemented respectively 39.3% and 28.6% feed requirements for piggery and poultry avenues. The RWH and IFS increased average cropping intensity from 100 to 168%. Introduction of vermicompost technology in IFS made it possible to recycle about 3.17 t of biomass to produce about 1.24 t mature compost annually. Inclusion of livestock components in model contributed to as high as 56.59% enhancement of net income. Integration of different components in IFS increased employment opportunities also up to 506 man-days/ha/year over the traditional system (72 man-days/ha/year). It can be concluded that water harvesting and IFS could be propagated as a sustainable and economically viable model for livelihood improvement of jhumias.

Reduction in the emission of methane is a challenge to the global scientific community. The global warming potential of methane is about 28–36 making it capable of trapping heat in the atmosphere and contribute to global warming. In this chapter we have described the mechanism and various pathways of methane formation, and discussed the mechanism of methane transport to atmosphere by diffusion, aerenchyma transport, and ebullition. Apart from this, we have also narrated various microbial and non-microbial sources of methane and various factors that control methane emission. Aerobic methane oxidation is a process by which methane produced under anaerobic environment are oxidized to carbon dioxide by methanotrophs, which has been explained in this chapter. Besides, we have discussed various methodologies of water, fertilizer, manure management for controlling methane emission.

A two-year (2015 and 2016) field experiment was carried out to study the surface energy budget and energy balance closure (EBC) in a tropical lowland rice paddy in Cuttack, India. Maintenance of a standing water layer in lowland irrigated rice ecosystem makes it unique and this strongly influences the surface energy balance which may alter the surface runoff, ground water storage, water cycle, surface energy budget, and possibly microclimate of the region. To study this, an experiment was conducted using eddy covariance system to measure the surface energy balance components during two cropping seasons (dry season, DS and wet season, WS) and two consecutive fallow periods (dry fallow, DF and wet fallow, WF). The rice was grown in puddled wet lands in DS and WS and the ground was left fallow (DF and WF) during the rest of the year. Results displayed that daily average latent heat flux at surface (LE) and at canopy height (LEc) dominated over sensible heat flux at surface (H) and canopy height (Hc), respectively due to the presence of water source coming from the standing water in the rice field. The EBC was evaluated by ordinary least square (OLS), energy balance ratio (EBR) and residual heat flux (RHF). In OLS, the slope ranged 0.38-0.89 (2015) and 0.28-0.99 (2016) during the study period. Average RHF was 10.3-12.0% higher in WS as compared to DS. It was concluded that the EBC estimated using RHF is the most suitable way to calculate closure for lowland rice paddy since it can distinguish different seasons distinctively, followed by OLS. Much variation was not observed in EBR after inclusion of storage terms (water, soil, photosynthesis, canopy) to the classical EBR.

Anthropogenic emission of greenhouse gas, destruction of vegetation, faulty agricultural practices, rampant use of fossil fuels bring a new challenge to the humanity in the form of climate change. In this chapter, we have tried to ensemble the information on modern techniques to monitor and measure the impact of climate change. The research facilities for assessing the impact of elevated CO2 and temperature exposure experiment are broadly divided into closed and semi-open to open systems. Growth cabinets and phytotrons are the examples of closed system tools, while open top chambers (OTC), free air carbon dioxide enrichment (FACE), temperature gradient tunnels (TGTs), and free air temperature enrichment (FATE) technologies are of the semi-open to open type. Climate change monitoring on real time basis is measured using eddy covariance techniques. This system measures the fluxes of carbon dioxide, methane, water vapor, and heat. Monitoring of carbon dioxide and methane provide the idea of net carbon balance of an agricultural system, while monitoring energy balance is useful to understand the energy budgeting of the ecosystem.

The projected rise in global elevated atmospheric CO2 level has well-pronounced impact on plant ecophysiology and economic productivity. Elevated atmospheric CO2 accelerated the leaf-level photosynthesis in C3 plants, reduced stomatal conductance, and enhanced resource use efficiency. The sensitivity was comparatively less for C4 and CAM plants. Under sufficient nutrient availability, the net increase in leaf-level assimilation amplified the net grain yield under elevated atmospheric CO2 exposure. However, the relative response in biomass partitioning pattern often varied among the individual crop species. Thus, the net impact on harvest index (HI) varied from one crop species to another. We also observed that the CO2 enrichment facilities have marked influence on the reported magnitude and pattern of crop response towards elevated atmospheric CO2 environment.

Net ecosystem methane exchanges (NEME) from lowland rice often show significant variations in diurnal, seasonal and yearly scales and with crop phenology. Air and soil temperatures, standing water, and radiation are believed to be primary drivers of such variations. We studied the dynamics of net ecosystem methane exchange in three consecutive years (2014–16) using eddy covariance technology. Wet season (July–October) showed higher diurnal methane flux variations than that of dry season (December–March) due to prolonged anoxic condition and higher methanogens in the former. Significant diurnal variations in NEME were also noticed during different crop growth stages. Variations were higher in flowering stage followed by ripening in 2015 and 2016. But in 2014, it was highest at panicle initiation (PI) stage. Principal component bivariate plot analysis and performance analytic correlation were performed for variables such as net ecosystem carbon dioxide exchange (NEE), NEME, sensible heat (Hs), latent heat (LE), photosynthetically active radiation (PAR), net radiation (NR), air temperature and soil temperature (5 cm depth) in order to assess their relationships. The NEME was positively correlated to air and soil temperatures in all the years. However, in year 2016, NEME also showed positive correlation to PAR and NR. These relationships could provide valuable information to partitioning and process-based simulation modelling for projecting and up scaling of NEME to regional and global scales.

Biochar plays a pivotal role in carbon storage-fractionation-mineralization process in soil. However, uncertainty still remains about the influence of biochar on these inter-related processes that links to C cycling in soil. A three years field experiment was initiated in 2013 at ICAR-National Rice Research Institute, Cuttack, India, to study the deviation in C mineralization and C fractions caused by the application of six doses of rice husk derived biochar (RHB), ranging from 0.5 t ha−1 to 10.0 t ha−1. The results showed an increase in cumulative CO2-C emission with increasing RHB rates. However, the model-fitted mineralization rates (dC/dt) did not show significant difference between treated and control soils at the end of incubation period in a laboratory study. In addition, microbial quotient and % C from RHB utilized showed a decreasing trend with increasing rates of RHB application, establishing the carbon sequestration potential of RHB. The highest rate (10.0 t ha−1) of RHB application accumulated maximum total organic C (3.26%) and a larger share of non-labile C (63.8%) among the treatments. An increase in rice grain yield (1–24%, depending on rate of RHB application) was observed with increasing rates of RHB which further established that RHB application not only enhanced C storage but also enhanced the productivity of rice by enhancing the soil fertility.

Soil bacterial communities are considered as an essential member of the microbial community, contributing to soil health. Continuous application of chemical fertilizers alters the bacterial community structure (BCS) thereby disturbing the soil biogeochemical cycling. The present study highlights the 16S rRNA amplicon sequencing-based variation of BCS through Illumina-MiSeq® in a 47 years old long-term fertilized paddy soil and its relation with grain yield (GY), straw biomass (SB) and various soil properties. The experiment comprising six treatments: control (no fertilizers), nitrogen (N), nitrogen + phosphorus (P) + potassium (K), farmyard manure (FYM), FYM + N and FYM + NPK. Data on rice crop performance indicated that GY and SB significantly (p ≤ 0.05) enhanced by 45.1%–49.3% and 36.9–39.4% in FYM + NPK compared to control. Relative abundance of bacterial phyla varied across inorganic and organic fertilizer treatments. Dominant phyla across all treatments were Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, and Firmicutes, accounting for about 80–85% of total operational taxonomic units (OTUs). N application alone over 47 years encouraged certain bacterial phyla (Firmicutes, Actinobacteria, and Nitrospira) while major (Proteobacteria, Acidobacteria and Cyanobacteria) and minor (Fibrobacteres, Spirochaetes, TM7 and GNO4) bacterial phyla were found to be suppressed compared to other treatments. Moreover, continuous use of chemical N in paddy soil, considerably suppressed some diazotrophs taxa Burkholderiales, Enterobacteriaceae, and other taxa Kaistobacter, Anaeromyxobacter, Bdellovibrio, and MND1. Redundancy analysis coupled with principal component analysis revealed that BCS was significantly influenced by soil pH and presence of higher nitrogen content. Interestingly, the highest proportion of bacterial OTUs was recorded in balanced fertilizer (NPK) (without FYM) and therefore, this result suggested for the first time that continuous application of NPK encouraged the beneficial bacterial community without compromising of GY and SB. Overall, the present study indicated that continuous application of N and NPK with or without FYM for more than four decades in paddy soil, encouraged certain BCS whereas, N application alone suppressed certain beneficial bacterial phyla, resulting in the alteration of soil biodiversity and rice productivity.

The beauty of a diode lies in its voltage-dependent nonlinear resistance. The voltage on a charging and discharging capacitor through a reverse-biased diode is calculated from basic equations and is found to be in good agreement with experimental measurements. Instead of the exponential dependence of charging and discharging voltages with time for a resistor-capacitor circuit, a linear time dependence is found when the resistor is replaced by a reverse-biased diode. Thus, well controlled positive and negative ramp voltages are obtained from the charging and discharging diode-capacitor circuits. This experiment can readily be performed in an introductory physics and electronics laboratory.

Temporal variation of ‘surface energy balance’ was quantified on tropical lowland rice for 4 years (2013–2016). High response (10 Hz) eddy covariance system was used to estimate real time data on net radiation (NR), sensible heat (Hs), latent heat (LE), air and soil temperature. Annual, monthly, diurnal as well as phenological crop stage wise variation were analysed. Majority of radiation received from sun was partitioned into latent heat (LE, 44–73%) followed by soil heat (G, 13–42%) and sensible heat (Hs 3–16%) in dry cropping season. This was primarily due to presence of stagnant water in this ecology throughout the cropping period except few days during harvesting. Average Hs was negative in the month of April because of higher evapotranspiration during full grown crop at its reproductive stage as well as stagnant water in field. LE was the major contributor of energy balance and consistently increased from active tillering to grain filling stages then gradually decreased in harvesting. Hs contributing more at the initial stages of rice. Diurnal variation showed maximum Hs during 12:00 to 13:00 hours, whereas, highest LE and G were noticed during 13:00 and 11:30–12:00 hours, respectively. LE and G regressed well than Hs with air temperature and NR.

A field experiment was conducted in 2015 to study the land surface energy fluxes from tropical lowland rice paddy in eastern India with an objective to determine the mass, momentum, and energy exchange rates between rice paddies and the atmosphere. All the land surface energy fluxes were measured by eddy covariance (EC) system (make Campbell Scientific) in dry season (DS, 1–125 Julian days), dry fallow (DF, 126–181 Julian days), wet season (WS, 182–324 Julian days), and wet fallow (WF, 325–365 Julian days). The rice was cultivated in dry season (January–May) and wet season (July–November) in low wet lands and the ground is kept fallow during the remainder of the year. Results showed that albedo varied from 0.09 to 0.24 and showed positive value from morning 6:00 h until evening 18:00 h. Mean soil temperature (Tg) was highest in DF, while the skin temperature (Ts) was highest in WS. Average Bowen ratio (B) ranged from 0.21 to 0.64 and large variation in B was observed during the fallow periods as compared to the cropping seasons. The magnitude of aerodynamic, canopy, and climatological resistances increased with the progress of cropping season and their magnitudes decreased during the end of both cropping seasons and found minimum during the fallow periods. At a constant vapor pressure deficit (VPD) at 0.16, 0.18, 0.15, and 0.43 kPa, latent heat flux (LE) initially increased, but later it tended to level off with an increase in VPD. The actual evapotranspiration (ETa) during both the cropping seasons was higher than the fallow period. This study can be used as a source of default values for many land surface energy fluxes which are required in various meteorological or air-quality models for rice paddies. A larger imbalance of energy was observed during the wet season as the energy is stored and perhaps advected in the fresh water.

Potassium (K)-fractions, thresholds of K release and fixation, quantity-intensity (Q/I) parameters of K, K-release kinetics, and K-fixation capacity were compared for their effectiveness in differentiating the effect of various nutrient management practices on K supplying capacity of an Aeric Endoaquept soil after 45 years of puddled rice cultivation. Soil samples (0–15 cm) were collected after the completion of 45 rice-rice cycles from an on-going long-term fertilizer experiment located in ICAR-National Rice Research Institute, Cuttack, India. The treatments involved control (unfertilized), N (nitrogen fertilizer), NP (N+ phosphorus fertilizer), NK (N+ potassium fertilizer), NPK (N + P + K fertilizer), FYM (farmyard manure), N + FYM, NP + FYM, NK + FYM, and NPK + FYM. Rice cultivation without K fertilizer application resulted in lower values of soil K parameters than the K-fertilized treatments. Treatment effects were most prominent on release threshold concentration (RTC), followed by cumulative K release, K-release rate constants, and K-fixation capacity. Parameters of K-release kinetics and Q/I relationships showed better correlation with rice grain yields than soil-K fractions. Soil K thresholds were closely related with exchangeable (Kex) and non-exchangeable K (Knx), but not clay minerals. Among the soil K parameters, RTC, cumulative K release (Kf) with 0.01 M CaCl2, release rate constants (b R and b S ) of parabolic diffusion equation, and K-fixation capacity were most effective in revealing the nutrient management induced variations in soil K fertility. In the studied soil, K-thresholds were significantly related to Kex and Knx.

Suitable method of application of urea briquette in flooded rice (Oryza sativa L.) not only increases nitrogen use efficiency, but at the same time sustain yield and reduce greenhouse gas emission in general and nitrous oxide emission in particular. Keeping this hypothesis, seven different treatments including manual and mechanical mode of application with two different type of applicators were tested in field in consecutive wet (2015) and dry (2016) seasons. Three row briquette applicator (TRBA) and top dressing applicator (TDA) were used in combination for basal and top dressing application along with prilled urea broadcasting and without application as well. It was observed the use of TRBA at basal with first top dressing by TDA and manual placement of urea briquette at second top dressing (TRBA + TDA) yielded highest @ 6.71 t ha−1 and 5.47 t ha−1 in the wet and dry seasons, respectively, with the highest agronomic use efficiency (36.3 kg kg−1). Average emission of methane from all treatments were higher (19.2–27.1%) during wet season than the dry season and vice versa in case of nitrous oxide (3.6–11.8%). Among the treated plots, TRBA + TDA recorded the lowest emission of nitrous oxide. The largest amount of ammonia was lost through volatilization after basal application of urea, followed by top dressing at the end of maximum tillering stage and panicle initiation stage. As a whole, volatilization loss of N was lowest in control (3.3–3.4 mg NH3-N m−2 d−1), followed by mechanical (27.6–33.9 mg NH3-N m−2 d−1) and manual (49.1–55.3 mg NH3-N m−2 d−1) method of urea briquette application. The population of nitrite oxidizers and heterotrophs were highest in prilled urea broadcasting. Soil dehydrogenase activity was the highest in urea briquette manual placement + top dressing applicator (UBMP + TDA, 148.0 μg–160.0 TPF g−1 soil d−1) treatment, while the urease activity was less was in urea applicator treated plots. Subsurface application of larger size urea (urea briquette) and applicator based precise placement of urea reduced the lossess of nitrogen through ammonia volatilization and nitrous oxide emission, thus enhanced nitrogen use efficiency. Apart from that, issue of adequate skilled labour for precise depth of application could be tackled by effectively adopting mechanical placement of urea briquette. The mechanical placement of briquette (relatively larger size particle) in tropical flooded rice is more precise and less labour intensive, hence this is an efficient environment friendly approach of N management.

The effect of long-term fertilizer and manure applications on short-range order (SRO) and crystalline mineral transformation was studied in a 47-year puddled rice-rice cropping system experiment in Odisha, India. The relationship of SRO minerals with phosphorus and potassium fixation capacity and soil carbon fractions was also evaluated. Soils from different treatment combinations of farmyard manure (FYM), nitrogen (N), phosphorus (P) and potassium (K) were separated in two ways: (i) removal of binding materials (ii) non-removal of binding materials (ultrasonic vibration), followed by fractionation of the contents into silt and clay. All crystalline minerals, SRO minerals, P and K fixation were measured in silt and clay. The X-ray diffractograms of clays (