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Dry chilli, which stands third in production from the spice industry, has influenced the Indian diet to a greater extent. The impact of climate change conditions on chilli crop could, in turn, impart the economy deeply. Hence, the future projection of dry chilli production will surely enrich knowledge about crop performance. Climate data from CCSM4 being downscaled from RegCM 4.4 was used in yield projection till the end of 21st century through DSSAT crop simulation for two major cultivars of chilli in Tamilnadu viz., TNAU chilli hybrid CO1 and K1 variety under rainfed conditions. TNAU chilli hybrid CO1 and K1 varieties have shown negative yield deviations for all the agroclimatic zones of Tamilnadu under variable time scales. However, southern zone was exclusive in exhibting positive yield by 7 percent and 5 percent, respectively, during the end of century. [ABSTRACT FROM AUTHOR]

Assessing the pulse of an important legume crop, red gram (Cajanus cajan L.) of Tamil Nadu under changing climate and framing adaptation strategies were formulated using the DSSAT model. The assessment was done for the popular variety of red gram, viz., CO(RG)7 with August 1st as sowing date, under constant CO2 (380ppm) and CO2 enrichment. The adaptation strategies such as altering the sowing date and 25 per cent increment in nitrogenous fertilizer were carried out with CO2 enrichment conditions. The yield was found to be adversely affected by the warming scenario of the climate system without CO2 fertilization. With the incorporation of enriched CO2 data, the average yield increases until the end of the century, but with temporal and spatial variations. Among the different agro climatic zones of Tamil Nadu, highest yield was recorded in Western Zone and lowest in Southern Zone. There was no response to application of Nitrogenous fertilizer. July 15 sowing was identified to be the best sowing for the base as well as future period for CO(RG)7.

Temperature is one of the most important environmental factors that influence the crop growth, its development, and yield. With the increase in the accumulation of GHGs in the atmosphere, there is a rise in surface temperature as compared to pre- industrial period. An experiment was conducted during rabi season of 2013- '14 to study the impact of elevated temperature with and without CO2 fertilization on rice (C3) and maize (C4) crops, using Temperature Control Chamber and Soil plant Atmospheric Research system at the Agro Climate Research Centre of Tamil Nadu Agricultural University, Coimbatore. Temperature elevation of 4 °C from the ambient level in the TCC and temperature elevation of 4 °C with 550 ppm CO2 in the SPAR chamber were considered for experimentation. Increase in temperature with or without CO2 enrichment affected the phenology and productivity of C3 and C4 plants under different magnitude. Rice and maize crops grown under 4 °C elevated temperature attained panicle initiation, flowering and maturity earlier than the crop grown under ambient condition. The treatment 4 °C elevated temperature also recorded reduced number of tillers in rice, number of leaves in maize and dry matter production in rice and maize. This treatment did record lower rice grain and straw yields . Maize grain and stover yields also got reduced. As far as the physiological response of C3 (rice) and C4 (maize) was considered, the photosynthetic rate was significantly low when the plants were kept under warmer environment than under ambient condition and the rate of decrease was higher in rice compared to maize. However, the CO2 enrichment compensated this reduced photosynthetic rate. The interaction effect between temperature and CO2 in rice indicated that CO2 enrichment had minimized the yield loss by 10 per cent as compared to three per cent obtained under maize crop. The transpiration rate and stomatal conductance were significantly increased in both rice and maize crops under elevated temperature compared to ambient condition and the rate of increase was higher in rice than in maize, yet, CO2 enrichment compensated these ill effects of elevated temperature to certain extent in maize, and to a considerable extent in rice. [ABSTRACT FROM AUTHOR]

An investigation to assess the greenhouse gases (GHG's) fluxes in rice cultivation under current and elevated temperature was carried out at Agro Climate Research Centre, Tamil Nadu Agricultural University, Coimbatore, during rabi season (November 2014 - March 2015). This experimentation was carried out with two temperature levels viz., current temperature at open environment and +2°C elevated temperature at Temperature Controlled Chamber. During the experimentation, GHG emission rate was evaluated. The nitrous oxide emission attained maximum at 15 DAT followed by 45 DAT and then decreased towards maturity. The methane emission rates increased with age of the crop, but attained maximum at harvesting stage. The methane emission rates from rice crop grown under open environment were higher than elevated temperature. The nitrous oxide emission rates from rice crop grown under +2°C elevated were higher than open environment. Methane is normally translocated through rice plants and the higher biomass generation under open environment led to higher methane translocation. The nitrous oxide emission was normally through microbial activity and the higher microbial activity was in elevated temperature led to more nitrous oxide emission. The tradeoff between CH4 and N2O emission has to be analyzed critically and developing appropriate nutrient and water management strategies and maintaining the soil redox potential at an intermediate range (-100 to +200 mV) would minimize emissions of both CH4 and N2O. Overall, the data have shown clear evidence that rice cultivation in future reduced methane emission but increase nitrous oxide emission. [ABSTRACT FROM AUTHOR]

A field experiment was conducted at Tamil Nadu Agricultural University, Coimbatore in the rabi season in order to assess the sustainability of SRI in changing climate. Three aspects of rice cultivation, GHG emission, water use, and Energy consumption were accounted to vindicate the sustainability of SRI over other cultivation systems. Three rice cultivation systems SRI (System of Rice Intensification), AWD(Alternate Wetting and Drying) and conventional were selected which differ in agronomic and water management practices. CH4, N2O and CO2 gas emissions from field were collected using static closed chamber and was analyzed using a gas chromatograph equipped with FID. Water irrigated to the field was measured in m3 using a water meter. The results showed that SRI method of cultivation recorded less GHG emissions and water use with higher yield. Alternate wetting and drying method of water management reduced methane emission in AWD by 41 per cent and SRI by 44.3 per cent when compared with conventional system. [ABSTRACT FROM AUTHOR]

The lowland rice cultivation is recognized as one of the major methane sources. The application of amendments that contain high amount of electron acceptors would inhibit the methanogenic activity and hence methane emission. Fly ash is a by-product containing ferro- alumino- silicate minerals whereas gypsum is sulphate of calcium. A field experiment was conducted to estimate the effect of fertilizers like Urea and Neem treated Urea and soil amendments like fly ash and gypsum along with recommended dose of fertilizers on the methane emission from the rice field. Gas samples were collected from the field using Static open-bottom perplex chamber technique and estimated in a Shimadzu GC-2014 gas chromatograph equipped with FID. The rate of methane emission was found to be lesser at the active tillering stage which attained a peak at the panicle initiation stage and then got declined till maturity stage. This trend was noticed irrespective of the treatments evaluated. The substitution of neem treated urea instead of urea had no significant impact on the methane emission whereas the application of either gypsum or fly ash or in combination along with RDF significantly decelerated the methane emission. [ABSTRACT FROM AUTHOR]

Weeds are one of the important biotic factor, compete the crop for its resources and difficult to eliminate completely from agricultural system. Weeds respond very quickly to stress and adopt easily than crops to climatic stress. In this context, a pot culture experiment in climate control chamber with three temperature levels (0°C, +2°C and +4°C increase over the ambient) and two moisture levels (supply of moisture at 100 %, and 60 % ET of previous day) was carried out at Agro Climate Research Centre, Tamil Nadu Agricultural University, Coimbatore during 2015 -16 to understand weeds response to future climate scenarios. The results inferred that, the problematic weed Cynodon dactylon had high acclimatization capacity and produced more growth under elevated temperature up to +4°C with sufficient moisture. The C4 pathway of bermuda grass helps that weed to utilise the moisture and temperature more efficiently even during stress and produce more growth. Moisture stress with increased temperature had negative effect on growth, but induced the early flowering and more seed production in Cynodon dactylon. It is concluded that, in near future with elevated temperature, the crop production in both dry and wet seasons would suffer from severe Cynodon dactylon menace. Hence, necessary precaution measures against Cynodon dactylon have to be included in climate change adaptation technologies. [ABSTRACT FROM AUTHOR]

In India, agriculture sector provides the largest livelihood support and contributes by 17.3 percent to the Gross Domestic Product (GDP). Maize is the third most important food crop after rice and wheat, occupying about 7.5 million hectares of land area in India. In Tamil Nadu maize is cultivated mainly as rainfed crop during Rabi season. Requirement of maize is growing fast and given the importance, a study was carried out at Agro Climate Research Centre, Tamil Nadu Agricultural University, Coimbatore during 2015-2016 to assess the impact of climate change on rainfed maize productivity over Tamil Nadu during mid-century (2040 to 2069) period. The Representative concentration pathway 4.5 and 8.5 was selected to represent the stabilization and over shoot pathways of emission. Maximum temperature was expected to increase to a maximum up to 4.7°C while minimum temperature to 5.7°C. Rainfall is anticipated to vary from a decrease of -33.0 percent to and increase of +45.1 percent.The future climate projected by these models was integrated with DSSAT to simulate the impact on rainfed maize productivity over Tamil Nadu. Under changing climate, rainfed maize productivity is expected to decline to a maximum of 30 percent from the current yield levels. [ABSTRACT FROM AUTHOR]

A study was conducted at Agro Climate Research Centre, Tamil Nadu Agricultural University, Coimbatore, during 2015-16 to improve the accuracy of numerical model rainfall forecast using astrometeorological principles. Daily rainfall forecast were developed for each one location from seven agro climatic zones of Tamil Nadu, through different source and methods viz., WRF (numerical model), astrometeorology (planet), probability, a private agency forecast and hybrid forecast (superimposing astro and probability forecast on WRF) and were compared using forecast accuracy ratio and critical success index. In general, irrespective locations and seasons, the hybrid forecast had higher forecast accuracy (0.75 to 0.88) and critical success index (0.56 to 0.76). Among the different individual forecasts, the astrometeorological forecast had highest forecast accuracy (0.74 to 0.87) and critical success index (0.52 to 0.71). The study concluded that, astrometeorology could be a good option for alternate forecasting method to numerical weather forecast and hybrid forecast developed by integrating astrometeorology, numerical and probability methods will improve the rainfall forecast accuracy and critical success index, in turn will increase the usability of forecast in agriculture. [ABSTRACT FROM AUTHOR]

Rainfall is a nature's gift carrying certain essential plant nutrients from atmospheric reactions. Rainfall contribute considerable amount of Nitrogen as equal parts of nitrate (NO3) and ammonical (NH3) forms and sulfur (SO4) for plant use. These nutrients in the rainfall had good impact in agricultural production during those days, when environmental conditions was better with less toxic substances in atmosphere. The throughfall, precipitation that drips from the foliage and runs down the boles of trees are substantially enriched with leached bio elements and which are mostly essential plant nutrients. Study during North East Monsoon 2015 (NEM) and Summer 2016 (SUM) inferred that, both the rainfall and through fall are potential source of plant nutrients and the amount of nutrients delivery varies with type of vegetation. It is quite interesting to note that the amount of nitrogen (both nitrate and ammoniacal form) delivered by rainfall and throughfall were worked out to nearly 33 and 68 kg/ha which is sufficient for the most of rainfed crops. Among the agro forestry tree species, throughfall from Azadirachta indica had higher N, K and Mg, throughfall from Casuarina equisetifolia had Ca which resulted in higher pH and EC, throughfall from Peltophorump terocarpum had P2O5 and Na and throughfall from Cassia fistula had more SO4.The study periods imputes collection, conservation and recycling of rainfall to sustain the productivity of crop, particularly rainfed agriculture. [ABSTRACT FROM AUTHOR]

The article focuses on the study on the impact of El Niño-Southern Oscillation (ENSO) induce rainfall on the productivity of maize farm in Tamil Nado, India. Topics discussed include the measurement of ENSO condition using the Southern Oscillation Index (SOI), the influence of SOI phases on the characteristics of rainfall during the rainfed cropping period, and the statistical analysis of the effect of SOI phase son maize growth and yield.

El Niño Southern Oscillation (ENSO) is one of the most important drivers of climate variability. To study the impact of ENSOonseasonal rainfall over Tamil Nadu, historical weather data for the period of 43 years (1971-2013) were categorized based on the ENSO episodes and the analysis was performed for assessing ENSO linked climate variability (onset and cessation) for North east monsoon rainfall (NEM: October - December) and rainfed cropping period (September - December) over Tamil Nadu. Onset was determined using the pentad analysis performed from 1st October through 31th October, considering first pentad with quantum of 10 mm of rainfall followed by four consecutive pentads of 10 mm of rainfall per pentad. The same approach was followed for deciding the onset of sowing rains for rainfed cropping period starting from 1st September to 10th October. In NEM and rainfed cropping period, cessation of monsoon was seen in December month. If the cessation didn't occur during December, the cessation time was noted in November month and the season was considered as the last day that received rainfall amount of > 2.5 mm. In NEM, higher per cent of years had onset in the slot from 1st to 5th of October (65.0, 63.4, 65.2 per cent of El Niño, La Niña and Neutral years, respectively). Few years were in neutral phase (26.3 %) and in El Niño (19.4 %) andunderLa Niña (15.2%) phase the results showed the onset happened between 6th and 10th of October. In most of the El Niño years (68 %), sowing rain occurred during 1st week of September (1st to 7th September), while in 40 per cent of the La Niña years sowing rain was delayed by one week and received during 2nd week of September. Cessation was earlier in most of the La Niña years as compared to El Niño and neutral years. [ABSTRACT FROM AUTHOR]

Rice production is reported to be a contributor to climate change through the release of greenhouse gases to the atmosphere especially methane under submerged field condition. A step towards reducing the GHGs emission, an experiment was conducted with eight different soil amendments combinations viz., recommended Dose of Fertilizers (RDF), fly ash, biochar, gypsum, Silica Solubilizing Bacteria (SSB), fly ash + SSB, biochar + SSB, gypsum + SSB were studied. Gas collection was done using chambers and samples were analyzed using Gas chromatography. Methane emission was observed at active tillering, panicle initiation, 50 per cent flowering and maturity stages. During the crop growth, application of fly ash had reduced emission rate followed by fly ash + SSB, gypsum and gypsum + SSB. Higher methane emission was found with the treatment of RDF followed by RDF + SSB, biochar and biochar + SSB. From the study, it was concluded that application of fly ash did reduce the methane emissions over the application of other soil amendments in rice crop. [ABSTRACT FROM AUTHOR]

The article presents a research study for analyzing the seasonal water requirement (ETc) of sorghum crop in the Coimbatore region of Tamil Nadu, India. Topics discussed include collection of rainfall and potential evapotranspiration (PET) data and the influence of leaf area index, wind turbulence and leaf temperature. The results of the study are presented.