A study was conducted to develop organic briquettes using biomass originating from slaughterhouse wastes and to investigate its potential as a nutrient source for plant growth.Dried rumen contents were mixed with fresh blood collected after bleeding of animals in different proportions and dried using tray drier. The dried rumen content-blood (RB) mixture was further mixed with commercially available coir pith in 12 different proportions. The rumen content-blood-coir pith (RBC) mixture was formed into briquettes using a hydraulic biomass briquetting machine. Each organic briquette was 5 cm in diameter and had an average weight of 30-40 g. The treatments were analyzed for pH, moisture content, electrical conductivity (EC), organic carbon (OC), total nitrogen, carbon: nitrogen ratio, total phosphorus and total potassium. Organic briquette having rumen content with 100 % blood and 80 % coir pith (T10) recorded the highest total nitrogen, total phosphorus and total potassium content. The treatments for plant growth studies were selected based on the criteria that each treatment had highest values for at least two of the three primary nutrients of nitrogen, phosphorus and potassium. The treatments T5, T7, T8, T10 and T12 were selected for plant growth studies. Pot experiment using selected briquettes was carried out to determine the effect of selected briquettes on growth parameters and yield attributes of okra (Abelmoschus esculentus).Nutrient release pattern of the selected organic briquettes was also studied. The best desirable growth parameters and yield attributes of okra was observed in T10. Availability of nutrients in the medium were relatively less during first two months of planting (MAP), however, it significantly increased between 3 MAP and 4 MAP, which resulted in better plant growth and fruit yield. The study showed that there is great potential for development of organic briquettes using slaughter house wastes as an eco-friendly process, which are compact, easy to transport and market, and ideal for grow bag cultivation and garden nurseries.

An experiment was carried out at Agricultural Research Station, Mannuthy, Kerala to evaluate the effect of nutripriming on tray nursery technique in rice. Nutripriming treatments viz. priming with 0.1% urea, 0.01% borax, 0.05% ZnSO4, combinations of urea with borax and ZnSO4, combination of urea, borax and ZnSO4, 1% Pseudomonas fluorescens and 1% PGPR mix I were applied to seeds grown in seedling trays filled with growing media containing 60% rice husk 154 charcoal + 20% soil + 20% coir pith compost. Combined application of urea, zinc and borax was superior with respect to growth parameters of seedling and mat characteristics. Higher Ca, Mg, S and B uptake was also observed in this treatment. Hence, nutripriming with 0.1% Urea + 0.05% ZnSO4 + 0.01% Borax was found to be a better practice for quality tray nursery production in rice.

The field experiments were conducted in farmer's field at five locations each of kole lands to study the effect of Magnesium (Mg) on yield and soil and plant nutrient status of rice during 2012-2013 and 2013-2014. The experiment was laid out in randomized block design with three replications. The treatments comprised of different levels of Mg viz; 40, 60, 80, 100, and 120 kg Magnesium sulphate(MgSO4)/ha along with control. Observations on growth characters yield attributes, yield and soil and plant nutrient status were recorded. The results revealed that application of 100 kg MgSO4 / ha recorded the maximum number of panicles/m2 (419.13), number of grains/panicle (109.36), thousand grain weight (28.78 g), grain (9.27 t/ha) and straw yield (9.04 t/ha) of rice. The results of pooled data on plant and soil nutrient status revealed that application of magnesium had a positive effect on nutrient content and availability of nutrients in soil. A significant positive correlation was also noticed between Mg application, yield attributes, yield and nutrient contents. The study concluded that application of 100 kg MgSO4 / ha was found to be optimum for correcting the deficiency in Mg deficient areas of kole lands under below sea level farming.

Rice is a staple food and its demand is substantially increasing with the growth of the global population. Phenological development was found to play a significant role in the distribution of carbon among plant organs, which has an impact on rice yield. Temperature affects plant phenology, and the current rapid climate change has revived interest in understanding and modelling plant phenology response to the warming trend. Two rice varieties viz., Jyothi (short duration variety) and Jaya (medium duration variety) were raised at Agriculture Research Station, Mannuthy, during the kharif season of 2021 and phenological observations viz., days to 50% flowering and physiological maturity were recorded. The phenophase has been also predicted from the Info-Crop and CERES-DSSAT for both varieties during the experimental period for validation. To study the phenology changes in future conditions i.e., near (2030), mid (2050) and end (2080) century, future weather data has been downloaded from the GFDL-CM3 climate model under RCP 4.5 and RCP 8.5 scenarios. Using the projected weather data, the phenophase of both varieties has been predicted using Info-Crop and CERES-DSSAT models. During the base period, Jyothi took 71 days and Jaya took 75 days to reach 50% flowering, while the total duration was found to be 101 days in Jyothi and 108 days in Jaya. In the case of 50% flowering, CERES-DSSAT predicted more accurately for Jyothi while InfoCrop predicted more accurately for Jaya. The prediction of physiological maturity was found to be more accurate using CERES-DSSAT in Jaya and Info-Crop in Jyothi. Validation results showed that both models can be used to predict the phenophases of rice varieties. The predicted duration during base period was compared with future duration. In Info-Crop model, the days to 50% flowering of Jyothi variety in near, mid and end century is expected to reduce by 3, 3 and 4 days in RCP 4.5 scenario and 1, 3 and 4 days in RCP 8.5 scenario whereas for Jaya variety, it is by 2, 3 and 3 days in RCP 4.5 and 1, 3 and 3 days in RCP 8.5 scenario respectively. CERES-DSSAT model predicted reduction of 50% flowering duration of Jyothi variety in near, mid and century by 1, 2 and 3 days in RCP 4.5 scenario and 1, 2 and 2 days in RCP 8.5 scenario whereas for Jaya variety, the reduction is by 2, 2 and 3 days in RCP 4.5 scenario and 1, 2 and 3 days in RCP 8.5 scenario respectively. The physiological maturity is projected to shorten by 3-6 days in Jyothi and 4-5 days in Jaya, by the end century. Results showed that the temperature rise in future can cause the considerable reduction in duration to attain 50% flowering and physiological maturity of rice varieties.

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