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Arsenic contamination in groundwater and its impact on human health has been reported as one of the world's biggest natural groundwater calamities to the mankind. In Assam, Arsenic concentration in groundwater above the permissible level has been reported from 20 districts, of which, maximum level of Arsenic concentration was found in Jorhat, Lakhimpur, Nalbari and Nagaon districts. In the present study Arsenic and Iron contamination of groundwater in Narayanpur Block and Sakhomato Block of North Bank Plain Zone of Assam was determined. Eighty seven numbers of ground water samples from Narayanpur Block and forty seven numbers from Sakhomato Block were collected from tubewells (15 feet to 75 feet deep) at different locations of the Blocks. The Arsenic content of analyzed samples from Narayanpur Block varied from 0 (zero) ppb to 102 ppb, of which, 48 (55.17%) samples were found below the WHO guideline value for drinking (less than 10 ppb); while 39 (44.83%) samples contained Arsenic above the guideline value (more than 10 ppb, WHO, 2011). In case of Sakhomato Block, all the 47 samples contain Arsenic below the critical limit of 10 ppb and hence found safe for drinking. Iron concentration of the samples having Arsenic concentration above the critical limit of 10 ppb from Narayanpur Block was analyzed with a view to ameliorating Arsenic toxicity through removal of Iron. The Iron concentration of the samples ranged from 10 ppm to 58.4 ppm. However, no significant correlation between Iron and Arsenic concentration was observed (r2=0.0403).

A field experiment conducted evaluated the efficacy of chlorantraniliprole 18.5SC @ 100 ml/ha, indoxacarb 15.8 SC @ 300 ml/ha, quinalphos 25 EC @ 1500 ml/ha, triazophos 40 EC @ 800 ml/ha, thiacloprid 21.7 SC @ 650 ml/ha and one botanical, neem oil @ 3 lit/ha against major pests of soybean. Among these, thiacloprid 21.7 SC was found tobe the most effective against flea beetle, Monolepta signata; quinalphos 25 EC against the tobacco caterpillar Spodoptera litura (F.) and blister beetle Mylabris phalerata Thunb; chlorantraniliprole 18.5SC against stem fly Ophiomyia phaseoli Tryon; and chlorantraniliprole 18.5SC and thiacloprid 21.7 SC against leaf folder Nacoleia vulgalis Guenee. The highest yield was obtained with thiacloprid 21.7SC treatment.

Field experiment conducted in 2013–2015 at the experimental cum research farm, School of Agricultural Sciences and Rural Development, Nagaland University, Medziphema campus, evaluated the effect of sowing dates and varieties against the large white butterfly (Pieris brassicae) on cabbage. The results revealed that late planting on 19th December harboured the maximum incidence, in terms of number of caterpillars/plant (8.50–2013–2014; 6.96–2014–2015, respectively). The pooled data showed a mean incidence of 7.3. Early planting on 19th November was observed with the least incidence. Among the varieties, the maximum incidence was observed in “Pride of India” (9.45–2013–2014; 7.47–2014–2015, respectively), with the pooled mean being 8.46. The lowest population was observed in “Green Express” (2.85–2013–2014; 1.78–2014–2015) and the pooled data showed an incidence of 2.32. The interaction of dates of planting and varieties was observed to be significant.

A field experiment was conducted during the kharif seasons of 2010, 2011 and 2012 at the research farm of All India Coordinated Research Project for Dryland Agriculture, Biswanath College of Agriculture, Assam Agricultural University, Biswanath Chariali with the objectives to find out the feasibility of intercropping green gram and black gram in sesame. The experiment was conducted with 11 treatments (T1-Sesame Sole, T2-Green gram Sole, T3-Black gram Sole, T4-Sesame + Greengram (1: 1), T5-Sesame + Greengram (2: 1), T6 Sesame + Greengram (2: 2), T7-Sesame + Greengram (3: 1), T8-Sesame + Blackgram (1: 1), T9-Sesame + Blackgram (2: 1), T10-Sesame + Blackgram (2: 2), T11-Sesame + Blackgram (3: 1).) in a Randomized Block Design with three replications. Considering the sesame as base crop, sesame, greengram and blackgram were sown simultaneously as per treatment during post kharif seasons (Mid August-Mid September). It was observed that intercropping of sesame in green gram and blackgram had significantly superior value in respect of the Sesame Equivalent Yield (SEY), Land Equivalent Ratio (LER), Rain Water Use Efficiency (RWUE) net return and B: C ratio. From the pooled data of three years, the highest SEY (13.85q/ha) was recorded by T8-Sesame + blackgram (1: 1) followed by Sesame + Greengram (2: 2) and Sesame + blackgram (2: 1). The highest LER (1.42), RWUE (7.42kg/ha/mm), Net return (39, 374/ha) and B: C ratio(4.40) was also recorded in Sesame + Blackgram (1: 1).

The effect of seasonal variation on the biochemical contents of the tender leaves of Lasia spinosa has been investigated. The concentration of nutrient like protein, fat, iron, calcium, potassium and ascorbic acid were found to increase during the monsoon season except carbohydrates and fibers. Among the non-nutrients but health protective phytochemicals as total alkaloids, flavonoids and phenolic compounds also showed increasing value during monsoon than pre-monsoon in Lasia spinosa. Therefore, the monsoon season could be adjudged as the best season for harvesting and consumption of the green Lasia to maximize the nutritional and medicinal potency when used for herbal formulation and as vegetable respectively.

Rhizomes of turmeric (Curcuma longa L.) are widely used for their medicinal as well as flavoring properties and in order to concentrate on biological means of promoting turmeric cultivation in Assam, a greenhouse experiment was conducted to evaluate the effects of native arbuscular mycorrhizal fungi (Glomus, Gigaspora and Acaulospora sp.) sourced from turmeric rhizosphere along with phosphate solubilizers (Bacillus megaterium) and nitrogen fixers (Azospirillum amazonense and Azotobacter sp.) on soil enzyme activities and microbial characteristics of soil under turmeric cultivation. The single, dual and consortium inoculations showed higher enzyme activities over control. Results revealed an increase in phosphatase (18.3–21.3 μmol p-nitrophenol g−1 h−1), dehydrogenase (83.4–100.5 nmol TPF g−1 h−1) and urease (83.2–99.5 μmol NH3-N g−1 h−1) enzyme activities along with an increase of 1.30–1.82 μg g−1 soil microbial biomass carbon content. Besides, mycorrhizal colonization rate showed a similar pattern in dual and consortium inoculation with single inoculation of arbuscular mycorrhizal fungi (95.2–97%) suggesting the plant growth promoting microbes as mycorrhiza helper bacteria for a clear preference as bioinoculants to be used for a sustainable agricultural strategy.