MSc

The programme entitled “Physiological, biochemical and yield attributes of bell pepper (Capsicum annuum var. grossum) as influenced by biochar amended with biofertilizers” was carried out at the Department of Plant Physiology, College of Agriculture, Vellayani during 2021-2022. The objective of the programme was to evaluate the physiological, biochemical and yield attributes of bell pepper as influenced by biochar amended with biofertilizers.
A pot culture study was carried out with bell pepper variety “California Wonder” in completely randomized design (CRD). It involved a combination of eight treatments which is inclusive of a control also, with three replications in each. The different treatments were T1-control, T2-biochar, T3-Azospirillum, T4-VAM, T5-Piriformospora indica, T6-biochar + Azospirillum, T7-biochar + VAM and T8-biochar + P. indica.
Different morphophysiological parameters like plant height, number of branches, photosynthetic rate, transpiration rate, chlorophyll content, leaf area index, root weight, root volume, shoot weight, root:shoot ratio, days to first flowering and days to first fruiting were studied. Of all the eight treatments that were studied, biochar + VAM (T7) was found to be the best treatment in increasing the morphophysiological parameters. Biochar + Azospirillum (T6) was observed to be on par with biochar + VAM (T7) in terms of photosynthetic rate, transpiration rate, leaf area index and shoot weight. Whereas, P. indica treated plants were found to be on par with biochar + VAM (T7) in terms of root characteristics. Also, P. indica proved to reduce the vegetative period and induce earliness of flowering in bell pepper plants.
Considering the biochemical parameters, flavonoid content, total soluble proteins and ascorbic acid content were found to increase under the influence of Azospirillum. Polyphenol content was found to increase upon the treatment with VAM. However, with the application of biochar there was enhancement in all the biochemical parameters, viz. biochar + Azospirillum (T6) proving to be the best in terms of flavonoids (4.87 mg g-1), total soluble proteins (23.67 mg g-1) and ascorbic acid content (129.92 mg 100g-1) while biochar + VAM (T7) in terms of polyphenols (24.34 mg g-1).
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VAM and Azospirillum were found to be on par with each other in terms of yield parameters, viz. number of fruits per plant, fruit weight and yield per plant. However, among all the treatments, biochar + VAM (T7) resulted in higher number of fruits per plant (7.33), fruit weight (76.42 g) and yield per plant (0.61 kg). Biochar + Azospirillum (T6) was found to be on par with biochar + VAM (T7) pertaining to fruit weight (74.72 g).
Among the biofertilizer treatments, nitrogen uptake by the crop was found to be significantly higher in Azospirillum (T3) while phosphorous and potassium uptakes were found to be higher in VAM (T4). Of all the eight treatments, biochar + Azospirillum (T6) recorded the highest nitrogen uptake (131.47 kg ha-1). Biochar + VAM (T7) recorded the highest phosphorous uptake (30.97 kg ha-1) by the crop and was significantly on par with VAM (T4). Also, biochar + VAM (T7) recorded highest potassium uptake (121.60 kg ha-1) which was significantly on par with biochar + Azospirillum (T6).
VAM was found to increase the organic carbon content of soil to a higher extent than other biofertilizers. Biochar amendment (T2) significantly recorded highest organic carbon content in the soil (2.99%). Microbial characteristics study also evidently proved that biochar increased the Azospirillum population (40-40.74%) in rhizosphere soil and VAM colonization percentage (5.88-7.5%) in root bits of bell pepper plants when compared to sole application of biofertilizers alone.
Based on the present study, it can be concluded that combined application of biochar and VAM biofertilizer could increase the performance of bell pepper plants and improve its physiological, biochemical and yield attributes while also improving the soil organic carbon content and microbial density.