Karuna, K.Sinha, Rajni2020-12-172020-12-172019-10-04https://krishikosh.egranth.ac.in/handle/1/5810156801A field experiment was conducted on Kinnow mandarin to find out the effect of fertigation on growth, physiological and biochemical parameters, nutrient acquisition by leaf, yield and granulation related changes in Kinnow mandarin at BAU, Sabour during the year 2016 and 2017 under different fertigation levels. There were five treatments comprising of ring and drip irrigation combined with fertilizers application in soil application and through drip system as fertigation. The experiment was conducted on 6-years old plants at Horticulture Garden, Bihar Agricultural College, Sabour. Observations on vegetative, physiological parameters and leaf nutrient status were recorded once in a year and biochemical analysis were done every month starting from September to December. Fertigation had significant effect on vegetative growth parameters of trees and response was good in comparison to soil application. The percent increase in plant height, stem girth and canopy spread was found maximum (87.69 %, 6.23 %, 70.22 % respectively) in treatment receiving 120 % NPK as fertigation (T1) which was at par with the treatment T2. The lowest was recorded in treatment with ring irrigation and broadcast methods of fertiliser application (T5). Fertigation treatments resulted in significant variation in leaf nutrient content in Kinnow. Higher nitrogen (2.81 %), phosphorus (0.19 %), potassium (1.71 %), iron (72.55 ppm), manganese (63.35 ppm), copper (20.54 ppm) and zinc (60.31 ppm) were recorded with fertigation with 120 % RDF (T1). Available nutrient distribution in soil had shown a decreasing trend with increasing soil depths (0-15 to 30-60 cm). Physiological parameters like photosynthesis (9.08 µmol/m2/sec), transpiration (0.82 µmol/m2/sec), stomatal conductance (0.33 µmol/m2/sec), leaf area (119.45 cm2) , chlorophyll a content (2.82 mg g-1), chlorophyll b content (0.43 mg g-1), total chlorophyll content ( 2.82 mg g-1) and total carotenoids content (2.03 mg g-1) in the leaves of Kinnow trees were observed maximum in T1 with minimum content in control (100 % RDF as soil application) whereas, internal CO2 concentration (312.93 ppm) was found highest in T1 but least in T4 (60 % RDF as fertigation). Fruit physical parameter like fruit weight (164.82 g), Fruit diameter (6.94 cm), fruit length (6.90 cm), was found maximum in T1 but highest juice per cent (44.76 %) in T2 and it increases as fruit matures and reached to maximum value in the month of December (M4). However, peel thickness (3.44 mm) was maximum in T1 and decreases from the month of September to December as fruit matures and undergoes towards ripening. No. of fruits at the time of harvest (59.25) and yield (12.64 kg /tree ) was found maximum in T1 and lowest in control. The maximum TSS (9.56 0Brix), TSS: acid ratio (12.13), ascorbic acid (32.35 mg/100 g ) ,total sugars per cent (6.84 %), flavonoids content (0.37 mg/ml ) in fruit juice and total carotenoids content (23.05 µg/g FW) in peel were found under fertigation with T1 and it’s value increases from the month of September to December as fruit matures and undergoes towards ripening while titrable acidity was found maximum (1.38 %) in control and with advancement in fruit maturation its value decreases. Total chlorophyll content in peel was recorded maximum( 23.57 µg/g FW) in T1 minimum in control and it decreases as fruit matures. Total phenols content (0.75 mg/ml) and total antioxidant activity (8.32 µmol Trolox /g FW) were found maximum in T1 and its value were more at the time of first sample investigation in the month of September (M1) then, it decreases in October month and then, again start to rise and reached to peak value at last harvest i.e. in the month of December (M4). Degree of granulation found maximum (1.75 %) in T4 (60 % RDF as fertigation) which is at par with T3 and minimum degree in T1. Enzymatic activity linked to granulation as like diastase activity was recorded highest (24.80 mol/min.) in T2 (100 % RDF as fertigation) and lowest (16.81 mol/min) in T4 and with advancement in fruit ripening diastase activity decreases. However, for the pectin esterase activity, there was non significant effect of the different fertigation treatments but its value decreases as fruit undergoes maturation. Therefore, it can be concluded that economically, fertigation with 100 % RDF, NPK can be recommended for splits application for young Kinnow orchards and harvest the fruit in the month of December which having all optimum measure of biochemicals that pertains its excellent fruit quality.EnglishThesis