A field experiment was carried out on 10 December 2015 and 05 December 2016 for tomato during rabi season at Central Farm, Regional Agricultural Research Station (RARS), Jessore. The experiment was laid out in Factorial Randomized Complete Block Design (RCBD) with four replications. There were six treatment combinations viz. T1P1U: 0% P ´ Without AM, T2P2U: 50% P ´ Without AM, T3P3U: 100% P ´ Without AM, T4P1AM: 0% P ´ With AM, T5P2AM: 50% P ´ With AM, T6P3AM: 100% P ´ With AM. The tested crop was tomato (cv. BARI Tomato-15). The unit plots measured 3 m × 3 m in size. Soil based arbuscular mycorrhizal (AM) inoculum were used in seed bed for producing tomato seedlings containing about 100 spores per 100 g soil and infected root pieces of the host plant was used at the rate of 1 kg soil inoculum m-2 in seedbed. A layer of AM inoculum was firstly placed in each bed and was covered with a thin soil layer of 1 cm. Seeds were sown in seed bed and transplanted after 30 days in field. The physical and chemical properties of the initial soil samples from seed bed and experimental fields at a depth of 0-15 cm were collected and analyzed following standard methods and presented.
Methods of chemical analysis:
Soil pH was measured by a combined glass calomel electrode (Jackson, 1958). Organic carbon was determined by wet oxidation method (Walkley and Black, 1947). Total N was determined by modified Kjeldahl method. Calcium, K and Mg were determined by NH4OAc extraction method. Copper, Fe, Mn and Zn were determined by DTPA extraction followed by AAS reading. Boron was determined by CaCl2 extraction method. Phosphorus was determined by Modified Olsen method (Neutral + Calcareous soils). Sulphur was determined by CaH4(PO4)2. H2O extraction followed by turbidimetric turbidity method with BaCl2.
Nitrogen, phosphorus, potassium, sulphur, zinc and boron were used in the form of urea, TSP, MoP, gypsum, zinc sulphate and boric acid, respectively. Recommended fertilizer dose (BARC, 2012) for tomato (160 kg N, 30 kg P, 60 kg K, 13 kg S, 1.5 kg Zn and 0.5 kg B kg ha-1) were used. Phosphorus was used in three levels (0% P, 50% P and 100% P). All K, S, Zn, B and 1/3rd amount urea were applied at the time of final land preparation and the remaining 2/3rd amount of urea-N were applied in two equal installments at 25 and 45 days of transplanting. All the intercultural operations such as irrigation, sticking, weeding, insect control etc. were done as and when necessary. Data on yield and yield components were recorded at maturity. The tomato was harvested on 16 March to 20 April 2016 and 12 March to 10 April 2017. The initial soil samples at a depth of 0-15 cm from the experimental fields were collected and analyzed following standard methods.
Statistical analyses were conducted using standard statistical procedures (Gomez and Gomez, 1984) implemented in Statistix 10. The data were examined by analysis of variance (ANOVA). Differences between the treatments were determined by ANOVA, and Fisher’s protected least significant difference (LSD) was calculated at the 0.05 probability level for treatment mean comparisons.