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We describe the development, construction, data analysis, initial calibration, and first results of the Leicester dual-beam imaging polarimeter (LE2Pol), an inexpensive dual-beam optical imaging polarimeter. LE2Pol is designed for a 20-inch telescope at the observatory of the University of Leicester, but can also be used as a visiting instrument on a wide range of small telescopes (≲1 m). We show how simple imaging polarimeters on small telescopes can be used to provide useful scientific and educational data at low cost.

A field experiment was conducted for two years in “Deep Black Soils” to study the residual and direct effect on growth, yield, monetary efficiency, nutrient uptake and soil properties after harvest...

A field experiment was conducted in clay soil in texture, low in organic carbon (0.27 and 0.32%), low in available nitrogen (210 and 204 kg/ha), medium in available phosphorus (24 and 29 kg/ha), high in available potassium (281 and 289 kg/ha) and slightly alkaline in reaction (pH 7.57 and 7.54) with normal electrical conductivity (0.33 and 0.38 dS/m) during the year 2017-18 and 2018-19, respectively to study the response of inter and intra row spacing of sugarcane by using single eye bud settling on nutrient content, uptake and soil fertility status after harvest of sugarcane at Main Sugarcane Research Station, Navsari, Navsari Agricultural University, Gujarat, India during 2017-18 and 2018-19. On the basis of pooled analysis, significantly higher total nitrogen, phosphorus and potassium uptake at harvest recorded under planting of single eye bud settling at 120 cm (R2) and remained at par with planting of single eye bud settling at 135 cm (R3) inter row spacing. Maximum total potassium uptake at harvest noted significantly under planting of single eye bud settling at 120 cm inter row spacing over rest of the treatments. Significantly superior total nitrogen and phosphorus uptake at harvest obtained under planting of single eye bud settling at 60 cm (S2) intra row spacing over rest of treatments. The interaction effect between different inter and intra row spacing showed that treatment combination 120 cm x 60 cm (R2S2) found significantly higher total nitrogen, phosphorus and potassium uptake at harvest which remained at par with 135 cm x 60 cm (R3S2). Nutrient content in cane and trash as well as soil nutrient status after harvest of crop did not show any significant influence due to different inter and intra row spacing of sugarcane.

Background: Intensive rice cultivation for longer periods continuously resulted in poor soil fertility. Inorganic fertilizers along with integrated and judicious use of different organic sources like FYM, vermicompost, green manure etc. could be an effective choice for enhancing crop yield. A synergistic effect on crop yield is reported through common use of fertilizer and organics which also improve soil fertility. The residual effects of organic manures applied to the preceding crops can be available to succeeding crop. Therefore, this experiments was planned to throw light on the use integrated nutrients through organic and inorganic sources on rice and its residual effect on succeeding greengram. Methods: A field experiment was conducted to study the effect of integrated nutrient management on rice-greengram cropping sequence at Navsari Agricultural University, Gujarat during 2012-15. Five nutrient combinations were evaluated in randomized block design for rice and its residual effect on productivity on succeeding greengram was studied with three fertilizer levels in split plot design. Result: Application of general recommended dose of fertilizers (RDF) to rice has increased growth, yield, quality, economics and improved soil properties and the residual effect to succeeding greengram have also gave significantly higher greengram seed yield and other important parameters and this was succeeded by application of 75% RDF through chemical fertilizer + 25% RDF through vermicompost. Among different levels of fertilizers to greengram, application of 100% RDF gave highest greengram seed yield, economics and soil parameters over other two levels.

Epoxy resin of 9,9′-bis-(3,5-dibromo-4-hydroxyphenyl) anthrone-10 (EANBr, EEW 490) was synthesized and was characterized by IR and 1HNMR . EANBr and EPK3251 cured resin (EANBrC) were characterized by DSC and TGA at 10°Cmin−1 under nitrogen atmosphere. Broad DSC endothermic transitions of EANBr (265.3 °C) and EANBrC (291.4 °C) are due to some physical change and further confirmed by no weight loss in their TG thermograms. EANBr and EANBrC are thermally stable up to 340 °C and 310 °C, respectively. EANBr has followed single step degradation kinetics, while EANBrC has followed two step degradation kinetics. EANBr followed apparently zero order kinetics, while EANBrC followed apparently second order (1.80) and first order (0.89) degradation kinetics, respectively. Ea and A values of EANBrC (299.7 kJmol−1 and 6.32 × 1020 s−1) were found higher than that of EANBr (201 kJmol−1 and 2.45 × 1013 s−1) due to more rigid nature of EANBrC. The ΔS* value of the first step degradation of EANBrC (146.3 JK−1 mol−1) was found much more than that of EANBr (4.6 JK−1 mol−1). Jute – EANBr composite (J-EANBr) was prepared by compression molding technique at 120 °C for 5 h and under 20 Bar pressure. The observed tensile strength, flexural strength, electric strength and volume resistivity of J-EANBr are 24.7 MPa, 19.0 MPa, 1.8 kVmm−1 and 3.5 × 1012 ohm cm, respectively. Water absorption in J-EANBr was carried out at 30 ± 2 °C against distilled water, 10% NaCl, 10% HCl, 10% HNO3, 10% H2SO4, 10% NaOH, and 10% KOH and also in boiling water. The equilibrium time and equilibrium water content for J-EANBr in different environments are 384–432 h; 12.7–15.2%, respectively. The observed equilibrium water content and diffusivity trends of J-EANBr are KOH>H2SO4>HCl>NaOH>H2O>NaCl and H2O>NaCl>NaOH>H2SO4>HCl>KOH, respectively. Good thermo-mechanical, electrical properties and excellent hydrolytic stability of J-EANBr may be useful for high temperature applications in diverse fields.

Dynamic DSC curing kinetics of epoxy resin of 9,9′-bis(4-hydroxyphenyl) anthrone-10 (EAN) was carried out at 5, 10, 15 and 20 °C min−1 heating rates in nitrogen atmosphere using 4,4′-diaminodiphenylsulfone (DDS), 4,4′-diaminodiphenylmethane (DDM) and tetrahydrophthalicanhydride (THPA) hardeners. Peak exotherms shifted toward higher temperature range with increasing heating rate. DSC data were analyzed by Ozawa, Kissinger and Flynn–Wall–Ozawa methods to derive activation energy (E a) and frequency factor (A). Observed trend in E a and A is EAN-DDS > EAN > EAN-THPA > EAN-DDM. For EAN-amine systems, both E a and A decreased with increasing conversion and for EAN-THPA they increased up to 30% conversion and then decreased slowly with increasing conversion. Friedman plots showed autocatalytic nature of the EAN-hardener systems. Autocatalytic nature is due to dehydration of secondary alcohol groups with simultaneous formation of allylic double bonds. EAN-THPA showed 1.34 and 0.34, respectively, for n and m orders of kinetics. The validity of kinetic model was performed by simulation analysis using obtained kinetic constants for EAN-THPA. Experimental and calculated curves are in agreement between α = 0.2–0.6. Thermogravimetric study at 10 °C min−1 heating rate in nitrogen atmosphere revealed that cured resins (310–337 °C) are more thermally stable than thermally cured EAN (279 °C) and followed either one- or two-step degradation kinetics.

On the basis of past 115 years (1901-2015) rainfall data of five districts of south Gujarat, the Mann-Kendall trend, Sen’s slope and regression slope showed that annual and monsoon rainfall at Valsad, Dang and Surat shows the increasing trend while, that of Navsari and Bharuch districts are declining. The monsoon season (summer monsoon) rainfall variability of Valsad, Dang, Surat, Navsari and Bharuch districts was recorded is 30.1%, 30.9%, 35.9%. 33.3% and 38.6%. The high coefficient of variation (CV) denoted that the variability of rainfall is not equally distributed and the amount of rainfall is lowest. The Bharuch district the annual and monsoon CV per cent denoted that the variability of rainfall in both seasons are very high. Valsad was recorded lowest CV with highest rainfall while the data are represent that variability of rainfall which can varies Bharuch to Dang in different districts of south Gujarat. The data shows that Dang district comes under high rainfall and Bharuch under low rainfall on south Gujarat. A low standard deviation indicates that the data points tend to be close to the mean of the set, while a high standard deviation indicates that the data points are spread out over a wider range of values. Similarly high SD is reported at Dang district because of high range of rainfall and lowest SD is found at Bharuch district because of low rainfall variability. The rainfall distribution different season viz., pre monsoon, monsoon post monsoon and winter season, the highest present contribution of rainfall is observed during monsoon season followed by post monsoon in all the five districts of south Gujarat. Rainfall contribution during remaining months was less than one per cent. While month wise analysis shows during monsoon season highest rainfall per cent contribution to annual rainfall is in July followed by August and June months at all the five districts of south Gujarat.

A field experiment was conducted during Rabi 2011 Navsari to assess the response of Rabi sweet corn to spacing and fertilizer levels under south Gujarat condition. The experiment comprised of sixteen treatment combinations consisting four levels of plant spacing (60 x 15, 45 x 20, 30 x 30 and 60 x 30 cm ) and four fertility levels (60-30, 90-45, 120-60 and 150-75 kg N-P 2 O 5 /ha).Plant spacing of 60 x 30 cm, 45 x 20 cm and 60 x 15 cm attained significantly higher plant height compared to 30 x 30 cm. While stem diameter and number of leaves per plant were not influenced by different spacing levels. The sweet corn plants exhibited significantly maximum values of yield attributes viz., cob length, cob girth, under spacing of 45 x 20 cm. Number of cobs per plant and cob yield per plant were higher under spacing of 60 x 30 cm. The highest green cob yield was recorded at spacing of 45 x 20 cm closely followed by 30 x 30 cm. Quality parameters viz., crude protein content in cob and fodder reducing and non-reducing sugar content of grains were higher at spacing 45 x 20 cm. The growth of sweet corn in terms of plant height, number of leaves per plant, stem diameter were maximum with application of 150-75 kg N-P 2 O 5 /ha. The sweet corn plants exhibited maximum values of yield attributes viz., number of cobs per plant under 150-75 kg N-P 2 O 5 /ha and found at par with those recorded under 120-60 kg NP 2 O 5 /ha. Whereas cob length, cob were under 120-60 kg N-P 2 O 5 /ha and found at par with those recorded under 150-75 kg N-P 2 O 5 /ha. Application of 150-75 and 120-60 kg N-P 2 O 5 /ha significantly increased green cob yield over 90-45 and 60-30 kg N-P 2 O 5 /ha. Quality parameters viz., protein content of cob and fodder were significantly enhanced. Thus, from the present study, it seems quite logical to conclude that higher production and net returns from Rabi sweet corn ( var. Madhuri ) can be secured by sowing the crop at 45 cm x 20 cm spacing and fertilizing with 120-60 kg N-P 2 O 5 /ha on clayey soil under south Gujarat condition.

A field experiment was conducted during Kharif seasons of 2014, 2015 and 2016 with an objective to assess the feasibility of weed and nutrient management in direct-seeded rice. The experiment was laid out in a factorial RBD with eighteen treatment combinations including six weed management treatments, viz. pretilachlor, pendimethalin, pretilachlor followed by (fb) bispyribac-sodium, pendimethalin fb bispyribac-sodium, weed free and weedy check and three nitrogen (N) levels, viz. 80, 100 and 120 kg N/ha with three replications. Significantly lower weed biomass was recorded with weed free which [2 hand weedings (HW) at 20 and 40 days after seeding (DAS)] was at par with pendimethalin 1.0 kg/ha pre-emergence treatment (PE) fb bispyribac-sodium 0.04 kg/ha, post-emergence treatment (PoE). Similarly, the highest weed control efficiency (WCE, 73.0%) and the lowest weed index (WI) were also recorded with weed free treatment, followed by pendimethalin 1.0 kg/ha fb bispyribac sodium 0.04 kg/ha (WCE, 71.2%). Rice growth and yield attributes, viz. plant height, effective tillers, panicles length, grains/panicle were improved significantly under combine application of PE and PoE herbicides either pendimethalin 1.0 kg/ha or pretilachlor 0.75 kg/ha (PE) fb bispyribac 0.04 kg/ha (PoE) and weed free [2 HW at 20 and 40 DAS]. Further, weed free treatment as well as pendimethalin 1.0 kg/ha fb bispyribac 0.04 kg/ha were found equally effective and recorded significantly higher rice grain and straw yield and nutrient use efficiency (NUE) with higher net returns compared to rest of treatments. Application of 120 kg N/ha significantly increased the plant height, effective tillers/plant, panicle length, grain/panicle, grain and straw yield, N content and NUE % over rest of the treatments in all aspects of yield and yield attributes. It was concluded that 2 HW at 20 and 40 DAS or application of pendimethalin 1.0 kg/ha fb bispyribac-Na 0.04 kg/ha for weed control appeared to be a viable strategy along with 120 kg N/ha for achieving higher and profitable yield of direct-seeded rice.

A field experiment was conducted during rabi 2011 at College Farm, Department of Agronomy, College of Agriculture, Navsari Agricultural University, Navsari to assess the response of rabi sweet corn (Zea mays L. var. saccharata Sturt) to spacing and fertilizer levels under south Gujarat conditions. The experiment comprising 16 treatment combinations consisting of four levels of plant spacing (60×15, 45×20, 30×30 and 60×30 cm) and four fertility levels (60–30, 90–45, 120-60 and 150-75 kg N-P2O5/ha). Plant spacing of 60×30 cm, 45×20 cm and 60×15 cm attained significantly higher plant height compared to 30×30 cm. While stem diameter and number of leaves per plant were not influenced by different spacing levels. The sweet corn plants exhibited significantly maximum values of yield attributes viz., cob length, cob girth, under spacing of 45×20 cm. Number of cobs per plant and cob yield per plant were higher under spacing of 60×30 cm. Highest green cob yield was recorded at spacing of 45×20 cm closely followed by 30×30 cm. The highest net returns (Rs. 60568/ha) and BCR (5.52) were recorded under plant spacing of 45×20 cm. The growth of sweet corn in terms of plant height, number of leaves per plant and stem diameter were maximum with application of 150-75 kg N-P2O5/ha. The sweet corn plants exhibited maximum values of yield attributes viz., number of cobs per plant under 150-75 kg N-P2O5/ha and found at par with those recorded under 120-60 kg N-P2O5/ha. Whereas cob length and cob girth were under 120-60 kg N-P2O5/ha and found at par with those recorded under 150-75 kg N-P2O5/ha. Application of 150-75 and 120-60 kg N-P2O5/ha significantly increased green cob yield over 90–45 and 60–30 kg N-P2O5/ha. Economic evaluation of fertility levels revealed that the highest net returns of Rs. 59509/ha and BCR of 5.46 were recorded with application of 120-60 kg N-P2O5/ha. Thus, from the present study, it seems quite logical to conclude that higher production and net returns from rabi sweet corn (var. Madhuri) can be secured by sowing the crop at 45×20 cm spacing and fertilizing with 120-60 kg N-P2O5/ha on clayey soil under south Gujarat conditions.

An experiment was conducted at the Instructional Farm, Navsari Agricultural University, Navsari (Gujarat) during kharif seasons of 2012 and 2013 on transplanted rice under rice-greengram cropping sequence in randomized block design with five treatments replicated four times. The treatment imparted to rice crop was integrated nutrient management viz., T1-General RDF (RDF: 100-30-00 kg N-P-K/ha+FYM @ 10 t/ha), T2-75% RDN through chemical fertilizer+25% RDN through biocompost, T3-75% RDN through chemical fertilizer+25% RDN through vermicompost, T4-75% RDN through chemical fertilizer+25% RDN through FYM and T5-Control. On the basis of pooled mean, the results indicated that application of general RDF (RDF+FYM @ 10 t/ha) recorded significantly highest grain and straw yields of rice as well as total NPK uptake by rice (grain and straw) than other treatments followed by 75% RDN through chemical fertilizer+25% RDN through vermicompost. However, maximum net returns and benefit ratio were noted with the application of 75% RDN through chemical fertilizer+25% RDN through biocompost followed by general RDF (RDF+FYM @ 10 t/ha).

A field experiment was conducted at Instructional Farm, N. M. College of Agriculture, Navsari Agricultural University, Navsari during rabi season in two consecutive years during 2010–11 and 2011–12 to study the effect of critical period of crop-weed competition on nutrient content and uptake by weed and rabi castor (Ricinus communis L.). The 12 treatments viz., weed free up to 30 DAS, weed free up to 60 DAS, weed free up to 90 DAS, weed free up to 120 DAS, weed free up to harvest, weedy up to 30 DAS, weedy up to 60 DAS, weedy up to 90 DAS, weedy up to 120 DAS, weedy up to harvest, two hand weedings and interculturing at 30 and 60 DAS and pendimethalin @ 1 kg/ha (as pre-emergence)+ one hand weeding and interculturing at 60 DAS were evaluated with three replications in a randomized block design (RBD). The results revealed that treatment weed free up to harvest recorded significantly lowest weed density, dry weight of weeds, nutrient uptake by weed and maximum in castor seed yield and nutrient uptake by plant followed by the treatment weed free up to 120 DAS and weed free up to 90 DAS. However, highest net monetary returns (Rs. 46.6 x 103/ha) and B: C ratio (3.02) were obtained with the treatment weed free up to 90 DAS which was found more critical period for crop weed competition.