Productivity and carbon sequestration potential of coconut-based cropping system as influenced by integrated nutrient management practices

A field experiment was carried out at Regional Coconut Research Station, Bhatye (DBSKKV, Dapoli), Maharashtra (India) during 2013-2018 to study the productivity and carbon sequestration potential as influenced by integrated nutrient management (INM) practices in coconut based cropping system. INM practices viz., T1- 75 per cent of RDF+25 per cent of N through organic recycling with vermicompost, T2- 50 per cent of RDF+50 per cent of N through organic recycling with vermicompost + vermiwash application + bio-fertilizer application + in situ green manuring (cowpea), T3- fully organic: 100 per cent N through organic recycling with vermicompost + vermiwash application + bio-fertilizer application + in situ green manuring (cowpea) and green leaf manuring + composted coir pith, husk incorporation and mulching with coconut leaves were imposed in coconut based cropping system involving nutmeg, cinnamon, banana and pineapple. For comparison, T4- control: monocrop of coconut with recommended NPK and organic manure was maintained. Four treatments were laid out in a block of 0.45 ha area each. Among the different INM practices, treatment T1 sequestered the highest amount of above ground (coconut + nutmeg) carbon stock (31.1 t ha-1) followed by T2 (30.3 t ha-1) and T3 (27.3 t ha-1). In contrast, the treatment T4 - coconut monocrop alone had sequestered 25.6 t ha-1. The below-ground soil carbon stock in the rhizosphere of different crops was the highest in the nutrient management under T3 followed by T2 and T1, whereas, it was the lowest in coconut monocrop. The productivity of the system was higher in the intercropping garden. The coconut nut yield (5-year average) was higher yield under T1 (147.2 nuts palm-1 year-1), followed by T2 (138.4 nuts palm-1 year-1) and T3 (123.6 nuts palm-1 year-1), whereas, monocrop had recorded a significantly lower number of nuts (97.2 nuts palm-1 year-1)

Heterosis for economic traits in coconut (Cocos nucifera L.)

Field studies conducted for a period of 12 years to assess the traits responsible for yield performance and heterosis of twelve coconut hybrids in comparison with three varieties showed that among the hybrids, GBGD x ECT recorded the highest mean yield of 127.6 nuts palm-1 year-1 and was on par with ECT x GBGD (106.9 nuts palm-1 year-1), COD x LCT (108.0 nuts palm-1 year-1) and WCT x MYD (107.6 nuts palm-1 year-1). Hybrid GBGD x PHOT recorded the highest fruit length (23.9 cm) followed by ECT x GBGD (23.3 cm). The hybrid ECT x GBGD recorded the highest values for most of the fruit characteristics viz., fruit breadth (17.3 cm), fruit weight (1180.0 g), husked fruit weight (758.0 g) and copra weight (231.1 g). The variety ‘Laccadive Ordinary’ recorded higher oil content (71.1%) compared to its hybrids, LCT x GBGD (70.8%), COD x LCT (70.0%) and LCT x COD (69.8%). Hybrids displayed substantial differences in their heterotic response for nut characters. The highest yielding hybrid, GBGD x ECT excelled its standard check by 40.8 per cent followed by LCT x COD (39.4%)

Bis(chalcogenones) as pincer ligands: isolation and Heck activity of the selone-ligated unsymmetrical C,C,Se-Pd pincer complex

The reaction of meta-phenylene-bis(1-methyl-1H-imidazole-2(3H)-selone) with [Pd-2(mu-Cl)(2)(2-C6H4CH2NMe2)(2)] in dry benzene and glacial acetic acid resulted in the formation of an unsymmetrical 5,6-membered C,C,Se-Pd(II) pincer complex through C-H bond activation and extrusion of one selenium. This is the first example of a C,C,Se-Pd(II) complex wherein the central Pd(II) is simultaneously coordinated to a selone and an N-heterocyclic carbene. The chelated complex of the type [PdL2](2+)2[PF6](L = bis(selone)) was isolated from the reaction of the bis(selone) with [PdCl2(PhCN)(2)] and NH4PF6. The unsymmetrical pincer complex was studied for Heck activity revealing its application as an acceptable catalyst in coupling of iodobenzene with acrylates and styrene

Synthesis, structure and reactivity of a selenoxide derived from a bulky selenide: Bis(2,4,6-trimethylphenyl) selenoxide

22-26Bis(2,4,6-trimethylphenyl) selenoxide has been synthesized by oxidation of bis(2,4,6-trimethylphenyl) selenide with aqueous H2O2 and characterized by elemental analysis and NMR spectroscopy (1H, 13C{1H} and 77Se{1H}). The single crystal X-ray diffraction analysis reveals that the selenium atom adopts a trigonal pyramidal configuration. The reactions of bis(2,4,6-trimethylphenyl) selenoxide with various thiols and other proton donor species in CDCl3 have been studied by 77Se{1H}; NMR spectroscopy that with thiols at room temperature regenerated the selenide. The data indicate that the selenoxide acts as a hydrogen bond acceptor to give Mes2Se=O…HX (Mes = 2,4,6-trimethylphenyl or mesityl) species

Palladium assisted formation of arylselenoacetone from diaryldiselenides in methanol-acetone

1510-1514The reaction of Na2PdCl4 with diaryldiselenide in methanol-acetone yields trans-[PdCl2{SeAr(CH2COMe)}2] (Ar = 2,4,6-Me3C6H2 and 2,4,6-iPr3C6H2) and [PdCl(SeAr)]n. The intermediate products in these reactions have been characterized by analytical and spectroscopic data and by single crystal X-ray diffraction studies. A plausible mechanism for the formation of arylselenoacetone in these reactions has been suggested

Chalcogenolato-bridged cyclometallated binuclear palladium complexes: Synthesis, spectroscopy, structures of [Pd2(μ−Cl)(μ−SMes)(C10H6NMe2–C,N)2]{[Pd_2(\mu-Cl)(\mu-SMes)(C_{10}H_6NMe_2–C,N)_2]} and [Pd2(μ−SePh)2(C10H6NMe2–C,N)2]{[Pd_2(\mu-SePh)_2(C_{10}H_6NMe_2–C,N)_2]}

Reactions of orthometallated binuclear palladium complexes with NaER, obtained by {NaBH_4} reduction of {R_2E_2} in methanol, gave complexes, {[Pd_2(\mu-ER)_2(C^\capY)_2]} {(HC^\capY)} = N,N-dimethylbenzylamine {(C_6H_5CH_2NMe_2)}, N,N-dimethylnaphthylamine {(C_10H_7NMe_2)}, tri-o-tolylphosphine ${P(tol-o)_3}$; ER=SePh, SeMes, TePh, TeMes $(Mes = 2,4,6-Me_3C_6H_2)$. Similar reactions of {[Pd_2(\mu-Cl)_2} (C_10H_6NMe_2–C,N)_2]} with ${Pb(SMes)_2}$ or MesSH in the presence of {NaHCO_3} gave chloro/thiolato-bridged complex ${[Pd_2(\mu-Cl)(\mu-SMes)(C_10H_6NMe_2–C,N)_2]}$. The newly synthesized complexes were characterized by elemental analysis, UV–Vis, IR, NMR {(^1H, ^{13}C, ^{31}P, ^{77}Se, ^{125}Te)} spectroscopy. These complexes crystallized out preferentially in sym-cis configuration. A low energy charge transfer transition has been identified from chalcogenolate centers to an emptyπ* orbital of cyclometallated ligand in absorption spectroscopy in these complexes. The structures of ${[Pd_2(\mu-Cl)(\mu-SMes)(C_10H_6NMe_2–C,N)_2]}$ (1) and ${[Pd_2(\mu-SePh)_2(C-10H_6NMe_2–C,N)_2]}$ (3) have been established by single crystal X-ray diffraction analyses. In the former, the two palladium atoms are held together by chloro and thiolato bridges whereas in the latter, the two phenylselenolato ligands bridge two palladium atoms. The pyrolysis of ${[Pd(\mu-TeMes)(C_10H_6NMe_2–C,N)]_2}$ (10) in a furnace gave {Pd_7Te_3} whereas thermolysis in TOPO afforded primarily {PdTe_2}