Mahan Singh

Planting methods and weed management to improve yield in dry-seeded rice

A field experiment was conducted to evaluate the effect of planting methods and weed management in direct dry-seeded rice during summer season of 2012 and 2013 at Agricultural Research Farm, Institute of Agricultural Sciences Banaras Hindu University, Varanasi (Uttar Pradesh). The treatment comprised of five rice planting treatments, viz. conventional tillage normal spacing [row to row (R × R) -18 cm], conventional tillage square planting (R×R-20 cm, plant to plant (P × P)-20 cm), conventional tillage paired row (9-27-9 cm), reduced tillage paired row (9-27-9 cm), reduced tillage square planting (R × R -20 cm, P×P-20 cm) in main plot and sub-plot consisted of four weed management treatments, viz. weedy, two hand weeding, pendimethalin 1.0 kg/ha fb azimsulfuron 17.5 g/ha + bispyribac 25 g/ha (tank mixed) at 15 DAS fb one hand weeding (HW), oxadiargyl 50 g/ha fb metsulfuron-methyl 2 g/ha + chlorimuron-ethyl 2 g/ha (ready mix) at 20 DAS fb 1 HW. Significant reduction in weed density and biomass was recorded in two hand weeding fb pendimethalin 1.0 kg/ha fb azimsulfuron 17.5 g/ha + bispyribac 25 g/ha (tank mixed) at 15 DAS fb 1 HW which resulted in improved growth and yield attributes and yield of rice. Amongst rice planting methods, conventional tillage normal spacing (R × R -18 cm) and conventional tillage paired row (9-27-9 cm) were able to compete with weeds more as compared to other rice planting methods resulting in lower weed density and weed biomass, enhanced rice growth and yield attributing characters and yield.

The diamagnetic susceptibilities of phthalic acid and phthalic anhydride

Summary1.The gram-molecular susceptibilities of carefully purified samples of phthalic acid and its anhydride are determined. The susceptibilities are: Phthalic acid, Xm=−81·24×10−6 Phthalic anhydride, Xm=−67·31×10−6 It is found that whereas the value of the gram-molecular susceptibility of phthalic acid found by Gray and Birse and ourselves is nearly equal, that for the anhydride is higher in our case.2.The difference in gram-molecular susceptibilities of dibasic acids and their anhydrides is nearly equal to that of water with minor variations, possibly due to different structures attached to the anhydride rings.3.The constitutive effect of the rings in the anhydrides of different dibasic acids has also been discussed.

The diamagnetic susceptibilities of succinic acid and succinic anhydride

Summary(1)Measurements have been made on the magnetic susceptibilities of succinic acid and its anhydride. The susceptibilities are:

CLXXVIII.—Studies on the dependence of optical rotatory power on chemical constitution. Part III. 1 : 4-Naphthylenebisiminocamphor

\chi _M = - 57 \cdot 47 \times 10^{ - 6} for the acid

Integrated weed management and crop establishment method for higher yield in direct-seeded rice

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The diamagnetic susceptibilities of succinic acid and succinic anhydride the influence of the anhydride ring structure on molecular diamagnetism

\chi _M = - 43 \cdot 85 \times 10^{ - 6} for the anhydride