R. K. Malik

NUTRIENT USE PATTERN IN THE IRRIGATED RICE-WHEAT CROPPING SYSTEM IN THE INDO-GANGETIC PLAINS OF HARYANA, INDIA

SUMMARY On-farm nutrient management practices were evaluated in the irrigated rice-wheat cropping system (RWCS) in northwestern India. Large farmers used comparatively higher doses of nutrients than small and medium farmers for both rice and wheat crops. On average, a field is treated with organic manure after every 15 years for rice and 53 years for wheat. Nitrogen use was generally more than the recommended dose for both crops. Phosphorus use in wheat was nearly as per recommendation, while in rice it was below the recommended dose. Potassium use was almost nil; however, the use of Zn (particularly in rice) is becoming common. Use of biofertilizers was negligible. Overall, farmers applied higher doses of organic manures, K, Zn and biofertilizers in rice than wheat, and there was increasing trend in their use with increase in the size of land holdings. Grain yield increased significantly with increase in the size of land holding in rice but remained almost same in wheat. This study generated comprehensive data on nutrient use pattern in the RWCS, thus providing necessary input to researchers, planners and developmental agencies who wish to enhance food security.

CdS nanorod–MFe2O4 (M = Zn, Co and Ni) nanocomposites: a heterojunction synthesis strategy to mitigate environmental deterioration

A facile strategy to encrust MFe2O4 (M = Zn, Co and Ni) nanoparticles over CdS nanorods via a two-step solvothermal method has been reported. The ferrite–CdS nanocomposites (NCs) were characterized using powder X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. A shift in the peak corresponding to the (311) plane confirmed the presence of different metal ions in the spinel ferrite lattice. However, no variation in the peak of CdS was observed which indicates that the phase and morphology of the CdS nanorods remain unaltered after hydrothermal treatment. High resolution transmission electron microscopy (HR-TEM) analysis revealed the efficacious attachment of the nanoferrite on the CdS nanorods. Optical studies of the NC samples provided information about the fabrication of the visible light responsive photocatalyst and covered the solar spectrum from 525 nm to 737 nm. From magnetic studies, CdS–CoFe2O4 and CdS–NiFe2O4 were found to be ferromagnetic in nature with a saturation magnetization of 26.4 and 15.5 emu g−1, respectively. Interestingly, a transition from ferromagnetic to super-paramagnetic was observed for the ZnFe2O4 loaded CdS nanorods. The photo-catalytic activities of the nanocomposites were studied by carrying out photo-degradation of rhodamine B and methylene blue dyes under visible-light irradiation. The maximum activity was observed in the case of the CdS–ZnFe2O4 nanocomposites.

Morphology Controlled CdS Nanostructures: A Proficient Visible-Light-Driven Photocatalyst

Abstract Visible light driven catalytically active CdS morphologies viz. nanoparticles, nanorods, nanospheres and nanoflowers were fabricated via facile and versatile solvothermal method by adjusting the experimental conditions. The fabricated samples were critically analyzed using Powder X-ray Diffraction, High Resolution Transmission Electron Microscopy, Brunauer-Emmett-Teller and UV-vis Diffused Reflectance Spectrum. Elemental composition of CdS samples was confirmed by using Energy Dispersive X-ray Spectroscopy. Crystallite size for CdS nanoparticles was found to be ∼ 4 nm while in case of other morphologies, it was found to be in range of 27-33 nm. Optical studies revealed the information about the band gap of visible light responsive photocatalysts and covered the solar spectrum from 525 nm to 650 nm. Photocatalytic activities of all the CdS morphologies were compared using methylene blue, methyl orange, safranin O, rhodamine B and remazol brilliant yellow as probe molecule. The different CdS morphologies were found to exhibit dissimilar catalytic efficacy, which was due to the fact that there was large difference in the surface area of the samples. The experimental results were found to be in accordance with the order: CdS nanoparticles > CdS nanorods > CdS nanospheres ∼ CdS nanoflowers. Therefore, CdS morphology with better catalytic activity can be deduced as an ideal catalyst for the treatment of dye waste water.

Interesting structural transformation of CdS from zinc blende into wurtzite during minuscule loading of magnetic nanoparticles: emergence of heterojunctions with enhanced photocatalytic performance

Interestingly, a structural transformation of zinc blende CdS nanoparticles into hexagonal wurtzite nanoparticles was observed during the formation of ferrite nanoparticles loaded onto the CdS heterojunction system. The interplanar spacing of 0.33 and 0.31 nm in the nanocomposites corresponds to the (002) and (101) planes of wurtzite CdS, providing direct proof of the conversion. On the other hand, the interplanar spacings of 0.29 and 0.25 nm could be indexed to the (220) and (311) planes of ferrite nanoparticles, revealing the successful decoration of ferrite nanoparticles over the CdS nanoparticles and nanorods. The band gap energy values of the CdS nanoparticles and nanorods decreased when they were decorated with the ferrite nanoparticles. The synthesized heterojunction showed enhanced photocatalytic performance for the mitigation of organic pollutants, without the need for an oxidant, when compared to both CdS and ferrite nanoparticles. This work not only enriches our knowledge of heterojunction formation, but also reveals that the combined effect of structural transformation and charge separation in the nanocomposites induced by the synergistic effect of CdS and ferrites could bring enhanced photocatalytic activity, suggesting the tremendous potential of these nanocomposites for water purification at an industrial level.

Long-term impact of crop establishment methods on weed dynamics, water use and productivity in rice-wheat cropping system

An experiment consisting of five establishment techniques in rice-wheat cropping sequence with different combinations of conventional tillage (CT), zero-tillage (ZT) and minimum tillage (MT) viz. CT-CT, ZT-CT, CT-ZT, ZT-ZT and MT-ZT) was conducted during 2003–2007 at the farm of a farmer in Haryana on a larger plot size of 0.4 ha under each treatment. During first year, grain yield of wheat did not differ significantly among different treatments but during 2004–05 to 2007–08, grain yield of wheat in ZT method of planting was either higher or at par with conventional ploughed method of planting but CT transplanting of rice was significantly more than ZT transplanted treatments except during first year when rains were very good at transplanting time. Weed dynamics after 4 years revealed that in rice crop, weed density of Echinochloa colona, E. crusgalli, Leptochloa chinensis, Cyperus spp. and broad-leaf weeds such as Ammania baccifera and Eclipta alba was more when rice was transplanted under ZT or MT conditions but in wheat, weed density of grassy weed Phalaris minor was less under ZT-ZT or MT-ZT treatments. After 4 years of continuous ZT in both rice and wheat crops, weed flora changed in favour of broad-leaf weeds. Bulk density of soil did not vary after 5 years of ZT-ZT conditions. Soil temperature of root zone in wheat crop planted under ZT conditions was more (0.7–1.7 OC) in first week of February and less (2.1-.3.8 OC) in first week of April as compared to conventional CT-CT practice of rice and wheat crops resulting in more grain yield of wheat due to temperature moderation and also due to a bit addition of organic matter in ZT conditions. Grain yield of rice planted under ZT or MT conditions was less mostly due to more weed infestation and it also consumed 4.8–184% more water as compared to CT method of puddle transplanted rice.

Strengthening Farmers’ Knowledge for Better Weed Management in Developing Countries

Of more than 3 billion people (nearly half of the world’s population) who live in rural areas, around 2.5 billion derive their livelihoods from agriculture, which remains crucial to developing countries for meeting the demands of affordable food, feed, energy, and the security of their populations. Approximately, three quarters of the world’s agricultural value is generated in developing countries and, in many of these, the agriculture sector contributes as much as 30 % to gross domestic product (GDP). GDP growth from agriculture benefits the incomes of poor people two to four times more than the GDP growth in other sectors of the economy.

Functionalized magnetic nanomaterials for rapid and effective adsorptive removal of fluoroquinolones: Comprehensive experimental cum computational investigations

Alarming growth of pharmaceutical residues in aquatic environment has elevated concerns about their potential impact on human health. Taking cognizance of this, the present study is focussed on the coating of cobalt ferrite nanoparticles with different functionalities and to use them as adsorbents for pharmaceutical waste. The thickness of the coating was analysed using Small angle X-ray scattering technique. Thorough study of the isotherms and kinetics were performed suggesting monolayer adsorption and pseudo kinetic order model, respectively. To get an insight of the interactions liable for adsorption of fluoroquinolones over the functionalized magnetic nanoparticles computational studies were undertaken. The results demonstrated substantial evidence proposing remarkable potential of these nanostructures as adsorbents for different pollutants with an additional advantage of stability and facile recoverability with a view to treat wastewater.