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Key soil parameters, organic matter, soil pH and plant nutrients determine the capacity of a soil to sustain plant and animal productivity. Conservation agriculture (CA) and crop diversification or intensification may change these soil parameters positively or negatively, which eventually affect long-term sustainability. We monitored these key soil properties (at depths of 0-15 and 15-30 cm) under CA-based sustainable intensification practices: zero-till (ZT), and crop residue retention, and crop rotations on Inceptisols and Entisols in the Eastern Ganga Alluvial Plains from 2014 to 2017. The rainfall of this sub-tropical region is 1273-3201 mm. Soil organic carbon (C) ranged within 0.46-1.13% and generally followed (positive) rainfall gradients. At all sites, the soil under ZT tended to have higher organic C than conventional tillage (CT). Soil pHH2o ranged within 5.7-7.8 across the region. At all sites, soil pH generally decreased under ZT compared to CT. This was most marked at some acidic soil sites where pH decreased by up to 0.4 units; the lower the initial soil pH, the higher was the decrease in pH under ZT practice. In contrast, the reverse trend was observed for soil organic C. Partial nutrient balances for N, P and K in rice-wheat and rice-maize systems were positive for N and P ( Additional keywords: cropping systems, maize, partial nutrient balance, rice, soil organic C, soil pH, South Asia, wheat. Received 14 June 2019, accepted 30 July 2019, published online 10 September 2019, Introduction Conservation agriculture (CA) and crop diversification or intensification are the major components of the emerging farming systems for ensuring food security in South Asia (Jat et al. 2014; Islam [...]

A commercially available electromagnetic simulator--MAGIC, a particle-in-cell (PIC) code--has been used to carry out a comparative study of the beam-wave interaction under uniform and tapered magnetic field profiles of a 42 GHz, 200kW gyrotron. The magnetic field profile across the resonant cavity varies by ±6.5% with a peak value of 1.615 T. The MAGIC simulation shows the desire performance of the gyrotron under both magnetic field conditions with an operating mode TE03 and a pitch factor of 1.26. The analysis of the simulated results show that stability in the power growth was reached more quickly and achieved higher output power in the case of a tapered magnetic field. PACS Nos: 07.57.Hm, 41.20.Jb Le simulateur eelectromagneetique MAGIC commercialement disponible est un code source de type PIC que nous avons utilise pour faire une etude comparee de l'interaction faisceau-onde sous champ magnetique uniforme et decroissant d'un gyrotron de 200 kW et 42 GHz. Le profil du champ magnetique dans la cavite resonante varie de [+ o -]6.5% avec une valeur pic de 1.615 T. La simulation MAGIC montre la performance deesireee du gyrotron sous les deux configurations magnetiques avec un mode TE03 d'utilisation et un coefficient de variation de 1.26. L'analyse des simulations montre que la stabilite de la montee en puissance est atteinte plus rapidement avec un profil de champ magnetique decroissant, qui permet aussi une plus grande puissance de sortie. [Traduit par la Redaction], 1. Introduction A gyrotron, based on the electron cyclotron maser (ECM) phenomenon, is a fast-wave device designed to produce high-power coherent millimetre and submillimeter wavelength radiation [1, 2]. In a [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.06.008 Byline: L.C. Ram (a), N.K. Srivastava (a), R.C. Tripathi (a), S.K. Jha (a), A.K. Sinha (a), G. Singh (a), V. Manoharan (b) Abstract: Long-term field trials using lignite fly ash (LFA) were carried out in rice crops during the period 1996-2000 at Mine I, Neyveli Lignite Corporation, Tamil Nadu. LFA, being alkaline and endowed with an excellent pozzolanic nature, silt loam texture, and plant nutrients, has the potential to improve the texture, fertility, and crop productivity of mine spoil. The rice crops were the first, third, fifth, and sixth crops in rotation. The other crops, such as green gram (second) and sun hemp (fourth), were grown as green manure. For experimental trials, LFA was applied at various dosages (0, 5, 10, 20, 50, 100, and 200t/ha), with and without press mud (10t/ha), before cultivation of the first crop. Repeat applications of LFA were made at the same dosages in treatments of up to 50t/ha (with and without press mud) before cultivation of the third and fifth crops. Press mud, a lightweight organic waste product from the sugar industry, was used as an organic amendment and source of plant nutrients. Also, a recommended dosage of chemical fertilizer, along with gypsum, humic acid, and biofertilizer as supplementing agents, was applied in all the treatments, including control. With one-time and repeat applications of LFA, from 5 to 20t/ha (with and without press mud), the crop yield (grain and straw) increased significantly (p Author Affiliation: (a) Central Fuel Research Institute, PO-FRI, 828108 Dhanbad, Jharkhand, India (b) Centre for Applied Research and Development, Neyveli Lignite Corporation Limited, Neyveli 607801, Tamil Nadu, India Article History: Received 3 October 2003; Accepted 21 June 2005

Analysis of [[delta].sup.18]O in igneous zircons of known age traces the evolution of intracrustal recycling and crust-mantle interaction through time. This record is especially sensitive because oxygen isotope ratios of igneous rocks are strongly affected by incorporation of supracrustal materials into melts, which commonly have [[delta].sup.18]O values higher than in primitive mantle magmas. This study summarizes data for [[delta].sup.18]O in zircons that have been analyzed from 1,200 dated rocks ranging over 96% of the age of Earth. Uniformly primitive to mildly evolved magmatic [[delta].sup.18]O values are found from the first half of Earth history, but much more varied values are seen for younger magmas. The similarity of values throughout the Archean, and comparison to the composition of the 'modern' mantle indicate that [[delta].sup.18]O of primitive mantle melts have remained constant ([+ or -] 0.2[per thousand]) for the past 4.4 billion years. The range and variability of [[delta].sup.18]O in all Archean zircon samples is subdued ([[delta].sup.18]O(Zrc)=5-7.5[per thousand]) ranging from values in high temperature equilibrium with the mantle (5.3 [+ or -] 0.3[per thousand]) to slightly higher, more evolved compositions (6.5-7.5[per thousand]) including samples from: the Jack Hills (4.4-3.3 Ga), the Beartooth Mountains (4.0-2.9 Ga), Barberton (3.5-2.7 Ga), the Superior and Slave Provinces (3.0 to 2.7 Ga), and the Lewisian (2.7 Ga). No zircons from the Archean have been analyzed with magmatic [[delta].sup.18]O above 7.5[per thousand]. The mildly evolved, higher Archean values (6.5-7.5[per thousand]) are interpreted to result from exchange of protoliths with surface waters at low temperature followed by melting or contamination to create mildly elevated magmas that host the zircons. During the Proterozoic, the range of [[delta].sup.18]O(Zrc) and the highest values gradually increased in a secular change that documents maturation of the crust. After ~1.5 Ga, high [[delta].sup.18]O zircons (8 to > 10[per thousand]) became common in many Proterozoic and Phanerozoic terranes reflecting [[delta].sup.18]O(whole rock) values from 9 to over 12[per thousand]. The appearance of high [[delta].sup.18]O magmas on Earth reflects non-uniformitarian changes in the composition of sediments, and rate and style of recycling of surface-derived material into magmas within the crust.