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Abstract A 3-year field experiment was setup to address the threat of underground water depletion and sustainability of agrifood systems. Subsurface drip irrigation (SDI) system combined with nitrogen management under conservation agriculture-based (CA) maize-wheat system (MWS) effects on crop yields, irrigation water productivity (WPi), nitrogen use efficiency (NUE) and profitability. Grain yields of maize, wheat, and MWS in the SDI with 100% recommended N were significantly higher by 15.8%, 5.2% and 11.2%, respectively, than conventional furrow/flood irrigation (CT-FI) system. System irrigation water savings (~ 55%) and the mean WPi were higher in maize, wheat, and MWS under the SDI than CT-FI system. There was saving of 25% of fertilizer N in maize and MWS whereas no saving of N was observed in wheat. Net returns from MWS were significantly higher (USD 265) under SDI with 100% N (with no subsidy) than CT-FI system despite with higher cost of production. The net returns were increased by 47% when considering a subsidy of 80% on laying SDI system. Our results showed a great potential of complementing CA with SDI and N management to maximize productivity, NUE, and WPi, which may be economically beneficial and environmentally sound in MWS in Trans-IGP of South Asia.

Owing to enormous increase in the automobile population, traditional petroleum fuels for internal combustion engines will be usable only for a few years. Moreover, by releasing toxic emissions into the atmosphere at higher levels these fuels create severe environmental problems. In general, Carbon-monoxide (CO), Unburnt hydrocarbons (UHC), and smoke are emissions emitted by engines. The pollution of the environment can be controlled by replacing petroleum fuel with the use of alternative fuels like acetylene gas, hydrogen, CNG, LPG etc. In this current research, an experimental investigation was carried out in Compression Ignition engine using acetylene fuel, further enhancing the performance and emission properties by using diethyl ether (DEE) and ethanol as oxygenated fuel. In view of the performance and outflow (emission) parameters optimizing valve of acetylene gas as 12 lpm with oxygenated fuels, the performance and outflow characteristics were improved. The findings show an enhancement in brake thermal-efficiency of up to 3 to 4%, a decrease in exhaust temperature and emissions like CO, UHC and smoke of up to 40%, 20%–30% and 10%–35% respectively, there is decrease in fuel consumption of 10%–30%. It was found that ethanol is better than diethyl ether and diesel fuels when used as an oxygenated fuel with acetylene gas. In view of the performance and emission parameters, the best oxygenated fuel is ethanol and the optimize blend for diesel engine is E15+A12.

Coconut-coir, a natural fiber, strong and lightweight, abundantly in India and Vietnam, can be an excellent choice to produce polymer composites. Due to the higher specific modulus and durability, these composites have a myriad of applications. This article provides a novel experimental research study on the fabrication and investigation of mechanical as well as thermal behavior of coir fiber/woven-carbon fiber/epoxy resin hybrid composite. The composite samples were formulated with distinct fiber weight percentages viz. 30%, 20%, and 10% using the vacuum bagging technique. Mechanical behavior (tensile, compressive, flexural, and impact strength) and thermal behavior (Thermogravimetric analysis) of coir fiber/carbon fiber/epoxy resin hybrid composites were studied according to the ASTM standards. Moreover, Scanning Electron Microscopy (SEM) was performed to examine the morphological characterization of tensile fractography specimens and analyze the properties of the fiber/matrix bonding of the surface before and after alkaline treatment. The treated fiber shows good matrix binding and less fiber pull-out as compared with untreated fibers. The result also revealed that the hybrid composite has more robust properties under mechanical loading than single fiber-reinforced composite.

Additive manufacturing has gained popularity among material scientists, researchers, industries, and end users due to the flexible, low cost, and simple manufacturing process. Among number of techniques, fused deposition modeling (FDM) is the most recognized technology due to easy operation, lower environmental degradation, and portable apparatus. Despite numerous advantages, the limitations of this technique are poor surface finish, dimensional accuracy, and mechanical strength, which must be improved. The present study focuses on the implementation of the genetic algorithm and Taguchi techniques to achieve minimum dimensional variability of FDM parts especially for polymeric biocomposites. The output has been measured using standard testing techniques followed by Taguchi and genetic algorithm analyses. Four response variables were measured and were converted into single variable with combination of different weightages of each response. Maximum weightage was given to width of FDM polymeric biocomposite parts which may play critical role in biomedical and aerospace applications. The advanced optimization and production techniques have yielded promising results which have been validated by advanced algorithms. It was found that layer thickness and orientation angle were significant parameters which influenced the dimensional accuracy whereas best fitness value was 0.377.

A total of 31 species of weeds belonging to 11 families was collected from rice fields in Fatehgarh District of Punjab between June and November 2017. Of the 31 species, 15 were dicots and 16 were monocots. Of the 11 families, six (Portulacaceae, Lythraceae, Solanaceae, Scrophulariaceae, Polygonaceae, and Commelinaceae) were represented by only one species each. Poaceae was the largest family represented by 10 species, followed by Asteraceae and Cyperaceae with five species each. The largest genus was Cyperus with four species, followed by Euphorbia, Echinochloa, and Eragrostis with two species each. Of the 31 weed species, 29 were annual and only two, Cyperus rotundus and Parthenium hysterophorus, were perennials. More detailed survey work is required on a regular basis to identify possible problematic weeds and new or improved control measures.

Acute lymphoblastic leukemia (ALL) is a cancer of the white blood cells and is typically well treated with combination chemotherapy, with a remission state after 5 years of 94% in children and 30-40% in adults. To establish how aggressive the disease is, further chromosome testing is required to determine whether the cancer is myeloblastic and involves neutrophils, eosinophils or basophils, or lymphoblastic involving B or T lymphocytes. This case study is on a 14-year-old patient diagnosed with a very aggressive form of ALL (positive for the Philadelphia chromosome mutation). A standard bone marrow transplant, aggressive chemotherapy and radiation therapy were revoked, with treatment being deemed a failure after 34 months. Without any other solutions provided by conventional approaches aside from palliation, the family administered cannabinoid extracts orally to the patient. Cannabinoid resin extract is used as an effective treatment for ALL with a positive Philadelphia chromosome mutation and indications of dose-dependent disease control. The clinical observation in this study revealed a rapid dose-dependent correlation.

Adenoviruses (AdVs) are icosahedral viruses with double-stranded DNA (dsDNA) genomes. Genome packaging in AdV is thought to be similar to that seen in dsDNA containing icosahedral bacteriophages and herpesviruses. Specific recognition of the AdV genome is mediated by a packaging domain located close to the left end of the viral genome and is mediated by the viral packaging machinery. Our understanding of the role of various components of the viral packaging machinery in AdV genome packaging has greatly advanced in recent years. Characterization of empty capsids assembled in the absence of one or more components involved in packaging, identification of the unique vertex, and demonstration of the role of IVa2, the putative packaging ATPase, in genome packaging have provided compelling evidence that AdVs follow a sequential assembly pathway. This review provides a detailed discussion on the functions of the various viral and cellular factors involved in AdV genome packaging. We conclude by briefly discussing the roles of the empty capsids, assembly intermediates, scaffolding proteins, portal vertex and DNA encapsidating enzymes in AdV assembly and packaging.

We present a case of 50-year-old male having unstable angina. A rare type of single coronary artery was identified during the Coronary angiogram. The left anterior descending (LAD) and left circumflex artery (LCX) had originated from the proximal segment of right coronary artery along with significant lesion in LCX. Computed tomographic (CT) coronary angiogram confirmed the origin and course following which successful percutaneous coronary intervention (PCI) was done to LCX. The incidence of this type of coronary anomaly is 0.004%. We emphasize the importance of having a CT coronary angiogram to identify the course before the intervention. The procedural risk during PCI in patients with single coronary ostium is high. Moreover, the angulation and course of the culprit artery also pose a challenge. Good coaxial guide support by using an appropriate guiding catheter is the key to success.

This study deals with anilofos tolerance and its mineralization by the common rice field cyanobacterium Synechocystis sp. strain PUPCCC 64. The organism tolerated anilofos up to 25 mg L(-1). The herbicide caused inhibitory effects on photosynthetic pigments of the test organism in a dose-dependent manner. The organism exhibited 60, 89, 96, 85 and 79% decrease in chlorophyll a, carotenoids, phycocyanin, allophycocyanin and phycoerythrin, respectively, in 20 mg L(-1) anilofos on day six. Activities of superoxide dismutase, catalase and peroxidase increased by 1.04 to 1.80 times over control cultures in presence of 20 mg L(-1) anilofos. Glutathione content decreased by 26% while proline content was unaffected by 20 mg L(-1) anilofos. The test organism showed intracellular uptake and metabolized the herbicide. Uptake of herbicide by test organism was fast during initial six hours followed by slow uptake until 120 hours. The organism exhibited maximum anilofos removal at 100 mg protein L(-1), pH 8.0 and 30°C. Its growth in phosphate deficient basal medium in the presence of anilofos (2.5 mg L(-1)) indicated that herbicide was used by the strain PUPCCC 64 as a source of phosphate.

Intensive tillage, removal or burning of crop residues, limited organic manure use, declining irrigation water resources and scarcity of labour are the major causes of soil degradation and unsustainability of rice (Oryza sativa L.) wheat (Triticum aestivum L.) system (RWS) in South Asia.Resource conservation technologies (RCTs) such as zero tillage (ZT), dry direct seeded rice (DSR) and crop residues retained as mulch have shown promise to increase the productivity and profitability of RWS in South Asia. Effects of RCTs on soil biological parameters are unclear and contradictory. We evaluated the effects of conservation agriculture practices on changes in soil biochemical properties at different growth stages of wheat grown as the fifth crop in RWS. Twelve treatment combinations of tillage, crop establishment and crop residue management included four main plot treatments in rice: (1) conventional tillage (CT)-DSR, (2) ZT-DSR, (3) DTR, ZT machine transplanted rice and (4) PTR, conventional puddled transplanted rice. The three subplot treatments were: (i) CTW-R, CT wheat with both rice and wheat residues removed, (ii) ZTW-R, ZT wheat with residues of both the crops removed and (iii) ZTW+R, ZT wheat with rice residue retained as surface mulch in subsequent wheat. Irrespective of rice establishment methods, mean wheat grain yield under ZTW+R was 6% and 10% greater than CTW-R and ZTW-R respectively. Soil enzyme activities increased (5-18%) under ZTW+R compared with ZTW-R and CTW-R at different growth stages of wheat. The residual effect of rice establishment methods was significant on soil enzyme activities during wheat cropping, which were highest under ZT-DSR followed by CT-DSR, DTR and PTR. Soil organic carbon content in the 0-7.5 cm layer was significantly higher (7-9%) under the ZTW+R treatment compared with all the other treatments. Principal component analysis (PCA) identified three enzyme activities (dehydrogenase, fluorescein diacetate and phosphatase), and soil organic carbon content as the most sensitive indicators for assessing soil quality for RWS based on conservation agriculture. The PCA discriminated rice establishment systems with rice residue as surface mulch from rice establishment systems without rice residue and the maximum tillering stage from the other stages of wheat. The present study provided reliable biochemical indicators to monitor soil biological quality changes in response to conservation agriculture practices in RWS. Additional keywords: Conventional tillage, rice establishment methods, rice straw retention, soil enzymes, wheat growth stages., Introduction Rice-wheat system (RWS) is an important cropping sequence for food security, employment, income and livelihood for millions of people in Asia (Singh et al. 2014). This system occupies ~13.5 [...]

Conventional tillage and crop establishment methods for the rice–wheat (RW) system are input intensive (water, labour and energy). About 24.5 million tonnes of rice residues are burnt every year on farms in north-western India before sowing of wheat, causing air pollution and soil health degradation. Therefore, alternative tillage, crop establishment and residue management practices are needed for long-term sustainability of the RW system. A 4-year field study evaluated four tillage and crop establishment methods in rice (in main plots) and three tillage and rice residue management methods in wheat (in subplots) for their effects on yield, soil fertility, and profitability of the RW system. Average rice yields were similar under conventional puddled transplanted rice (PTR) and conventional till dry seeder rice (CTDSR). Both of these treatments produced significantly greater yields (10–16%) compared with zero till DSR (ZTDSR) and ZT machine transplanted rice in non-puddled soil, respectively, regardless of tillage and straw management methods in the previous wheat crop. Wheat yields in ZT wheat (ZTW) with 100% surface retention of rice residue (+R) were significantly greater than conventional till without residue retention after 2 years of experimentation, and accompanied by significant increases in macro-nutrient (potassium) availability in soil. The ZTW−R (no residue) treatment produced 15% lower wheat yield than ZTW+R. System yield was highest in CTDSR-ZTW+R, which was 5% higher than the conventional practice PTR-CTW−R, resulting in Rs 17 000 ha−1 greater net returns. The sustainability of conventional rice–wheat production systems in northwestern India has become a major concern for addressing the issues of energy, labour, water scarcity and quality. Resource conservation technologies such as zero tillage with residue retention showed higher productivity, profitability and potential in improving the soil health. The adoption of sowing of wheat into rice residues can achieve high crop productivity and income, while avoiding ill effects of straw burning on the environment. [ABSTRACT FROM AUTHOR]

Concerns regarding the detrimental effects of burning crop residues on human health and the environment have increased interest in alternative uses of crop residues. We examined the in situ use of crop residue as a source of supplemental N for succeeding crops in rice (Oryza sativa L.)-based cropping systems at three sites during 3 yr. The experiments included a rice--wheat (Triticum aestivum L.) rotation at Yixing, Jiangsu province, China; a rice-wheat rotation at Ludhiana, Punjab, India; and double-rice cropping at Taojiang, Hunan Province, China. The supply of N from crop residues was assessed in the absence of fertilizer N as the difference in total plant N between plots with and without residue. At Yixing, incorporation of wheat residue before rice significantly increased the N supply to the rice by 14 kg N [ha.sup.-1] averaged across 3 yr. At Ludhiana, incorporation of rice residue before wheat reduced the N supply by 3 kg N [ha.sup.-1] to the wheat, but increased the N supply by 5 kg N [ha.sup.-1] to the rice crop following the wheat. In all cases, the return of crop residues had no net benefit on crop yield when fertilizer N was supplied at rates sufficient to eliminate N deficiency. The incorporation of crop residues did not increase the N supply to the succeeding crop during its vegetative growth phase, but the N supply to the crop at later growth stages was often increased. Adjustments in the timing and rate of fertilizer N are probably necessary to optimally supply N to crops receiving residues. Abbreviations: [AE.sub.N], agronomic efficiency for applied fertilizer nitrogen; DAS, days after sowing; DAT, days after transplanting; INS, indigenous nitrogen supply; LCC, leaf color chart.

Rice (Oryza sativa L.)-wheat (Triticum aestivum L.) farmers in India burn or remove residues to facilitate seedbed preparation. Incorporation of residues before planting of the next crop generally decreases yields due to N immobilization. Since a window of about 40 d is available between rice harvest and wheat planting, the effect of time of incorporation on rice residue decomposition and N mineralization-immobilization was studied in 1992-1993. The mass loss of residue was 25% for a 10-d, 35% for a 20-d, and 51% for a 40-d decomposition period before wheat planting. Nitrogen release from residue ranged from 6 to 9 kg [ha.sup.-1] during the wheat season. The immobilization of urea N decreased when residue was allowed to decompose for 10-d or longer. Based on these studies, a long-term (1993-2000) experiment was conducted on a sandy loam soil to examine the effect of rime of residue incorporation before sowing wheat when compared with burning or removal of residue on yields, N-use efficiency, and soil fertility. The effect of wheat residue incorporation with green manure (GM, Sesbania cannabina L.) on subsequent rice yields was also determined. Residue incorporation for 10 to 40 d had no effect on wheat yields. Rice yields increased (0.18-0.39 Mg [ha.sup.-1]) when wheat residue was incorporated with GM. Starter N applied at residue incorporation did not influence wheat yields but decreased N recovery efficiency. Physiological efficiency was higher when rice straw was incorporated in wheat and when wheat straw plus GM were incorporated in rice than when rice straw was incorporated for 10 d or when the straw was burned. The long-term application of rice residue increased C accumulation in soil.

The sustainability of the rice (Oryza sativa L.)-wheat (Triticum aestivum L.) rotation is important to Asia's food security. Intensive cropping with no return of crop residues and other organic inputs result in the loss of soil organic matter (SOM) and nutrient supply, and is assumed to be nonsustainable. We evaluated seven treatments comprised of various combinations of green manure (GM; Sesbania cannabina L.); wheat straw (WS), farmyard manure (FYM), and area on yields and yield trends; P and K balance; and soil fertility in a rice-wheat experiment (1988-2000) on a loamy sand in Punjab, India. Rice yields were comparable with GM + urea, WS + GM + urea, and urea alone, but yields were reduced when FYM was supplemented with N. Except during 1 yr, integrated use of FYM and GM produced equal or higher rice yields than other GM based treatments. Wheat straw incorporation reduced average lice yields by 7% compared with WS removal. After 5 yr of continuous application, FYM and WS were at par in increasing rice yields. Organic materials applied to rice had no residual effect on wheat yields except FYM, which increased yield by about 6% compared with urea alone. Rice yield declined by 0.02 to 0.13 Mg [ha.sup.-1] [yr.sup.-1 but wheat yields remained unchanged. Soil C increased with the application of WS and FYM. Potassium balance was highly negative. Although the causes of yield decline are unknown, inadequate K applications and changes in the climatic parameters are possible reasons.

Biochar has received attention due to its potential for mitigating climate change through carbon sequestration in soil and improving soil quality and crop productivity. This study evaluated the effects of rice straw biochar (RSB) and rice husk ash (RHA) each applied at 5 Mg ha−1 and four N levels (0, 40, 80, and 120 kg ha−1) on soil fertility, growth, and yield of rice and wheat for three consecutive rice–wheat rotations. RSB significantly increased electrical conductivity, dehydrogenase activity, and P and K contents when compared to control (no amendment) up to 7.5 cm soil depth. Both RSB and RHA did not influence shoot N concentration in wheat plant but significantly increased P and K concentrations at 60 days after sowing. Grain yields of both rice and wheat were significantly higher in RSB as compared to control (no amendment) and RHA treatments. While the highest grain yields of rice and wheat were observed at 120 kg N ha−1 in RHA and no biochar-treated plots, a significant increase in grain yields was observed at 80 kg N ha−1 in RSB treatment, thereby saving 40 kg N ha−1 in each crop. Both agronomic and recovery N efficiencies in rice and wheat were significantly higher in RSB-amended soil compared to control. Significant positive correlations were observed between soil N, P, and K concentrations and total N, P, and K concentrations in aboveground biomass of wheat at 60 days after sowing. This study showed the potential benefits of applying RSB for improving soil fertility and yields of rice and wheat in a rice–wheat system. [ABSTRACT FROM AUTHOR]

Knowledge about optimal P rates for wheat (Triticum aestivum L.)-rice (Oryza sativa L.) cropping is insufficient because of nutrient availability differences between aerobic and anaerobic soil. We assessed P management strategies in a wheat-rice rotation on a Typic Ustochrept at Ludhiana, India. Seven P fertilizer treatments applied to wheat and rice, respectively, (PO-O, P0-26, P13-13, P26-0, P26-13, P39-0, and P26-26; treatment abbreviations used include P applied to wheat followed by P applied to rice, both in kg [ha.sup.-1]) were compared from 1990 to 1997. Grain yield and seasonal P accumulation by wheat were highest for higher P rates and remained stable in treatments with P applied to wheat. Phosphorus application to rice increased P accumulation by rice, but did not consistently increase rice yields because flooding decreased soil P sorption and increased P diffusion resulting in higher P supply to rice relative to wheat. Indigenous soil P supply measured in wheat was 5.8 to 8.0 kg P [ha.sup.-1], as compared with 14.9 to 18.1 kg P [ha.sup.-1] in rice. Phosphorus adsorbed by ion-exchange resin capsules placed in situ was five times greater under rice than under wheat. Applying only 26 kg P [ha.sup.-1] to wheat and no P to rice was not economical and led to a negative P balance and a decline in soil P. Applying 32 kg P [ha.sup.-1] to wheat and 15 kg P [ha.sup.-1] to rice was optimal for achieving short-term economic and long-term agronomic goals when both grain and straw were removed from the field. These findings require further validation at other sites, at higher rice yield levels, and for different straw management.

Bagasse and rice husk are two important agro-industrial by-products that are used as fuel in the sugar and rice mill industries, thus producing large quantities of bagasse ash (BA; 0·05 of bagasse) and rice husk ash (0·20 of rice husk) as waste material. Applying BA and rice husk ash (RHA) to agricultural land improves yield, nutrient uptake and chemical fertility of soil, particularly with special reference to available phosphorus (P) and potassium (K). The present field experiment was conducted for 3 years to evaluate the P fertilizer value of these agro-industrial waste materials in a wheat–rice system (WRS). The experiment was laid out in a split-plot design with RHA and BA applied at 10 t/ha and including a no-amendment control as the main plot treatments and three levels of fertilizer P (0, 13 and 26 kg P/ha; designated P0, P13 and P26, respectively) as sub-plot treatments to wheat in WRS. Application of fertilizer P increased the wheat grain yield up to P26 in the un-amended control treatment. However, a significant response of wheat to fertilizer P was also observed up to P13 in the presence of BA and RHA, thereby saving 50% of fertilizer P. Both RHA and BA increased wheat productivity by 12 and 16%, respectively, over the un-amended control. The subsequent rice crop also produced 14% higher paddy yield when the two ashes were applied along with P13 to the previous wheat crop. The increases in grain yield were accompanied by significant increases in the uptake of P and K, and P content (Olsen P) in the soil. The application of recommended P (P26) in un-amended plots resulted in a negative P balance of 9·3 kg P/ha/year. On the other hand, the application of BA alone and RHA along with P13 resulted in neutral/slightly positive P balance. A strong linear relationship (R2 = 0·98) was observed between P balance and Olsen-P build up in the soil. It may be concluded that application of BA and RHA has the potential to increase system productivity and reduce the cost of inputs in terms of reduced application of fertilizer P to wheat and rice. [ABSTRACT FROM PUBLISHER]

Sequestration of soil organic carbon ( SOC) is an important strategy to improve soil quality and to mitigate climate change. To investigate changes in SOC under conservation agriculture ( CA), we measured SOC concentrations after seven years of rice ( Oryza sativa L.)-wheat ( Triticum aestivum L.) rotations in the eastern Indo-Gangetic Plains ( IGP) of India under various combinations of tillage and crop establishment methods. The six treatments were as follows: conventional till transplanted rice followed by conventional till wheat ( CTR- CTW), CTR followed by zero-till wheat ( CTR- ZTW), ZT direct-seeded rice followed by CTW ( ZTDSR- CTW), ZTDSR followed by ZT wheat both on permanent raised beds with residue ( PBDSR- PBW+R), and ZTDSR followed by ZTW both with ( ZTDSR- ZTW+R) and without residues ( ZTDSR- ZTW). We hypothesized that CA systems (i.e. ZT with residue retention) would sequester more carbon (C) than CT. After seven years, ZTDSR- ZTW+R and PBDSR- PBW+R increased SOC at 0-0.6 m depth by 4.7 and 3.0 t C/ha, respectively, whereas the CTR- CTW system resulted in a decrease in SOC of 0.9 t C/ha. Over the same soil depth, ZT without residue retention ( ZTDSR- ZTW) only increased SOC by 1.1 t C/ha. There was no increase in SOC where ZT in either rice or wheat was followed by CT in the next crop (i.e. CTR- ZTW and ZTDSR- CTW), most likely because the benefit of ZT is lost when followed by tillage. Tillage and crop establishment methods had no significant effect on the SOC stock below the 0.15-m soil layer. Over the seven years, the total carbon input from above-ground residues was ca. 14.5 t/ha in ZTDSR- ZTW+R and PBDSR- PBW+R, almost sixfold greater than in the other systems. Our findings suggest that the increased biomass production achieved through a combination of ZT and partial residue retention offers an opportunity to increase SOC whilst allowing residues to be used for other purposes. [ABSTRACT FROM AUTHOR]

Cultivation of high-yielding crop varieties and intensive cropping has depleted the soil fertility in Northwest (NW) India, resulting in the appearance of multi-nutrient deficiencies in different crops and cropping systems. In the present investigation, geo-referenced soil samples from Indian Punjab were analyzed to map fertility status using a Geographical Information System (GIS). Soil texture, which affects soil hydraulic properties and soil strength, varied from sandy to clayey loam, with majority (47.3%) of the cultivated area being sandy loam. About 95% of the total area of the state shows pH between 6.5 and 8.5 (40% of the area between pH 6.5 and 7.5 and 54% between 7.5 and 8.5) and electrical conductivity (EC) <0.8 dS m−1. Calcium carbonate (CaCO3) with <5% values represents 97% area of the state. The GIS-based maps indicate that irrespective of the agroclimatic variations, more than 90% of the soils showed low to medium soil organic carbon (OC) content and 50% low to medium (<22.4 kg P ha−1) available phosphorus (P) content with a marginal (7%) deficiency of potassium (K). The dominance of low to medium status of available P in these soils could be due to the mining of soil P by the rice–wheat cropping system practiced in the region. The intensively cultivated soils of Indian Punjab showed 11% of soil samples were low in zinc (Zn), 15% low in manganese (Mn), 2% low in copper (Cu), and 12% low in iron (Fe). Availability of micronutrients increased with increase in OC content and decreased with increase in sand content, pH, and CaCO3. GIS-based maps are effective in identifying hot spots, which need immediate attention and call for strategic planning for sustainable management. [ABSTRACT FROM PUBLISHER]

In intensive rice–wheat systems of north-west (NW) India, surface retention of rice residues in wheat has been recommended instead of burning. Optimum nitrogen (N) management for zero till (ZT) wheat sown into rice residues may to differ from that of conventional practice ( in-situ burning of residues followed by intensive tillage prior to sowing). Therefore, we conducted several on-farm and on-station field experiments in 2007–2008 to 2012–2013 to evaluate N management practices for ZT wheat sown into rice residues using the Happy Seeder. The optimum N rate for wheat planted into rice residues in fields with no or only a short history of rice residue retention was 120 kg N ha −1 , the current recommendation for conventional practice. Short-term (up to 20 d) soil N mineralization was lower in undisturbed soil than disturbed soil, while the total amount of N mineralization was similar after 40 d, suggesting that over the crop season, total soil N mineralization may be similar in tilled and non-tilled soil. Ammonia volatilization loss from urea broadcast over the residue covered surface, followed by irrigation, was low (<2 kg ha −1 ) regardless of time of urea application. Band placement of 20% of the fertilizer N as diammonium phosphate at seeding, and topdressing of the remaining 80% as urea in two equal doses before first and second irrigations produced higher grain yield and N use efficiency than other treatments. However, surface residue retention reduces the rate of soil drying and in some situations this delays the time of the second irrigation and thus N fertilizer application beyond the optimum time. Therefore, the effect of banding various proportions of the urea N between the rows at sowing was investigated. The results showed that, on a loam soil, up to 75% of the recommended N fertilizer can be applied at sowing, 24 kg N ha −1 as DAP with the seed and 66 kg N ha −1 as urea drilled between every second wheat row, without loss of yield. In conclusion, a better applied N management strategy for ZT wheat than currently practiced is drilling of 24 kg N ha −1 as diammonimum phosphate into the soil at seeding followed by two top-dressings of 48 kg N ha −1 each just prior to first and second irrigations. [ABSTRACT FROM AUTHOR]

Abstract: Large quantities of rice husk ash (RHA), bagasse ash (BA) and coal fly ash (FA) are available in many Asian countries as waste materials, which create a serious disposal problem. Recycling of these ashes on agricultural land can help to improve physical and chemical fertility of soil. The present field experiment was conducted for three and half years to explore the possibilities to utilize these waste materials as soil amendments to improve productivity of rice–wheat system (RWS). The treatments consisted of application of RHA and BA at 10Mgha−1 to either wheat or to rice or to both wheat and rice and 20Mgha−1 to rice alone. The rates used for FA were 15 and 30Mgha−1. Addition of RHA and BA significantly increased the grain yield of wheat and rice but FA caused small increases in crop yields. Direct application of RHA and BA to wheat was significantly superior than their application to rice in the RWS. Direct application of RHA and BA to wheat resulted in 25 and 24% increase in mean grain yield of wheat and 10 and 11% increase in subsequent rice crop, respectively. However, direct application to rice resulted in 8 and 11% yield increase in rice and 10 and 14% increase in subsequent wheat for RHA and BA, respectively. Application of RHA and BA at 20Mgha−1 to rice resulted in lower RWS productivity than that applied at 10Mgha−1 to wheat. There was no significant effect of these ashes on heavy metal contents in grain and straw of the 7th crop of wheat. Application of three types of ashes generally resulted in positive P balance in RWS, however, K balance remained negative. These results suggest that RHA and BA can be recycled successfully in rice–wheat system to improve its productivity with no adverse effect on soil health. [Copyright &y& Elsevier]