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Biofertiliser is considered a promising biofortification intervention that can integrate with plant breeding as well as agronomic measures to overcome malnutrition in regions where the staple diet is cereal. This study was conducted to improve maize (Zea mays L.) productivity and biofortification with zinc (Zn) through the application of Zn-solubilising biofertilisers. Four pre-isolated, promising Zn-solubilising Bacillus strains, Bacillus sp. ZM20, B. aryabhattai ZM31, B. aryabhattai S10 and B. subtilis ZM63, were coated on maize seeds by forming slurry-based sole- and co-inoculated biofertilisers. The treated maize seeds were grown in a spring season (Trial I) and the experiment was repeated the following year on the same field (Trial II). The seed-applied co-inoculated Bacillus biofertiliser formulations significantly promoted antioxidant enzyme activities (ascorbate peroxidase, peroxidase and superoxide dismutase), growth and yield attributes, and nutrient accumulation in maize grains during both field trials compared with sole-inoculated biofertiliser formulations. Application of ZM31–ZM63 biofertiliser formulation showed a greater increase in these attributes than other biofertiliser formulations, as well as an increase in grain iron (Fe) concentration (up to 1.69-fold in Trial I and 1.77-fold in Trial II) and Zn concentration (up to 1.50-fold in Trial I and 1.41-fold in Trial II) relative to the uninoculated control. Fe and Zn concentrations in maize grains resulting from the application of seed-based Bacillus biofertiliser formulations could fulfill the minimum required level of these nutrients for daily intake. From the study, recommendation can be made to apply Zn-solubilising bioinoculants for the biofortification of maize grains to overcome malnutrition issues in regions with cereal-based staple diets.

The effects of different land-use types on physicochemical properties and erodibility indices in suitable utilization of soil are the most important issue to be investigated. That’s why the current study was carried out to investigate changes in physical, chemical soil properties and erodibility indexes under different land-use types i.e., larch-fir forests, adjacent pasture, and riparian areas. Soil samples were collected from different land use in the Meydan Pond micro-basin. Five subsamples were taken at the 0–10 cm depth at five different sampling spots in each one of the three land-use systems (i.e., forest, pasture, and riparian areas). Results showed that silt content was around 38% higher in the forest soils over pasture and the riparian areas. Dispersion rate (80%) and erosion ratio (11%) were significantly higher in riparian areas over the pasture. In conclusion, pasture soils are resistant to erosion due to the higher amount of clay percentage (95%) and aggregation rate (38%) as compared to riparian areas that are more erodible. It is concluded that the river basin should be arranged according to the land capability classes’ principles to protect the soil's fertile layer from erosion to achieve the maximum productivity of crops.

Poor soil fertility due to continuous depletion of micronutrients is a major problem for the production of Prunus domestica L. Low level of soil organic matter and calcareous parent material decrease the bioavailability of these micronutrients to plum plants. Thus, less micronutrients uptake resulted in deterioration of plum fruit quality and decreased yield. On the other hand, balance and correct combination of micronutrients used as a foliar has potential to overcome this problem. Foliar application method provides plants a chance for rapid and easy uptake of micronutrients. Therefore, the present research was carried out to select the best combination of micronu-trients using foliar method. Aim of the study was to select a balanced combination of micronutrients for better production and improved quality of plum (Prunus domestica L., variety Fazal manai) fruit. Seven treatments in three replications were applied. Our results showed that the quality of fruit was significantly improved through the application of T6 micronutrients consortia. A significant increase in total soluble solids (16%), fruit yield per tree (92%) and fruit size (12%) validated the effectiveness of treatment T6 (Zn + Cu + Fe + Mn + B = 0.5% + 0.2% + 0.5% + 0.5% + 0.1%) over control. Application of treatment T6 also enhanced quality attributes, that is, juice acid-ity (22%), juice sugar (22%) and juice contents (16%), as compared to control. It is concluded that use of treatment T6 as a foliar application is a better approach for significant improvement in quality and yield attributes of plum in micronutrients deficient conditions.

Soil quality and crop productivity can be improved by the combined soil application of organic amendments and synthetic fertilizers. We evaluated the sole and combined effects of sugarcane-bagasse ...

Lentil (Lens culinaris Medik) is an important component of the human diet due to its high mineral and protein contents. Abiotic stresses, i.e., drought, decreases plant growth and yield. Drought causes the synthesis of reactive oxygen species, which decrease a plant’s starch contents and growth. However, ACC-deaminase (1-aminocyclopropane-1-carboxylate deaminase) producing rhizobacteria can alleviate drought stress by decreasing ethylene levels. On the other hand, caffeic acid (CA) can also positively affect cell expansion and turgor pressure maintenance under drought stress. Therefore, the current study was planned with an aim to assess the effect of CA (0, 20, 50 and 100 ppm) and ACC-deaminase rhizobacteria (Lysinibacillus fusiform, Bacillus amyloliquefaciens) on lentils under drought stress. The combined application of CA and ACC-deaminase containing rhizobacteria significantly improved plant height (55%), number of pods per plant (51%), 1000-grain weight (45%), nitrogen concentration (56%), phosphorus concentration (19%), potassium concentration (21%), chlorophyll (54%), relative water contents RWC (60%) and protein contents (55%). A significant decrease in electrolyte leakage (30%), proline contents (44%), and hydrogen peroxide contents (54%), along with an improvement in cell membrane stability (34% over control) validated the combined use of CA and rhizobacteria. In conclusion, co-application of CA (20 ppm) and ACC-deaminase producing rhizobacteria can significantly improve plant growth and yield for farmers under drought stress. More investigations are suggested at the field level to select the best rhizobacteria and CA level for lentils under drought.

COVID-19 caused by SARS-CoV-2 is declared global pandemic. The virus owing high resemblance with SARS-CoV and MERS-CoV has been placed in family of beta-coronavirus. However, transmission and infectivity rate of COVID-19 is quite higher as compared to other members of family. Effective management strategy with potential drug availability will break the virus transmission chain subsequently reduce the pressure on the healthcare system. Extensive research trials are underway to develop novel efficient therapeutics against SARS-CoV-2. In this review, we have discussed the origin and family of coronavirus, structure, genome and pathogenesis of virus SARS-CoV-2 inside human host cell; comparison among SARS, MERS, SARS-CoV-2 and common flu; effective management practices; treatment with immunity boosters; available medication with ongoing clinical trials. We suggest medicinal plants could serve as potential candidates for drug development against COVID-19 infection.

Worldwide, the dietary deficiency of zinc (Zn) is prevailing in almost all arid and semi-arid regions. Zinc deficiency is not only the major constraint of lower yield, but also dietary Zn deficiency in cereals grains may cause increasing malnutrition and chronic health problems in human. Exogenous application of Zn through basal soil nutrition might be a useful option to recover Zn deficiency in mung bean. Therefore, field study was conducted to optimize the optimum level and method of Zn nutrition to enhance crop yield and Zn biofortification of mung bean through basal application. Zinc was applied at 0, 5, 10 and 15 kg/ha as basal application and side dressing, and in combination (50% basal application + 50% side dressing). The results highlighted that Zn nutrition prominently improved the mung bean yield as compared with control (no Zn applied). The maximum grains yield and Zn concentration in grains were obtained where Zn was applied at 15 kg/ha as basal application as compared with all other combinations. Better improvement in grain yield was due to significant increase in more number of pods and grain size owing to welldeveloped root system, improved leaf area index and high chlorophyll contents in mung beans leaves. Amongst all applied Zn nutrition’s the basal application of Zn (15 kg/ha) was a viable option to get higher yield and Zn biofortification of mung bean.

Background and purpose: Increasing zinc (Zn) concentration in rice grains can help improve Zn nutrition of people. The combinations of Zn and nitrogen (N) applications at panicle initiation were investigated for Zn biofortification in rice. Materials and methods: Rice (cv. Super Basmati) seedling were grown in pots having a calcareous soil. All possible combinations of four Zn (control, Soil 6 mg Zn kg–1, foliar 2 × 0.2% Zn and soil + foliar Zn) and three N (control, soil 20 mg N kg–1 and foliar 0.5% N) levels were imposed at panicle initiation. At maturity, grains were analysed for Zn and proteins. Results: Grain protein concentration was significantly increased with foliar Zn treatments, and with soil and foliar N. Maximum grain Zn concertation (30 mg kg–1) was achieved with application of soil Zn + foliar Zn + foliar N. At each N level, Zn application by either method significantly increased grain Zn concentration over control. This increase in grain Zn concertation at N levels was 36 to 54% with soil Zn + foliar Zn, 27 to 45% with foliar Zn and 9 to 15% with soil Zn over its control level. Conclusions: Grain Zn concentration was significantly increased with soil N when combined with soil Zn, and with foliar N when combined with foliar Zn treatments. Conclusively, foliar N combined with soil + foliar Zn is the best combination of late Zn and N application for agronomic Zn biofortification in rice.

High lead (Pb) concentration in soils is becoming a severe threat to human health. It also deteriorates plants, growth, yield and quality of food. Although the use of plant growth-promoting rhizobacteria (PGPR), biochar and compost can be effective environment-friendly amendments for decreasing Pb stress in crop plants, the impacts of their simultaneous co-application has not been well documented. Thus current study was carried, was conducted to investigate the role of rhizobacteria and compost mixed biochar (CB) under Pb stress on selected soil properties and agronomic parameters in mint (Mentha piperita L.) plants. To this end, six treatments were studied: Alcaligenes faecalis, Bacillus amyloliquefaciens, CB, PGPR1 + CB, PGPR2 + CB and control. Results showed that the application A. faecalis + CB significantly decreased soil pH and EC over control. However, OM, nitrogen, phosphorus and potassium concentration were significantly improved in the soil where A. faecalis + CB was applied over control. The A. faecalis + CB treatment significantly improved mint plant root dry weight (58%), leaves dry weight (32%), chlorophyll (37%), and N (46%), P (39%) and K (63%) leave concentration, while also decreasing the leaves Pb uptake by 13.5% when compared to the unamended control. In conclusion, A. faecalis + CB has a greater potential to improve overall soil quality, fertility and mint plant productivity under high Pb soil concentration compared to the sole application of CB and A. faecalis.

Fixation of carbon dioxide (CO2) for the production of organic compounds is carried out globally by microbes. These microbes provide food for the survival of heterotrophs in terms of organic C through CO2 fixation. The most familiar pathway of carbon (C) fixation is Calvin–Benson–Bassham cycle. This pathway is adopted by plants, microbes, and algae for inorganic C fixation in natural environment. However, there are a number of other pathways as well that are specifically adopted by microbes for C fixation. By adopting these pathways, microbes follow diversified chemical and biochemical strategies. This chapter is providing basic knowledge about the fixation of CO2 by microbes, mechanism involved in the fixation of CO2, and the enzymes which regulate these mechanisms. Five major pathways, i.e., Calvin-Benson-Bassham cycle, reductive tricarboxylic acid cycle, 3-hydroxypropionic acid (3-HP) cycle, reductive acetyl-CoA (rACo) pathway, and carboxylases, are discussed in this chapter. Four C-fixing pathway enzymes have been described in the chapter. In the near future, it is expected that new pathways will also be established due to number and diversity of microorganisms.

Carbon (C) cycling and sequestration are two paradigms in global C stabilisation. On one part, continuous biogeochemical cycling of carbonaceous C (organic C) and C dioxide-C (CO2-C) are all vital and essential for life on the planet earth. There can be no life without C, in addition to hydrogen, oxygen and other elements known to science. The problem lies with excess CO2-C which remains in relative gaseous phase in the environment of soil, water and air. The global limit of CO2-C continues to rise in the era of agricultural, industrial and human civilisations that depend primarily on burning of fossil fuel, coupled with other anthropogenic activities like bush burning, deforestation, logging, gas flaring in crude oil exploration and wastes disposal. These have come with consequent environmental consequences, namely, global warming, climate change, melting of arctic ice, rise in sea level, flooding, tsunami, acidification, acid rain, desertification, pollution and habitat degradation/losses. To mitigate C excesses in the environment, scientists and researchers have tried several schemes/approaches in C sink, popularly referred to as “sequestration”. The rate of sequestration in atmosphere, lithosphere and hydrosphere depends on the available methods and resources. In atmosphere, C-sequestrations have involved reforestation or afforestation to securely capture CO2-C and store as nutrients in plant parts in the form of cellulose, hemicelluloses, starch, carbohydrate and glucose. In lithosphere, C-sequestrations have involved organic matter amendments/deposition, alley farming, silviculture and agroforestry. In hydrosphere, C-sequestrations have involved ocean fertigation with iron (Fe++) fillings required by phytoplankton as nutrients. The limitation for atmospheric sink lies on global deforestation/logging for agriculture and timber, while that of lithospheric sequestration lies on high-input agriculture that makes use of inorganic fertilisers, agrochemicals and agricultural mechanisation/processing/storage that depends on burning of fossil fuel, bush burning and bush clearing for land preparation/agricultural activities. The limitation of hydrospheric sequestration lies on cost, availability and affordability of Fe++ fillings. Whichever method of C sink, successes and failures come with global welcome as scientists, agriculturists and researchers strive to test, develop and adapt all local, regional, national and international options, including integrated approaches/methods/formulas. The chapter “Carbon stabilisation in tropical ecosystem” is geared towards highlighting the importance of carbon sink in our ecosystem. The methods and systems of C sink or storage vary from one location to another. But the idea remains that excess gaseous carbon dioxide-C in the environment is very inimical to environmental health, and all options required for their sink and stabilisation in the environment should be accelerated all over the world to avoid what this chapter likens to “carbon holocaust”.

In the presented chapter, various aspects related to carbon stabilization and storage in the form of biochar (an important soil amendment) are discussed. The following questions were considered: (i) what is the current general knowledge on biochar and its physicochemical composition, (ii) how manufacturing conditions affect biochar characteristics, including their role in carbon stabilization, (iii) how biochar contributes to soil carbon balance and storage, (iv) what are the effects of biochar on water retention in soil, soil erosion, production yields and economic productivity in agriculture, (iv) what are the effects of biochar on soil microbial community and activity, and (v) how biochar affects other soil amendments and their roles in soil. The present studies assess scientific outcomes and results which conclude that soil organic matter gained by organic residues can be used to enhance soil carbon storage. Following the published scientific results, the biochar amendment appears to be a promising way for increasing the stocks of recalcitrant carbon in the soil from a long-term perspective. Future research should focus on the designing, production, and use of enriched biochar, e.g. with nutrients, minerals, or microorganisms, to improve soil physicochemical properties, supply nutrients, and prevent their leaching. The fertilizer supplies accessible nutrients available to plants, and biochar can sequester depleted elements and prevent leaching of the added ones.

Management of inorganic fertilizer is very important to obtain maximum crop yield and improved nutrient use efficiency in cereal crops. Fixation of phosphatic fertilizers in alkaline soils due to calcareousness is one of the major hurdles. It induces phosphorus nutritional stress that can decrease the yield of maize and wheat. Selection of a suitable application method and proper stage of crop for phosphorus (P) fertilizer has prime importance in better uptake of P and crop production. Among different application methods, soil and foliar application are widely adopted. In wheat and maize, knee height + tasseling and stem elongation + booting are critical stages towards P deficiency. That is why field trials were conducted to evaluate the supplemental effect of foliar P on maize and wheat yields. For that, 144 mM KH2PO4 was applied as foliar at knee height + tasseling and stem elongation + boot stages in maize and wheat, respectively. Soil application of 0, 20, 40 and 60 kg P ha&minus, 1 was done through broadcast and band methods. Results showed that foliar spray of 144 mM KH2PO4 at knee height + tasseling and stem elongation + boot stages in wheat and maize significantly enhanced grains yield and phosphorus use efficiency (PUE) where P was applied as banding or broadcast at the time of sowing. A significant decreasing trend in response to increasing soil P levels validated the efficacious role and suitability of foliar P. In conclusion, the use of P as foliar at knee height + tasseling and stem elongation + boot stages is an efficacious way to manage P fertilizer.

Cadmium (Cd) is one of the heavy metals that negatively affects the growth of plants. High solubilization in water leads Cd to enter into plants quite easily, thus decreasing seed germination, photosynthesis, and transpiration. It also shows an antagonistic effect with many of the plants&rsquo, nutrients like Mn, Ca, K, Mg and Fe. Nowadays, inoculation of plants with ACC deaminase (ACCD) rhizobacteria to mitigate Cd&rsquo, s adverse effects has drawn the attention of environmental microbiologists. The rhizobacteria secrete organic compounds that can immobilize Cd in soil. Therefore, this study was accomplished to investigate the effect of ACCD plant growth promoting rhizobacteria (PGPR) on the bitter gourd under Cd stress. There were six treatments consisting of two ACCD PGPR (Stenotrophomonas maltophilia and Agrobacterium fabrum) strains and inorganic fertilizers at two levels of Cd, i.e., 2 (Cd2) and 5 mg kg&minus, 1 soil (Cd5). The results showed A. fabrum with the recommended NPK fertilizer (RNPKF) significantly increased the vine length (48 and 55%), fresh weight (24 and 22%), and contents of chlorophyll a (79 and 50%), chlorophyll b (30 and 33%) and total chlorophyll (61 and 36%), over control at the two Cd levels i.e., Cd2 and Cd5, respectively. In conclusion, the recommended NPK fertilizer + A. fabrum combination is a very effective treatment with which to immobilize Cd in soil for the improvement of bitter gourd growth.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Bentonite-based organic amendments may have the potential to enhance soil microbial properties. The experiment was carried out from 2014 to 2017 comprising four treatments: NPK fertilizer (nitrogen, phosphorus and potassium mineral fertilizer as a control), NPK + cattle manure, NPK + bentonite, and NPK + combination of manure with bentonite (MB) to verify this hypothesis. The effect of treatments on seven different soil microbial properties was measured: dehydrogenase activity (DHA), bacterial phospholipid fatty acid content, fungal phospholipid fatty acid content, microbial biomass carbon (Cmic), 16S rDNA, 18S rDNA, and ammonia-oxidizing bacteria in soil. The results showed that solely bentonite treatment increases the bacterial and fungal biomass, which was further confirmed by the increased 16S rDNA and 18s rDNA gene copy numbers. The only significantly decreased values upon treatment with solely bentonite were recorded for DHA and Cmic. The ammonia-oxidizing bacteria population increased with the sole application of bentonite and reached its maximum value when bentonite was applied with manure. The MB treatment showed the highest value for all seven measured properties. In summary, the application of bentonite solely might increase or decrease the soil activity, but its addition, along with manure, always promotes an abundance of soil microorganisms and their activity. The co-application of bentonite with manure altered the soil microbial properties in a 3-year field experiment in favor of increased microbial biomass, which is beneficial for agriculture and environment and reveals the potential for the restoration of polluted lands.

In calcareous soil, the significant portion of applied phosphorus (P) fertilizers is adsorbed on the calcite surface and becomes unavailable to plants. Addition of organic amendments with chemical fertilizers can be helpful in releasing the absorbed nutrients from these surfaces. To check out this problem, a field experiment was conducted for two years to determine the effect of P fertilizers and humic acid (HA) in enhancing P availability in soil and their ultimate effect on growth, yield and P uptake of wheat in calcareous soils. The experiment was comprised of five levels of P (0, 45, 67.5, 90 and 112.5 kg P2O5 ha&minus, 1) as a single superphosphate (SSP) and 2 levels of locally produced humic acid (with and without HA) arranged in a two factorial randomized complete block design (RCBD) with three replications. Wheat plant height, spike length, number of grains per spike, 1000-grain weight, grain, straw and biological yield were significantly improved by the addition of HA with SSP. Very often, the performance of 67.5 kg P2O5 ha&minus, 1 with HA were either similar or better than 90 or even 112.5 kg P2O5 ha&minus, 1 applied without HA. Post-harvest soil organic matter, AB-DTPA extractable and water-soluble P, plant P concentration and its uptake were also significantly improved by the addition of HA with SSP compared to sole SSP application. It was evident that P efficiency could be increased with HA addition and it has the potential to improve crop yield and plants P uptake in calcareous soils.

The temperature increase around the world is leading to generation of drought, which is a big threat to the productivity of crops. Abiotic stresses like drought increase the ethylene level in plants. In higher plants, 1-aminocyclopropane-1-carboxylate (ACC) is considered as the immediate precursor of ethylene biosynthesis. The application of ACC-deaminase (ACCD) possessing rhizobacteria could ameliorate the harmful results of drought stress by transforming ACC into non-harmful products. Biogas slurry (BGS) improves the water-holding capacity and structure of the soil. Thus, we speculated that the integrated application of ACCD possessing rhizobacteria and BGS might be an efficient approach to mitigate the drought stress for better wheat productivity. A field experiment was conducted under skipped irrigation situations. On the tillering stage (SIT) and flowering stage (SIF), the irrigations were skipped, whereas the recommended four irrigations were maintained in the control treatment. The results of this field experiment exposed that the ACCD possessing rhizobacterial inoculations with BGS considerably improved the stomatal and sub-stomatal conductance, transpiration and photosynthetic rates up to 98%, 46%, 38%, and 73%, respectively, compared to the respective uninoculated controls. The Pseudomonas moraviensis with BGS application improved the grain yield and plant height up to 30.3% and 24.3%, respectively, where irrigation was skipped at the tillering stage, as compared to the uninoculated controls. The data obtained revealed that the P. moraviensis inoculation + BGS treatment significantly increased the relative water content (RWC), catalase (CAT) activity, ascorbate peroxidase (APX) activity, as well as grain and shoot phosphorus contents, up to 37%, 40%, 75%, 19%, and 84%, respectively, at SIF situation. The results depicted that the P. moraviensis with BGS application under drought stress could be applied for enhancing the physiological, yield, and growth attributes of wheat.

Consumption of heavy metals, especially lead (Pb) contaminated food is a serious threat to human health. Higher Pb uptake by the plant affects the quality, growth and yield of crops. However, inoculation of plant growth-promoting rhizobacteria (PGPR) along with a mixture of organic amendments and biochar could be an effective way to overcome the problem of Pb toxicity. That’s why current pot experiment was conducted to investigate the effect of compost mixed biochar (CB) and ACC deaminase producing PGPR on growth and yield of spinach plants under artificially induced Pb toxicity. Six different treatments i.e., control, Alcaligenes faecalis (PGPR1), Bacillus amyloliquefaciens (PGPR2), compost + biochar (CB), PGPR1 + CB and PGPR2 + CB were applied under 250 mg Pb kg-1 soil. Results showed that inoculation of PGPRs (Alcaligenes faecalis and Bacillus amyloliquefaciens) alone and along with CB significantly enhanced root fresh (47%) and dry weight (31%), potassium concentration (11%) in the spinach plant. Whereas, CB + Bacillus amyloliquefaciens significantly decreased (43%) the concentration of Pb in the spinach root over control. In conclusion, CB + Bacillus amyloliquefaciens has the potential to mitigate the Pb induced toxicity in the spinach. The obtained result can be further used in the planning and execution of rhizobacteria and compost mixed biochar-based soil amendment.

Cadmium is acute toxicity inducing heavy metal that significantly decreases the yield of crops. Due to high water solubility, it reaches the plant tissue and disturbs the uptake of macronutrients. Low uptake of nutrients in the presence of cadmium is a well-documented fact due to its antagonistic relationship with those nutrients, i.e., potassium. Furthermore, cadmium stressed plant produced a higher amount of endogenous stress ethylene, which induced negative effects on yield. However, inoculation of 1-amino cyclopropane-1-carboxylate deaminase (ACCD), producing plant growth promoting rhizobacteria (PGPR), can catabolize this stress ethylene and immobilized heavy metals to mitigate cadmium adverse effects. We conducted a study to examine the influence of ACCD PGPR on nutrients uptake and yield of bitter gourd under cadmium toxicity. Cadmium tolerant PGPRs, i.e., Stenotrophomonas maltophilia and Agrobacterium fabrum were inoculated solely and in combination with recommended nitrogen, phosphorus, and potassium fertilizers (RNPKF) applied under different concentration of soil cadmium (2 and 5 mg kg&minus, 1 soil). Results showed that A. fabrum with RNPKF showed significant positive response towards an increase in the number of bitter gourds per plant (34% and 68%), fruit length (19% and 29%), bitter gourd yield (26.5% and 21.1%), N (48% and 56%), and K (72% and 55%) concentration from the control at different concentrations of soil cadmium (2 and 5 mg kg&minus, 1 soil), respectively. In conclusion, we suggest that A. fabrum with RNPKF can more efficaciously enhance N, K, and yield of bitter gourd under cadmium toxicity.

The excessive use of chemicals and inorganic fertilizers by farmers to increase crop yield is detrimental to the environment and human health. Application of biostimulants such as seaweed extract (SWE) in agriculture could be an effective and eco-friendly alternative to inorganic fertilizers. Biostimulants are natural organic degradable substances. Their application serves as a source of nutrition for crops, possibly improving growth and productivity when applied in combination with the fertilizers. The current study was conducted to evaluate the vegetative growth, reproductive behavior and quality attributes of four onion cultivars, &lsquo, Lambada&rsquo, &lsquo, Red Bone&rsquo, Nasarpuri&rsquo, and &lsquo, Phulkara&rsquo, in response to different concentrations of commercial SWE. Four levels of SWE extract were used, 0% (control), 0.5%, 1%, 2%, and 3%, which were applied as a foliar spray to each cultivar. The application of 0.5% SWE caused a significant increase in total soluble solids, mineral content (N, P, and K), bulb weight and yield. Application at 3% SWE increased ascorbic acid as compared to control. The cultivars responded in different ways regarding bulb dry weight and bulb and neck diameter. Among all cultivars, &lsquo, showed the maximum bulb dry matter, &lsquo, showed enhanced neck diameter whereas &lsquo, showed maximum leaf length. It is concluded that 0.5% SWE increased the yield, nutrient contents, and total soluble solids (TSS) of the four onion cultivars whereas 3% SWE, the highest concentration, increased ascorbic acid in different onion cultivars.

Soil salinityaffects the growth andyield of crops. The stress of soil salinity on plants can be mitigated by inoculation of plant growth promoting bacteria (PGPR). The influence of PGPRinoculation on wheat (Triticumaestivum L.) crop productivity under salinitystress has not been properly addressed so far. Therefore, the present study was conducted to investigate the effects of various PGPR strains (W14, W10 and 6K; alone and combined) at several growth attributes of wheat plant under different soil salinity gradients (3, 6 and 9 dSm-1). The growth attributes of wheat (height, roots, shoots, spikes, grains quality, biological and economical yield, nutrients N, P and K in grains) were highly affected by salinity and decreased with increasing salinity level. The PGPR inoculation substantially promoted growth attributes of wheat and prominent results were observed in W14×W10×6K treatment at 3dSm-1. The results suggest that inoculation of PGPR is a potential strategy to mitigate salinity stress for improving wheat growth and yield.

Due to increasing demand of P fertilizers and gradual decrease in P resources, recyclable P is the focus of researchers in recent years. Sewage sludge (SS) is a municipal waste that contains appreciable amounts of P and probably other nutrients. In present study, the effects of various SS and their biochars (450 °C for 2 h) were investigated on soil properties and P uptake in wheat (Triticum aestivum) with and without P fertilizer. The biomass of plants and grain yield were significantly increased with application of SS and their biochars as compared to the control treatment either without or with P application. Moreover, there was significant interaction between treatments and P application for the concentration of K, and P in shoots and roots of wheat. Shoot P concentration was not significantly affected with SS than biochars whereas root P concentration was higher in SS treatments than respective biochars. Higher increase in Olsen's P concentration was observed in populated area sludge applied-soil as compared to disposal sludge and their biochars. Overall, it is observed that SS application increased the wheat yield and P concentrations in plants than control depending upon SS types whereas biochar application decreased the P concentration in roots. Grain yield and P concentration in shoots were not significantly affected for the treatment with P fertilizers than without P. Sewage sludge and their biochars might be a potential source of P but further research is needed to recommend the use of modified SS-biochars as source of available P for crops.

Several studies have been carried out to examine nitrous oxide (N2O) emissions from agricultural soils in the past. However, the emissions of N2O particularly during amelioration of acidic soils have been rarely studied. We carried out the present study using a rice-rapeseed rotation soil (pH 5.44) that was amended with dolomite (0, 1 and 2 g kg−1 soil) under 60% water filled pore space (WFPS) and flooding. N2O emissions and several soil properties (pH, NH4+ N, NO3−-N, and nosZ gene transcripts) were measured throughout the study. The increase in soil pH with dolomite application triggered soil N transformation and transcripts of nosZ gene controlling N2O emissions under both water regimes (60% WFPS and flooding). The 60% WFPS produced higher soil N2O emissions than that of flooding, and dolomite largely reduced N2O emissions at higher pH under both water regimes through enhanced transcription of nosZ gene. The results suggest that ameliorating soil acidity with dolomite can substantially mitigate N2O emissions through promoting nosZ gene transcription.

Soil N2O emissions are generally larger from soil with straw incorporated, and adjusting soil pH can substantially affect the mineralization of incorporated straw. However, the interactive effects of straw return and adjustment of soil pH on N2O emissions have not been well studied. Therefore, we investigated the role of adjusting soil pH using dolomite with incorporated crop straw in changing soil properties and N2O emissions. We performed a 105‐day incubation study in which dolomite was added to a rice (Oryza sativa L.) (C/N: 36) and green bean (Phaseolus vulgaris L.) straw (C/N: 17) amended acidic soil (Ultisol). The pH of the original soil (4.92) steadily increased to 5.35 and 5.45 at day 105 in rice and green bean straw treatments, respectively. Application of dolomite increased pH to a maximum value of 6.35 in the rice straw + dolomite and 6.55 in the green bean straw + dolomite amended soil at day 105 following establishment of the trial. Application of dolomite and the crop straws significantly increased soil microbial biomass C (MBC), dissolved organic C (DOC) and nitrate (NO3−), whereas it had a short‐term effect on exchangeable ammonium (NH4+). The Ultisol amended with green bean straw emitted larger cumulative N2O emissions (7.25 mg N2O‐N kg−1) during the 105‐day study than soil amended with rice straw (4.23 mg N2O‐N kg−1) and the control soil (1.42 mg N2O‐N kg−1). Dolomite application significantly (P ≤ 0.001) decreased N2O emissions from both rice and green bean straw treatments by increasing soil pH. The results of the current study can help to mitigate N2O emissions and so improve field management.

Fresh surface water supplies are gradually becoming insufficient in arid and semi-arid regions of the world. Thus, farmers in these areas are being forced to use poor quality sewage water. Irrigating vegetable crops with sewage water having high metal concentration may affect growth and biochemical processes of plants. Biochar (BC) can sorb these metals and may reduce their toxic effects on plants. Thus, a greenhouse experiment was conducted to study the influence of cotton stalks derived biochar (CSDB) at control (0%) and 1%; ground water (GW; 0.01 ppm Cd); cadmium-contaminated water (CCW; 2 ppm Cd); and sewage water (SW; 0.13 ppm Cd) on growth and biochemical processes of tomato (Solanum lycopersicum) plants. On an average, additions of 1% BC significantly (p ≤ 0.05) enhanced dry weight of roots (36%) and shoots (52%) of plants as compared to without BC application. Biochar (1%) decreased shoot Cd concentration by 33% at SW and 100% at CCW. The Cd uptake was increased by 33% with the BC + CCW treatment. Soil organic matter (SOM) was increased 1.2 times while pH and EC were increased by 5 and 47%, respectively, in 1% BC amended soil. Biochar application alleviated toxic effects of Cd and improved growth as well as productions of photosynthetic and accessory pigments in tomato plants.

Application of fertilizer at the right time is necessary for profitable yields. Phosphorus (P) and zinc (Zn) are important nutrients often found deficient in calcareous soils. Plant growth promoting rhizobacteria may increase availability of P and Zn from such soils. A pot experiment was conducted to compare the basal and late applications of Zn and P with or without rhizobacteria inoculation for improving fodder yield of maize (Zea mays L.). The application times of Zn (5 mg kg–1) and P (30 mg kg–1) fertilizers to plants with or without rhizobacteria inoculation were (i) basal P + basal Zn, (ii) late P + basal Zn, (iii) basal P + late Zn, and (iv) late P + late Zn. Basal doses were applied at sowing and late applications were applied 30 days after. As compared to basal applications of both P and Zn, optimum fodder yields were achieved with basal P + late Zn without rhizobacteria inoculation, and with late P + basal Zn with rhizobacteria inoculation. Uptake of Zn and P, and root growth were also i...