Search

The effectiveness of organic manures (pig, poultry and farmyard manure, compost and vermicompost) as acid soil amendment for addressing Al toxicity and P deficiency was investigated using groundnut (cv. ICGS-76 crop) in comparison with conventional liming agent (CaCO3). The organic manures' ash alkalinity and calcium carbonate equivalent varied from 5876 to 9506 K mol H+ kg−1 × 10−6 and 236 to 476 kg tonne−1 product, respectively. The exchangeable acidity (27.5% and 22.5%, respectively) and readily soluble Al (by 45% and 56%, respectively) in soil decreased significantly; whereas soil pH, organic carbon and microbial biomass carbon increased under the application of poultry and pig manure. In contrast to dehydrogenase and β-glucosidase enzymes, the activity of acid phosphomonoesterase in soil amended with pig and poultry manures decreased markedly. Better physicochemical and yield attributing characters (chlorophyll content, leaf thickness, cell membrane integrity, stomatal frequency, root length, root to shoot ratio, shoot dry weight, NPK uptake, pod yield and harvest index) and yield (66% and 64%, respectively) under poultry and pig manure could be related to improvement in soil fertility. Incubation study further corroborated that pig and poultry manures are the potential sources of amendments for amelioration of acid soils. [ABSTRACT FROM AUTHOR]

Success and acceptability of the bio energy conversion technology to a large extent depend upon management of the inevitable by-products generated during the conversion process. By-products can be considered favourable as organic fertilizer as they retain nutrients with varying composition depending upon input biomass. However, characteristics of these heterogeneous resources with respect to feedstock and processing conditions have to be assessed to state on their agricultural and environmental benefits. Therefore, 3 types of anaerobic digestion by-products (digestate) from surplus biomass viz. cow dung, Ipomoea carnea:cow dung (60:40 dry weight basis) and rice straw:green gram stover:cow dung (30:30:40 dry weight basis) and one gasification by-product (biochar) from rice husk are considered to understand the fertilizer prospects. Considering 3 potential application options, digestate from each feedstock option was further processed as separated solid, separated liquid and ash from solid digestates. Thus, a total of 10 by-products were investigated for understanding their prospects as fertilizer using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X ray Spectroscopy (EDX) and phyto-toxicity test to have a broad insight in terms of their organic, mineral, elemental composition, morphological feature and potential phyto-toxicity. In general, irrespective of origin of feedstock, solid digestate, ash digestate and char showed similarity in terms of composition of functional groups with some degree of variation in relative content as reflected by FTIR analysis. Dominance of organic functional groups in separated solid digestates compared to liquid fraction indicated the former as favourable organic amendments. Quartz was the prevalent mineral phase in all separated solid, ash digestate and rice husk char. Digestates in ash phase represent more concentrated plant nutrient source with higher content of K, Ca, P, Na and Mg than their respective solid phase. Application of ash digestates and char is likely to improve adsorptive capacity of soil for water and nutrient due to presence of relatively uniformly distributed porous particles. Liquid fraction of Ipomoea digestates exhibited inhibitory effect on seed germination of greengram ( Vigna radiate) with significant reduction of germination index. Inhibitory effects of by-products were found to correlate negatively with their electrical conductivity and ammonia-nitrogen content. Understanding on spectroscopic, morphological and phytotoxic properties of different application options of bioenergy by-products would be useful for assessment of their appropriate use in agriculture. [ABSTRACT FROM AUTHOR]

Alternative fertilizer resources have drawn attention in recent times in order to cope up with ever increasing demand for fertilizer. By-products of bioenergy system are considered favourable as organic fertilizer due to their ability to recycle plant nutrients. Present study evaluates fertilizer suitability of by-products of two bioenergy systems viz. 3 types of anaerobic digestion by-products (digestate) from local surplus biomass such as cowdung, Ipomoea carnea:cowdung (60:40) and ricestraw:green gram stover:cowdung (30:30:40) and one gasification by-product (biochar) from rice husk. Digestates were assessed considering 4 different application options of each viz. whole, solid, liquid and ash from solid digestates. Digestate characteristics (organic matter, macronutrients, micronutrients and heavy metal content) were found to be a function of feedstock and processing (solid liquid separation and ashing). Ipomoea carnea based digestates in all application options showed comparatively higher N, P, K, NH+4- N, Ca, Mg, S and micro nutrient content than other digestates. Separation concentrated plant nutrients and organic matter in solid digestates, making these suitable both as organic amendments and fertilizer. Separated liquid digestate shared larger fraction of ammonium nitrogen (61-91% of total content), indicating their suitability as readily available N source. However, fertilizer application of liquid digestate may not match crop requirements due to lower total nutrient concentration. Higher electrical conductivity of the liquid digestates (3.4-9.3 mS cm-1) than solid digestates (1.5-2 mS cm-1) may impart phyto- toxic effect upon fertilization due to salinity. In case of by-products with unstable organic fraction i.e. whole and solid digestates of rice straw:green gram stover:cowdung digestates (Humification index 0.7), further processing (stabilization, composting) may be required to maximize their fertilizer benefit. Heavy metal contents of the by-products were found to be within the permitted range specified for organic fertilizer (vermicompost) in India. However, higher Al content of the digestates in whole, solid and ash phase (0.06-16.97g kg-1 fresh matter) can be a concern in acid soil which may cause Al toxicity. Understanding on agrochemical characteristics of bioenergy by-products with varying feedstock and application option is expected to promote their valorization opportunities considering user specific requirements. In the context of agriculturally dominant but energy deficient rural Indian scenario, integrated production of bioenergy and by-product based fertilizer could be very significant to meet the critical additional requirement of both energy and fertilizer. [ABSTRACT FROM AUTHOR]

This study assessed how land use change from native deciduous forest to tropical fruit orchards viz. guava ( Psidium guajava L. cv. Allahabad Safeda) and sapota ( Manilkara achras Mill. cv. Cricket Ball) under humid subtropics of India impacts the soil physical, chemical and biological properties. This study also validated whether the existing orchard management practices are adequate to maintain sustainable soil quality in different guava and sapota orchards established along a chronosequence by comparing the changes in soil quality attributes between native forest (considering as baseline ecosystem) and orchards. The land-use-induced change caused significant reduction in soil physical properties (12.0 to 31.4%), chemical properties (8.8 to 61.5%), earthworm density (32.0 to 58.7%), earthworm biomass (43.6 to 68.0%) and soil enzyme activities (8.8 to 54.1%) beneath orchards relative to native forest. There was significant increase in bulk density (12 to 14%), available-P (104 to 296%) and DTPA-Fe content (36.3 to 81.4%) in orchard soils. The combined results of the principal component analysis and the analysis of similarity revealed that stronger influencing factor of variability in soil quality attributes was in the order of land-use change > orchard age > orchard type. The soil deterioration index (SDI) values (ranged from − 35.3 to − 77.8%) for orchard soils relative to FS indicated that orchard soils were in the serious state of deterioration in terms of physico-chemical and biological properties; and the extent of deterioration of soil quality increased with the increase of orchard age (r = 0.57*, P < 0.01). Soil organic carbon showed a significant positive correlation with earthworm populations, soil enzyme activities and pH and these soil attributes were the important factors influencing SDI values. In conclusion, the progressive deterioration of orchard soil quality over time was the outcome of poor/inadequate management of soil organic matter (SOM) in guava and sapota orchards. As a result, there is a need for modification of existing SOM management practices. The reason is that they are not as efficient enough to help prevent the deterioration of soil quality in orchards over time, after conversion from baseline ecosystem. [ABSTRACT FROM AUTHOR]

The choice of cultivation system in arable agriculture exerts a strong influence not only on soil health and crop productivity but also on the wider environment. Conservation tillage using non-inversion methods conserves soil carbon, reduces erosion risk and enhances soil quality. In addition, conservation tillage has been shown to sequester more carbon within the soil than inversion tillage, reducing carbon dioxide losses to the atmosphere. Stable, well structured topsoils that develop following long-term conservation tillage lead to more energy efficient systems due to the reduced power requirements for cultivation. Long-term experiments, e.g. more than 20 years, that confirm the impact of conservation tillage over an extended period are not common. Here we evaluate the impact of different tillage methods and winter wheat straw management, either incorporated or removed, on organic matter turnover and soil quality indicators. No-till, chisel and mouldboard ploughing was carried out for 23 years on a silty clay loam soil in South West England that was not considered suitable for non-inversion tillage due to weak soil structure. In order to assess the effect of contrasting cultivation and straw disposal method on soil carbon dynamics, a range of assays were conducted, including water extractable organic carbon, hot water extractable carbohydrate, microbial biomass carbon, activity of β-glucosidase and acid phosphatase enzymes, C sequestration and the natural abundance of 13C. Our results show that the soil organic carbon concentration in the topsoil was greater under no-till than mouldboard ploughing, while a reverse trend was observed in the lower depths. A 14-17% increase in soil organic carbon was observed in the topsoil for chisel plough and no-till treatments compared to mouldboard ploughing. Water extractable organic carbon was found to constitute only 1-7% of the microbial biomass carbon. Hot water extractable carbohydrate was one of the most sensitive indicators of soil quality and had a significant a negative correlation with bulk density and positive correlation with soil organic carbon microbial biomass carbon β-glucosidase and acid phosphatase. The choice of cultivation method exerted a major control on microbial and carbon dynamics. No-till and chisel ploughing maintained carbon in the soil surface horizons, which will benefit the stability of this weakly structured soil, but mouldboard ploughing distributed carbon more uniformly throughout the soil profile, particularly when straw was incorporated, hence leading to the retention of more carbon in the soil profile. [ABSTRACT FROM AUTHOR]

Global warming is causing increased temperatures that are affecting crop yield and sustainability. To harness the diversity present in rice germplasm, 1100 rice genotypes from the north-eastern Himalayan region (NEHR) were evaluated for high yield stability and marker-trait associations using SSR markers under ambient and elevated temperature conditions in the CO2-temperature gradient chamber (CTGC). Compared to ambient temperature, most agro-morphological traits showed a decreasing trend under elevated temperature, while PCV, GCV, heritability, and GAM tended to increase with elevated temperature. Pollen fertility percentage ranged from 5.4 to 99.4% at ambient temperature and from 3.4 to 98.6% at elevated temperature. The yield per plant (YPP) was significantly positively associated with traits like plant height (PH), panicle length (PL), number of tillers per plant (NT), number of effective tillers per plant (NET), number of filled grains per panicle (NFGPP), spikelet fertility percentage (SFP), and panicle weight (PW), under ambient and elevated temperature conditions. The polymorphism information content (PIC) values of markers associated with heat tolerance ranged from 0.02 to 0.77, with an average of 0.26. A total of 91 alleles were detected, ranging from 2 (RM570, RM225) to 11 (RM364), with an average of 3.14 alleles per marker. The AMOVA results showed that a significant percentage of variation was attributed to the genotypes within the population (67.50%). Based on the FST value (6.42%), genotypes from Meghalaya and Tripura were significantly differed from those outside the NEHR. Model-based clustering revealed that 86 genotypes had more than 80% genetic purity to their respective ancestry. In comparison, seven genotypes (Sojkyrleh, RCPL 1–123, RCPL 1–136, RCPL 1–74, RCPL 1–188, Sialkathi and Bapnah) had less than 80% genetic purity and were considered admixtures. Two markers, RM234 and RM7364, were found to be significantly associated with yield per plant under elevated temperature conditions using both the general linear model (GLM) and mixed linear model (MLM) approach. Genotypes such as TRC-2016–291, TRC-2007–1, TRC-2016–426, Daya, Badjhania, TRC-2016–624, TRC-2016–33, Nania, TRC-2016–51, Aati Ghal and TRC-2016–153, which exhibited superior performance for yield and component traits were selected as high yielding for the elevated temperature conditions of NEHR. [ABSTRACT FROM AUTHOR]

The present study acknowledged climate variability induced periodic variation in localized extreme weather event occurrences under diverse agro-eco regions of Eastern Himalayas of India during the past five decades. The widespread rise in warm nights (TN90p; 0.31–1.67 days year−1), reduced daily rainfall intensity (SDII), and changes in other weather extremes, viz. temperature and precipitation extremes, signified clear signals on regional atmospheric warming across eastern India. The agro-ecological regions under extended Bramhaputra valley and coastal belts of south Bengal experienced the most persistent shifts in temperature extremes, while the upper Himalayan range extended from North Bengal to Arunachal Pradesh experienced the steepest decline in average daily rainfall intensity and other absolute quantitative estimates of precipitation extremes over past five decades. Together with El Niño and La Niña events, large-scale global atmospheric circulations particularly expansion of warmer Pacific Warm Pool (PWP) and changes in Atlantic Meridional Mode (AMM) contributed to the periodic dynamics in weather extreme occurrences from monthly to annual time scale over eastern India. Our findings will be useful for better understanding of regional climatology, designing, and successful implantation of location-specific suitable agricultural policies towards climate change adaptation in near future. [ABSTRACT FROM AUTHOR]

This study explores the high-precision mapping (1 : 50 K stratified random sampling) of spatial variability in soil acidity (pH), soluble aluminium (Al) and plantavailable micronutrients (Fe, Mn, Cu and Zn extracted by DTPA) for the acid soils of the Meghalaya Plateau northeastern Himalaya, India. Results revealed that soils in nearly 88% of the total geographical area (TGA: 22,429 sq. km) fell below the pH limit of 5.5, of which significant areas (13.9% TGA) were strongly acidic in reaction (pH < 4.5). In close to 90% of the plateau soils, Al exceeded the critical toxicity threshold (>9.0 mg kg–1). Over 93% of the soils were high in Fe concentration (>10.5–100.0 mg kg–1). Mn, Cu, and Zn were found to be deficient in 12% (Mn < 5.0 mg kg–1), 20% (Cu < 0.6 mg kg–1), and 27% (Zn < 0.9 mg kg–1) of TGA respectively. The multi-micronutrient composite maps of Fe, Mn, Cu and Zn displayed an intricate spatial dimension in the deficiency zones. The study concludes that there is a pressing need to manage site-specific micronutrients to improve crop productivity and the quality of the produce. [ABSTRACT FROM AUTHOR]

Weather forecasts are important for the planning of agricultural operations, especially during times of heightened climatic variability. This study analyzed and verified the medium-range weather forecast issued by the India Meteorological Department (IMD) for different weather parameters over four locations in the northeastern hill (NEH) region of India considering five years of daily datasets. Results revealed good overall accuracy of the forecast over the NEH region. The accuracy of relative humidity (>80%), rainfall (>79%), and wind speed (>70%) were good, and the accuracy of temperature was average, with the usability values for maximum temperatures (44.7–62.7%) comparatively better than for minimum temperatures (38.5–58.6%). The correlation coefficient between the observed and forecasted values was positive (0.24–0.70) and statistically significant for most of the cases, indicating that the forecast could capture variations. Field experiments for maize crops showed that a near-real-time weather forecast-based agro-advisory could manage the uncertainties related to the in-season weather and thereby help in its day-to-day management, which is depicted by the statistically significant (p < 0.05) improvements in the yield of maize. The accuracy of the minimum temperature was poor during winter and post-monsoon seasons, when it plays a crucial role in the determination of optimal growing conditions. Usability of the maximum temperature needs improvement during the pre-monsoon season, as crop cultivation over the region starts from this season due to the high probability of assured rainfall. Therefore, the forecasts were found to be useful but in need of improvement for minimum temperature, which is very crucial for the region. [ABSTRACT FROM AUTHOR]

• The red-fleshed genotypes were superior for quality attributes and antioxidant activity over the white-fleshed genotypes. • Psisdium guineense was the most diverse among the various genotypes/species, and all the red flesh genotypes were close to each other. • The majority of traits have high heritability and genetic advance, are controlled by additive gene action, and are highly responsive to selection. • Fruits of RCG-11 (lower seed number), RCGH-1, and RCGH-4 were stable for fruit weight and can be promoted for commercial production and crop improvement programmes. Guava (Psidium guajava L.) is an important fruit crop in the tropical and sub-tropical world. The morphological, biochemical, and molecular (using 56 microsatellite markers) characterization was carried out on 18 guava genotypes and related species (P. guineense) during 2018–2022. The present study exhibited a wider range of variability: fruit weight (61.5–68.4 g); fruit diameter (4.20–7.91 cm); total soluble solids (8.50–13.40 °Brix); titrable acidity (0.20–0.64%); reducing sugar (2.55–7.00 mg glucose /g); ascorbic acid (76.4–196.3 mg/100 g); total phenol (125.9–305.4 mg GAE/100 g pulp); and total flavonoid content (172.30–948.5 mg QE/100 g pulp). The antioxidant activities (FRAP and DPPH) showed a favorable relationship with ascorbic acid, total phenol, total flavonoid, and total flavonol content. Red-fleshed genotypes were found superior for all the quality parameters over white-fleshed genotypes. The molecular analysis generated 213 alleles from 56 markers, with 2–9 alleles per locus (mean = 3.80). Apart from the genetic diversity, the improved cultivars were also distinguished by a set of markers: RCGH-4 (mPGCIR-184 and mPGCIR-194); RCGH-1 (mPGCIR-108 and mPGCIR-243); RCG-11 (mPGCIR-206 and mPGCIR-325); and RCGH-7 (mPGCIR-16 and mPGCIR-19). The cluster analysis indicated that P. guineense was the most diverse of the cultivated species, and all the red flesh genotypes were close to each other. Furthermore, RCG-11 had a lower seed content (58.89 per 100 g pulp), while RCGH-1 and RCGH-4 were stable for fruit weight and seed number, which can be promoted for commercial production and future crop improvement programs. [Display omitted] [ABSTRACT FROM AUTHOR]

Overburden and acid drainage from coal mining is transforming productive agricultural lands to unproductive wasteland in some parts of Northeast India. We have investigated the adverse effects of acid mine drainage on the soil of rice paddy and productivity by comparing them with non-mined land and abandoned paddy fields of Jaintia Hills in Northeast India. Pot experiments with a local rice cultivar ( Myngoi ) as test crop evaluated biological productivity of the contaminated soil. Contamination from overburden and acid mine drainage acidified the soil by 0.5 pH units, increased the exchangeable Al 3 + content 2-fold and its saturation on clay complexes by 53%. Available sulfur and extractable heavy metals, namely Fe, Mn and Cu increased several-fold in excess of critical limits, while the availability of phosphorus, potassium and zinc contents diminished by 32–62%. The grain yield of rice was 62% less from fields contaminated with acid mine drainage than from fields that have not suffered. Similarly, the amounts of vegetation, i.e. shoots and roots, in pots filled with soil from fields that received acid mine drainage were 59–68% less than from uncontaminated land (average shoot weight: 7.9 ± 2.12 g pot − 1 ; average root weight: 3.40 ± 1.15 g pot − 1 ). Paddy fields recovered some of their productivity 4 years after mining ceased. Step-wise multiple regression analysis affirmed that shoot weight in the pots and grain yield in field were significantly ( p < 0.01) and positively influenced by the soil's pH and its contents of K, N and Zn, while concentration of S in excess of threshold limits in contaminated soil significantly ( p < 0.01) reduced the weight of shoots in the pots and grain yield in the field. [ABSTRACT FROM AUTHOR]

"Huanglongbing" (HLB) or citrus greening is the most devastating diseases of citrus that affects all cultivars causing systematic death of trees worldwide. The disease is associated with the presence of the phloem-limited α-proteobacteria ' Candidatus Liberibacter asiaticus', 'africanus', and 'americanus'. The Asian Citrus Psyllid (ACP), is the main vector that transmits the pathogen while feeding the leaves of citrus trees, affecting fruit traits including fruit shape and size, ripening, and quality of fruits and compromising plant health, eventually leading to economic loss to the citrus industry. In this review, the history of HLB, its pathosystem, and geographical distribution with a primary focus on the various diagnostic measures that are in practice are described. The HLB identification in the field is the most challenging task for the growers as the symptoms of asymmetrical, blotchy mottling patterns on leaves are often confused with nutritional deficiency. The unavailability of precise methods for identification of HLB at the initial infection is of major concern. Hence, the development of field-based detection methods could help citrus growers to take protective measures to minimize disease spread in citrus plantations. The review also highlights the existing detection and management options of HLB as well as the perspectives in this research field. [Display omitted] • Huanglongbing (HLB) is associated with death of citrus trees worldwide. • HLB symptoms are often confused with nutritional deficiencies. • The laboratory HLB detection is commonly carried out at a late infection stage. • The point of care early detection of HLB remains a challenge. • Detection of HLB at early infection stage seems to be crucial for its management. [ABSTRACT FROM AUTHOR]

Abstract: We used a long-term arable cultivation experiment to investigate spatial relationships between earthworm populations and soil physico-chemical properties using Spatial Analysis by Distance Indices methods (SADIE). Red-blue analyses showed that soil C and N were both spatially heterogeneous (patchy) as were total and juvenile earthworm counts. In contrast, theta probe and shear vane measurements, adult earthworm counts and earthworm biomass did not exhibit patchiness. All potential relationships between data classes were analysed using SADIE spatial association tests. Soil chemical properties were generally dissociated from earthworms whereas physical properties were positively associated. These results were largely attributable to juvenile counts, suggesting that this age group may be a more sensitive indicator of spatial relationships between earthworms and soil properties than are adults. We also found that earthworm counts had stronger spatial associations with soil chemical properties than did biomass; the obverse was seen with the measures of soil physical properties. This may provide evidence that earthworm dynamic responses vary between different aspects of the soil environment. [Copyright &y& Elsevier]