Soil degradation and mitigation in agricultural lands in the Indian Anthropocene

Current widespread and intensive soil degradation in India has been driven by unprecedented levels of population growth, large-scale industrialization, high-yield agriculture, urban sprawl and the spread of human infrastructure. The damage caused to managed and natural systems by soil degradation threatens livelihoods and local services and leads to national socio-economic disruption. Human-induced soil degradation results from land clearing and deforestation, inappropriate agricultural practices, improper management of industrial effluents and wastes, careless management of forests, surface mining, urban sprawl, and ill-planned commercial and industrial development. Of these, inappropriate agricultural practices, including excessive tillage and use of heavy machinery, over-grazing, excessive and unbalanced use of inorganic fertilizers, poor irrigation and water management techniques, pesticide overuse, inadequate crop residue and/or organic carbon inputs, and poor crop cycle planning, account for nearly 40% (121 Mha) of land degradation across India. Globally, human activities related to agriculture contribute to the transgression of four of the nine Planetary Boundaries proposed by Rockström et al. (2009): Climate Change, Biodiversity Integrity, Land-system Change, and altered Phosphorus and Nitrogen Biogeochemical Flows. This review focuses on how knowledge of soil processes in agriculture has developed in India over the past 10 years, and the potential of soil science to meet the objectives of the United Nations' Sustainable Development Goal 2: Zero Hunger (End hunger, achieve food security, improved nutrition and promote sustainable agriculture), using the context of the four most relevant Planetary Boundaries as a framework. Solutions to mitigate soil degradation and improve soil health in different regions using conservation agricultural approaches have been proposed. Thus, in this review we (1) summarize the outputs of recent innovative research in India that has explored the impacts of soil degradation on four Planetary Boundaries (Climate Change, Biodiversity Loss, Land-system Change, and altered Biogeochemical Flows of Phosphorus and Nitrogen) and vice-versa; and (2) identify the knowledge gaps that require urgent attention to inform developing soil science research agendas in India, to advise policy makers, and to support those whose livelihoods rely on the land.     

Morpho-physiological and biochemical response of maize (Zea mays L.) plants fertilized with nano-iron (Fe3O4) micronutrient

Nano-sized formulations of micronutrient iron (Fe) were found to substantially alter the growth and metabolism of maize plants. Plants fertilized with the optimal recommended dose of Fe in the nano-form (54 μM) registered an enhancement in morphological features, viz. plant height, biomass (shoot and root), and diminution in antioxidant enzyme activities than the plants fertilized with the sub-optimal dose of Fe in the macroform (salts). However, half of the recommended dosage of Fe (27 μM) in the nano-form positively influenced leaf area and proline content of plants too. This indicated that there is a possibility of reducing the dose of Fe supplement for plants in the nano-form to increase the nutrient use efficiency in a major cereal crop like maize. This may open a new era in plant nutrient management with a scope for improvement in nutrient use efficiency using nano-nutrient formulations.     

Carbon fibres and plasma-preserved tendon allografts for gap repair of flexor tendon in bovines: gross,microscopic and scanning electron microscopic observations

The efficacy of carbon fibres and plasma-preserved tendon allografts for gap repair in the superficial digital flexor tendon in the mid-metatarsal region was evaluated in 12 crossbred calves. Experimental tenectomies were performed, followed by implantation of carbon fibres in group I (12 legs) and plasma-preserved tendon allografts in group II (12 legs). Gross observations in group I showed filling of the defect with granulation tissue with more vascularity on day 7, which was less prominent at day 14. On day 30, the neotendon formed was slightly thicker and comparable to normal tendon in appearance and texture. On day 90, it exhibited all the characteristics of a fully developed tendon. Whereas, in group II increased vascularity at the site and encapsulation of the graft with connective tissue in early periods was observed. The gap between graft and host was filled with fibrous connective tissue. Peritendinous adhesions were maximum on day 7 which were gradually reduced in both groups. Microscopically, an acute inflammatory reaction in the periphery of carbon fibres was observed on day 7. Immature fibroblasts were arranged in a haphazard pattern at this stage. By day 14, numerous newly formed capillaries and comparatively more mature fibroblasts were present in between and around the carbon fibres which were aligning parallel to the longitudinal axis of the tendon. By day 30 the healing tissue exhibited longitudinal orientation of collagen fibres and was at a more advance stage of maturation. By day 90, the neotendon formed simulated the picture of normal tendon. In the grafted tendon group, there was normal healing tissue at the functional sites between host and grafted tendon. The fibroblastic activity appeared to be both extrinsic and intrinsic in origin. The connective tissue had invaded the graft to a variable distance and there was resorption of graft which was replaced by newly formed connective tissue on day 90. Scanning electron microscopic observation revealed formation of neotendon between carbon fibre strands, resulting in thickening of the implant. In later stages parallel collagen fibres resembling normal tendon were observed in both groups.     

Effects of C:N ratio and substrate integration on periphyton biomass, microbial dynamics and growth of Penaeus monodon juveniles

An outdoor growth trial was conducted for 75 days to investigate the effect of C:N ratio and bamboo substrate (S) in brackish water shrimp culture. Penaeus monodon juveniles (0.35 ± 0.03 g) were stocked in experimental tanks with and without bamboo substrate. C:N ratio of 10 and 20 was manipulated with shrimp feed containing 32 % crude protein and rice flour as carbohydrate source. Addition of substrate and higher C:N ratio (CN20+S) significantly reduced (p < 0.01) inorganic nitrogen NH₃–N by 48.2 %, NO₃–N by 41.6 %, NO₂–N by 42.7 % compared with CN10. Substrate addition significantly (p < 0.05) reduced the turbidity by 22.4 % (CN10+S against CN10) and 20.7 % (CN20+S against CN20). Periphyton biomass and total heterotrophic bacterial load were significantly higher (p < 0.05) in CN20+S in comparison with CN10+S treatment. The autotrophic index increased from 123.4 ± 0.62 to 158.9 ± 3.8 for CN10+S and, 121.8 ± 1.6 to 228 ± 9.11 for CN20+S system. Provision of substrate and carbohydrate addition resulted in the highest body weight, 4.87 ± 0.12 g in CN20+S against 3.66 ± 0.07 g in CN20 and 2.90 ± 0.12 g in CN10 through provision of natural food in the form of periphytic algae and heterotrophic bacterial community. Treatment with substrates showed a higher survival rate by 7 % in comparison with without substrate treatments as it acted as shelter to shrimp during molting and there by reduced cannibalism. Thus, our results demonstrated that high C:N ratio and substrate addition improved growth, reduced FCR and better water quality conditions.     

Variation in the seed and oil yields and oil quality in the Indian germplasm of opium poppy Papaver somniferum

The variation in the seed shape, colour and yield, and content, yield and fatty acid composition of seed oil of 109 accessions of opium poppy Papaver somniferum, (majority of them Indian land races), was investigated. The seeds were white, pale yellow or light brown in colour, reniform or round in shape and varied in size up to three fold. The oil content, seed and the oil yield varied between 26 to 52%, 1.0 to 7.4 g/plant and 0.4 to 2.7 g/plant, respectively. The % content of palmitic, oleic and linoleic acid in the seed oil ranged between 9.3 to 40.0%, 7.5 to 58.4% and 0.7 to 72.7%, respectively. On average basis, the levels of major fatty acids in the seed oil were: oleic (37.1%) > palmitic (27.3%) > linoleic acid (17.2%). The palmitoleic, stearic and linolenic acids were present in the oils of only some of the accessions. Two of the accessions yielded linoleic acid rich seed oil of about the same quality as soybean and maize oils, and in four accessions, the proportion of palmitic, oleic and linoleic acids was roughly equal. The palmitic acid was relatively less and linoleic acid more in the seed oil from accessions rich in oil content. The oil that contained higher amount of oleic acid also contained higher amount of palmitic acid and relatively lower amount of linoleic acid. The correlation analyses revealed a strong positive relationship between seed yield and oil yield (r = +0.81), oil yield and oil content (r = +0.54) and oleic acid and palmitic acid content in the seed oil (r = +0.49), and a weak positive relationship between oil content and linoleic acid content of oil (r = +0.24), and a negative correlation was observed between oil content and palmitic acid content (r = –0.32), palmitic acid and linoleic acid (r = –0.55) and oleic acid and linoleic acid contents of oil (r = –0.68). The observations have permitted selection of accessions that are high seed and oil yielding and/or rich in linoleic, palmitic and oleic acids or containing palmitic, oleic and linoleic acids in about equal amounts.     

Pharmacokinetic studies of levofloxacin after oral administration in healthy and febrile cow calves

The present experiment was designed to study the pharmacokinetics of levofloxacin in six healthy cross bred female cow calves (4 to 6 months age) weighing between 40 to 80 kg. Plasma from blood was separated by centrifugation at 10,000 rpm. Quantitative estimation of levofloxacin was done by UV-VIS spectrophotometer at 286 nm. The mean maximum plasma concentration (Cp_max ) of levofloxacin in febrile calves (5.28?±?0.32 µg/ml) did not differ significantly as compared with healthy calves (4.50?±?0.22 µg/ml) after single dose (20 mg/kg) oral administration. The mean therapeutic plasma concentration ( Cp_ther ) of levofloxacin was maintained for longer period in febrile calves (10 h) as compared to healthy calves ( 8 h). The mean maximum urine concentration (Cu_max) in febrile (40.86?±?2.19 µg/ml) also did not differ significantly as compared with healthy calves (39.38?±?2.43 µg/ml). No significant difference in various pharmacokinetic parameters of plasma was observed in healthy calves ( β?=?0.23?±?0.01/h ; t1/2 β?=?3.00?±?0.17 h and MRT?=?4.66?±?0.14 h ) and febrile calves ( β?=?0.23?±?0.01/ h; t1/2 β?=?3.05?±?0.16 h and MRT?=?5.04?±?0.14 h ) . The mean value of β, and t ½ β calculated in urine also did not differ between healthy and febrile calves. However, the value of MRT(3.79?±?0.07 h) and Cl_B(1.65?±?0.09 ml/kg/min) calculated in urine of febrile calves significantly(p?B?=?2.09?±?0.13 ml/kg/min). Based on kinetic profile levofloxacin may be given orally at the dose rate of 1.49 mg/kg B.W.at 8 h intervals in febrile calves.     

Wildlife (Boselaphus tragocamelus)-small ruminant (goat and sheep) interface in the transmission of 'Bison type' genotype of Mycobacterium avium subspecies paratuberculosis in India

Information on Mycobacterium avium subspecies paratuberculosis (MAP) genotypes infecting different animal species in India is limited. Presence of MAP was investigated in free ranging antelopes (locally known as Nilgai/blue bulls/Boselaphus tragocamelus) using direct microscopy, culture, IS900 PCR and IS1311 PCR-REA. IS900 elements of MAP from Nilgai and previously isolated from goats were sequenced and compared to establish inter-species transmission between free ranging Nilgai and closed farm herds and flocks of goats and sheep sharing common grazing and water resources. Fecal samples were collected from two geographical regions (Mathura and Kanpur Dehat districts) separated by 300km, in North India. Of the 42 fecal samples cultured, MAP colonies were recovered from 23.8% samples (Nilgai). Of the 10 positive fecal samples, two were in 'Super shedder' (>1000cfu/g) category and rest were moderate (<10-100cfu/g) shedders. None of the Nilgai from Kanpur Dehat was positive in culture. The 229bp fragment targeting specific IS900 sequence was amplified from template DNA isolated from all the positive MAP cultures of Nilgai. Using IS1311 PCR-REA, MAP colonies were genotyped as 'Bison type'. Goatherds and a sheep flock located at Central Institute for Research on Goats (CIRG), shared 303.52ha of land (Mathura district of Uttar Pradesh) with Nilgai and were endemic for MAP infection. MAP strains isolated from goats and sheep have been genotyped as 'Bison type'. Nucleotide sequence of the insertion elements (900) from MAP 'Bison type' strain (S5) of goat origin and MAP (B42) from Nilgai showed difference of 2 (1%) base pairs at the 11th and 12th position (Genbank accession number EU130943). Study is first report on sharing (inter-species transmission) of a new 'Bison type' genotype of MAP between free ranging wildlife (Nilgai population) and domestic animals (farm goatherds and sheep flocks) in India.