Subtropical India Research Articles

Measures to Minimize the Growing Menace of Red Rot of Sugarcane in Subtropical India

Measures to Minimize the Growing Menace of Red Rot of Sugarcane in Subtropical India

Phytochemical Screening of Bombaxceiba Flowers

Abstract- Traditional knowledge of medicinal plants is showing important and significant values to society. Bombaxceiba is an important medicinal plant of tropical and subtropical India. Its medicinal usage has been reported in the traditional systems of medicine such as Ayurveda, Siddha and Unani. The present study includes the detailed exploration of phytochemical properties of various extracts of Bombaxceiba in an attempt to provide a direction for further research. Flowers of Bombaxceiba were air-dried and its coarsely powdered samples were subjected to Soxhlet extraction using diverse solvents (petroleum ether, chloroform , ethanol, ethyl acetate and distilled water)). Freshly prepared extracts were exposed to standard phytochemical analysis for qualitative estimation of phytoconsituents. Phytochemical analysis r e v e a l e d t h e p r e s e n c e o f s e v e r a l phytochemicals viz., alkaloids, flavonoids, steroids, phenol, tannins, steroid, terpenoids and glycocides. The methanolic extract displayed the pr e s enc e of highest phytochemical compounds. It may be due to the higher solubility of active components in this solvent as compared to other solvents. The studies justify the use of Bombaxceiba in traditional medicines. The investigation further propose that the metabolites present in leaf tissue of Bombaxceiba can be potential source of novel natural antibacterial and antioxidant agents which may be of prospective application in food industry as an antioxidant.

Phytochemical Screening of Bombaxceiba Flowers

Abstract- Traditional knowledge of medicinal plants is showing important and significant values to society. Bombaxceiba is an important medicinal plant of tropical and subtropical India. Its medicinal usage has been reported in the traditional systems of medicine such as Ayurveda, Siddha and Unani. The present study includes the detailed exploration of phytochemical properties of various extracts of Bombaxceiba in an attempt to provide a direction for further research. Flowers of Bombaxceiba were air-dried and its coarsely powdered samples were subjected to Soxhlet extraction using diverse solvents (petroleum ether, chloroform , ethanol, ethyl acetate and distilled water)). Freshly prepared extracts were exposed to standard phytochemical analysis for qualitative estimation of phytoconsituents. Phytochemical analysis r e v e a l e d t h e p r e s e n c e o f s e v e r a l phytochemicals viz., alkaloids, flavonoids, steroids, phenol, tannins, steroid, terpenoids and glycocides. The methanolic extract displ ayed the pr e s enc e of highe st phytochemical compounds. It may be due to the higher solubility of active components in this solvent as compared to other solvents. The studies justify the use of Bombaxceiba in traditional medicines. The investigation further propose that the metabolites present in leaf tissue of Bombaxceiba can be potential source of novel natural antibacterial and antioxidant agents which may be of prospective application in food industry as an antioxidant. Keywords: Phytochemical, Bombaxceiba, Antioxidant

Ecosystem-atmosphere carbon and water exchanges of subtropical evergreen and deciduous forests in India

We studied the ecosystem-atmosphere carbon and water fluxes and their coupling at a broadleaf deciduous forest (Kaziranga National Park, KNP) and a coniferous evergreen forest (Kosi-Katarmal watershed, KKM) in subtropical India using the eddy covariance measurements. We analysed the data statistically in a bigleaf framework to compare the annual and seasonal carbon and water exchanges and their drivers at the two sites. The broadleaf deciduous forest at KNP varies from a weak annual carbon sink (−29 g C m−2 y-1) to a moderate source (+207 g C m−2 y-1), while the coniferous-dominated forest at KKM is a strong carbon sink (from −635 to −900 gC m−2 y-1). The component fluxes GPP and TER are much larger, and intra-annual variations are much stronger at KNP than at KKM. We found potential and actual evapotranspiration, as well as the evaporative fraction, to be higher at the broadleaf deciduous than at the coniferous forest. At both the sites, canopy-atmosphere decoupling coefficient is highest during the wet period and, as a whole, the broadleaf deciduous forest remains less tightly coupled to the atmosphere compared to its coniferous evergreen counterpart. At KNP, the biological carbon uptake primarily governs the ratio of intercellular to ambient CO2 concentrations (Ci/Ca), whereas at KKM it is the seasonality of surface conductance. The seasonal cycle of photosynthetic capacity (Vcmax25) is stronger at the deciduous forest than the coniferous forest, where photosynthetic capacity is retained at higher level during the winter. At both the sites, surface conductance and its intra-annual variability, due to environmental and physiological factors, and seasonal cycle of leaf-area, are the main factors controlling the seasonal patterns of surface-atmosphere coupling and ecosystem Ci/Ca. The Ci/Ca is found to decrease inversely with the square root of VPD at both the sites with the variation being similar in monsoon but widely divergent in winter. Our results will have direct implications in improving the parameterizations of the studied forest types in these models to improve their performances over this region.

Subsoiling Affecting Soil Quality Parameters and Sugarcane Yield in Multiratooning System in Subtropical India

ABSTRACT Soil compaction in the plow layer of soils is becoming a serious concern because of conventional tillage practices adopted by sugarcane growers utilizing a rotavator, particularly in medium to heavy textured soils. Continuous use of machinery causes compaction in the plow layer; thus strategic tillage practices have become an essential component in intensive agriculture. Keeping these points in view, a field experiment was conducted in split plot design considering four pre-plant tillage treatments, i.e., (i) one subsoiling (SS) followed by two harrowings (H) (ii) subsoiling alone and direct planting through Sugarcane Cutter Planter (SS) (iii) one plowing through moldboard (MB) plow and two harrowings (MB+H) (iv) and conventional practice (CP) in main plots and three ratoon management treatments viz., (i) HW:Three hand weedings (HW) (ii) integrated weed management (IWM), trash mulching at the time of ratoon initiation and application of microbial consortia (TM +MC) in subplots. Results on bulk density in surface and subsurface layers indicated a significant reduction due to subsoiling. Higher availability of N (252 to 310.2 kg ha−1) was analyzed with adoption of subsoiling as compared to conventional practice (218.4 to 224 kg N ha−1). Subsoiling improved soil microbial biomass carbon (SMBC) by 39% to 73% and 32.20% to 46% as compared to conventional practice in 0–15 cm and 15–30 cm depth, respectively. Among all the primary tillage treatments, sub soiling enhanced SMBC at the highest level (1574 mg C/kg soil/day in 0–15 cm soil depth). Sugarcane (97.26 t ha−1) and sugar (11.87 t ha−1) yields also improved significantly under subsoiling as compared to other pre-plant tillage treatments. Subsoiling before planting also increased mean ratoon cane (117.6 t ha−1) and sugar yields (14.48 t/ha). In addition to trash mulching and application of microbial consortia in ratoon crop proved effective for sustaining higher ratoon yields in sugarcane. Short title: Minimum tillage affecting soil quality parameters and sugarcane yield

Indian goose berry fortified, anti-oxidant rich bael (Aegle marmelos) fermented beverage.

Bael (Aegle marmelos Correa), an important fruit of Indian subtropics, traditionally utilized in the preparation of preserve, candy, squash, RTS, etc. has immense therapeutic potential. An attempt was made to develop a bael based low alcoholic sweet fermented beverage ( may be called as bael cider), anti-oxidant fortified with 0.25 per cent bael leaf or 10 per cent Indian goose berry (Emblica officinalis Gaertn.) juice in separate batches. Unfortified bael pulp based drink was kept as control. The ameliorated pulp was fermented at 30 ± 2ºC using Saccharomyces cerevisiae. The gooseberry blended bael fermented beverage had higher anti-oxidant content in the form of phenolics (323mg/100ml) than leaf extract added fermented beverage (265mg/100ml) and control (266mg/100ml). Sensory evaluation of product revealed that gooseberry blended fermented beverage scored higher (8.2/10) than bael leaf blended fermented beverage (7.9/10) and control (7.0/10). Twelve months maturation study of beverage revealed increase in reducing sugars and decrease in phenolic content in all the treatments. Bael fermented beverage with gooseberry blend retained highest phenolic content (257mg/100ml) and sensory score 7.8/10. The study inferred that an acceptable quality fermented drink could be prepared from bael-gooseberry blend, which could be stored for one year with higher antioxidant value and minimum deterioration in the quality.

Carbon Dynamics in Climate Smart Agriculture Precision Land Leveling Practices on Topsoil Microbial Community Changes and Soil Organic Carbon in Cereal Based Cropping Systems of Sub-Tropical India: A Review

The role of soil microorganisms in the biogeochemical process and nutrient cycling of soil is critical and is colossally impacted by agronomic management practices. In order to establish climate-smart precision land leveling practices in cereal based cropping systems, comprehension of the land bacterial local area and supplement nutrient dynamics under differentiating management practices is of most extreme significance. Climate smart agriculture (CSA) practices are gaining traction in subtropical India as a viable alternative to conventional cereal-based cropping systems for reversing natural resource depletion. Sustainable soil management alternatives that sequester carbon in the soil, reduce greenhouse gas (GHG) emissions and help intensify production, all while enhancing the natural resource base. Aggregate-associated soil organic carbon (SOC) contents in 0-15 cm depth were recorded highest SOC at 15-30 cm depth in Precision Land Leveling (PLL) systems as 9.4% for both M-P-MbPLL and M-W-MbPLL. Highest PON change in arable cropping system (30.9 & 40.1%) was found in O-W-Mb with precision land levelling plots followed by R-P-O with precision land levelling plots (26.1 & 35.8%) as compared to R-W and S-W system. The values of LFOC in surface soil were 194.7, 187.9, 176.2, 170.9, 168.5, 150.6, 132.8 and 123.8 mgkg−1 in R-P-O, R-C-O, M-W-Mb, O-W-Mb, M-P-Mb, R-P-Mb, R-W and S-W with precision land leveling treatments. Therefore, adopting Climate Smart Agriculture Precision Land leveling practices can dramatically boost system productivity in cereal-based cropping systems by improving SOC and soil biological quality. The overview literature accrued indicate that CSA based totally totally management has a remarkable impact on top soil resilience in phrases of relative abundances of bacterial groups, soil organic carbon & to be had plant nutrients and as a result may additionally play a vital function within the sustainability of the extensive cereal based cropping systems.

Continuous Rice Cropping System with Integrated Use of Inorganic and Organic Sources of Nutrients for Soil Quality Improvement

Maintenance of soil quality is considered to be the key to attain sustainability in agricultural production and thus to achieve food security. In this study we tried to answer a research question as to whether integrated application of inorganic and organic sources of nutrients can maintain productivity and soil quality in rice-rice cropping system. To address this, total 27 physical, chemical (including organic C and soil fertility parameters) and biological (including enzyme activities) properties of an acidic sandy loam soil, which were subjected to different nutrient management (NM) practices for nine years of rice-rice cropping under submergence in subtropical India were critically assessed. Seven NM practices comprised of organic [farmyard manure (FYM)], inorganic fertilizers (sources of N, P, K, S, Zn, and B) and some of their combinations were tested using randomized complete block design with four replications. Integrated use of inorganic fertilizers (NPK) and organic manure (FYM) sustained productivity of rice-rice cropping system and aggraded soil quality as compared to only inorganic fertilizers even with inclusion of S, Zn and B. The NPK+FYM was superior among the NM practices to improve physical, chemical and biological properties of soil. Cation exchange capacity, non-exchangeable K and microbial biomass C were screened as the most sensitive attributes for assessing soil quality. Although the present study demonstrated the positive influence of integrated NM, application of even 80-17.5-50 kg N-P-K along with 5 Mg FYM ha-1 in each rice season failed to maintain total K content in soil. This suggested for readjustment of dose of inorganic fertilizers and organic manure and their application schedule for adequate replenishment of K in acidic sandy loam soil under rice-rice cropping in subtropical climate.

Performance of medicinal crops in mango (Mangifera indica) based intercropping system under dryland conditions of Jammu subtropics

Mango (Mangifera indica L.) based agroforestry system offers spatial advantage for intercropping in Indian subtropics. Mango is planted at wide spacing to accommodate the large crowns needed to support the fruit yield. Wider spacing of the trees provides the vacant space to the orchardist to grow suitable and synergistic crop (vegetables/ medicinal plants) to supplement his income. The present investigation was done to screen out the best intercrop out of the four crops, viz. ginger, turmeric, kalmegh and stevia that can be grown in old mango orchards. The experiment was laid out at Experimental Farm of Advance Centre for Horticulture Research (ACHR), Sher-e-Kashmir University of Agricultural Sciences and Technology, Udheywala, Jammu, which is located at an altitude of 327m above mean sea level, between 32073´ N latitude and 74087´ E longitude. Mango orchard selected for the study had a very dense canopy and thus the interception of light was only 30-40 percent than that in the open. The results revealed that shade had profound influence on the survival, growth and yield of ginger, turmeric, stevia and kalmegh. The higher values for plant height, number of leaves, were recorded in ginger and turmeric under shade compared to stevia and kalmegh. Stevia had a very poor survival percentage (11.99%) under mango as compared to open. Likewise ginger had a poor survival percentage (13.22%) in the open compared to that under the mango canopy. Thus, it was concluded that under the subtropical conditions of Jammu region, ginger, turmeric and kalmegh can be grown successfully as intercrops under partial shade of mango trees, however, stevia cannot be integrated. The most remunerative crop among the four, in terms of yield was turmeric followed by ginger and kalmegh.

Exploring potential of different fungicides for management of red rot of sugarcane under sub-tropical India

Red rot is one of the most devastating diseases of sugarcane which imposes major limitations to the profitable cultivation of this crop. The disease is primarily transmitted through sett borne inoculum in field. Although fungicides have been effectively used for disease control in several crops; there have been limited studies exploring potential of fungicides for management of sett transmitted red rot under field conditions. As such, field experiments were carried out over two crop seasons (2018–2019, 2019–2020) to evaluate six systemic fungicides and one systemic resistance inducing chemical (salicylic acid) for red rot management. The fungicides and salicylic acid (SA) were applied as sett treatment at time of planting to red rot pre-inoculated setts of variety Co 1148 and data on red rot, number of millable canes (NMC) and yield recorded in the experiment. In both years, highest red rot incidence was recorded in control plots (55–59%). Application of the fungicides and SA showed a reduction in red rot incidence over control but the extent of reduction varied considerably (10.6–39.4% reduction) across the treatments over the 2 years. Overall, among the seven fungicides evaluated, sett treatment with two fungicides (Tebuconazole + Trifloxystrobin and Thiophanate methyl) consistently resulted in > 30% reduction in red rot incidence over control in both years along with significantly higher NMC over control. Significant variations were also recorded in yield among the treatments with the above two fungicides exhibiting > 40% yield increase over control during 2018–2019 and > 27% yield increase during 2019–2020 crop season. The current study establishes that the fungicides Thiophanate methyl and Tebuconazole + Trifloxystrobin have the potential to control sett borne inoculum of red rot, which is the primary mode of red rot transmission in nature, to the tune of 30–40%. These fungicides have the potential to be exploited further either alone or in combination with other management options as part of developing effective red rot management strategy.

Stock and stability of organic carbon in soils under major agro-ecological zones and cropping systems of sub-tropical India

We evaluated long-term impact of agro-ecological zones and cropping systems on stock and stability of organic C in soils along depth. Sixty geo-referenced soil samples were collected from Terai (TZ) and New Alluvial (NAZ) agro-ecological zones of Wet Bengal. In each zone, soil samples were drawn at 0−0.3, 0.3−0.6 and 0.6−0.9 m depth from rice-potato-jute (R-P-J), rice-vegetables-vegetables (R-V-V), vegetables-vegetables-vegetables (V-V-V) and rice-rice (R-R) cropping systems. Total organic C (TOC) in soils and its pools viz., easily oxidizable Walkley and Black C (CWB), very labile (CVL), labile (CL), less labile (CLL), non-labile (CNL), active (CAP), and passive (CPP) were measured separating on the basis of ease of oxidation with chromic acid for computing different indices of soil organic C (SOC). Among the cropping systems, on average, rice-based systems had higher TOC and CNL than non-rice (V-V-V) one, particularly in NAZ; while non-rice system had a higher per cent allocation of SOC in CVL. Again, a greater per cent of SOC occurred in CPP and CAP under rice-based and non-rice systems, respectively. Anaerobiosis thus facilitated formation of a higher proportion of SOC in recalcitrant pools. Stratification ratios of organic C were higher for soils under NAZ than those under TZ, and also for soils under rice-based systems than those under non-rice one indicating a better soil quality in the former than the latter zone and systems. This was again corroborated with higher values of carbon management index for NAZ than TZ and R-R than V-V-V systems. Further, the recalcitrant indices (RIs) of SOC were higher for soils of TZ than those of NAZ, contrary to the values of lability index (LI). Among the cropping systems, V-V-V had the highest LI values followed by R-V-V > R-P-J = R-R. Along depth, the values of RIs increased, but LI decreased. There was thus an overriding influence of rice and its ecology on the stock and stability of SOC masking the influence of its companion crops in rice-based systems. Therefore, rice-based systems, grown by default in many regions, had a better C economy in soils of this sub-tropical part of the world.

Integrated Application of Ethrel and Microbial Consortia: Effect on Dry Matter Accumulation, Its Partitioning, and Nutrients Uptake in Late-planted Sugarcane Under Subtropical Indian Condition

Late (summer) planting of sugarcane is very much common in subtropical India. Due to the adoption of sugarcane–ratoon–wheat cropping system in the region, sugarcane planting is delayed. Delay in planting of sugarcane reduces the period of tillering. Thus to improve tillering, growth, and yield of late-planted sugarcane, a field experiment was conducted to assess the four levels of seed cane material (S1: conventional 3 bud setts, S2: sett soaking in water for 4 h S3: sett soaking in 100 ppm ethrel solution for 4 h and S4: foliar application of 100 ppm ethrel and mixture of 1% urea on seed cane, one week before planting) and two levels of NPK fertilizers with and without microbial consortia (M1: 50% of recommended NPK with microbial consortia (Pseudomonas fluorescens (phosphate-solubilizing bacteria) + Gluconacetobacter + Trichoderma); M2: Recommended NPK (150 kg ha−1, 25 kg ha−1, 50 kg ha−1 without microbial consortia). Foliar spray of ethrel increased total N uptake by 47.27% at the harvest stage (145.9 kg ha−1). An improvement of 36.40% in P accumulation was recorded with foliar application of ethrel on seed cane as compared to control during the tillering phase. However, P improvement in stalk increased to the level of 18.71 kg ha−1 at harvest stage. Foliar spray of ethrel accumulated 33.04% higher K than control (124.4 kg a−1) at harvest. About 26.16% improvement in individual cane weight was recorded with foliar application of ethrel. Thus, foliar application of ethrel improved sugarcane (73.15 t ha−1) and sugar yield (8.55 t ha−1). Integrated use of microbial consortia and 50% of recommended NPK could bring forth 9.85% (68.48 t ha−1) and 7.86% (8.10 t ha−1) improvement in sugarcane and sugar yields over the recommended NPK in summer-planted sugarcane in subtropical India.

Effect of plant growth regulators (PGRS) on germination, yield and quality of sugarcane in sub-tropical India

Effect of plant growth regulators (PGRS) on germination, yield and quality of sugarcane in sub-tropical India

Microbiome analysis of rhizospheres of plant and winter-initiated ratoon crops of sugarcane grown in sub-tropical India: utility to improve ratoon crop productivity

One plant and one to two ratoon crops are the predominant patterns of sugarcane cultivation in sub-tropical part of India. Despite high agricultural inputs, yield of ratoon crop gets dwindled in the subsequent years. The microbial community, particularly bacteria and fungi, in the rhizosphere and their interaction with the root system, in general influences plant productivity. For the present study, an early maturing sugarcane variety (CoLk 94184), was used to establish plant and winter-initiated ratoon crops in 2016-2018. Soils pertaining to both plant and ratoon rhizospheres were subjected to biochemical analysis, microbial DNA isolation and high-throughput sequencing of 16S rRNA genes to assess the microbial diversity and associated characteristics impacting cane yield. Although alpha diversity of bacterial community was observed high in the soils of both plant and ratoon crops, the species richness/diversity was more in plant crop. Bacterial community structure in the rhizosphere of plant crop was predominantly consisted of phyla Actinobacteria (35.68%), Gemmatimonadetes (29.26%), Chloroflexi (26.73%) and Proteobacteria (16.68%), while ratoon rhizosphere revealed dominance of Acidobacteria (20.77%) and Bacteroidetes (10.7%). Though studies revealed the presence of rich bacterial community in the rhizospheres of both plant and ratoon crops of sugarcane, dominance of Acidobacteria and meager proportion of Actinobacteria and Proteobacteria in ratoon crop possibly limited its productivity. Along with high total phenols (7.27mg/g dry wt), ratoon crop depicted less active root system as revealed by scanning electron microscopy. Dominance of thermophilic bacterial phyla Chloroflexi and Gemmatimonadetes which was observed in sugarcane rhizosphere supports better crop growth in drought. However, management of soil microbial community is required to improve the ratoon crop productivity.

Participatory GIS Mode of Sustainable Surface and Groundwater Management Practices Involving NGOs in India

Groundwater resources plays important role in agro-biodiversity and environmental conservation perspectives. Surface and groundwater have played a significant role in the agrarian economics in the developing economics particularly in India. At the same time, the tropical and sub-tropical India is the largest groundwater user in the world through unregulated construction and utilization of millions of private wells in the last five decades exploited groundwater availability and sustainable regeneration issues. Hence, in order to improve the surface and groundwater conservation, regeneration, management and protection for sustainable utilization of Groundwater requires a participatory and coordinated action. Nationwide, many national and regional Non Government Organisations (NGOs) are functioning in the line of effective surface and ground water management the community. The recent Geographical Information Systems (GIS) based technologies also supports for drought mitigation and climate change adaptation. This study highlights the important NGOs led sustainable Groundwater management practices under various local hydro geological settings and agro economic realities for up scaling the community driven sustainable Groundwater management.

Evaluation of Physico-Chemical Composition in Bulbs of Red, Yellow, and White Onion (Allium Cepa L.) Genotypes of Sub-Tropical India

In this study, thirty onion (Allium cepa L.) genotypes grown in sub-tropical region of India were analysed for different physico-chemical attributes. There were significant differences among genotypes, and the onion genotypes showed a tendency to be classified according to different colours. The cultivars of the same colour exhibited similar tendencies in terms of accumulating most of the analysed components. About 1.78 fold variation in dry matter (%) and 2 fold variation in fresh weight per bulb were recorded among coloured onions. Red genotype D-888-B possessed maximum contents of TS and NRS, while the yellow coloured genotype POH-5 accumulated highest RS and lowest NRS contents. Maximum values of fructans (3.68 g/100 g DW), AIS (6 g/100 g DW), protein (10.61 g/100 g DW), and FAA (4.24 g/100 g DW) were also found in red coloured genotypes D-715-B, D-97-B, PR-305, and D-PS-121-B, respectively. Proline content in different genotypes was found to vary about 6.9 fold. The correlation studies showed a positive relationship between most of the quality parameters. Our results suggested that red group genotypes were better than yellow and white groups for all the studied parameters except for RS, which makes red genotypes more suitable for processing purposes.

Identification of two new Alternaria isolates on sugar beet (Beta vulgaris L.) plants in Lucknow, India

Two hitherto Alternaria species, viz., A. ashwinii and A. dilkushana causing leaf spot on the margins of flavescent and older leaves of sugar beet (Beta vulgaris L.) are being reported for the first time from sub-tropical India. The new strain of fungi was isolated and morpho-taxonomic characters were studied in depth and compared to previous reported Alternaria strains on sugar beet crop in local cultivated field. The comparative analysis revealed variations within different fungal identification traits, viz., symptomatology, hyphae, conidiophore and conidial characteristics that differentiate from previous reported Alternaria strains on sugar beet crop in local area. The new taxon has been proposed as A. ashwinii Mall, Misra, Kumar and Pathak sp. nov. (MB 827099) and A. dilkushana Mall, Misra, Kumar and Pathak sp. nov. (MB 827096). This study will help in giving new direction to molecular diagnostics of these strains. The study also opens up path for future work on its ITS region (referred to as official DNA barcoding), in identifying the various protein coding genes used for boosting or replacing ITS region in species identification of fungi. Highlights Diseases are foremost restraint in attaining high sucrose content and yield in Sugar beet. Amongst the various diseases of Sugar beet, foliar diseases are the most common ones. Foliar diseases are often ignored though they cause substantial losses to yield and sucrose content. Identified two new fungal strains of Alternaria in sugar beet in sub-tropical India.

Sugarcane Yield Using Minimum Tillage Technology Through Subsoiling: Beneficial Impact on Soil Compaction, Carbon Conservation and Activity of Soil Enzymes

Adverse effect of intensive tillage practices on soil chemical and biological properties is already known. Soil organic carbon maintains porosity, releases nutrients for crop growth and also provides shelters to microbes. However, maintaining soil organic carbon at higher level and increasing crop productivity have become two faces of a single coin. Without addressing both issues simultaneously, the sustainability of production system will be far away. Strategic tillage intervention in no-tillage plots for sustaining long-term productivity is gaining importance. Strategic tillage through subsoiling/ripping of soil up to 45 cm depth at about 1 m spacing before sugarcane planting is feasible in sugarcane-based system. Thus, keeping the above points in view, the experiment was conducted during 2015–2017 with hypotheses of (i) whether the minimum tillage (once subsoiling) could maintain soil physical, chemical and biological parameters to sustain sugarcane productivity for longer period and (ii) how the mouldboard ploughing and/or conventional tillage practice affects these parameters and crop yields. The experiment was laid out in four preplant tillage treatments, i.e., one subsoiling (SS) and two harrowings, minimum tillage through subsoiling and direct planting of sugarcane through IISR Cutter Planter (SS), one ploughing through mouldboard plough and two harrowings (MBP + H) and conventional practice (CP—two ploughings through cultivator and one through rotavator) with six replications in randomized block design. The effect of these treatments was recorded on various soil physical, chemical and biological parameters vis-a-vis infiltration rate, cumulative infiltration and optimizing sugarcane yield in subtropical India. The results concluded that minimum tillage and direct planting of sugarcane through Sugarcane Cutter Planter could break hard impervious layer and improve soil physical, chemical and biological parameters besides improving sugarcane and sugar yields. Minimum tillage favoured build-up of soil organic carbon (SOC) and also release of nutrients for crop growth, which optimized rhizospheric environment as compared to conventional practice. Minimum tillage through subsoiling had shown major effect in reducing soil compaction in subsurface layers (bulk density—1.52 Mg m−3 (SS) vs 1.61 Mg m−3 through MBP + H). During tillering period, basic infiltration rate could reach the level of 7.5 mm/hr in SS plots compared to 5.5 mm/hr in conventional practice (CP). Minimum tillage recorded the highest SOC at all the crop growth stages. The highest mean SOC was recorded during grand growth phase (13.51 Mg ha−1). Minimum tillage altered lower amount of soil and showed the highest population of soil bacteria (log10 6.90x 105). Thus, the minimum tillage through subsoiling significantly improved sugarcane (96.32 t ha−1) and sugar yields (12.14 t ha−1) as compared to conventional tillage/mouldboard ploughing.

Zero tillage and residue retention impact on soil aggregation and carbon stabilization within aggregates in subtropical India

Studying the impact of different tillage systems on soil organic matter (SOM) dynamics is essential to define better strategies to improve soil fertility and soil organic carbon (SOC) sequestration. We used density fractionation to assess the changes in SOM in an Inceptisol following nine-years of contrasting tillage under wheat (Triticum aestivum) based cropping systems. The major objective of the study was to investigate the amount of C content within soil aggregates as influenced by tillage and residue management. For this a nine-year old experiment was conducted with two tillage practices in main plots (zero-tillage: ZT and conventional tillage: CT) and four residue management practices in sub-plots (No residue: NR, wheat residue: WR, soybean residue: SR and wheat + soybean residue: WR + SR). The results indicated that SOC content increased by ∼48, 42 and 36%, respectively, in WR + SR, SR and WR plots compared with the NR plots in the 0-5 cm soil layer. The SOC content within macroaggregates were ∼30 and 25% higher in the ZT plots than CT in the 0-5 and 5-15 cm soil depths, respectively. The intra-aggregate particulate organic matter (iPOM) inside microaggregates within macroaggregates (iPOM_mM) was ∼16% higher in the CT than the ZT plots. Tillage management had no significant effect on light fraction inside microaggregates within macroaggregates (LF_mM) and iPOM_mM SOC contents inside microaggregates within macroaggregates (mM) in the surface soil, but residue management improved LF_mM and iPOM_mM SOC contents. The WR + SR, SR and WR plots had ∼73, 40 and 35% more LF_mM SOC content, respectively, than NR plots. Within free microaggregates in the surface soil, the LF_m SOC content was significantly enhanced due to ZT operation by ∼61% than the CT plots but not by crop residue addition. The iPOM_mM and iPOM_m fraction accounted for about ∼35 and 51% of the total SOC content within macroaggregates and microaggregates, respectively. That indicates the role of iPOM fraction in SOC sequestration within the soil aggregates in tropical Inceptisol. Plots under ZT had ∼38% more C content inside microaggregates within macroaggregates (mM) than CT (2.31 Mg ha-1), indicating ZT management could be adopted for C stabilization within aggregates.

Evaluation of yield potential and nutritional quality of various cultivars of barnyard millet (Echinochloa frumentacea L.) grown under subtropical India

Evaluation of yield potential and nutritional quality of various cultivars of barnyard millet (Echinochloa frumentacea L.) grown under subtropical India