Gulab Singh Yadav

Role of Legumes in Soil Carbon Sequestration

The soil organic carbon (SOC) pool is the key indicator of soil health and quality which in turn plays a vital role to soil sustainability. The continuous uses of unsustainable agricultural approaches have depleted most of the SOC pool of global agricultural lands. Promoting cultivation of leguminous crops, grasses, shrubs, and trees offers multiple advantages, e.g., augmenting crop and soil productivity and adapting to climate change by increasing resilience of agroecosystems. As per model-based prediction by World Bank, the cumulative soil carbon (C) sequestration of pulses in Asia and Africa is expected to be 33.0 and 35.12 Mg ha−1, respectively, by 2030. Legumes have the potential to reduce the CO2 emitted during the manufacturing of chemical nitrogenous fertilizers through their biological nitrogen fixation (BNF) capacity. Therefore, the main advantage of using legumes is to ensure that the BNF which in turn reduces the amount of nitrogen (N) fertilizer required for the succeeding crop. A meta-analysis study suggested that the legumes have the capacity to store 30% higher soil organic carbon (SOC) when compared to other species; this is because of their N-fixing ability. The leguminous vegetation improves soil health and soil C content as per the nature of the specific crop. The C sequestration potential and the amount of organic C returned by leguminous species to soil depend largely on specific legume species, growth behavior, root morphology and physiology, leaf morphology, climatic conditions, structure and aggregation, prevailing cropping system, and agronomic interventions during crop growth period. The aboveground plant biomass (e.g., plant leaves, branches, stem, foliage, fruits, wood, litter-fall) and the belowground plant biomass (e.g., dead roots, carbonaceous substances from root exudates, rhizospheric deposition, and legume-promoted microbial biomass C) directly contribute to the SOC pool.

Cereal-Legume Cropping System in Indian Himalayan Region for Food and Environmental Sustainability

The Indian Himalayan Region (IHR) is extended from Jammu and Kashmir to the northeastern part of the country and shows a great differentiation in climatic, edaphic, geological, vegetation, and other features due to complex variegation of agroecosystems which leads to diverse agroecological zones. Agriculture is the important source of livelihood of the region, and rice (Oryza sativa L), wheat (Triticum aestivum L.), and maize (Zea mays L.) are the main crops of the entire IHR. Unsustainable agricultural practices, such as monocropping, conventional tillage, indiscriminate use of fertilizers and pesticides, etc., apart from land degradation and cropland scarcity have serious implications for livelihood security in IHR. Under such scenario, there is a need to diversify cropping pattern to make the entire agricultural system sustainable and environmentally secure. Inclusions of legumes in cereal-based cropping system either as intercrop or in sequence of crop rotation are the most promising options for diversified sustainability of the system and enhance the cropping intensity. Diverse habitat of IHR favors the growth and development of an amazing variety of legumes and other crops which make this region the rich hub for agricultural crop diversity specifically the legume crops. Broad bean (Vicia faba), horse gram (Macrotyloma uniflorum), field pea (Pisum sativum), black gram (Vigna mungo), adzuki bean (Vigna angularis), cowpea (Vigna unguiculata), soybean (Glycine max), lentil (Lens esculenta), green gram (Vigna radiata), beans (Phaseolus sp.), lathyrus (Lathyrus sativus), pigeon pea (Cajanus cajan L), etc. are some of the legumes cultivated by the farming communities in IHR. Rice bean [Vigna umbellata (Thunb.) Ohwi and Ohashi and mucuna/velvet bean [ Mucuna pruriens (L.) DC.] are some of the specific legumes grown abundantly in the eastern IHR which has immense food and natural resource conservation values. Albeit the legume species provides food, fuel, fodder, etc. and has multifarious roles in agriculture and natural resource conservation, their ability to fix atmospheric nitrogen in root nodules and subsequently contributions to the soil fertility give them the unique identity. Legume-based systems improve several aspects of soil fertility, such as soil organic carbon (SOC) and humus content and nitrogen and phosphorus availability, suppress weed growth through smothering effects, increase production per unit area, enhance land use efficiency, reduce runoff and soil loss, etc. Inclusion of legume provides sustainability to nonlegume cereal component by enriching soil fertility and increasing system productivity and returns. Significant reductions in the release of greenhouse gases, viz., carbon di-oxide, nitrous oxide etc., are a logical consequence of reduced fertilizer and energy use in arable systems with legumes. Pulses are considered the key crops for intensification of rice and maize-fallows of IHR due to their short-duration, hardy, and low-input requiring nature, hence offers a tremendous opportunity to utilize residual soil moisture.

Cereal+Legume Intercropping: An Option for Improving Productivity and Sustaining Soil Health

Intercropping is the system of simultaneously growing two or more crops on the same land area with a definite row arrangement. However, it is very much important to ensure that component crops do not compete with each other for space, moisture, nutrients, and solar radiation. Cereal+legume intercropping provides a greater scope for minimizing the adverse impact of moisture and nutrient stress in addition to improving system productivity and soil health. Researchers reported significant enhancement of system productivity in intercropping besides supplying diversified food. By improving chemical, biological, and physical environment in the soil, legumes can check the declining productivity of cereal-based cropping system. It is important to identify the best intercrops and to assess appropriate doses of nitrogen (N) for the cereal components in intercropping systems considering the sparing effect of biological nitrogen fixation (BNF) from the leguminous component. A number of indices such as land equivalent ratio, crop equivalent yield, relative crowding coefficient, competition ratio, aggressivity, actual yield loss, etc. have been suggested to evaluate the competition between cereal and legume intercrops and advantage of intercropping compared to sole cropping. Although there are some constraints for practicing cereal+legume intercropping systems in large scales like limited availability of good-quality seeds, biofertilizers, and technical and proper scientific knowledge for the complex intercropping system, there is a very good potential to increase the productivity and profitability from resource-poor agricultural systems by adopting this system besides reducing farmers’ risks and improving the soil quality in the long term.

Seaweed extract as organic bio-stimulant improves productivity and quality of rice in eastern Himalayas

Enhancing productivity through integrated nutrient management is pertinent to sustainable intensification of agricultural ecosystems. Field experiments were conducted during 2012 and 2013 in Eastern Himalayas with extracts from Kappaphycus alvarezii (K sap) and Gracilaria edulis (G sap) to assess growth, productivity and quality enhancement of rice (Oryza sativa). A Petri dish experiment was also conducted to assess the efficacy of saps in improving germination percentage and seedling vigour of rice seedlings. Field experiment included foliar spray of K and G saps (2.5, 5, 10 and 15% concentrations) with 100% recommended dose of fertilizers (RDF) along with water spray + 100% RDF (control). The rice seeds soaked with lower concentrations (2.5 and 5%) of K and G saps recorded higher germination percentage, root and shoot length and seedling vigour index as compared to water soaking. Whilst soaking in higher concentrations (7.5% and above) reduced the germination percentage and seedling vigour index. Foliar spray of K or G sap at 5% and above concentrations + 100% RDF significantly increased plant height, dry matter accumulation, chlorophyll index, crop growth rate, yield attributes and yield of rice (5.4 to 18.4% higher) as compared to control. Application of K or G sap at 10% concentrations + 100% RDF also increased micro-nutrient (Fe, Cu, Zn and Mn) and protein concentration in rice grains. Thus, foliar application of 10% K or G sap along with 100% RDF is a recommendable option for improving yield and quality of rice and sustaining soil fertility in eastern Himalayas and similar agroecosystems elsewhere.

Population Dynamics of Citrus Butterfly, Papilio demoleus L. (Lepidoptera: Papilionidae) in Kinnow (Citrus nobilis × Citrus deliciosa) as Influenced by Abiotic Factors

Citrus is the largest cultivated group of fruits in the world, which includes mandarin, sweet orange, limes, lemons, tangerines and grape fruit. In the group of citrus plants, mandarin is the largest cultivated fruit in India and world, whereas sweet orange is the second largest growing species among the group of citrus fruits. Mandarin (Citrus reticulata Blanco) belongs to the family Rutaceae and is widely cultivated fruit plant in tropical and subtropical regions. It occupies premier position due to its high vitamin–C and juice content with pleasant aroma and flavour. In India, mandarin is mostly grown in International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 02 (2018) Journal homepage: http://www.ijcmas.com

Determination of dimethoate, lambda-cyhalothrin and malathion residues in guava fruits using GCMS-tandem mass spectrometry

Tephritidae fruit flies are considered key insect pest in guava which cause yield loss and degradation of quality. A trial was conducted in guava orchard during 2013 to study residue dissipation rate of two organophosphates, dimethoate and malathion and one synthetic pyrethroid insecticide, lambda-cyhalothrin. The insecticides were applied at recommended and double of the recommended dose on semi-ripe guava fruits. The fruits were randomly sampled at different time intervals, i.e. 0 (2 h), 3, 7 and 10 days after spray. After extraction and clean-up, the residues were estimated using GCMS tandem mass spectrometry. The half-life values at single and double dose applications were found to be 6.72 and 8.15 days for dimethoate, 4.41 and 4.71 days for lambda-cyhalothrin and 3 and 3.3 days for malathion. The residues reached below maximum residue limit (MRL) on zero day following recommended dose application of all insecticides. In double dose application, residues reached below MRL on zero day in malathion and lambda-cyhalothrin and on 3rd day in dimethoate. Washing of guava fruits removed 42.9 and 45.2% dimethoate, 33 and 36.8% lambda-cyhalothrin, 50 and 54.5% malathion residues at single and double dose applications in 0 day samples. Lambda-cyhalothrin was found most effective followed by dimethoate and malathion for controlling fruit fly in guava.