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In the present investigation, an attempt was made to determine the direct effects of fertilizers on various soil properties like acidification, organic matter content, the content of essential and toxic trace metals in soils and food grains under long term (>25 years) fertilizer experiment. Soil and plant samples were collected from Bengaluru center of All India Coordinated Research Project on Long-Term Fertilizer Experimental site in the sub-regions AESR 8.1 of India, with the treatments e.g. control, 100% N, 100% NP, 100% NPK, 150% NPK, 100% NPK + Lime, 100% NPK+ farmyard manure (FYM) at 0 to 60 cm depth with an interval of 15 cm. Laboratory analysis was conducted to know the vertical distribution of heavy metals and micronutrient cations in soil and plant produce by following the standard method. The DTPA soil Zn remained unchanged with the higher rates of N application, i.e. 100% N. There was very little effect of N, NP, and NPK application on the buildup of DTPA-able Zn, Fe, Mn, and Cu content in both the soils. However, the application of NPK + FYM showed a buildup in comparison to control for Fe 10 mg kg−1, Mn 18 mg kg−1, Zn 1.23 mg kg−1, and Cu 0.84 mg kg−1 in soil. Continuous fertilizer application contributed a meager amount accumulation of Cd, Pb, Ni, Co, and Cr in the soil under the finger millet – maize cropping sequence. The estimation of heavy metals in food grains, supposed to come from fertilizers, lime materials applied in soil was also of our concern. All the cited heavy metals were present in the maize and finger-millet grains. Risk assessment to human health (Hazard Quotient, HQ) for the intake of heavy metals through consumption of contaminated food grains was computed and observed that the values of 'HQ' for all the crops were far less than unity (<1) and safe for the consumers. [ABSTRACT FROM AUTHOR]

Glauconite is a potassium (K) bearing mineral, which generally contains 6–10% K2O and mostly available in various natural deposits in India. Glauconite mineral was converted to nano-particle form by grinding in a high-energy ball mill. The release of K from glauconite nano-particle in soil was studied in a pot culture experiment. Five different treatments viz., 0 mg K2O kg−1, 100 mg K2O kg−1, 150 mg K2O kg−1, 200 mg K2O kg−1 used glauconite nano-particle (GNP) as a K source and 100 mg K2O kg−1 from muriate of potash (MOP), were applied in soil to grow maize (Zea mays L.) plant. The highest K+ concentration was observed in shoot at the application of 200 mg K2O kg−1 through GNP and recorded 2 times more K+ concentration in shoots as compared to 0 mg K2O kg−1 treatment whereas 1.1 times more than the MOP treated soil at 5th harvesting stage. Selected plant physiological parameters namely electrical conductivity of plant cell, height, leaf area and nitrate reductase activity were also recorded maximum at 200 mg K2O kg−1 GNP treated soil. Overall, glauconite nano-particle could supply K throughout the growth period and enhanced biomass yield of maize plant without showing any K deficiency symptom. [ABSTRACT FROM AUTHOR]

India is the largest producer, consumer and exporter of turmeric (Curcuma longa L.). The Lakadong variety of turmeric is endemic to Jaintia Hills of Meghalaya, India. It is considered as the best quality turmeric containing 7.5% curcumin, which is about three times higher than the other varieties (2-3%). This study identifies potential sites for turmeric cultivation in Jaintia Hills using geospatial techniques, viz. analytical hierarchical process (AHP) and weighted overlay analysis (WOA). WOA identified a total of 162,263.70 ha suitable for the expansion of Lakadong variety of turmeric in Jaintia Hills, of which 18% was highly suitable, 31% moderately suitable and 32% was marginally suitable. In the case of AHP, 21% area was found to be highly suitable, 25% moderately suitable and 45% marginally suitable. [ABSTRACT FROM AUTHOR]

A column study was conducted to determine the effect of city compost, lime, gypsum, and phosphate on cadmium (Cd) mobility in three well-recognized benchmark soils of India [viz., (Islamnagar) Vertisol, (Amarpur) Inceptisol, and (Khala) Alfisol]. Columns made of PVC were filled with soil treated with different treatment doses [viz., 0.5% city compost, 1% city compost, 2% city compost, 2.5 t lime/ha, 5 t lime/ha, 2.5 t lime/ha+0.5% city compost, 2.5 t gypsum/ha, 2.5 t gypsum/ha+0.5% city compost, and 100 kg P2O5/ha as potassium phosphate (KH2PO4). The columns were leached with 100 mg L-1 Cd under saturated condition. The amount of water moving through the soils was measured as the pore volume. A delayed breakthrough curve (BTC) of Cd in the presence of lime has been observed in all the studied benchmark soil series. Among the treatments, lime application reduced the movement of Cd from surface soil to lower depth of soil to a large extent resulted in 9, 25, and 45% more retention of Cd in surface soil of the Islamnagar, Amarpur, and Khala series respectively. Explanation for reduced Cd mobility in limed soil can be derived from pH changes of soils. In comparison to control soil, phosphate application caused 6, 21, and 30% more retention of Cd in surface soil in the Islamnagar, Amarpur, and Khala series, respectively. Combined application of lime and city compost reduced the movement of Cd in the soil profile. It appears that organic matter controls the sorption of Cd in soils. The amount of Cd sorbed increased with increasing organic carbon content, but gypsum application may leach Cd beyond the root-zone depth. A rapid breakthrough curve was observed under gypsum-treated soils. Retardation factor revealed that a somewhat lower degree of Cd retention occurred in the Khala series, which might possibly be attributed to less clay content and low pH. Overall, the column study indicated that total Cd accumulation occurred up to depths of 5-7.5 cm, 7.5-10 cm, and 10-15 cm in soils of Islamnagar, Amarpur, and Khala series, respectively. [ABSTRACT FROM AUTHOR]

Speciation study of microelements in soils is useful to assess their retention and release by the soil to the plant. Laboratory and greenhouse investigations were conducted for five soils of different agro-ecological zones (viz., Bhuna, Delhi, Cooch-Behar, Gurgaon, and Pabra) with diverse physicochemical properties to study the distribution of zinc (Zn) among the soil fractions with respect to the availability of Zn species for uptake by rice plant. A sequential extraction procedure was used that fractionated total soil Zn into water-soluble (WS), exchangeable (EX), specifically adsorbed (SA), acid-soluble (AS), manganese (Mn)-oxide-occluded (Mn-OX), organic-matter-occluded (OM), amorphous iron (Fe)-oxide-bound (AFe-OX), crystalline Fe-oxide-bound (CFe-OX), and residual (RES) forms. There was a wide variation in the magnitude of these fractions among the soils. The studies revealed that more than 90% of the total Zn content occurred in the relatively inactive clay lattice and other mineral-bound form (RES) and that only a small fraction occurred in the forms of WS, EX, OM, AFe-OX, and CFe-OX. Rice (Oryza sativa L.) cultivars differ widely in their sensitivity to Zn deficiency. Results suggested that Zn in water-soluble, organic complexes, exchange positions, and amorphous sesquioxides were the fractions (pools) that played a key role in the uptake of Zn by the rice varieties (viz., Pusa-933-87-1-11-88-1-2-1, Pusa-44, Pusa-834, Jaya, and Pusa-677). Isotopic ally exchangeable Zn (labile Zn) was recorded higher in Typic Ustrochrept of Pabra soil, and uptake of Zn by rice cultivars was also higher in this soil. The kinetic parameters such as maximum influx at high concentrations (Imax) and nutrient concentration in solution where influx is one half of Imax (Km) behaved differentially with respect to varieties. The highest Imax value recorded was 9.2×10-7 µmol cm-2 s-1 at the 5 mg kg-1 Zn rate for Pusa-933-87-1-11-88-1-2-1, and the same was lowest for Pusa-44, being 4.6×10-7 µmol cm-2 s-1 at the 5 mg kg-1 Zn rate. The Km value was highest for Pusa-44 (2.1×10-4µmol cm-2 s-1) and lowest for Pusa-933-87-1-11-88-1-2-1 (1.20×10-4µmol cm-2 s-1). The availability of Zn to rice cultivars in Typic Ustrochrepts of Bhuna and Delhi soils, which are characterized by higher activation energy and entropy factor, was accompanied by breakage of bonds or by significant structural changes. [ABSTRACT FROM AUTHOR]

Rice accounts for a significant contribution to the total food grain production in India. As the rice production area either stabilizes or declines, and there is a wide gap between projected demand and current level of production, vertical growth in production through hybrid rice is a practically feasible and adoptable technology. This paper attempts to elucidate the current scenario, strategies and agro-techniques for seed as well as grain production, quality parameters and economic aspects of hybrid rice in India. As the, seed production of hybrid rice is knowledge and labor intensive, different agro-techniques need to be adopted to make it more successful. The two parental lines should be sown and transplanted at the right time with an isolation distance of 50-100 m. For synchronized flowering, the differential seeding of parental lines can be based on their effective accumulated temperature (12-27°C) from seeding to flowering. The optimum ratio for plants of the seed to pollen parent should ensure 3.5 spikelets of the seed parent for each spikelet of the pollen parent. Thus the commonly used seed to pollen parent ratios are 10:3, 6:2 and 14:2. Cultural practices like controlling weeds and pests, roguing of off-types are essential. Application of GA3 at 15-20 g ha-1 should be sprayed with ULV sprayer to overcome poor panicle exsertion of parental lines. The agronomic practices for large scale grain production include the seed rate of 15 kg ha-1, optimum seeding density of 10-20 g m-2 in the nursery, transplanting of a single seedling per hill with the spacing of 15 cm × 15 cm. Though nutrient requirement differs with type of soil and initial fertility, a general dose of 120-150 kg N, 60 kg P2O5 and 50 kg K2O and 20 kg S ha-1 is required. Application of ZnSO4 @ 40 kg ha-1 once in every three crop seasons is needed in the Zn-deficient areas. The grain quality characteristics include long slender (LS) grain, 60-70% milling and 24-31% amylose content. Seed quality control is another essential requirement that should be maintained throughout the process of seed production. A net profit of Rs. 25000 ($ 550) per ha can be obtained by taking up hybrid rice seed production. Moreover, integrated efforts of policy makers, researchers, extension workers and farmers would be desirable to make hybrid rice cultivation a successful endeavor in India. [ABSTRACT FROM AUTHOR]