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Not AvailableTwo pedon from teak and two from sandalwood-supporting soils occurring on different landforms were studied for their morphology, DTPA-extractable micronutrient cations and some relevant physico-chemical soil properties in Seoni district, Madhya Pradesh. Teak-supporting Parasia pedon (plateau) was characterised by shallow, dark reddish brown soils with argillic clay horizon (Clayey Typic Haplustalf) whereas Mohgaon (undulating basaltic plateau) pedon had very deep solum, dark reddish brown, clayey soil with more than 50 per cent gravels (Clayey-skeletal Typic Rhodustalf). The sandalwood (natural)-supporting Salaia pedon (foot slope) was characterised by shallow, dark reddish brown to reddish brown soils classified as Clayey Typic Haplustept whereas other pedon (scarp slope) was shallow, very dark greyish brown, Clayey Typic Haplustept. The pH of the soils varied from 5.9 to 6.7 in teak-growing soils but it was 6.8 to 7.0 in sandalwood-growing soils. The organic carbon varied from 1.26 to 2.37 % in teak-growing soils which was higher than the sandalwood-growing soils and it ranged from 0.37 to 1.56 %. Cation exchange capacity ranged from 8.53 to 31.31 cmol(p+)kg-1 and 34.27 to 39.70 cmol(p+)kg-1 in teak and sandalwood-growing soils respectively. The soils had DTPA-Fe (1.68 to 36.04 mg kg-1),Mn (13.64 to 136.7 mg kg-1), Zn (0.60 to 2.60 mg kg-1) and Cu -1 (1.38 to 20.38 mg kg-1) in teak supporting soils. In sandalwood-supporting soils DTPA-Fe ranged from 6.68 to 14.94 mg kg-1, Mn (53.82 to 78.52 mg kg-1), Zn (0.48 to 1.40 mg kg-1)and Cu (7.60 to 10.98 mg kg-1). In general, pH showed negative correlation with micronutrient cations while, clay content and OC had positive correlation with DTPA-Fe, Mn, Zn and Cu. Surface layer of the soil had higher concentration of DTPA-extractable cations.Not Availabl

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Not AvailableStudies to evaluate the release threshold level of potassium in Vertisols (shrink-swell soils) in different agro-ecological regions of India and how that may help in K fertility interpretations are rare. Thus the objectives of this study were (i) to evaluate the K status of Vertisols through release threshold levels and (ii) to relate the findings with soil K release and fertilizer management. Three established soil series samples were collected from Vertisols of different agro-ecological regions of India. Release threshold level (RTL) was assessed after equilibrating soil with 0.01M CaCl2 solution having series of soil: solution ratio, after which the remaining amount of exchangeable K was extracted with 1N NH4OAc (pH 7). Total amount of K extracted (KT = K desorbed in CaCl2 solution plus K extracted with 1 N NH4OAc) remained more or less constant with decreasing K-level up to a certain value ( say threshold value) below which KT increased sharply indicating K release from non-labile form. The threshold value in terms of K concentrations (Release Threshold Concentration) of Panjari, Nagpur, Maharashtra (TypicHaplusterts, Sub-humid dry), Teligi, Bellary, Karnataka (SodicHaplusterts, Semi-arid dry) and Kheri, Jabalpur, Madhya Pradesh (TypicHaplusterts, Sub-humid moist) soils were 0.044 – 0.049, 0.034 – 0.062 and 0.043 – 0.11 m M, respectively. The high release threshold K levels in terms of concentration and activity ratio (AR) were observed in soils of Teligi and Kheri series as compared to soils of Panjari series due to high content of trioctahedral mica in the former two soils. The relationships between clay minerals, release threshold level, exchangeable potassium and non-exchangeable potassium determined by 1 N HNO3 and sodium tetra-phenylborate (NaBPh4) have been discussed.Not Availabl

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Not AvailableStudies to evaluate the release threshold level of potassium in Vertisols (shrink-swell soils) in different agro-ecological regions of India and how that may help in K fertility interpretations are rare. Thus the objectives of this study were (i) to evaluate the K status of Vertisols through release threshold levels and (ii) to relate the findings with soil K release and fertilizer management. Three established soil series samples were collected from Vertisols of different agro-ecological regions of India. Release threshold level (RTL) was assessed after equilibrating soil with 0.01 M CaCl2 solution having series of soil: solution ratio, after which the remaining amount of exchangeable K was extracted with 1 N NH4OAc (pH 7). Total amount of K extracted (KT = K desorbed in CaCl2 solution plus K extracted with 1 N NH4OAc) remained more or less constant with decreasing K-level up to a certain value (say threshold value) below which KT increased sharply indicating K release from non-labile form. The threshold value in terms of K concentrations (Release Threshold Concentration) of Panjari, Nagpur, Maharashtra (Typic Haplusterts, Sub-humid dry), Teligi, Bellary, Karnataka (Sodic Haplusterts, Semi-arid dry) and Kheri, Jabalpur, Madhya Pradesh (Typic Haplusterts, Sub-humid moist) soils were 0.044–0.049, 0.034–0.062 and 0.043–0.11 mm, respectively. The high release threshold K levels in terms of concentration and activity ratio (AR) were observed in soils of Teligi and Kheri series as compared to soils of Panjari series due to high content of trioctahedral mica in the former two soils. The relationships between clay minerals, release threshold level, exchangeable potassium and non-exchangeable potassium determined by 1 N HNO3 and sodium tetra-phenyl borate (NaBPh4) have been discussed.Not Availabl

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Not AvailableThis article critically reviews the information regarding potassium (K) status of Indian soils based on research conducted since 1929. The patterns and lacunae regarding potassium consumption in India are also mentioned. The role of minerals in potassium availability vis-à-vis forms of potassium is discussed and elucidated with suitable clay mineralogical evi- dences. The article also highlights concepts of potassium availability to plants in Indian shrink-swell soils. Authors have pointed out the inefficacy of the universal method used for assessing plant-available K (1N NH4OAc) in Indian shrink-swell soil, as observed from extensive K response studies. The current practicesof assessing only plant available K arenot adequate to detect native changes in soil potassium. This paradoxical situation necessitates revision and revalidation of the existing potassium fertilizer rec- ommendations, which are being adopted since four decades. A holistic research envisaging soil test crop response and mineralogical studies will help in revising potassium evaluation methods in India,leading to judicious fertilizer application by the farmers.Not Availabl

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Not AvailableVertisols have the capacity to shrink andswell, inducing cracks and distinctive soil structure throughout the soil profile. In India they occur in various agro-ecological regions such as humid tropical (HT), sub-humid moist (SHM), sub-humid dry (SHD), semi-arid moist (SAM), semi-arid dry (SAD) and arid dry (AD) climatic environments and thus indicates an array of soils in a climosequence. In this study benchmark Vertisols, Panjari is from sub-humid (dry), Kheriis from sub-humid (moist) region, Teligi and Akola soils are from semi-arid (dry) and Nimone is from arid agro-ecological region. All the Vertisols in general are characterized by dark colour, angular to sub-angular blocky structure, clayin texture and calcareous. These soils have high bulk density and high water retention capacity. These soils have deep wide-opened desiccation cracks at the surface which extend deep into the profiles and the depth of cracks increases with aridity. Soils of all climates are dominated by Ca2+ ion in their exchange complex throughout the depth. However, in the sub-humid climate Mg2+ ions tends to dominate in the lower horizon. Whereas the semi-arid dry (Akola) soils have high Na+ ions in their exchange complex. The soils are slightly alkaline to strongly alkaline in nature and poor in organic matter. The CEC varied from 59.3 to 68.2cmol (p+) kg-1 in soil of Panjari series which is highest followed by Teligi series profile. The calcium carbonate (CaCO3) shows gradual increase with depth in all the soil profiles, though it is preferentially accumulated in the sub-surface horizons of lower rainfall region soils.In climosequence the soils of the sub-humid region are generally TypicHaplusterts, soils of semi-arid region are Typic/Sodic/Calcic Haplusterts and soils of arid region are Sodic/ Calcic/ AridicHaplusterts. The present study demonstrates how the soil properties of Vertisols in a different climate may help in inferring the change in climate in a geologic period.Not Availabl

Grain Nutrients Variability in Pigeonpea Genebank Collection and Its Potential for Promoting Nutritional Security in Dryland Ecologies

Pigeonpea, a climate-resilient legume, is nutritionally rich and of great value in Asia, Africa, and Caribbean regions to alleviate malnutrition. Assessing the grain nutrient variability in genebank collections can identify potential sources for biofortification. This study aimed to assess the genetic variability for grain nutrients in a set of 600 pigeonpea germplasms conserved at the RS Paroda Genebank, ICRISAT, India. The field trials conducted during the 2019 and 2020 rainy seasons in augmented design with four checks revealed significant differences among genotypes for all the agronomic traits and grain nutrients studied. The germplasm had a wider variation for agronomic traits like days to 50% flowering (67-166 days), days to maturity (112-213 days), 100-seed weight (1.69-22.17 g), and grain yield per plant (16.54-57.93 g). A good variability was observed for grain nutrients, namely, protein (23.35-29.50%), P (0.36-0.50%), K (1.43-1.63%), Ca (1,042.36-2,099.76 mg/kg), Mg (1,311.01-1,865.65 mg/kg), Fe (29.23-40.98 mg/kg), Zn (24.14-35.68 mg/kg), Mn (8.56-14.01 mg/kg), and Cu (7.72-14.20 mg/kg). The germplasm from the Asian region varied widely for grain nutrients, and the ones from African region had high nutrient density. The significant genotype x environment interaction for most of the grain nutrients (except for P, K, and Ca) indicated the sensitivity of nutrient accumulation to the environment. Days to 50% flowering and days to maturity had significant negative correlation with most of the grain nutrients, while grain yield per plant had significant positive correlation with protein and magnesium, which can benefit simultaneous improvement of agronomic traits with grain nutrients. Clustering of germplasms based on Ward.D2 clustering algorithm revealed the co-clustering of germplasm from different regions. The identified top 10 nutrient-specific and 15 multi-nutrient dense landraces can serve as promising sources for the development of biofortified lines in a superior agronomic background with a broad genetic base to fit the drylands. Furthermore, the large phenotypic data generated in this study can serve as a raw material for conducting SNP/haplotype-based GWAS to identify genetic variants that can accelerate genetic gains in grain nutrient improvement