Current Science

Tapas Bhattacharyya ¹, S. P. Wani ¹, P. Chandran ², P. Tiwary ², D. K. Pal ², K. L. Sahrawat ¹, M. Velayutham ²

Affiliations
1 International Crops Research Institute for Semi-Arid Tropics, Hyderabad 502 324, IN
2 National Bureau of Soil Survey and Land Use Planning, Nagpur 440 010, IN

Abstract

The soil-forming factors, especially climate, vegetation and topography, act on a range of rock formations and parent materials leading to the development of different kinds of soils. Through concerted efforts, soil datasets generated earlier are used to develop maps and soil information systems at different scales. Progress in basic and fundamental research on the formation of Indian soils as related to climate, relief, organisms, parent materials and time has helped in developing the soil information system.

Keywords

Agriculture, Information Technology, Landuse Planning, Soils.

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M. C. Sarathjith ¹, B. S. Das ², S. P. Wani ³, K. L. Sahrawat ³, A. Gupta ²

Affiliations
1 International Crops Research Institute for the Semi-Arid Tropics, Bamako, BP-320, ML
2 Indian Institute of Technology Kharagpur, Kharagpur 721 302, IN
3 International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Hyderabad 502 324, IN

Abstract

Diffuse reflectance spectroscopy (DRS) operating in wavelength range of 350-2500 nm is emerging as a rapid and non-invasive approach for estimating soil nutrient content. The success of the DRS approach relies on the ability of the data mining algorithms to extract appropriate spectral features while accounting for non-linearity and complexity of the reflectance spectra. There is no comparative assessment of spectral algorithms for estimating nutrient content of Indian soils. We compare the performance of partialleast- squares regression (PLSR), support vector regression (SVR), discrete wavelet transformation (DWT) and their combinations (DWT-PLSR and DWT-SVR) to estimate soil nutrient content. The DRS models were generated for extractable phosphorus (P), potassium (K), sulphur (S), boron (B), zinc (Zn), iron (Fe) and aluminium (Al) content in Vertisols and Alfisols and were compared using residual prediction deviation (RPD) of validation dataset. The best DRS models yielded accurate predictions for P (RPD = 2.27), Fe (RPD = 2.91) in Vertisols and Fe (RPD = 2.43) in Alfisols, while B (RPD = 1.63), Zn (RPD = 1.49) in Vertisols and K (RPD = 1.89), Zn (RPD = 1.41) in Alfisols were predicted with moderate accuracy. The DWT-SVR outperformed all other approaches in case of P, K and Fe in Vertisols and P, K and Zn in Alfisols; whereas, the PLSR approach was better for B, Zn and Al in Vertisols and B, Fe and Al in Alfisols. The DWT-SVR approach yielded parsimonious DRS models with similar or better prediction accuracy than PLSR approach. Hence, the DWT-SVR may be considered as a suitable data mining approach for estimating soil nutrients in Alfisols and Vertisols of India.

Keywords

Diffuse Reflectance Spectroscopy, Discrete Wavelet Transformation, Partial-Least-Squares Regression, Soil Nutrient Contents, Support Vector Regression.

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T. Bhattacharyya ¹, Suhas P. Wani ², D. K. Pal ³, K. L. Sahrawat ², S. Pillai ², A. Nimje ², B. Telpande ³, P. Chandran ³, Swati Chaudhury ²

Affiliations
1 Dr Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli 415 712, IN
2 International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 324, IN
3 National Bureau of Soil Survey and Land Use Planning, Amravati Road, Nagpur 440 010, IN

Abstract

Associated red and black soils are common in the Deccan plateau and the Indian peninsula. The red soils are formed due to the progressive landscape reduction process and black soils due to the aggradation processes; and they are often spatially associated maintaining their typical characteristics over the years. These soils are subject to changes due to age-long management practices and the other factors like climate change. To maintain soil quality, it is essential to monitor changes in soil properties preferably using benchmark (BM) soil sites. One such example lies at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) farm in Patancheru, India where red (Patancheru) and black (Kasireddipalli) soils co-exist in close association under almost similar topographical condition, which also represents very commonly occurring spatially associated soils. The database generated over the years for these two dominant soils that are under cultural practices for the last 2-3 decades, helps us understand the relative changes in properties over a time scale. To do this exercise, we revisited the BM spots as the data on the original characterization of these soils since the development of the farm, are available, for comparative evaluation. We also attempted to make prediction of future changes in properties for these two important and representative black and red soils of the ICRISAT farm in Patancheru, India.

Keywords

Associated Red and Black Soils, Changes, ICRISAT Farm, Monitor, Soil Quality.

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K. L. Sahrawat ¹

Affiliations
1 International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 324, IN

Abstract

The semi-arid tropical (SAT) regions are notably characterized by low rainfall and high temperatures, and hence low natural primary productivity and soil fertility. However, to adequately respond to the title of our article as to how fertile are SAT soils, there is a need to critically review the current literature on the fertility status of SAT soils. Little attention has been paid in the past to determining the fertility status of SAT soils supporting rainfed production systems despite the fact that the SAT soils are relatively fragile than their irrigated counterparts; and this is due to their widespread degradation and lack of investment in building up the fertility. However, as in the case of other agroecosystems, the soils in the SAT regions vary widely in various fertility parameters. For example, the results of survey of large numbers of farmers' fields in the SAT regions of India, by the ICRISAT and its partners, showed that they vary widely in soil pH, salts (electrical conductivity, EC), organic C (an index of available N) and major (N and P), secondary (S) and micronutrients (B and Zn) although the soils were low in organic C with widespread deficiencies of these nutrients. From the results discussed in this article, it is concluded that in general, the soils in the SAT regions are low in fertility; however, they vary widely in various fertility parameters.

Keywords

Farmers’ Fields, Fertility Status, Organic Carbon, Major and Micronutrients, Semi-Arid Tropics, Soil Testing.

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D. K. Pal ¹, T. Bhattacharyya ², K. L. Sahrawat ², Suhas P. Wani ²

Affiliations
1 National Bureau of Soil Survey and Land Use Planning (ICAR), Amravati Road, Nagpur 440 010, IN
2 International Crops Research Institutes for the Semi-Arid Tropics, Patancheru 502 324, IN

Abstract

Most published research on soil degradation in general emphasizes the role of anthropogenic factors. Even among the natural soil degradation processes the regressive pedogenic processes that lead to the formation of CaCO₃ and concomitant development of subsoil sodicity and the adverse effects of palygorskite on the soils of the semi-arid tropics (SAT), have received little global attention as the natural processes of chemical degradation of soils. Studies in India during the last two decades, however, have demonstrated the important role of regressive pedogenic processes in natural degradation of major soil types in the Indian SAT regions. The present article summarizes the research on natural degradation of soils in the Indian SAT. The management practices to reclaim the degraded soils are also discussed with examples.

Keywords

CaCO₃ Formation, Regressive Pedogenesis, Remedial Measures, SAT Soils, Subsoil Sodicity.

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Swati Chaudhury ¹, T. Bhattacharyya ¹, Suhas P. Wani ¹, D. K. Pal ², K. L. Sahrawat ¹, Ankush Nimje ¹, P. Chandran ², M. V. Venugopalan ³, B. Telpande ²

Affiliations
1 International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 324, IN
2 National Bureau of Soil Survey and Land Use Planning, Amravati Road, Nagpur 440 010, IN
3 Central Institute for Cotton Research, Nagpur 440 010, IN

Abstract

Soil organic carbon (SOC) and rainfall are generally positively related, whereas a negative relationship between soil inorganic carbon (SIC) and rainfall with some exception is observed. Land use pattern in black soil region (BSR) of the semi-arid tropical (SAT) India, consists of 80% under agriculture, followed by forest, horticulture, wasteland and permanent fallow. For sustainable agriculture on these soils, there is a concern about their low OC status, which warrants fresh initiatives to enhance their OC status by suitable management interventions. In the BSR region, cotton, soybean and cereal-based systems dominate but it is not yet clear as to which cropping system in the SAT black soils is most suitable for higher OC sequestration. Many short-term experiments on cotton or cereal-based systems clearly suggest that cotton or cereal-based cropping systems including leguminous crops perform better in terms of SOC sequestration whereas soybean-legume combination do not add any substantial amount of OC. In sub-humid bioclimatic zones (1053-1209 mm mean annual rainfall), soybean is grown successfully with wheat or fallowing, and SOC concentration is maintained at 0.75% in the 0.30 m soil layer under integrated nutrient management. In view of enhancement and maintenance of OC in many shortterm experiments conducted in various agro-climate zones of SAT, it is realized that OC accumulation in soils of the semi-arid ecosystem with suitable cropping and management practices could be substantial especially in cotton-pigeon pea rotation, and thus the discussed crop rotations in each major bio-climatic zone stand for wide acceptance by the SAT farmers.

Keywords

Land Use and Cropping Systems, Rainfall, Soil Carbon, Vertisol and Associated Soils.

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T. Bhattacharyya ¹, D. K. Pal ², Suhas P. Wani ¹, K. L. Sahrawat ¹

Affiliations
1 ICRISAT Development Center, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, IN
2 Formerly at National Bureau of Soil Survey and Land use Planning, Nagpur 440 033, IN

Abstract

Soils in the semi-arid tropics (SAT) are subject to chemical degradation mostly due to climatic reasons which make the pedo-environment hostile to form calcium carbonate. This triggers an overall deterioration of soil properties affecting its physical and chemical parameters. Such soils require management interventions which may include chemical and other phytoremediation process. The present paper details this process of degradation in light of resilience of these soils of SAT.

Keywords

Chemical Degradation, SAT, Soil Properties, Soil Resilience.

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Tapas Bhattacharyya ¹, Suhas P. Wani ², K. L. Sahrawat , D. K. Pal ²

Affiliations
1 Dr Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli 415 712, IN
2 ICRISAT Development Centre, International Crops Research Institute for the Semi-Arid Tropics, Hyderabad 502 324, IN

Abstract

Soil and water form the basis of all terrestrial life. Their resources vary widely and are affected by natural and anthropogenic perturbations. Ancient civilizations and cultures emerged and sustained on good soils; and some of them went into oblivion when soil and water resources were degraded irreversibly. Even during the contemporary period, good-quality soil and water resources form a powerful engine of economic development and ensured food security.

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