Mid-infrared (MIR) spectroscopy is emerging as one of the most promising technologies, as it is a rapid and cost-effective alternative to routine laboratory analysis for many soil properties. This study was conducted to evaluate the potential of mid-infrared spectroscopy for the rapid and nondestructive measurement of some important soil properties of Alfisols. A total of 336 georeferenced soil samples fromthe 0–15 cm soil layer of Alfisols that were collected from the eastern Indian states of Odisha and Jharkhand were used. The partial least-squares regression (PLSR), random forest, and support vector machine regression techniques were compared for the calibration of the spectral data with the wet chemistry soil data. The PLSR-based predictive models performed better than the other two regression techniques for all the soil properties, except for the electrical conductivity (EC). Good predictions with independent validation datasets were obtained for the clay and sand percentages and for the soil organic carbon (SOC) content, while satisfactory predictions were achieved for the silt percentage and the pH value. However, the performance of the predictive models was poor in the case of the EC and the extractable nutrients, such as the available phosphorus and potassium contents of the soil. Specific regions of the MIR spectra that contributed to the prediction of the soil SOC, the pH, and the clay and sand percentages were identified. The study demonstrates the potential of the MIR spectroscopic technique in the simultaneous estimation of the SOC content, the sand, clay, and silt percentages, and the pH of Alfisols from eastern India.

Sustainability of cereal-based cropping system is important for the livelihood and food security in semi-arid regions. The present study explores the impact of long-term organic and inorganic nutrients and integrated fertilization practices of soil test crop response (STCR) approach of inductive-cum-targeted yield model on soil physical properties and its correlation with soil organic carbon (OC) under pearl millet–wheat in sandy-loam soils of semiarid north-west regions of India. Results showed that OC in the soils significantly increased in farm yard manure (FYM) and integrated treatments up to a maximum of 135% and 148%, respectively, in a period of 8 years over the control in surface soils (0–15 cm). The increase in OC significantly increased the infiltration rate (IR), hydraulic conductivity (HC), soil water retention at all suctions, water stable aggregates (WSA) (> 0.25 mm) and mean weight diameter of the soil aggregates, while decreased the bulk density (BD) and penetration resistance (PR) both at surface and subsurface soil layers. Soil OC also showed a negative correlation with BD (r = −0.955) and PR (r = −0.820). The hydraulic properties of the soil, viz., soil water retention, showed a high positive correlation with field capacity (r = 0.973), 0.922 for permanent wilting point (r = 0.922), HC (r = 0.938), IR (r = 0.973), and WSA (r = 0.979) with OC. Thus, long-term application of organic material in conjunction with NP improved soil physical health, provided better environment to grow crops through improved nutrient concentration and its translocation that ultimately helps to achieve yield target through STCR (Soil Test Crop Response) approach of inductive-cum-targeted yield model.

Soil phosphorous (P) can limit plant growth due to its fixation which stipulates the changes occuring due to imbalanced fertilization in pearl millet-wheat system. The study was aimed to identify the long-term effect of fertilizers and manures on availability of P due to changes in soil inorganic (Pi) and organic P (Po) pools at 0–15, 15–30, 30–60, and 60–90 cm. A sequential methodology was used to determine the effect of fertilizers and manures w.r.t. control (CK) on pools of P and their distribution in soil profile. Fertilizers and manures significantly increased the total and available P concentration. Labile (LOP) and moderately labile (MLOP) organic phosphorous concentrations significantly (P < .05) impacted throughout the soil profile. However, moderately and highly stable organic P pools (MSOP & HSOP) were significantly higher at surface soils. Integrating manures with fertilizers (NPKM) for 10 years increased the LOP and MLOP by 121.5 and 50.0%, while the concentration of MSOP and HSOP was higher under fertilizer treatments (NPK and BF_STCR) at surface soils. The P_i associated with Saloid-P, Aluminium-P, and Iron-P showed decreasing concentration, while calcium-phosphorous concentration increased at all soil depths. The increase in residual-P was more pronounced at lower depths. The proportion of Pi to the total P increased to 16.8% in fertilizer treatments at 30–60 and 60–90 cm soil, while Po proportions increased to 21.0% at 0–15 cm soil. Integrating manures with fertilizers could be a viable nutrient management practice of enhancing the Po and Pi and their availability to plants in sandy soils of Inceptisols.

To develop fertilizer prescription equations for maize, a field experiment was conducted on Inceptisol of Agricultural Research Farm, Banaras Hindu University, Varanasi during kharif 2012 by using integrated plant nutrient management system on the basis of STCR approach. Soil test data, maize grain yield and NPK uptake by maize crop were used for obtaining four important basic parameters viz., nutrients required to produce one tonne (1 t) of maize grain (NR), contribution of nutrients from fertilizers (%CF), contribution of nutrients from soil (%CS) and contribution of nutrients from organic matter (%CFYM). It was found that 19.4, 5.70 and 18.4 kg of N, P2O5 and K₂O, respectively were required for producing 1 t maize grain. The per cent contribution of nutrients from soil, fertilizer and FYM were 18.2. 13.4 and 8.18 for N; 49.6, 11.7 and 7.87 for P2O5; and 19.4, 25.4 and 9.96 for K₂O, respectively. By using these basic parameters, ready reckoner of fertilizer doses was prepared for varying soil test values and desired yield targets of maize for NPK alone and NPK with FYM.