Evaluation of multi-nutrient extractants for determination of available P, K, and micronutrient cations in soil

Sanjay K. Sharma, Ankita Sharma, Surinder Rana, Naveen Kumar
  • Journal of Plant Nutrition, February 2018, Taylor & Francis
  • DOI: 10.1080/01904167.2018.1426019

Evaluation of multinutrients extractants

What is it about?

Sixty soil samples (0–0.15 m depth) collected randomly from different districts of Himachal Pradesh were used to evaluate ammonium bicarbonate-diethylenetriaminepenta acetic acid (AB-DTPA) and acid ammonium acetate-ethylene diamine tetra acetic acid (AAAc-EDTA) over standard methods for P, K, and micronutrient cations. Among Olsen P, Bray P1, AB-DTPA P, and AAAc-EDTA P, available P (kg ha−1) varied from 7.8 to 44.3, 9.5 to 61.1, 6.5 to 38.8, 10.5 to 52.1; available K (kg ha−1) among NH4OAc, AB-DTPA, and AAAc-EDTA ranged from 103.6 to 372.3, 86.6 to 364.9, and 74.6 to 362.5. In case of micronutrients cations, AB-DTPA in general, extracted more amounts as compared to DTPA alone. AAAc-EDTA correlated highly with the Olsen P. AB-DTPA-K and AAAc-EDTA-K correlated well with standard method (NH4OAc) however; AAAc-EDTA had higher correlation with AB-DTPA for K extractability. Among methods for micronutrients highest significant correlations were observed between AB-DTPA and DTPA for Cu, Fe, and Zn.

Why is it important?

The specific chemical methods for extracting particular nutrients are quite effective and accurate in estimating the available content of different nutrients in the soil, but these involve separate extractants and procedures for extraction. Therefore, these procedures are more time consuming, laborious, cumbersome, and costly because of more use of chemicals, glassware, and energy. In order to overcome these issues, multi-nutrient extractants offer a suitable alternative, as more than one nutrient can be extracted in one go.

Perspectives

Sanjay Sharma (Author)
CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur

Wide variations were observed in the contents of P under different methods. Bray P1 method of phosphorus determination extracted more amount of available P followed by AAAc-EDTA, Olsen, and AB-DTPA methods. AB-DTPA, AAAc-EDTA, and Bray P1 methods of phosphorus analysis were very well correlated with the Olsen method of phosphorus determination. Available K contents determined by AB-DTPA as well as AAAc-EDTA were quite close to the standard method of K determination and all these methods were well correlated with each other. The contents of all the micronutrients extracted by AB-DTPA and DTPA exhibited stronger correlation in comparison to that with AAAc-EDTA. Both the multi-nutrient extractants are rapid, less labor consuming, and cheaper in comparison to conventional methods. However, there is need for understanding the factors responsible for differential extraction of nutrients with AB-DTPA/AAAc-EDTA by including some more soil properties. The final recommendations on suitability of AB-DTPA/AAAc-EDTA for soil testing would require studies on correlation between the nutrients uptake (P, K, and micronutrient) by different crops and the nutrients extracted/applied based on soil analysis with AB-DTPA/AAAc-EDTA extractants

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http://dx.doi.org/10.1080/01904167.2018.1426019

The following have contributed to this page: Sanjay Sharma