Fast and Simultaneous Determination of Soil Nutrient Contents using Near Infrared Technology

Abstract

This presented study aimed to apply the near infrared technology as a rapid and simultaneous technique in in determining soil macro nutrients in from of Potassium (K) and Phosphorus (P) contents. The absorbance spectra data of 26 bulk of soil sample amounted 40g per each were acquired in wavelength range from 1000 – 2500 nm with 4x optical gain and 0.2 nm resolution windows. Meanwhile, actual soil nutrient contents were measured using standard laboratory wet analysis respectively. To obtain robust and accurate prediction models, spectra data were enhanced by means of smoothing and baseline shift correction (BSC) approaches. Predicted soil nutrient contents were obtained by using principal component regression (PCR) followed by leverage validation. The results showed that both K and P contents of soil samples can be determined simultaneously with maximum correlation coefficient 0.88 for K and 0.96 for P prediction. Based on reposted performances, it may conclude that near infrared technology can be used and applied to determine soil macro nutrient contents rapidly and simultaneously.