Empower Innovations in Routine Soil Testing

Conventional soil tests are commonly used to assess single soil characteristics. Thus, many different tests are needed for a full soil fertility/soil quality assessment, which is laborious and expensive. New broad-spectrum soil tests offer the potential to assess many soil characteristics quickly, but often face challenges with calibration, validation, and acceptance in practice. Here, we describe the results of a 20 year research program aimed at overcoming the aforementioned challenges. A three-step approach was applied: (1) selecting and establishing two contrasting rapid broad-spectrum soil tests, (2) relating the results of these new tests to the results of conventional soil tests for a wide variety of soils, and (3) validating the results of the new soil tests through field trials and communicating the results. We selected Near Infrared Spectroscopy (NIRS) and multi-nutrient 0.01 M CaCl2 extraction (1:10 soil to solution ratio; w/v) as broad-spectrum techniques. NIRS was extensively calibrated and validated for the physical, chemical, and biological characteristics of soil. The CaCl2 extraction technique was extensively calibrated and validated for ‘plant available’ nutrients, often in combination with the results of NIRS. The results indicate that the accuracy of NIRS determinations is high for SOM, clay, SOC, ECEC, Ca-CEC, N-total, sand, and inorganic-C (R2 ≥ 0.95) and good for pH, Mg-CEC, and S-total (R2 ≥ 0.90). The combination of the CaCl2 extraction technique and NIRS gave results that related well (R2 > 0.80) to the results of conventional soil tests for P, K, Mg, Na, Mn, Cu, Co, and pH. In conclusion, the three-step approach has revolutionized soil testing in The Netherlands. These two broad-spectrum soil tests have improved soil testing; have contributed to increased insights into the physical, chemical, and biological characteristics of soil; and have thereby led to more sustainable soil management and cropping systems.

Effects of Extraction Technique and Solvent on Phytochemicals, Antioxidant, and Antimicrobial Activities of Cultivated and Wild Rosemary (Rosmarinus officinalis L.) from Taounate Region (Northern Morocco)

This work was set up to investigate the effects of domestication, solvent, and extraction technique on extracts yield, total phenolics content (TPC), flavonoids content (TFC), antimicrobial (minimal inhibitory concentration, MIC), and antioxidant (IC50) activities in rosemary aerial parts at flowering stage. Although solvent was the main variability source in our data, all tested factors significantly impacted yield, TPC, TFC, MIC, and IC50. These results were confirmed via principal component analysis, which separated solvents, extraction techniques, and rosemary types on the first three components accounting for more than 99% of data variability. Better values of yield (4.17 ± 0.30 –21.58 ± 0.93% DM ), TPC (12.48 ± 1.17–34.72 ± 1.65 mg GAE/g DM), TFC (6.51 ± 1.79–25.02 ± 1.53 mg QE/g DM), MIC (8.17 ± 1.04–24.20 ± 0.98 μg/mL), and IC50 (50.02 ± 0.08–390.00 ± 1.00 µg/mL) were obtained in the case of wild rosemary with Soxhlet extraction especially when combined with more polar solvents (ethanol and methanol). It could be concluded that domestication had negative effects on rosemary phytochemicals and associated antimicrobial and antioxidant activities. Rosemary extracts could serve as important ingredients as food preservatives, antimicrobial agents, and nutraceuticals.