A Comparison of Different Leaf-Sampling Techniques Used in the Foliar Diagnosis of Sugarcane in Different Countries

Abstract

Several different methods of sampling sugarcane leaves for foliar diagnosis are used in as many different countries. In order to evaluate the values obtained for nitrogen, phosphorus, potassium, and moisture, four of these were used in an experiment at this Station, and the results compared. The following findings were regarded as significant: 1. The Hawaiian, British Guiana, and Mauritius sampling methods gave closely similar values. 2. The Puerto Rican method, wherein the midrib of the leaf is included, gave lower nitrogen and phosphorus values, and higher potash values. 3. The individual cane leaves from Nos. 3(+l) to 6(+4) showed no appreciable variation in nitrogen, but a decrease in phosphorus, potassium, and sheath moisture with increasing leaf number. 4. The analysis of the various parts of the cane leaf blade showed that the lamina was higher in nitrogen and phosphorus but lower in potassium than the midrib. 5. The optimum leaf-nutrient values for the various countries and techniques were compared after appropriate adjustments were made to standardize them on a common basis. In general, the leaf values were similar regardless of country, method, or cane variety.