000			01541nam a2200217Ia 4500
008			220216s9999 xx 000 0 und d
100			_aJoseph M
245		0	_aDiagnosis and recommendation integrated system 1. Formulation of DRIS norms for Hevea brasiliensis
260			_bIndian Journal of Natural Rubber Research _c1993
300			_a111-116
520			_aThe diagnosis and recommendation Integrated System (DRIS) involves the use of nutrient concentration ratios to determine the relative sufficiency of nutrients within the plant tissue. A data bank comprising yield, leaf nutrient concentration for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) and soil fertility status from 1200 individual fields from 15 estates representing the major rubber growing regions of South India was built. DRIS norms for the nutrients N, P, K, Ca and Mg were developed from a regrouped data set having uniformity in age and system of tapping. The variance ratio (low yield/high yield) was highly significant for the nutrient combinations involving Mg indicating the direct role of Mg on latex yield. The mean valuesa and the corresponding cv from the high yielding population for the ratio N/P, K/N, K/P, Ca/N, Ca/P, Ca/K, Ca/Mg, N/Mg, P/Mg and K/Mg were selected as the standard norms.
650			_aData bank
650			_aDRIS
650			_aFoliar diagnosis
650			_aHevea brasiliensis
650			_aIndia
700			_aMathew M
700			_aRanganathan C R
700			_aSethuraj M R
942			_cJS
999			_c57149 _d57149