EFFECTS OF A WASHING PROCESS OF CATTLE MANURE ASH ON ROOT AND SHOOT GROWTH OF KOMATSUNA (BRASSICA RAPA VAR. PERVIRIDIS) AT THE SEEDLING STAGE

Abstract

   This study aims at testing the effects of a washing process on the germination of komatsuna (Brassica rapa var. perviridis) for three days. Cattle manure ash (CMA) was washed with deionized water to reduce electrical conductivity (EC). Not-washed ash (NWA) and washed ash (WA) were used in this experiment. Solutions extracted from NWA and WA (solid:water = 1:20) were diluted at different ratios and had EC values ranging from 0.6 to 28.4 deci-Siemens (dS) m^-1. Potassium (K) solutions (1, 2, 3, and 4 dS m^-1 as KCl) and phosphorus (P) solutions (5.2 and 2.5 mg P L^-1 as KH₂PO₄, adjusted to EC of 1 or 2 dS m^-1) were used for germination tests. Results showed that the washing process reduced EC and therefore enhanced shoot elongation. However, the washing process did not affect germination rates (p > 0.05). Stimulation of root and shoot elongation was seen at EC less than 3 dS m^-1 and K ranging from 3.5 to 16 mM. Potassium in NWA and WA was a stimulating factor for the elongation of roots and shoots for three days in the seedling stage, but K was reduced to 67% in the WA extract. Meanwhile, soluble P negligibly affected the growth of roots and shoots. In conclusion, K in both NWA and WA promoted the growth of roots and shoots. The washing process should be considered when EC is limited to less than 3 dS m^-1 by application rates.