Utilization of latex serum as rie fertilizer

Abstract

To investigate the effects of control latex serum (CS) and deproteinized latex serum (DS) on growth of rice seedlings in hydroponic culture, the 7 day-old rice seedlings cv. Suphan Buri 1 (SPR 1) and Khao Dawk Mali 105 (KDML 105) were cultured in 150 ml opaque bottles, which contained tap water and Hoagland solution compared with 1%, 3%, 5%, 7% and 9% of both latex sera. During 14 days after germination, the rice plants were rapidly grown in Hoagland solution but they became yellow and died at 22 days. Both rice cultivars responded best to 1%-3% of both sera until 26 days. The results indicated that latex sera can be used for rice seedlings better than Hoaglan solution. The effect of both sera on growth and yield of these two rice cultivars was investigated in pot experiment using 30 kg/rai of ammonium phosphate fertilizer (N:P2O5:K2O=16-20-0) as control treatment comparing with 1-9% latex serum (13-117 kgN/rai) with ten replications The results indicated that 9% CS promoted shoot growth about 1.3 fold and 1.6 fold in SPR 1 and KDML 105, respectively compared with control treatment. It also produced more or less similar grain yield but showed 16 and 10 days delay flowering time, respectively compared with chemical fertilizer. Control serum gave significantly higher yield than deproteinized serum. Accordingly, the effect of CS in combination with ammonium phosphate fertilizer on growth and yield was studied by defining that 100F is application of 30 kg/rai ammonium phosphate fertilizer 16-20-0 and 100S is 117 kgN/rai of latex serum compared with untreated control, 25F+75S, 50F+50S and 75F+25S. The results showed that both rice cultivars applied with 50F+50S produced the highest shoot dry weight and produced grain yield of 2.2 fold over that of 100F. It showed 5 days delay flowering time in SPR 1 and 3 days earlier in KDML 105. In comparison, fixed amount of 100S, added with increase chemical fertilizer 10F, 25F and 50F was performed comparing with 100F. The results indicated that 100S+50F was the best treatment as evident by maximum increase of shoot and root dry weights 2-3 fold over that of 100F and grain yield of 1.8-2.8 fold in KDML 105 and SPR 1, respectively. Flowering was 2 days earlier in KDML 105 and 6 days delay in SPR 1. Besides highest grain yield, analysis of chemical composition indicated that latex serum increased level of nitrogen content in the straws and seeds significantly. Apparently, latex serum did not affect Zn content in the straws, seeds, and soils. It can be concluded that when applied 58 kgN/rai of latex serum in combination with 15 kg/rai ammonium phosphate fertilizer (16-20-0), rice plants produced the maximal grain yield and increased N content in the straws and seeds.