Physiological basis of improved performance of super rice (Oryza sativa) to deep placed fertilizer with precision hill-drilling machine

Abstract

Field experiment on deep placement of fertilizers was carried out using precision hill-drilling machine with the objective of determining super rice growth and photosynthesis characteristics, as well as grain quality in South China. With 'no fertilizer' as control, the four fertilizer combinations were 100 kg N ha-1, 100 kg N ha-1 + 60 kg SiO2 ha-1, 125 kg N ha-1, and 125 kg N ha-1 + 60 kg SiO2 ha-1. Super rice special fertilizer comprised 12.5% N, 6.0% P2O5, 10.0% K2O and 15% organic matter. The super rice varieties were Yuejingsimiao 2 (inbred) and Peizataifeng (hybrid) common in South China. The design was split-plot with three replications. Plant height, LAI, SPAD and net photosynthetic rate (NPR) were affected by both variety and fertilizer. Application of 100 kg N ha-1 gave highest GS activity at booting 125 kg N ha-1 resulted in a favorable GS activity from booting to full-heading. SPS activity at booting was highest with 125 kg N ha-1 + 60 kg SiO2 ha-1. Application of 100 kg N ha-1 + 60 kg SiO2 ha-1 to Peizataifeng showed higher GS and SPS activity at booting, and gave the highest head rice rate. While milled rice yield was not, brown rice yield, head rice recovery, rice with chalkiness, and chalky ratio were affected by variety and fertilizer. Treatments were significantly different from each other in polished grain protein and amylose content. Yuejinsimiao 2 fertilized with 125 kg N ha-1 + 60 kg SiO2 ha-1 recorded the highest protein content and non-fertilized Peizataifeng the least. While Peizataifeng fertilized with 125 kg N ha-1 accumulated the highest amount of amylose, Yuejinsimiao 2 fertilized with 100 kg ha-1 + 60 kg SiO2 ha-1 had the least. In hybrid Peizataifeng, grain amylose was lower with the silicon-added fertilizers. In inbred Yuejinsimiao 2, grain protein was least when no fertilizer was applied and it increased with addition of silicon and increase in N% of fertilizer. We concluded that deep application of rice special fertilizer can improve growth and photosynthesis characteristics, as well as the quality of super hybrid rice.