Effects of phosphorus application and irrigation-water aeration on yield and zinc uptake and allocation in rice at maturation stage

Abstract

【Objective】 Bioavailable phosphorus and oxygen are key factors affecting root activity and crop yield. The objective of this paper is to elucidate how phosphorus fertilization and irrigation-water aeration combined to affect root physiological traits, zinc absorption and allocation in rice and grain yield at maturation stage. 【Method】 The experiment was conducted in pots using the variety of Liangyou 608 as the model plant. It consisted of two irrigation treatments: aerating irrigation (OI) and conventional irrigation (NI), and four phosphorus fertilizations: 0.00 (P1), 1.35(P2), 2.7 (P3), 4.05g /pot (P4). In each treatment, we measured root activity, root acid phosphatase activity at different growth stages, as well as zinc allocation and grain yield at maturation stage. 【Result】 ① Phosphorus fertilization reduced zinc content in the iron-manganese films by 33.38% to 60.41%, while oxygenating irrigation water increased the transfer coefficient of zinc from root to straw by 24.98% to 113.15%. Aeration and phosphorus fertilization combined to increase zinc content in straw, but reduce the transfer coefficient of zinc from straw to grains. ② The combination OI+P1 gave the highest grain yield, 1000-grain weight, effective panicle numbers and zinc distribution, which were 140.45 g/pot, 27.57 g, 29.00 per plant and 29.52%, respectively. ③ Phosphorus application increased root activity at tillering stage, reduced root acid phosphatase activity at filling stage, inhibited the absorption and accumulation of zinc in roots at maturation stage, promoted transfer of zinc from straw to grain, and increased grain yield and seed setting rate. Aeration and phosphorus fertilization reduced the activity of root acid phosphatase at tillering stage, increased the activity of root acid phosphatase at filling stage, and increased the zinc content in rice straw and grain, but reduced the number of effective panicles, seed setting rate and the transferability of zinc from straw to grain. 【Conclusion】 Phosphorus fertilization combined with irrigation-water aeration affects the formation of rice yield due to their influence on the physiological characteristics of the rice roots at tillering and filling stages, as well as zinc translocation to grains. Irrigation-water oxygenation promoted the absorption and distribution of zinc in rice straw.

Keywords

• root activity
• root acid phosphatase activity
• zinc absorption
• yield
• phosphorus application
• oxygen aeration
• the interaction of oxygenation and phosphorus application