Effects of Planting Method on Root Growth and Nitrogen Uptake of Rice

Abstract

【Objective】 Water and nutrient uptake by plants is modulated by their root architecture. This paper investigates the impact of planting method on root distribution of rice and the associated nitrogen uptake and grain yield. 【Method】 The variety Jiyujing was used as the model plant. The experiment compared three planting methods: transplanting under flooding condition (TFR), direct drill under dry condition followed by flooding cultivation (DDSF), direct drill under dry condition followed by alternate wet and dry cultivation (DDSA). For each treatment, we measured morphological and physiological traits of the roots, nitrogen absorption from the top 0~20 cm soil layer, as well as the ultimate grain yield. 【Result】 ① Compared to TFR, both DDSA and DDSF increased the dried weight of the roots, root diameter and root distribution in the top 0~10 cm soil layer, while reducing roots in the 10~20 cm soil layer, during the primary growth period. ② After the young spike differentiation stage, DDSF reduced root activity and other physiological traits, while DDSA enhanced root vitality and other physiological traits. ③ The significance of the impact of planting method on yield, total nitrogen accumulation, nitrogen absorption after the post-flowering and during the grain-filling and maturity stages was ranked in the order of TFR > DDSA > DDSF. Transplanting increased deep rooting and root activity, resulting in high nitrogen accumulation and grain yield. 【Conclusion】 The alternate dry-wet irrigation combined with direct drill also increased deep rooting, enhanced root vitality, thereby promoting nitrogen absorption and grain yield. It is a potential cultivation practice to enhance nitrogen utilization and yield of the rice.

Keywords

• rice
• planting patterns
• root distribution
• nitrogen accumulation
• composition of root bleeding sap
• yield