不同耕作方式对杂交水稻根系特性及产量的影响

Effects of Different Tillage System on the Root Properties and the Yield in Hybrid Rice

目的探明不同耕作方式下杂交水稻根系特性及增产的机制。方法在田间试验条件下,研究不同耕作方式(翻耕和免耕)对直播稻和移栽稻根系特性和产量的影响。结果无论直播或移栽,免耕稻最高分蘖期的根冠比、单蔸根干重、根系总吸收表面积和活跃吸收表面积均高于翻耕稻,其成熟期0～5cm土层的根重、根重密度和5～10cm、10～20cm土层的比根长也比翻耕稻高。在移栽条件下,免耕稻成熟期0～5cm土层的根长、根长密度和根表面积高于翻耕稻,其最高分蘖期的根系32P吸收总量和根系氧化力分别比翻耕稻平均增加40.72%、13.81%;在直播条件下,免耕稻最高分蘖期、孕穗期、齐穗期的根系32P吸收总量和根系氧化力分别比翻耕稻平均增加54.56%、19.53%、2.80%和12.59%、24.06%、74.19%,其孕穗期的地上部32P的转运率比翻耕稻平均增加13.68%,而其根系残留率比翻耕稻平均降低10.22%。无论移栽或直播,免耕稻的有效穗数比翻耕稻低,但其每穗粒数高于翻耕稻。在直播和移栽条件下,免耕稻的产量平均分别为8979.0kg·ha-1和8588.0kg·ha-1,比翻耕稻分别增产2.30%和1.19%,但未达到5%的显著水平。结论免耕稻相对于翻耕稻有明显的增产优势,是其根系特性的一种响应。

[ Objective] To ascertain the root properties of hybrid rice and mechanism of increasing yield under different tillage system. [Method] The effects of no-tillage （NT） and conventional tillage （CT）on root properties and yield of direct broadcasted （DB） hybrid rice and raise seedlings and transplanted （RT） hybrid rice on the conditions of field experiments were studied. [ Results ] The results showed that the root/shoot ratio, root dry weight, root absorbing surface area and root active absorbing surface in NT at maximum tillering stage were higher than those in CT. Furthermore, the root weight and root weight density in 0-5 cm soil layer and the specific root length in 5-10 cm and 10-20 cm soil layer of NT at mature stage were higher than those of CT no matter which rice establish method was adopted. The root length and root length density and root surface area in 0-5 cm soil layer of NT at mature stage were higher than those of CT, and also the total 32p activity absorbed by rice roots and oxidation ability of rice roots of NT rice at maximum stage were 40.72% and 13.81% higher than those of CT on the average in RT, respectively. In DB condition, the total ^32p activity absorbed by roots and the root oxidation ability in NT at maximum stage, booting stage and full heading stage were 54.56% and 12.59%, 19.53% and 24.06%, 2.80% and 74.19% higher than those of CT on the average, respectively. In addition, the partitioning of ^32p absorbed by root into aerial parts in NT rice at booting stage was 13.78% higher than that of CT on the average, while the root residual rate of ^32p in NT at the same stage was 6.84% lower than that in CT rice on the average. The effective panicle in NT was lower than that in CT, while the spikelet number per panicle in NT was higher than that in CT no matter which rice establish method was adopted. The rice yield of NT rice reached to 8979.0 kg·ha^-1 and 8588.0 kg·ha^-1, increasing by 2.30%, 1.19%, compared with CT on the average on DB and RT condition, respectively, although the difference was not significant between CT and RT. [Conclusion] The rice yield superiority in NT was obvious compared with in CT, which was the reaction of good root properties in NT.