机械旱直播方式对水稻氮磷钾吸收转运及分配的影响

为了明确机械旱直播模式下水稻主要生育时期氮、磷、钾素吸收利用特征,以杂交籼稻(F优498)和常规粳稻(徐稻4号)为试材,通过免耕机械旱直播(B1)、"调墒、两旋"机械旱直播(B_2)2种机械旱直播处理,并以人工撒播(B_3)处理为对照,研究其对直播稻养分吸收、转运、分配及产量的影响,并探讨不同生育阶段养分累积及转运间的相互关系。结果表明,品种及直播方式对水稻主要生育时期氮素和钾素的累积、转运、分配及最终产量均存在显著的调控作用;且直播处理下各生育阶段氮、磷、钾养分间吸收与转运存在显著的协同效应,对促进抽穗至成熟期各养分向籽粒的转运和提高产量影响显著;但直播处理下水稻对磷素的吸收和转运与氮、钾素间的协同性降低。不同直播处理下,F优498在产量及各生育时期养分吸收、转运各指标整体上均显著高于徐稻4号。与B_3相比,同一品种下机械旱直播各处理均能不同程度地提高主要生育时期养分的累积,促进抽穗至成熟叶片和茎鞘中养分转运,尤其能显著提高杂交稻抽穗至成熟叶片氮素、钾素转运率,进而显著促进抽穗至成熟氮素、钾素转运贡献率,提升籽粒中氮素、钾素所占稻株氮素及钾素累积总量的比例,发挥出氮素和钾素协同吸收与利用的耦合效应,是机械旱直播水稻高产的重要原因。不同机械旱直播处理下,B_2比B_1处理能进一步不同程度地提高机械旱直播水稻抽穗至成熟期养分的累积,促进叶片和茎鞘养分的转运,利于抽穗至成熟茎鞘中钾素的累积,最终促进了产量的提高,为最佳的机械旱直播方式。

Effects of mechanical dry direct-sowing modes on absorption, translocation and distribution of nitrogen, phosphorus and potassium in rice

Abstract: In order to clarify the nutrient utilization characteristics of mechanical dry direct-sowing rice, the objective of this experiment was to study the effects of different mechanical dry direct-sowing modes on absorption, translocation and distribution of nitrogen (N), phosphorus (P), potassium (K), and yield in rice. Two rice cultivars of indica hybrid rice F you 498(143 days growth duration) and conventional japonica rice Xudao 4 (145 days growth duration) were planted with two mechanical dry direct-sowing modes, including no-tillage land and mechanic drilling simultaneously (B1), regulating soil moisture and two rotary tillage before mechanic drilling (B2). Manual broad-cast sowing (B3) was set as control. The dry direct-sowing machine of this study was modified by Nanjing Agricultural University and was re-modified by Sichuan Agricultural University. This machine had 6 drills and sowing depth 2.0 cm, drill spacing 28.0 cm, working width 1.50 m. Motive power of this machine was the Shanghai New Holland tractor (SNH504). This test adopted row spacing 20.0 m × 1.50 m, each plot covered 30 m2 of seeding amount was 30.0 kg per hectare of indica hybrid rice F you 498, 37.5 kg per hectare of conventional japonica rice Xudao 4 respectively. The nitrogen fertilizer amount was 180 kg/hm2. The N application ratios was applied on 4 splits: 50% basal, 30% tillering fertilizer at 3rd leaf stage, 10% panicle N-fertilizer at 4th leaves emerged from the top, 10% ear granular fertilizer at full heading stage. The phosphate fertilizer application was only one base fertilizer. The potash fertilizer application ratio of basic fertilizer, tillering fertilizer and ear granular fertilizer was 2:1:1. The other management measures were at a uniform with high-yield cultivation. The results showed that there was an obvious regulatory effect of rice cultivars and direct-sowing modes on grain yield, absorption and translocation of N, K at the mainly growth stages. There existed significantly positive correlations between the amounts of N, P and K absorption and utilization, which could promote nutrient translocation during filling stage and yield, but the correlation coefficient of P and N, P and K significantly decreased at the mainly growth stages. Under different direct-sowing treatments, the various indicators on yield and nutrient utilization characteristics of F you 498 were significantly higher than those of Xudao 4. Compared with B3 treatment, mechanical direct-seeding treatments under the same variety promoted the accumulations of N, P, and K at the mainly growth stages, increased nutrient translocation in leaf and stem-sheath during filling stage, especially significantly enhanced transportation efficiency of N and K in hybrid rice, and further facilitated translocation conversion rate of N and K in different vegetative organ, played the coupling effect of absorption and utilization of N and K, then to promoted yield, which is the important reason for mechanical direct-sowing rice further to increase yield. Under different mechanical direct-sowing treatments, compared with B1, B2 treatment was the best model in this paper referred as the mechanical direct-sowing treatments, which could further increase nutrient accumulation and translocation from heading to maturity stage in various degrees consequently, promote nutrient accumulation in panicle as well as promote yield.