不同移栽密度下氮素调控对杂交中稻-再生稻产量和稻米品质的影响

Effects of Nitrogen Management and Plant Density on Grain Yield and Quality of Mid-sea-son Hybrid Rice in Rice-Ratoon Rice System

为了明确移栽密度和氮素调控对杂交中稻头季、再生季产量形成特点和稻米品质的影响,以旌优127为材料,于2016—2017年在四川泸州进行大田试验。结果表明,同一移栽密度下,杂交中稻头季、再生季和两季总产量随施氮量的增加呈先增加后下降的趋势;高密(D3,24万丛/hm2)条件下,N2处理(测苗定氮施肥)施氮量较N1处理(225kg/hm2)平均减少了7.8%,但其头季产量、再生季产量和两季总产量却较N1处理分别增加了4.9%、15.4%和6.8%;随移栽密度的增加,杂交中稻头季、再生季有效穗数呈增加趋势,每穗粒数呈下降趋势(除2017年再生季外);头季稻N1处理有效穗数较N2处理平均高了5.7%,但其每穗粒数和颖花量较N2处理分别低了9.2%和3.1%;再生季N2处理有效穗数、每穗粒数、颖花量较N1处理分别高了10.2%、9.0%、18.2%。与N1处理相比,N2处理头季稻米蛋白质含量平均增加了6.9%,但再生季平均降低了1.8%。不同密肥组合间杂交中稻头季、再生季稻米加工品质、外观品质、粒型差异较小,以D3N2组合处理的糙米率、精米率、整精米率相对较高,垩白粒率和垩白度相对较低。因此,建议在本研究区域杂交中稻-再生稻生产体系中,头季移栽密度24万丛/hm2与测苗定量施氮技术搭配较为适宜。

A field experiment was conducted at Luzhou City in 2016-2017, in order to explore the effects of plant density and nitrogen management on yield formation and quality of hybrid mid-season rice in rice-ratoon rice system. The results showed that, under the same transplanting density, the yield of main rice and ratoon rice increased first and then decreased with the increase of nitrogen application rate. Under the condition of high density (D3, 2.4×105 hills/hm2), the nitrogen application amount under N2 treatment (precision fertilizer based on the leaf measured, PFLM)was decreased by 7.8% on average compared with N1 treatment(N application rate was 225 kg/hm2), but the yield in the first season, the yield in regeneration season and the total yield in the two seasons were increased by 4.9%, 15.4% and 6.8% respectively compared with N1 treatment. With the increase of transplanting density, the number of effective panicles in the first season and regeneration season of hybrid rice showed an increasing trend, the grain number per spike showed a decreasing trend (except ratoon rice in 2017). In the first season, the effective panicle number of N1 treatment was 5.7% higher than that of N2 treatment on average, but the grain number per panicle and spikelets were 9.2% and 3.1% lower than that of N2 treatment, respectively;in the regeneration season, the effective panicle number, grain number per panicle and spikelets of N2 treatment were 10.2%, 9.0% and 18.2% higher than that of N1 treatment, respectively. Compared with the N1 treatment, the protein content of N2 treatment was increased by 6.9% on average in the first season, but decreased by 1.8% in the regeneration season. The processing quality, appearance quality and grain size in the first season and regenerated season were less different between different treatments. In general, the brown rice rate, milled rice rate, head rice rate with D3N2 combination were relatively high, while the chalky grain rate and chalkiness degree were relatively low. Therefore, it is suggested that in the ratoon rice production system in the study area, the transplanting density of 2.4×105 hills/hm2 with PFLM technique were more suitable.