Exploring the effects of sowing date and ecological points on the yield of semi-winter wheat is of great significance.This study aims to reveal the effects of sowing date and ecological points on the climate resources...Exploring the effects of sowing date and ecological points on the yield of semi-winter wheat is of great significance.This study aims to reveal the effects of sowing date and ecological points on the climate resources associated with wheat yield in the Rice–Wheat Rotation System.With six sowing dates,the experiments were carried out in Donghai and Jianhu counties,Jiangsu Province,China using two semi-winter wheat varieties as the objects of this study.The basic seedlings of the first sowing date (S1) were planted at 300×10^(4)plants ha^(-1),which was increased by 10%for each of the delayed sowing dates (S2–S6).The results showed that the delay of sowing date decreased the number of days,the effective accumulated temperature and the cumulative solar radiation in the whole growth period.The yields of S1 were higher than those of S2 to S6 by 0.22–0.31,0.5–0.78,0.86–0.98,1.14–1.38,and 1.36–1.59 t ha^(–1),respectively.For a given sowing date,the growth days increased as the ecological point was moved north,while both mean daily temperature and effective accumulative temperature decreased,but the cumulative radiation increased.As a result,the yields at Donghai County were 0.01–0.39 t ha–1lower than those of Jianhu County for the six sowing dates.The effective accumulative temperature and cumulative radiation both had significant positive correlations with yield.The average temperature was significantly negatively correlated with the yield.The decrease in grain yield was mainly due to the declines in grains per spike and 1 000-grain weight caused by the increase in the daily temperature and the decrease in the effective accumulative temperature.展开更多
Dry direct-seeded rice(DDR) sown using a multifunctional seeder that performs synchronous rotary tillage and sowing has received increased attention because it is highly efficient,relatively cheap,and environmentally ...Dry direct-seeded rice(DDR) sown using a multifunctional seeder that performs synchronous rotary tillage and sowing has received increased attention because it is highly efficient,relatively cheap,and environmentally friendly.However,this method of rice production may produce lower yields in a rice–wheat rotation system because of its poor seedling establishment.To address this problem,we performed field experiments to determine the rice yield at five seedling density levels(B1,B2,B3,B4,and B5=100,190,280,370,and 460 seedlings m-2,respectively) and clarify the physiological basis of yield formation.We selected a representative high-quality rice variety and a multifunctional seeder that used in a typical rice–wheat rotation area in 2016 and 2018.The proportion of main stem panicle increased with increasing seedling density.There was a parabolic relationship between yield and seedling density,and the maximum yield(9.34-9.47 t ha-1) was obtained under B3.The maximum yield was associated with a higher total spikelet number m-2 and greater biomass accumulation from heading to maturity.The higher total spikelet number m-2 under B3 was attributed to an increase in panicle number m-2 compared with B1 and B2.Although the panicle numbers also increased under B4 and B5,these increases were insufficient to compensate for the reduced spikelet numbers per panicle.Lower biomass,smaller leaf area,and lower N uptake per plant from the stem elongation stage to the heading stage were partially responsible for the smaller panicle size at higher seedling density levels such as B5.The higher biomass accumulation under B3 was ascribed to the increases in the photosynthetic rate of the top three leaves m-2 of land,crop growth rate,net assimilation rate,and leaf area index.Furthermore,the B3 rice population was marked by a higher grain–leaf ratio,as well as a lower export ratio and transport ratio of biomass per stem-sheath.A quadratic function predicted that 260-290 seedlings m-2 is the optimum seedling density for achieving maximum yield.Together,these results suggested that appropriately increasing the seedling density,and thereby increasing the proportion of panicles formed by the main stem,is an effective approach for obtaining a higher yield in DDR sown using a multifunctional seeder in a rice–wheat rotation system.展开更多
Mechanical pot-seedling transplanting is an innovatively developed transplanting method that has the potential to replace mechanical carpet-seedling transplanting. However, the initial pot-seedling transplanting machi...Mechanical pot-seedling transplanting is an innovatively developed transplanting method that has the potential to replace mechanical carpet-seedling transplanting. However, the initial pot-seedling transplanting machine lacked optimized density spacing and limited yield potential for japonica rice. Therefore, ascertaining the optimized density by wide-narrow rows and the appropriate transplanting method for yield formation and grain quality of japonica rice is of great importance for high-quality rice production. Field experiments were conducted using two japonica rice cultivars Nanjing 9108 and Nanjing 5055 under three transplanting methods in 2016 and 2017: mechanical pot-seedling transplanting with wide-narrow row(K, average row spacing of 30 cm);equidistant row(D, 33 cm×12 cm);and mechanical carpet-seedling transplanting(T, 30 cm×12.4 cm). In addition, five different density treatments were set in K(K1–K5, from 18.62×10~4 to 28.49×10~4 hills ha^(–1)). The results showed that the highest yield was produced by a planting density of 26.88×104 hills ha^(–1) in mechanical pot-seedling transplanting with wide-narrow row with a greater number of total spikelets that resulted from significantly more panicles per area and slightly more grain number per panicle, as compared with equidistant row, and yield among density in wide-narrow row showed a parabolic trend. Compared with mechanical carpet-seedling transplanting, the treatment of the highest yield increased yield significantly, which was mainly attributed to the larger sink size with improved filled-grain percentage and grain weight, higher harvest index, and increased total dry matter accumulation, especially the larger amount accumulated from heading stage to maturity stage. With the density in wide-narrow row decreasing, processing quality, appearance quality, and nutrition quality were all improved, whereas amylose content and the taste value were decreased. Compared with mechanical carpet-seedling transplanting, mechanical pot-seedling transplanting improved processing quality and nutrition quality, but decreased amylose content and deteriorated appearance quality. These results suggested that mechanical pot-seedling transplanting with wide-narrow row coupling produced a suitable planting density of 26.88×10~4 hills ha^(–1) and may be an alternative approach to improving grain yield and quality for japonica rice.展开更多
There is limited information about the influence of slow or controlled release fertilizer(S/CRF) on rice yield and quality. In this study, japonica rice cultivar Nanjing 9108 was used to study the effects of three dif...There is limited information about the influence of slow or controlled release fertilizer(S/CRF) on rice yield and quality. In this study, japonica rice cultivar Nanjing 9108 was used to study the effects of three different S/CRFs(polymer-coated urea(PCU), sulfur-coated urea(SCU), and urea formaldehyde(UF)) and two fertilization modes(both S/CRF and common urea(CU) as basal fertilizer, S/CRF as basal and CU as tillering fertilizer) on rice yield and quality. CU only was applied separately as control(CK). Results showed that, rice grain yield, chalky kernel rate, chalky area, overall chalkiness, and the content of gliadin, glutenin, and protein, all showed the trends of UF>PCU>SCU within the same fertilization mode, and showed the trends of S/CRF as basal and CU as tillering fertilizer>both S/CRF and CU as basal fertilizer within the same type of S/CRF. In contrast, the contents of amylose, amylopectin, and starch, as well as taste value, and peak and hot viscosity showed trends of SCU>PCU>UF, and the trends of both S/CRF and CU as basal fertilizer>S/CRF as basal and CU as tillering fertilizer. Among S/CRF treatments and fertilization modes, taste values of cooked rice were positively correlated with amylose, amylopectin, and starch contents, as well as gel consistency, peak viscosity, hot viscosity, and cool viscosity, while negatively correlated with globulin, gliadin, glutenin, and protein contents. The types of S/CRF and fertilization modes are important for improving rice yield and quality. Compared to CK, higher yield and similar quality of rice was achieved with UF as basal and CU as tillering fertilizer, and similar yield with improved appearance and eating and cooking quality of rice was achieved with either both UF and CU as basal fertilizer, or PCU as basal and CU as tillering fertilizer.展开更多
There is limited information about the combined effect of shading time and nitrogen(N) on grain filling and quality of rice. Therefore, two japonica super rice cultivars, Nanjing 44 and Ningjing 3, were used to study ...There is limited information about the combined effect of shading time and nitrogen(N) on grain filling and quality of rice. Therefore, two japonica super rice cultivars, Nanjing 44 and Ningjing 3, were used to study the effect of shading time and N level on the characteristics of rice panicle and grain filling as well as the corresponding yield and quality. At a low N level(150 kg N ha^(–1), 150 N), grain yield decreased(by 21.07–26.07%) under the treatment of 20 days of shading before heading(BH) compared with the no shading(NS) treatment. These decreases occurred because of shortened panicle length, decreased number of primary and secondary branches, as well as the grain number and weight per panicle. At 150 N, in the treatment of 20 days of shading after heading(AH), grain yield also decreased(by 9.46–10.60%) due to the lower grain weight per panicle. The interaction of shading and N level had a significant effect on the number of primary and secondary branches. A high level of N(300 kg N ha^(–1), 300 N) could offset the negative effect of shading on the number of secondary branches and grain weight per panicle, and consequently increased the grain yield in both shading treatments. In superior grains, compared with 150 N NS, the time to reach 99% of the grain weight(T_(99)) was shortened by 1.6 to 1.7 days, and the grain weight was decreased by 4.18–5.91% in 150 N BH. In 150 N AH, the grain weight was 13.39–13.92% lower than that in 150 N NS due to the slow mean and the maximum grain-filling rate(GR_(mean )and GR_(max)). In inferior grains, grain weight and GR_(mean) had a tendency of 150 N NS>150 N BH>150 N AH. Under shaded conditions, 300 N decreased the grain weight due to lower GR_(mean) both in superior and inferior grains. Compared with 150 N NS, the milling and appearance qualities as well as eating and cooking quality were all decreased in 150 N BH and 150 N AH. Shading with the high level of 300 N improved the milling quality and decreased the number of chalky rice kernels, but the eating and cooking quality was reduced with increased chalky area and overall chalkiness. Therefore, in the case of short term shading, appropriate N fertilizer could be used to improve the yield and milling quality of rice, but limited application of N fertilizer is recommended to achieve good eating and cooking quality of rice.展开更多
稻麦两熟地区,旱直播水稻生产受前茬小麦收获、全量麦秸秆还田及耕整地质量不高等因素的影响,常采用迟播期、大播量、高基本苗和主茎成穗为主的“独秆”栽培模式,而配套该模式直播稻优质丰产的氮肥管理技术尚缺乏系统的研究。以优质食...稻麦两熟地区,旱直播水稻生产受前茬小麦收获、全量麦秸秆还田及耕整地质量不高等因素的影响,常采用迟播期、大播量、高基本苗和主茎成穗为主的“独秆”栽培模式,而配套该模式直播稻优质丰产的氮肥管理技术尚缺乏系统的研究。以优质食味粳稻南粳9108为材料,采用机械旱直播方式,基本苗为380×10^(4) hm^(-2),设置不同叶龄期(六、七、八、九和十叶龄期)氮肥追施处理及氮肥追施用量(纯氮180 kg hm^(-2)和225 kg hm^(-2))处理,以基本苗380×10^(4) hm^(-2)和300×10^(4) hm^(-2)的旱直播精确定量氮肥管理(纯氮270 kg hm^(-2),基肥︰分蘖肥︰穗肥=3.5︰3.5︰3.0)为对照,系统比较研究“独秆”栽培模式下,全程氮肥在分蘖中后期施用对旱直播水稻产量和品质的影响。结果表明,随追施叶龄的延后,水稻产量呈先增后降趋势,八叶期追施氮肥水稻产量显著高于其他处理,且追施量增加,水稻产量进一步提高。与2组对照相比,在纯氮180 kg hm^(-2),氮肥减量33.3%情况下,不施氮素基肥配合八叶期一次性追施氮肥,可显著提高水稻产量5.10%和8.65%;在纯氮225 kg hm^(-2),氮肥减量16.7%情况下,不施氮素基肥配合八叶期及7 d后二次追肥可显著提高水稻产量7.46%和11.09%。不施氮素基肥配合八叶期追施氮肥水稻产量提高的原因是,保障较大穗型的基础上增加有效穗数,显著提高群体颖花量,同时保持较高水平的结实率和千粒重。随追肥叶龄延后,水稻整精米率呈增加趋势,垩白度呈增大趋势,蛋白质含量增加,直链淀粉含量下降,食味值呈降低趋势。与2组对照相比,不施氮素基肥配合八叶期追施氮肥的水稻,加工品质提高,整精米率提高0.67%~2.23%;外观品质变好,垩白度降低3.6%~14.5%;营养品质提升,蛋白质含量增加3.03%~14.08%;蒸煮食味品质呈变优趋势,直链淀粉含量下降4.23%~10.95%;食味值无显著差异。综上所述,“独秆”栽培模式下基肥不施氮肥配合全程氮肥在分蘖中后期适宜叶龄施用可实现稻麦两熟地区旱直播稻迟播期、大播量和高基本苗生产方式的提质增产生产。展开更多
从24个甬优系列籼粳杂交稻品种(系)中,根据不同产量水平和氮素农学利用率筛选出具有代表性的3种类型(高产氮高效、高产氮中效、中产氮中效),系统比较各类型产量和氮素农学利用率,以探究高产氮高效型籼粳杂交稻产量和氮素吸收利用特征。...从24个甬优系列籼粳杂交稻品种(系)中,根据不同产量水平和氮素农学利用率筛选出具有代表性的3种类型(高产氮高效、高产氮中效、中产氮中效),系统比较各类型产量和氮素农学利用率,以探究高产氮高效型籼粳杂交稻产量和氮素吸收利用特征。结果表明,高产氮高效型产量显著高于高产氮中效型和中产氮中效型,分别高4.04%~4.38%和13.37%~13.41%,其高产原因在于群体颖花量大,能达到5.87×10^8~6.20×10^8 hm^-2。与高产氮中效型和中产氮中效型相比,高产氮高效型成穗率高,能保持在68.83%~70.05%;抽穗期叶面积指数高,且生育后期衰减平缓,成熟期叶面积指数在3.85以上;抽穗至成熟期干物质积累量大,达7.91~7.99 t hm^-2,全生育期干物质量可达21.15~21.46 t hm^-2。在氮素吸收利用方面,高产氮高效型总吸氮量显著高于高产氮中效型和中产氮中效型,分别高5.07%~5.14%和4.50%~5.96%;拔节至抽穗期和抽穗至成熟期氮素吸收速率表现为高产氮高效型>高产氮中效型>中产氮中效型,花后茎鞘氮素转运量、穗部氮素积累量和氮素收获指数也有相同表现;氮素回收利用率、农学利用率、生理利用率和偏生产力均以高产氮高效型最高;高产氮中效型除氮素回收利用率和百千克籽粒吸氮量外,其他各项氮素利用指标均高于中产氮中效型。展开更多
Understanding the differences in yield traits of rice among pothole seedling of mechanical transplanting(PSMT), carpet seedling of mechanical transplanting(CSMT) and mechanical direct seeding(MDS) is of great importan...Understanding the differences in yield traits of rice among pothole seedling of mechanical transplanting(PSMT), carpet seedling of mechanical transplanting(CSMT) and mechanical direct seeding(MDS) is of great importance not only for rice scientists but also for rice farmers to develop a high-yield production system under mechanical conditions in a rice-wheat rotation system. However, such traits are yet to be studied among rice varieties of japonica-indica hybrid rice(JIHR), japonica conventional rice(JCR) and indica hybrid rice(IHR). Field experiments were conducted in 2014 and 2015, where six cultivars of the three rice types JIHR, JCR and IHR were grown individually with PSMT, CSMT and MDS methods, under respective managements for each method to achieve the maximum attainable yield. Results showed that(i) the PSMT significantly increased grain yield of JIHR by 22.0 and 7.1%, of JCR by 15.6 and 3.7% and of IHR by 22.5 and 7.4%, compared to MDS and CSMT on average across the two years, respectively. The highest yield was produced by the combination of JIHR and PSMT;(ii) high yield under PSMT was mainly attributed to large sink capacity and high-efficient dry matter accumulation. With sufficient panicles per hectare, the increase of spikelet number per panicle, especially the increase in spikelet number of the secondary rachis-branches was determined to be the optimal approach for developing a large sink capacity for rice under PSMT. The optimal tillers development, large leaf area index at heading stage, and high leaf area duration, crop growth rate and net assimilation rate during grain-filling phase could be the cause of sufficient dry matter accumulation for rice under PSMT;(iii) moreover, the PSMT favored plant growth as well as enriched the stems plus sheaths during grain-filling phase, as compared with CSMT and MDS. These results suggest that PSMT may be an alternative approach to increasing grain yield in a rice-wheat rotation system in the lower reaches of the Yangtze River in China.展开更多
以优质食味粳稻南粳9108为材料,纯氮270 kg hm^(-2)施氮条件下,设置了钵苗机插、毯苗机插2种栽培方式,将控释肥与速效氮肥以5∶5的比例混合,其中控释肥由4种不同释放期(40、80、100、和120 d)肥料按照1∶4的比例混合形成了3种配比方式,...以优质食味粳稻南粳9108为材料,纯氮270 kg hm^(-2)施氮条件下,设置了钵苗机插、毯苗机插2种栽培方式,将控释肥与速效氮肥以5∶5的比例混合,其中控释肥由4种不同释放期(40、80、100、和120 d)肥料按照1∶4的比例混合形成了3种配比方式,分别为40+80、40+100、40+120,同时设置常规分次施肥(CK)为对照,研究不同机械化栽培方式下控释肥配比对迟熟中粳水稻产量形成以及氮素积累的影响。结果表明,相同肥料处理下,钵苗机插2年产量较毯苗机插分别增加了3.9%和4.9%,其原因是钵苗机插能够提高中后期的光合物质积累,获得较大的穗型,具有更高的每穗粒数、结实率以及千粒重。钵苗机插与毯苗机插栽培方式下,40+80和40+100控释肥处理2年产量均高于CK,40+100控释肥处理产量最高,2年较CK分别显著增加7.3%和9.2%,其原因在于40+100控释肥处理具有更高的有效穗数和群体颖花量。与40+80和40+120控释肥处理相比,40+100控释肥处理与南粳9108的养分吸收规律更为匹配,即保证了前期分蘖的发生,又保证了后期稳定的光合物质生产,获得稳定的穗数、穗粒数以及粒重,2年的氮素回收利用率、氮素农学利用率、氮素生理利用率和氮肥偏生产力较CK分别显著增加了10.0%~12.5%、24.6%~30.5%、11.4%~18.6%和7.3%~9.1%。综上所述,钵苗机插较毯苗机插具有明显优势,是利于优质粳稻获得高产的栽培方式,同时40+100控释肥配比能够较好的满足优质粳稻各个阶段的养分需求,能够获得高产,可作为优质粳稻高产的简化施肥方案。展开更多
氮素穗肥用量和结实期遮光可通过影响叶片光合和植株氮营养状况对水稻籽粒碳氮代谢能力产生调节作用,从而形成不同特征的稻米品质。为探明氮素穗肥用量与结实期遮光复合作用对常规粳稻品质的影响,于2019—2020年以生育期相近的常规粳稻...氮素穗肥用量和结实期遮光可通过影响叶片光合和植株氮营养状况对水稻籽粒碳氮代谢能力产生调节作用,从而形成不同特征的稻米品质。为探明氮素穗肥用量与结实期遮光复合作用对常规粳稻品质的影响,于2019—2020年以生育期相近的常规粳稻淮稻5号、南粳9108和扬农香28为材料,设置40.5 kg hm^(-2)(N1)、81.0 kg hm^(-2)(N2)、121.5 kg hm^(-2)(N3)3个氮素穗肥用量处理,并于抽穗至成熟期采用人工遮阴方式控制水稻冠层光照,包括100%自然光照(S0)和50%自然光照(S50)处理,研究了结实期不同光氮处理组合对稻米品质的影响效应。结果表明:糙米率、精米率、整精米率在S0条件下随氮素穗肥用量的增加呈先升后降趋势,在S50条件下呈下降趋势,其中S0N2处理的整精米率最高,加工品质较好;垩白粒率和垩白度均呈S50N3>S50N2>S50N1>S0N3>S0N2>S0N1的趋势,且穗肥氮素用量的增加和结实期遮光对稻米提高垩白粒率和垩白度具有累加作用。穗肥氮素用量增加和结实期遮光均降低直链淀粉含量和胶稠度,提高蛋白质含量,其中谷蛋白的变异系数高于其他蛋白组分。穗肥氮素用量增加和结实期遮光不利于稻米食味值评分,不同品种的食味特征值对食味值评分的直接影响有差异。水稻淀粉的峰值黏度、崩解值随穗肥氮素用量增加和结实期光照强度下降而降低,消减值则上升,光氮复合作用增加了上述指标的差异。在穗肥氮素用量与结实期遮光复合作用下从直链淀粉含量和蛋白质含量比值趋势性变化来分析,结实期植株碳氮代谢能力强弱发生了变化。直链淀粉含量和蛋白质含量均与稻米食味值评分呈极显著的负相关关系,其中蛋白质的相关系数更大。因此,适量减施氮素穗肥有利于水稻结实期遭遇寡照后的稻米加工品质、外观品质及蒸煮食味品质提升,并且降低直链淀粉含量特别是蛋白质含量可能是提升稻米食味的有效途径,以期为优质水稻丰产调优栽培技术的更新提供依据。展开更多
Several studies have demonstrated the effect of planting methods on rice yield, but information on the climate resources is limited. This study aims to reveal the effects of planting methods on climate resources assoc...Several studies have demonstrated the effect of planting methods on rice yield, but information on the climate resources is limited. This study aims to reveal the effects of planting methods on climate resources associated with rice yield in a rice-wheat rotation system in the lower reaches of the Yangtze River, China. Field experiments were conducted in 2014 and 2015 with two japonica, two indica hybrid, and two japonica-indica hybrid varieties grown under three mechanized planting methods: carpet seedling of mechanical transplanting(CT), mechanical direct seeding(DS), and pot-hole seedling of mechanical transplanting(PT). The rice yield and total dry matter under PT were greater than those under CT and DS methods. Besides, the entire growth duration and daily production showed significant positive relations with rice yield. Compared with CT and DS, the effective accumulated temperature and cumulative solar radiation of rice under PT were higher in phenological phases. In addition, the dry matter/effective accumulated temperature and solar energy utilization of rice under CT and DS were higher during vegetative phase and lower during reproductive and grain filling phases in contrast to PT. The mean daily temperature and mean daily solar radiation in the entire growth duration showed significant positive correlation with rice yield, total dry matter, and harvest index. This study demonstrated that when the mean daily temperature is <25.1°C in vegetative phase and >20.1°C in grain filling phase, rice yield could be increased by selecting mechanized planting methods. Most varieties under PT method exhibited high yield and climate resources use efficiency compared with CT and DS. In conclusion, the PT method could be a better cultivation measure for high rice yield, accompanied with high temperature and solar radiation use efficiency in a rice-wheat rotation system in the lower reaches of the Yangtze River, China.展开更多
基金the Jiangsu Demonstration Project of Modern Agricultural Machinery Equipment and Technology, China (NJ2020-58, NJ2019-33, NJ2021-63)。
文摘Exploring the effects of sowing date and ecological points on the yield of semi-winter wheat is of great significance.This study aims to reveal the effects of sowing date and ecological points on the climate resources associated with wheat yield in the Rice–Wheat Rotation System.With six sowing dates,the experiments were carried out in Donghai and Jianhu counties,Jiangsu Province,China using two semi-winter wheat varieties as the objects of this study.The basic seedlings of the first sowing date (S1) were planted at 300×10^(4)plants ha^(-1),which was increased by 10%for each of the delayed sowing dates (S2–S6).The results showed that the delay of sowing date decreased the number of days,the effective accumulated temperature and the cumulative solar radiation in the whole growth period.The yields of S1 were higher than those of S2 to S6 by 0.22–0.31,0.5–0.78,0.86–0.98,1.14–1.38,and 1.36–1.59 t ha^(–1),respectively.For a given sowing date,the growth days increased as the ecological point was moved north,while both mean daily temperature and effective accumulative temperature decreased,but the cumulative radiation increased.As a result,the yields at Donghai County were 0.01–0.39 t ha–1lower than those of Jianhu County for the six sowing dates.The effective accumulative temperature and cumulative radiation both had significant positive correlations with yield.The average temperature was significantly negatively correlated with the yield.The decrease in grain yield was mainly due to the declines in grains per spike and 1 000-grain weight caused by the increase in the daily temperature and the decrease in the effective accumulative temperature.
基金the Jiangsu Agriculture Science and Technology Innovation Fund, China (CX(20)1012)the Jiangsu Demonstration Project of Modern Agricultural Machinery Equipment and Technology, China (NJ2020-58)+3 种基金the Jiangsu Technical System of Rice Industry, China (JATS[2020]432)the National Key Research and Development Program of China (2016YFD0300503)the earmarked fund for China Agriculture Research System (CARS-01-27)the Yangzhou University Scientific Research and Innovation Program, China (XKYCX20_022)。
文摘Dry direct-seeded rice(DDR) sown using a multifunctional seeder that performs synchronous rotary tillage and sowing has received increased attention because it is highly efficient,relatively cheap,and environmentally friendly.However,this method of rice production may produce lower yields in a rice–wheat rotation system because of its poor seedling establishment.To address this problem,we performed field experiments to determine the rice yield at five seedling density levels(B1,B2,B3,B4,and B5=100,190,280,370,and 460 seedlings m-2,respectively) and clarify the physiological basis of yield formation.We selected a representative high-quality rice variety and a multifunctional seeder that used in a typical rice–wheat rotation area in 2016 and 2018.The proportion of main stem panicle increased with increasing seedling density.There was a parabolic relationship between yield and seedling density,and the maximum yield(9.34-9.47 t ha-1) was obtained under B3.The maximum yield was associated with a higher total spikelet number m-2 and greater biomass accumulation from heading to maturity.The higher total spikelet number m-2 under B3 was attributed to an increase in panicle number m-2 compared with B1 and B2.Although the panicle numbers also increased under B4 and B5,these increases were insufficient to compensate for the reduced spikelet numbers per panicle.Lower biomass,smaller leaf area,and lower N uptake per plant from the stem elongation stage to the heading stage were partially responsible for the smaller panicle size at higher seedling density levels such as B5.The higher biomass accumulation under B3 was ascribed to the increases in the photosynthetic rate of the top three leaves m-2 of land,crop growth rate,net assimilation rate,and leaf area index.Furthermore,the B3 rice population was marked by a higher grain–leaf ratio,as well as a lower export ratio and transport ratio of biomass per stem-sheath.A quadratic function predicted that 260-290 seedlings m-2 is the optimum seedling density for achieving maximum yield.Together,these results suggested that appropriately increasing the seedling density,and thereby increasing the proportion of panicles formed by the main stem,is an effective approach for obtaining a higher yield in DDR sown using a multifunctional seeder in a rice–wheat rotation system.
基金funded by the National Key Research Program of China(2016YFD0300503)the Key Research Program of Jiangsu Province,China(BE2016344 and BE2018355)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China。
文摘Mechanical pot-seedling transplanting is an innovatively developed transplanting method that has the potential to replace mechanical carpet-seedling transplanting. However, the initial pot-seedling transplanting machine lacked optimized density spacing and limited yield potential for japonica rice. Therefore, ascertaining the optimized density by wide-narrow rows and the appropriate transplanting method for yield formation and grain quality of japonica rice is of great importance for high-quality rice production. Field experiments were conducted using two japonica rice cultivars Nanjing 9108 and Nanjing 5055 under three transplanting methods in 2016 and 2017: mechanical pot-seedling transplanting with wide-narrow row(K, average row spacing of 30 cm);equidistant row(D, 33 cm×12 cm);and mechanical carpet-seedling transplanting(T, 30 cm×12.4 cm). In addition, five different density treatments were set in K(K1–K5, from 18.62×10~4 to 28.49×10~4 hills ha^(–1)). The results showed that the highest yield was produced by a planting density of 26.88×104 hills ha^(–1) in mechanical pot-seedling transplanting with wide-narrow row with a greater number of total spikelets that resulted from significantly more panicles per area and slightly more grain number per panicle, as compared with equidistant row, and yield among density in wide-narrow row showed a parabolic trend. Compared with mechanical carpet-seedling transplanting, the treatment of the highest yield increased yield significantly, which was mainly attributed to the larger sink size with improved filled-grain percentage and grain weight, higher harvest index, and increased total dry matter accumulation, especially the larger amount accumulated from heading stage to maturity stage. With the density in wide-narrow row decreasing, processing quality, appearance quality, and nutrition quality were all improved, whereas amylose content and the taste value were decreased. Compared with mechanical carpet-seedling transplanting, mechanical pot-seedling transplanting improved processing quality and nutrition quality, but decreased amylose content and deteriorated appearance quality. These results suggested that mechanical pot-seedling transplanting with wide-narrow row coupling produced a suitable planting density of 26.88×10~4 hills ha^(–1) and may be an alternative approach to improving grain yield and quality for japonica rice.
基金the National Key R&D Program of China (2016YFD0300503)the Key Research Program of Jiangsu Province, China (BE2016344)+3 种基金the National Rice Industry Technology System, China (CARS01-27)the National Nature Science Foundation of China (31701350)the Program for Scientific Elitists of Yangzhou University, Chinaa Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, China
文摘There is limited information about the influence of slow or controlled release fertilizer(S/CRF) on rice yield and quality. In this study, japonica rice cultivar Nanjing 9108 was used to study the effects of three different S/CRFs(polymer-coated urea(PCU), sulfur-coated urea(SCU), and urea formaldehyde(UF)) and two fertilization modes(both S/CRF and common urea(CU) as basal fertilizer, S/CRF as basal and CU as tillering fertilizer) on rice yield and quality. CU only was applied separately as control(CK). Results showed that, rice grain yield, chalky kernel rate, chalky area, overall chalkiness, and the content of gliadin, glutenin, and protein, all showed the trends of UF>PCU>SCU within the same fertilization mode, and showed the trends of S/CRF as basal and CU as tillering fertilizer>both S/CRF and CU as basal fertilizer within the same type of S/CRF. In contrast, the contents of amylose, amylopectin, and starch, as well as taste value, and peak and hot viscosity showed trends of SCU>PCU>UF, and the trends of both S/CRF and CU as basal fertilizer>S/CRF as basal and CU as tillering fertilizer. Among S/CRF treatments and fertilization modes, taste values of cooked rice were positively correlated with amylose, amylopectin, and starch contents, as well as gel consistency, peak viscosity, hot viscosity, and cool viscosity, while negatively correlated with globulin, gliadin, glutenin, and protein contents. The types of S/CRF and fertilization modes are important for improving rice yield and quality. Compared to CK, higher yield and similar quality of rice was achieved with UF as basal and CU as tillering fertilizer, and similar yield with improved appearance and eating and cooking quality of rice was achieved with either both UF and CU as basal fertilizer, or PCU as basal and CU as tillering fertilizer.
基金grants from the National Key Technology R&D Program of China (2016YFD0300503)the Key Research Program of Jiangsu Province, China (BE2016344)+3 种基金the earmarked fund for China Agriculture Research System (CARS-01-27)the National Nature Science Foundation of China (31701350)the Program for Scientific Elitists of Yangzhou University, Chinafunded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘There is limited information about the combined effect of shading time and nitrogen(N) on grain filling and quality of rice. Therefore, two japonica super rice cultivars, Nanjing 44 and Ningjing 3, were used to study the effect of shading time and N level on the characteristics of rice panicle and grain filling as well as the corresponding yield and quality. At a low N level(150 kg N ha^(–1), 150 N), grain yield decreased(by 21.07–26.07%) under the treatment of 20 days of shading before heading(BH) compared with the no shading(NS) treatment. These decreases occurred because of shortened panicle length, decreased number of primary and secondary branches, as well as the grain number and weight per panicle. At 150 N, in the treatment of 20 days of shading after heading(AH), grain yield also decreased(by 9.46–10.60%) due to the lower grain weight per panicle. The interaction of shading and N level had a significant effect on the number of primary and secondary branches. A high level of N(300 kg N ha^(–1), 300 N) could offset the negative effect of shading on the number of secondary branches and grain weight per panicle, and consequently increased the grain yield in both shading treatments. In superior grains, compared with 150 N NS, the time to reach 99% of the grain weight(T_(99)) was shortened by 1.6 to 1.7 days, and the grain weight was decreased by 4.18–5.91% in 150 N BH. In 150 N AH, the grain weight was 13.39–13.92% lower than that in 150 N NS due to the slow mean and the maximum grain-filling rate(GR_(mean )and GR_(max)). In inferior grains, grain weight and GR_(mean) had a tendency of 150 N NS>150 N BH>150 N AH. Under shaded conditions, 300 N decreased the grain weight due to lower GR_(mean) both in superior and inferior grains. Compared with 150 N NS, the milling and appearance qualities as well as eating and cooking quality were all decreased in 150 N BH and 150 N AH. Shading with the high level of 300 N improved the milling quality and decreased the number of chalky rice kernels, but the eating and cooking quality was reduced with increased chalky area and overall chalkiness. Therefore, in the case of short term shading, appropriate N fertilizer could be used to improve the yield and milling quality of rice, but limited application of N fertilizer is recommended to achieve good eating and cooking quality of rice.
文摘稻麦两熟地区,旱直播水稻生产受前茬小麦收获、全量麦秸秆还田及耕整地质量不高等因素的影响,常采用迟播期、大播量、高基本苗和主茎成穗为主的“独秆”栽培模式,而配套该模式直播稻优质丰产的氮肥管理技术尚缺乏系统的研究。以优质食味粳稻南粳9108为材料,采用机械旱直播方式,基本苗为380×10^(4) hm^(-2),设置不同叶龄期(六、七、八、九和十叶龄期)氮肥追施处理及氮肥追施用量(纯氮180 kg hm^(-2)和225 kg hm^(-2))处理,以基本苗380×10^(4) hm^(-2)和300×10^(4) hm^(-2)的旱直播精确定量氮肥管理(纯氮270 kg hm^(-2),基肥︰分蘖肥︰穗肥=3.5︰3.5︰3.0)为对照,系统比较研究“独秆”栽培模式下,全程氮肥在分蘖中后期施用对旱直播水稻产量和品质的影响。结果表明,随追施叶龄的延后,水稻产量呈先增后降趋势,八叶期追施氮肥水稻产量显著高于其他处理,且追施量增加,水稻产量进一步提高。与2组对照相比,在纯氮180 kg hm^(-2),氮肥减量33.3%情况下,不施氮素基肥配合八叶期一次性追施氮肥,可显著提高水稻产量5.10%和8.65%;在纯氮225 kg hm^(-2),氮肥减量16.7%情况下,不施氮素基肥配合八叶期及7 d后二次追肥可显著提高水稻产量7.46%和11.09%。不施氮素基肥配合八叶期追施氮肥水稻产量提高的原因是,保障较大穗型的基础上增加有效穗数,显著提高群体颖花量,同时保持较高水平的结实率和千粒重。随追肥叶龄延后,水稻整精米率呈增加趋势,垩白度呈增大趋势,蛋白质含量增加,直链淀粉含量下降,食味值呈降低趋势。与2组对照相比,不施氮素基肥配合八叶期追施氮肥的水稻,加工品质提高,整精米率提高0.67%~2.23%;外观品质变好,垩白度降低3.6%~14.5%;营养品质提升,蛋白质含量增加3.03%~14.08%;蒸煮食味品质呈变优趋势,直链淀粉含量下降4.23%~10.95%;食味值无显著差异。综上所述,“独秆”栽培模式下基肥不施氮肥配合全程氮肥在分蘖中后期适宜叶龄施用可实现稻麦两熟地区旱直播稻迟播期、大播量和高基本苗生产方式的提质增产生产。
文摘从24个甬优系列籼粳杂交稻品种(系)中,根据不同产量水平和氮素农学利用率筛选出具有代表性的3种类型(高产氮高效、高产氮中效、中产氮中效),系统比较各类型产量和氮素农学利用率,以探究高产氮高效型籼粳杂交稻产量和氮素吸收利用特征。结果表明,高产氮高效型产量显著高于高产氮中效型和中产氮中效型,分别高4.04%~4.38%和13.37%~13.41%,其高产原因在于群体颖花量大,能达到5.87×10^8~6.20×10^8 hm^-2。与高产氮中效型和中产氮中效型相比,高产氮高效型成穗率高,能保持在68.83%~70.05%;抽穗期叶面积指数高,且生育后期衰减平缓,成熟期叶面积指数在3.85以上;抽穗至成熟期干物质积累量大,达7.91~7.99 t hm^-2,全生育期干物质量可达21.15~21.46 t hm^-2。在氮素吸收利用方面,高产氮高效型总吸氮量显著高于高产氮中效型和中产氮中效型,分别高5.07%~5.14%和4.50%~5.96%;拔节至抽穗期和抽穗至成熟期氮素吸收速率表现为高产氮高效型>高产氮中效型>中产氮中效型,花后茎鞘氮素转运量、穗部氮素积累量和氮素收获指数也有相同表现;氮素回收利用率、农学利用率、生理利用率和偏生产力均以高产氮高效型最高;高产氮中效型除氮素回收利用率和百千克籽粒吸氮量外,其他各项氮素利用指标均高于中产氮中效型。
基金The Special Fund for Agro-scientific Research in the Public Interest(201303102)the Major Independent Innovation Project in Jiangsu Province,China(CX(15)1002)+3 种基金the National Key Research Program of China(2016YFD0300503)the Science and Technology Plan of Jiangsu Province,China(BE2015340)the Research Innovation Program for College Graduates of Jiangsu Province,China(KYLX15_1369)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China supported this study
文摘Understanding the differences in yield traits of rice among pothole seedling of mechanical transplanting(PSMT), carpet seedling of mechanical transplanting(CSMT) and mechanical direct seeding(MDS) is of great importance not only for rice scientists but also for rice farmers to develop a high-yield production system under mechanical conditions in a rice-wheat rotation system. However, such traits are yet to be studied among rice varieties of japonica-indica hybrid rice(JIHR), japonica conventional rice(JCR) and indica hybrid rice(IHR). Field experiments were conducted in 2014 and 2015, where six cultivars of the three rice types JIHR, JCR and IHR were grown individually with PSMT, CSMT and MDS methods, under respective managements for each method to achieve the maximum attainable yield. Results showed that(i) the PSMT significantly increased grain yield of JIHR by 22.0 and 7.1%, of JCR by 15.6 and 3.7% and of IHR by 22.5 and 7.4%, compared to MDS and CSMT on average across the two years, respectively. The highest yield was produced by the combination of JIHR and PSMT;(ii) high yield under PSMT was mainly attributed to large sink capacity and high-efficient dry matter accumulation. With sufficient panicles per hectare, the increase of spikelet number per panicle, especially the increase in spikelet number of the secondary rachis-branches was determined to be the optimal approach for developing a large sink capacity for rice under PSMT. The optimal tillers development, large leaf area index at heading stage, and high leaf area duration, crop growth rate and net assimilation rate during grain-filling phase could be the cause of sufficient dry matter accumulation for rice under PSMT;(iii) moreover, the PSMT favored plant growth as well as enriched the stems plus sheaths during grain-filling phase, as compared with CSMT and MDS. These results suggest that PSMT may be an alternative approach to increasing grain yield in a rice-wheat rotation system in the lower reaches of the Yangtze River in China.
文摘以优质食味粳稻南粳9108为材料,纯氮270 kg hm^(-2)施氮条件下,设置了钵苗机插、毯苗机插2种栽培方式,将控释肥与速效氮肥以5∶5的比例混合,其中控释肥由4种不同释放期(40、80、100、和120 d)肥料按照1∶4的比例混合形成了3种配比方式,分别为40+80、40+100、40+120,同时设置常规分次施肥(CK)为对照,研究不同机械化栽培方式下控释肥配比对迟熟中粳水稻产量形成以及氮素积累的影响。结果表明,相同肥料处理下,钵苗机插2年产量较毯苗机插分别增加了3.9%和4.9%,其原因是钵苗机插能够提高中后期的光合物质积累,获得较大的穗型,具有更高的每穗粒数、结实率以及千粒重。钵苗机插与毯苗机插栽培方式下,40+80和40+100控释肥处理2年产量均高于CK,40+100控释肥处理产量最高,2年较CK分别显著增加7.3%和9.2%,其原因在于40+100控释肥处理具有更高的有效穗数和群体颖花量。与40+80和40+120控释肥处理相比,40+100控释肥处理与南粳9108的养分吸收规律更为匹配,即保证了前期分蘖的发生,又保证了后期稳定的光合物质生产,获得稳定的穗数、穗粒数以及粒重,2年的氮素回收利用率、氮素农学利用率、氮素生理利用率和氮肥偏生产力较CK分别显著增加了10.0%~12.5%、24.6%~30.5%、11.4%~18.6%和7.3%~9.1%。综上所述,钵苗机插较毯苗机插具有明显优势,是利于优质粳稻获得高产的栽培方式,同时40+100控释肥配比能够较好的满足优质粳稻各个阶段的养分需求,能够获得高产,可作为优质粳稻高产的简化施肥方案。
文摘氮素穗肥用量和结实期遮光可通过影响叶片光合和植株氮营养状况对水稻籽粒碳氮代谢能力产生调节作用,从而形成不同特征的稻米品质。为探明氮素穗肥用量与结实期遮光复合作用对常规粳稻品质的影响,于2019—2020年以生育期相近的常规粳稻淮稻5号、南粳9108和扬农香28为材料,设置40.5 kg hm^(-2)(N1)、81.0 kg hm^(-2)(N2)、121.5 kg hm^(-2)(N3)3个氮素穗肥用量处理,并于抽穗至成熟期采用人工遮阴方式控制水稻冠层光照,包括100%自然光照(S0)和50%自然光照(S50)处理,研究了结实期不同光氮处理组合对稻米品质的影响效应。结果表明:糙米率、精米率、整精米率在S0条件下随氮素穗肥用量的增加呈先升后降趋势,在S50条件下呈下降趋势,其中S0N2处理的整精米率最高,加工品质较好;垩白粒率和垩白度均呈S50N3>S50N2>S50N1>S0N3>S0N2>S0N1的趋势,且穗肥氮素用量的增加和结实期遮光对稻米提高垩白粒率和垩白度具有累加作用。穗肥氮素用量增加和结实期遮光均降低直链淀粉含量和胶稠度,提高蛋白质含量,其中谷蛋白的变异系数高于其他蛋白组分。穗肥氮素用量增加和结实期遮光不利于稻米食味值评分,不同品种的食味特征值对食味值评分的直接影响有差异。水稻淀粉的峰值黏度、崩解值随穗肥氮素用量增加和结实期光照强度下降而降低,消减值则上升,光氮复合作用增加了上述指标的差异。在穗肥氮素用量与结实期遮光复合作用下从直链淀粉含量和蛋白质含量比值趋势性变化来分析,结实期植株碳氮代谢能力强弱发生了变化。直链淀粉含量和蛋白质含量均与稻米食味值评分呈极显著的负相关关系,其中蛋白质的相关系数更大。因此,适量减施氮素穗肥有利于水稻结实期遭遇寡照后的稻米加工品质、外观品质及蒸煮食味品质提升,并且降低直链淀粉含量特别是蛋白质含量可能是提升稻米食味的有效途径,以期为优质水稻丰产调优栽培技术的更新提供依据。
基金financially supported by grants from the Major Independent Innovation Project in Jiangsu Province,China(CX(15)1002)the Agricultural Science and Technology Innovation Fund in Jiangsu Province,China(CX(12)1003-09)+3 种基金the National Key Research Program of China(2016YFD0300503)the Science and Technology Plan of Jiangsu Province,China(BE2015340)the Research Innovation Program for College Graduates of Jiangsu Province,China(KYLX15_1369)Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Several studies have demonstrated the effect of planting methods on rice yield, but information on the climate resources is limited. This study aims to reveal the effects of planting methods on climate resources associated with rice yield in a rice-wheat rotation system in the lower reaches of the Yangtze River, China. Field experiments were conducted in 2014 and 2015 with two japonica, two indica hybrid, and two japonica-indica hybrid varieties grown under three mechanized planting methods: carpet seedling of mechanical transplanting(CT), mechanical direct seeding(DS), and pot-hole seedling of mechanical transplanting(PT). The rice yield and total dry matter under PT were greater than those under CT and DS methods. Besides, the entire growth duration and daily production showed significant positive relations with rice yield. Compared with CT and DS, the effective accumulated temperature and cumulative solar radiation of rice under PT were higher in phenological phases. In addition, the dry matter/effective accumulated temperature and solar energy utilization of rice under CT and DS were higher during vegetative phase and lower during reproductive and grain filling phases in contrast to PT. The mean daily temperature and mean daily solar radiation in the entire growth duration showed significant positive correlation with rice yield, total dry matter, and harvest index. This study demonstrated that when the mean daily temperature is <25.1°C in vegetative phase and >20.1°C in grain filling phase, rice yield could be increased by selecting mechanized planting methods. Most varieties under PT method exhibited high yield and climate resources use efficiency compared with CT and DS. In conclusion, the PT method could be a better cultivation measure for high rice yield, accompanied with high temperature and solar radiation use efficiency in a rice-wheat rotation system in the lower reaches of the Yangtze River, China.
