Effect of Transplanting Density on Rice Yield,Nitrogen Uptake and ^(15)N-fertilizer Fate

[Objective] The aim of this study was investigated the rice yield, nitrogen uptake and ^15-fertilizer fate at different transplanting density to provide scientific ba- sis for improving the yield of rice and applying reasonably fertilizer. [Method] A field experiment was carried out to study the effect of different transplanting density on rice yield, nitrogen （N） absorption, sources of N uptake by rice and the N balance in the plant-soil systems by using ^15-labelled urea. [Result] There were no significant differences in rice yields and total N uptakes by rice between treatments 30 cm × 30 cm and 40 cm × 40 cm, but the yield of rice and total N absorption in the two treatments were remarkably higher than those in 50 cm × 50 cm treatment. The amounts of total N uptake by rice were in the range of 112.3-162.7 kg/hm2 in the three transplanting densities. The result showed that about 1/3 of the total N uptake by rice was supplied by application fertilizer and the other 2/3 was obtained from the soil N pool. The ^15N-labelled urea absorbed by rice, residual in soil and lost accounted for 16.3%-26.1%, 17.0%-20.9% and 53.0%-66.7% of the total fertilizer, respectively. A great deal of ^15N-labelled urea was lost during the rice growing season. [Conclusion] Considering the rice yield and environmental protection, the transplanting density of 30 cm×30 cm was recommended in the hilly area of Sichuan basin in the southwest China.

Effect of wide-narrow row arrangement in mechanical pot-seedling transplanting and plant density on yield formation and grain quality of japonica rice

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.

Effects of Transplanting Density on Yield Formation Characteristics of Purple Rice

Liangtianzi 1 was used as a material to study the effects of transplanting density on the yield formation characteristics of purple rice. The results showed that the whole growth period of Liangtianzi 1 was 146 d. Its biomass yield was above 10 t/hm^2, while its economic yield was only about 3 t/hm^2. Transplanting density had a large impact on the number of effective panicles, number of grains par panicle, seed setting rate and yield of purple rice variety. In this study, the planting spacing of 20.0 cm × 20.0 cm gained the highest yield, 3.63 t/hm^2. Key techniques for high-yielding cultivation of Liangtianzi 1 remain to further research.

Research on the Effect of Planting Density on Rice Yield and Quality

Planting density is of great significance in adjusting the population structure of rice,increasing yield and reducing the cost. And suitable planting density can not only bring the yield potential of rice population into full play, obtain the maximum grain yield per unit area, but save labor, protect the environment and improve rice quality. This article summarizes the impact of planting density on rice growth, yield, the components as well as qualities at an attempt to provide theoretical guidance for high yield and quality cultivation of rice.

Effects of soilless substrates on seedling quality and the growth of transplanted super japonica rice

This study was conducted to investigate the effects of soilless substrates of hydroponically grown long-mat seedlings （HLMS） on seedling quality and field growth characteristics of transplanted super japonica rice. A widely grown conventional super japonica rice cultivar （Wuyunjing 23） was selected as the test material. The effect of HLMS on seedling quality, mechanical transplantation quality, field growth characteristics, yield, and benefit-cost ratio were compared with seedlings grown in organic substrates and traditional nutritive soil, whJch was selected as the control. Root number, root twJstJng power and root activity of seedlings cultivated by HLMS were decreased compared to that of the organic substrates andcontrol. However, seedling root length as well as aboveground growth were increased compared to the organic substrates and control seed- lings. In the HLMS, the content of gibberellin acid （GA3） decreased while abscisic acid （ABA） content increased compared to that of the organic substrates and control seedlings. During the early stages after transplanting, the re-greening of HLMS was delayed compared to that of the organic substrates and control seedlings. Nevertheless, there were no significant differences in tiller dynamics and crop yield among the HLMS, organic substrates and control treatments. The effects of HLMS on seedling production were similar to those of the organic substrates and traditional nutritive soil in the present study, suggesting that HLMS have the potential to replace traditional nutritive soil in seedling production without decreasing crop yield. Finally, it is important to reduce organic substrates and topsoil dependence during rice seedling production and worthwhile to consider HLMS popularization and its application on a larger scale.

Effects of different machine transplanting methods on the physiological and yield characteristics of late rice in China

To address problems caused by rice machine transplanting such as injury to the seedlings and recovery period that extend growth period,this study explored the effects of different machine transplanting methods on the physiological and yield characteristics of late rice in China,and determine the appropriate machine transplanting method for late rice,which was expected to provide a basis for high-yield and high-efficient cultivation of machine-transplanted late rice.Hybrid indica rice Taiyou 398 and conventional indica rice Jing Gangruanzhan were selected as the research objects,and large-pot carpet seedling machine transplanting(M1),conventional pot carpet seedling machine transplanting(M2)and ordinary carpet seedling machine transplanting(M3)were adopted respectively to analyze their effects on seedling quality,population physiological characteristics,yield and its components and economic benefits of late rice.The results showed that compared with M2 and M3,M1 achieved higher seedling quality,showing significant advantages in the early stage despite average root entwining force that met the requirement of machine transplanting.The seedlings transplanted using M1 had shorter recovery period after mechanical transplanting,with earlier tillering,earlier peak seedling,and slower declining of stems and tillers in the late stage;the peak seedling number was not high,but the effective tiller number and earbearing tiller percentage were significantly higher than those achieved by the other two machine transplanting methods.Also,M1 achieved stronger photosynthetic capacity of flag leaves before HS,with more photosynthetic products in stems and leaves transported to panicles and more efficiently after HS.Compared with seedlings transplanted using M2 and M3,the recovery period of those transplanted using M1 was shortened by 3 and 5 d,the heading stage(HS),and maturity stage(MS)were advanced,which effectively reduced the risk and impact of“cold dew wind”on machine-transplanted late rice.M1 had significant yield increase advantage and economic benefit,with better grain maturity,and“larger panicles,more panicles,more and fuller grains”.M1 achieved an average yield increase of 10.31%-11.10%,20.67%-25.10%in 2 years,and an average income increase of 18.65%-131.06%and 62.85%-323.78%,respectively.Therefore,vigorously developing M1 is the key to the high-yield and high-efficient cultivation of machine-transplanted late rice in China.

Study on Sowing Date for Mechanicaltransplanting Rice under Wheat-Rice Cropping System in Chengdu Basin

Nurturing sturdy mechanical-transplanting seedlings is the key to achieve high yield using mechanical-transplanting technology under wheat-rice cropping conditions in Chengdu Basin. In this study, super hybrid rice II You 602 was adopted as experimental material, to investigate the effects of sowing date on seedling growth,transplanting quality, growth process and yield of mechanical-transplanting seedlings in wheat-rice cropping region of Chengdu Basin, thus exploring supporting high-yield cultivation techniques for mechanical-transplanting technology in Chengdu Basin, Results showed that the appropriate sowing date for mechanical transplanting in wheatrice cropping region of Chengdu Basin was April 10-15, and the appropriate seedling age was 45-50 d, which led to the highest yield of mechanical-transplanting seedlings. Although postponing sowing was conducive to improving transplanting quality and increasing the percentage of earbearing tillers, it would result in lagged group growth, poor spike quality and reduced effective number of panicles, grain number, seed-setting rate, 1 000-seed weight and other yield components, thus declining the yield. Yield reduction rate would be above 10% with sowing date postponed by 15 d.

Effects of Plant Spacing,Row Spacing and Seedling Number Allocation on the Growth Dynamics of Different Populations of Two Types of Rice Varieties

[Objectives]This study was conducted to construct high-yielding,high-quality,and high-light-efficiency population structures of different types of rice varieties.[Methods]The effects of plant spacing,row spacing and seedling number allocation on stems and tillers,leaf area and dynamic traits of high-yielding rice populations(more than 9750 kg/hm^(2))and low-yielding populations(less than 9750 kg/hm^(2))were studied by two kinds of representative rice varieties with different tiller ability and panicle sizes in cold regions.[Results]Decreasing the plant and row spacing and increasing the number of planted seedlings per hole advanced the heading date and made the number of stems and tillers in the population increase.The impact on the super rice variety with fewer tillers and heavier panicles was greater than that of conventional variety with more tillers and lighter panicles.The stems and tillers of the high-yielding high-quality populations grew steadily in the early stage of development,until an appropriate number of panicles was reached at the critical leaf age for productive tillers(June 25),and the peak seedlings should appear in the jointing stage(July 9)with a small number(that value of Longjing 21,the super rice variety with fewer tillers and heavier panicles,was about 1.2 times the expected panicle number,and that of the conventional variety with more tillers and lighter panicles,Kongyu 131,was about 1.1 times the expected panicle number).The populations gradually declined since then,until reaching an appropriate number of panicles at the heading stage.The high-yielding high-quality populations had a higher leaf area index at the heading stage.The value of Longjing 21,the super rice variety with fewer tiller and heavier panicles,reached about 6.0,and that of Kongyu 131,the conventional variety with more tillers and lighter panicles,reached about 4.5.The values decreased thereafter.At the maturation stage,the leaf area index of Longjing 21 remained above 2.5,and that of Kongyu 131 remained above 2.0.[Conclusions]This study has an important guiding role and significance for their high-yielding and high-quality supporting cultivation in cold regions.

不同育苗方式对机插秧苗素质、栽插质量及水稻产量的影响

为探明常规育苗、托盘育苗和漂浮育苗3种方式对水稻育苗及大田生长的影响,以‘南粳9108’为供试材料,比较相同播量下3种方式所育秧苗素质差异及对栽插质量、大田生长和产量的影响。结果表明:3种育苗方式成苗率在71.7%-75.0%,其中漂浮育苗最高,三者的地上部性状无显著差异,但常规育苗根系数量及长度较托盘育苗和漂浮育苗分别增加21.4%、16.1%和3.3%、9.8%;漂浮育苗的空穴率和伤秧率分别为0.39%、0.78%,栽插质量最优;漂浮育苗分蘖高峰期分蘖数较托盘育苗和常规育苗分别增加9.8%和24.0%,但单株生物量积累有所降低;漂浮育秧最终成穗数较托盘育苗、常规育苗增加7.2%和8.1%,但每穗实粒数降低4.9%、4.6%,在最终产量上三者之间无显著差异。综合来看,3种育苗方式都可育出健壮秧苗,并且栽插质量、大田生长和产量表现良好,在生产上可根据实际情况进行选择。

增密减肥处理对籼型杂交稻产量及生长发育的影响

为探究增密减肥对水稻地上部干物质积累、产量等的影响,在2021—2022年,采用有序机抛技术,设置3种移栽密度,低密度(low density,LD)、中密度(medium density,MD)和高密度(high density,HD)分别为18万株hm^(-2)、22万株hm^(-2)和27万株hm^(-2),设置3种施肥量水平,低肥料(low fertility,LF)、中肥料(medium fertility,MF)和高肥料(high fertility,HF)分别为450 kg hm^(-2)、525 kg hm^(-2)和675 kg hm^(-2)进行大田试验。结果表明:中密中肥(medium density and medium fertilizer,MDMF)处理的产量最高,与低密高肥(low density and high fertilizer,LDHF)相比,MDMF处理的产量2年平均增幅3.15%,显著增加了有效穗数,稳定了其他产量因素,但收获指数增幅不高,甚至降低。齐穗期前高密高肥(high density and high fertilizer,HDHF)处理的地上部干物质量最高,2年平均增幅0.17%,齐穗后MDMF处理的地上部干物质量最高,2年平均增幅0.16%。MDMF处理在各生育时期的叶面积指数(leaf area index,LAI)、叶绿素相对含量(soil and plant analyzer development,SPAD)与LDHF处理相差不大,但MDMF处理的SPAD衰减率和LAI衰减率维持在较高水平,2021年和2022年MDMF处理条件下水稻SPAD衰减率分别为12.65%和16.85%,LAI衰减率分别为6.42%和6.74%。随着移栽密度和肥料的增加水稻分蘖数增加。由以上可知,适当的增密减肥可增加有效穗数,构造较高的群体结构和地上部干物质量,增加齐穗期至成熟期籼型杂交稻群体光合物质的生产及转运能力,保持了源的稳定,增加了产量库容量而获得高产,籼型杂交稻生产上宜采用栽插密度为22万株hm^(-2)和施肥量为525 kg hm^(-2)的组合。

氮密互作对优质食味水稻盐粳939产量和品质的影响

研究了不同氮肥施用量(纯氮0、90、150、210、270 kg/hm^(2))和种植密度(30 cm×18 cm、30 cm×14 cm、30 cm×10 cm)互作对优质食味水稻盐粳939产量和品质的影响。结果表明:不同施氮量和种植密度对盐粳939的产量和品质影响显著。低密高氮依然是产量显著提高的手段;在兼顾产量的前提下:在密度30 cm×18 cm、施氮量10 kg/667 m^(2)的条件下可获得较好的外观品质;在密度30 cm×10 cm、施氮量10 kg/667 m^(2)的条件下可获得较好的食味品质。低氮条件下水稻的氮素利用率等指标会显著提高。

7个优质粳稻品种在寿光地区的种植鉴定

在潍坊市寿光市进行7个粳稻品种比较试验,对参试品种的农艺性状、产量、抗性及稻米品质表现进行汇总分析。结果表明,津原U99表现早熟、优质、丰产性较好,适于寿光试验区作优质米种植。圣稻22、圣香1826丰产性好、米质优良、中感稻瘟病,应加强稻瘟病的防治。津原U99、润农303、润农11表现抗稻瘟病,津原985高感稻瘟病,圣稻2620感稻瘟病。该试验为当地品种的合理选择提供了参考依据。

钵体苗不同穴距机插对华南优质籼稻产量的影响

钵体苗机插能缩短水稻缓苗时间,促进早生快发,提高群体光合能力,增加生物量和稻谷产量。然而,钵体苗不同穴距机插对华南优质籼稻群体指标和稻谷产量的研究鲜有报道。以华南地区种植面积较广的杂交籼稻品种泰丰优208和常规籼稻品种南晶香占为材料,设置4种穴距处理(A_(1)处理穴距12.4 cm、A_(2)处理穴距14.5 cm、A_(3)处理穴距17.9 cm和A_(4)处理穴距20.7 cm),研究钵体苗不同栽插穴距处理对分蘖数、叶面积指数、光合势、生物量和产量等指标的影响。结果显示,随穴距的缩小,分蘖数、叶面积指数、光合势和生物量都呈现逐渐增加的趋势,与农户传统穴距17.9 cm(A_(3)处理)相比,A_(1)处理在分蘖中期、幼穗分化始期和抽穗期的分蘖数分别增加36.2%~38.7%、 37.3%~42.4%和21.5%~36.9%;叶面积指数分别增加30.8%~55.9%、16.4%~41.0%和37.7%~53.1%;生物量分别增加32.0%~38.6%、20.1%~34.2%和37.1%~59.0%。分蘖中期到幼穗分化始期和幼穗分化始期到抽穗期的光合势分别增加17.9%~49.2%和28.1%~49.2%。稻谷产量与抽穗期分蘖数、幼穗分化始期叶面积指数和生物量、分蘖中期至幼穗分化始期光合势、成熟期生物量和有效穗数均呈显著正相关。上述结果表明,在华南双季稻区,钵体苗机插适当增加栽插密度能提高水稻前期分蘖数、叶面积指数、光合势和生物量,保持后期群体指标优势,从而增加稻谷产量。

早稻舜达135特早栽培高产技术研究

舜达135是绍兴市舜达种业有限公司与中国水稻研究所联合育成的早熟常规早籼稻新品种。为充分发挥该品种早熟、高产优势,在特早栽培条件下(播种期比绍兴传统播期提早10~15 d)开展了不同梯度机插密度和肥料用量对比试验。结果表明,不同机插密度对舜达135有效穗数和产量有极显著影响,对穗粒数和结实率影响未达到显著水平;不同氮肥水平和氮肥水平与机插密度的互作对舜达135有效穗数、穗粒数、结实率和产量的影响均不显著;以种植密度25 cm×14 cm、纯氮施用量150 kg/hm^(2)的处理实际产量最高,达9 633.45 kg/hm^(2)。在2021年和2022年示范中,特早栽培条件下舜达135百亩示范方产量分别达到10 563.00 kg/hm^(2)和10 258.05 kg/hm^(2)。通过2年的示范,总结提出了舜达135特早栽培高产技术。

种植方式对水稻产量及品质的影响

种植方式对水稻的产量和品质的形成至关重要。本研究以粳稻日本晴为材料,采用人工直播和人工移栽等密度的两种种植方式,分析其对产量形成与稻米品质的影响。结果表明,人工移栽稻的产量显著高于人工直播稻,产量增加了23.7%~23.9%;整精米率显著高于人工直播稻,垩白米率和垩白大小两种种植方式各有优势。生物量和生理指标测定发现,植株上三叶的叶面积从拔节期到抽穗后25 d间均显著高于人工直播方式,增加了15%~35%。人工移栽稻的光合荧光参数与人工直播稻差异不显著,但株高显著高于人工直播稻,干物质的积累量在拔节期和抽穗期显著高于人工直播稻。在不同生长阶段人工移栽稻积累更多的非结构性碳水化合物,尤其是在抽穗后15 d茎和穗中更多,增加了10%左右。表明干物质积累、上三张叶片的叶面积、抽穗后15 d茎和穗中非结构性碳水化合物的积累量及抽穗后叶片对产量和籽粒的贡献是移栽稻与直播稻在产量和稻米品质方面产生差异的重要原因。

栽插期对机插秧水稻产量及品质的影响

近年来,水稻机插秧发展迅速,相关技术逐渐成熟。为进一步研究不同栽插期对机插秧水稻产量及品质的影响,以淮稻5号为研究对象,进行4个栽插期处理的对比试验。结果表明:栽插期对机插秧水稻产量有明显影响,以6月15日栽插产量最高,较6月30日栽插增产5.3%,在秧龄相近的情况下,栽插越晚产量越低;随着栽插期的推迟,稻米加工品质和外观品质总体呈下降趋势。生产上应抓住适期,争取早栽,以实现水稻产质量的提高。

水稻密播短秧龄机插秧试验

水稻密播短秧龄机插对于水稻节本增效具有重要意义,探索合适的技术参数对于水稻生产至关重要。为探索通过育秧时增加每盘播种量,同时适当缩短秧龄,从而减少单位面积秧盘用量、降低育秧成本的可行性,本试验设4个播量处理,研究其对水稻秧苗素质、群体动态、产量及其构成因素和经济效益的影响。结果表明,播量130 g/盘和150 g/盘处理秧苗素质较好,株高较高,分蘖成穗率较高,产量及其构成因素较高,经济效益较好,可有效节约秧盘成本,进而实现节本增效目标。这一创新技术可在陕西地区推广。

控释氮肥一次性减量基施和密植对机插粳稻产量、品质及经济效益的影响

为探究控释氮肥一次性减量基施及密植对机插粳稻产量、品质和经济效益的影响,明确最优氮肥和栽插密度组合处理,以南粳5718为供试材料,在施用225 kg/hm^(2)纯氮条件下,将3种控释期(60 d、80 d、100 d)的控释肥和3个栽插密度(每穴栽插苗数分别为6、8、10)进行组合,共设置9种组合方式,并设置对照(CK)为300 kg/hm^(2)纯氮施用量+每穴栽插苗数为4+常规分次施肥,调查产量及其形成特征、稻米品质和经济效益的差异。结果表明,2021、2022年各减氮处理中产量最高的均为80-6处理,较其他减氮处理产量显著提高,较CK产量显著降低4.77%~5.17%。拔节期至抽穗期,80-6处理的干物质积累量与其他减氮处理相比总体增加。在稻米品质指标方面,各减氮处理的垩白粒率、垩白度较CK降低,营养品质(蛋白质含量)显著降低,但在外观品质、食味品质方面均得到显著改善。在经济效益方面,80-6处理实现了2021、2022年控释肥一次性基施下的最高经济效益,经济效益较CK增加3.60%~5.28%。因此认为,80-6处理在减氮和保证稳产的前提下,可以提升稻米品质,同时能够获得较高经济效益,可作为机插粳稻丰产优质高效协同的一次性减氮施肥处理的氮肥和栽插密度组合。

播种量和秧龄对机插籼粳杂交稻秧苗素质、产量和加工品质的影响

适宜的播种量与秧龄搭配是保障水稻丰产优质的前提。以籼粳杂交稻甬优6711为供试品种,采用两因素(播种量、秧龄)裂区设计,以探明不同秧龄和播种量处理(T1,秧龄20 d、播种量50 g/盘;T2,秧龄20 d、播种量70 g/盘;T3,秧龄30 d、播种量50 g/盘;T4,秧龄30 d、播种量70 g/盘)对机插稻秧苗素质、产量和加工品质的影响。结果表明,T2和T3处理的产量较高,较T1处理分别增产24.7%和25.2%,较T4处理分别增产17.4%和17.8%。与20 d秧龄处理相比,30 d秧龄处理显著增加苗高、茎基宽、百苗地上及地下部干物质量;70 g/盘播种量处理较50 g/盘播种量处理显著降低苗高、茎基宽和发根力。整体而言,T3处理的秧苗素质最好。从稻米加工品质来看,与20 d秧龄处理相比,30 d秧龄处理的精米率和整精米率均显著下降,但糙米率差异不显著;与50 g/盘播种量处理相比,70 g/盘播种量处理能显著提高糙米率和精米率,但对整精米率影响小。综合来看,T2处理的稻米加工品质最优,而T3处理降低了稻米加工品质。因此,在苏北杂交中粳稻种植区,选择短秧龄、高播量搭配(T2)能同时获得丰产优质,长秧龄、低播量搭配(T3)能获得丰产,但稻米加工品质显著下降。

移栽期和种植密度对恩施雪茄烟叶品质的影响

为探究移栽期和种植密度对雪茄烟烟叶产量和品质的影响,在恩施崔坝基地展开试验。设置3个移栽期处理(4月20日、4月30日、5月10日)和6个种植密度处理(100 cm×40 cm、100 cm×45 cm、100 cm×50 cm、110 cm×40 cm、110 cm×45 cm、110 cm×50 cm),比较不同移栽期的烟株生育期、农艺性状、产量及等级结构、外观质量和感官评吸质量,选择最佳移栽期进行移栽,探究不同种植密度对烟株农艺性状、产量及等级结构的影响。结果表明:随着移栽期的推迟,烟株生育期明显缩短,集中在旺长期,与气温呈明显负相关;随着移栽期的推迟,烟叶的产量和品质均下降。此外,不同种植密度对烟株的生长具有一定影响。随着种植密度的增大,烟株的株高、最大叶长和叶宽整体上先增后减,适当增加行距和减小株距有利于提高产量。综合认为,恩施崔坝基地雪茄烟茄衣品种‘楚雪26号’的最佳移栽期在4月20日—4月30日,110 cm×50 cm的种植密度使烟株的农艺性状表现最好,110 cm×40 cm的种植密度能获得更高的经济效益。