Major Physiological Characters of Different Double Cropping Rice Varieties by Different Mechanical Transplanting Methods

Muying LI,Chengkuan HUANG,Xueming TAN,Qinghua SHI,Xiaohua PAN

Key Laboratory of Crop Physiology,Ecology and Genetic Breeding,Ministry of Education/Jiangxi Key Laboratory of Crop Physiology,Ecology and Genetic Breeding/Collaborative Innovation Center for Modern Production of Double Cropping System,Jiangxi Agricultural University,Nanchang 330045,China

Responsible editor:Xiaoxue WANG Responsible proofreader:Xiaoyan WU

With transferring of rural labors,the issue of aging is deteriorating in rural areas and it has become a tendency for modern rice development.Currently,most mechanical productions of rice are dominated by farming and harvesting.By mechanical farming,because of seedling cultivation,land consolidation,and transplanting qualities,rejuvenation period of seedlings keeps longer and the productive earing term shorter.What’s worse,lower tillering leaf position would lose by mechanical transplanted rice[1],resulting in yield loss caused by insufficient ear number[2].Therefore,mechanical transplanting of rice develops quite slowly.Recently,thanks for government supports and agriculture technical staffs efforts,mechanical planting of rice reached 20% nationwide in 2012,and the area of mechanical planting in northeastern reclamation area and Jiangsu Province took up to over 60%[3].However,the advancement in different areas tends to be volatile,especially for southern double-cropping paddy areas where me chanical planting develops slowly[3-5].The causes,besides long-term growth period of some highly-yielding varieties[6-8],some bottleneck problems exist in the cultivation technology.Firstly,the demands on transplanting technology maintains higher and the density of flat seedling is high by mechanical transplanting,so that nutritive area of individual seedling is small and it is difficult to cultivate seedlings with high quality[9-10].At present,farmers are far from well grasping seedling cultivation technology,and consequently,the cultivated seedlings can not meet the demands of use of rice transplanters[11-13].Secondly,the qualities of transplanters and transplanting lead to longer seedling rejuvenation period and fiercer competition among seedlings the same hold,affecting development of transplanted rice[13-15]and rice yields.Nevertheless,mechanical transplanting is a necessary development trend of rice.The research,therefore,explored yields and physiological traits of double-cropping rice by mechanical transplanting in different growth periods in Jiangxi Province recently in order to provide references for selection and highly-yielding cultivation of double-cropping and resolving the bottleneck problems of mechanical transplanting.

Materials and Methods

Test materials

The test was conducted in Guangfu Village,Fuangfu Town,Nanchang County in 2012 (Table1)[U1]and rice transplanters included PF455S rice transplanter and 2Z-455 rice transplanter.

Specifications of mechanical transplanting

In the research,rice in two transplanting belts,totaling 8 rows,were tested with row length of 25 m in different treatments.For Dongyang PF455S rice transplanter,linespace kept 30 cm,and plant distance 11.7 cm,with test plots of 60 m2.In contrast,as for Fulaiwei 2Z-455 rice transplanter,wide-line space was 30 cm,narrow-line space 23.8 cm,and plant distance 13 cm,with test plots of 54 m2.Different treatments were repeated twice,and the density was 23.49×104clumps per hm2.

Field management

Seedling cultivation Early rice was sown on March 24 in a greenhouse with plastic trays.For PF455S rice transplanter,the seedling tray was 58 cm×28 cm×2.5 cm,with sowing quantities of 100 g per tray for normal rice and 67 g/tray for hybrid rice.As for 2Z-455 rice transplanter,the seedling tray was 58 cm×22 cm×2.5 cm,with sowing quantities of 78 g per tray for normal rice and 52 g/tray for hybrid rice.In contrast,late rice was sown on June 28 with plastic hard-trays and seedlings were cultivated with moist sludge in paddy fields.In addition,the density of seedlings was 67 g per tray with PF455S rice transplanter and 52 g per tray with 2Z-455 rice transplanter.

Field managementEarly rice was transplanted on April 19.Specifically,N fertilizers mainly referred to pure N at 180 kg/hm2,P fertilizers referred to P2O5at 80 kg/hm2,and K fertilizer K2O at 180 kg/hm2.N fertilizer can be classified into base fertilizer,tillering fertilizer and earing fertilizer with a rate at 5:2:3;P fertilizer was totally applied as base fertilizer and K fertilizer applied as per tillering fertilizer (as base fertilizer):earing fertilizer at 7:3.Late rice can be applied.On the other hand,late rice was transplanted on July 17.Specifically,N fertilizer (pure N) was applied at 195 kg/hm2,P fertilizer(P2O5)was applied at 80 kg/hm2,and K fertilizer applied at 195 kg/hm2.Furthermore,N fertilizer was applied as per base fertilizer:tillering fertilizer:earing fertilizer at 4:2:4;P fertilizer was totally applied as base fertilizer;K fertilizer was applied as per tillering fertilizer (base fertilizer):earing fertilizer at7:3.It is notable that N,P and K compound fertilizers and Ca,Mg and P fertilizers were sources of base fertilizer and urea and KCl were sources of additional fertilizers.Base fertilizer was applied to fields at land consolidation;tillering fertilizer was applied 10 d after transplanting; earing fertilizer was applied in the 2nddifferentiation term of young ears.Seedlings were transplanted with thin water; tillering proceeded with little water; alternate wetting and drying irrigation was conducted during grain-filling stage; irrigation stopped a week before harvesting.

Table1 Test materials and growth days

Measurement methods

In maturing stage,80 clumps rice were surveyed in terms of the number of productive ear,seeds were explored based on five repetitions with 5 clumps rice.In different treatment stages,150 clumps rice were harvested successively to dry seeds and compute yields.Leaf area was measured as per sample dry-weighing method.Specifically,the number of average tiller per clump was surveyed and seedlings from 5 clumps were sampled to measure leaf area in peak-tillering stage,ear differentiation stage,heading stage,milk-ripening stage,and ripening stage.Moreover,photosynthetic potential was concluded as per average leaf area and the days when green leaf last (m2).Additionally,differentiation and degradation of branch and glumous flower were observed as per trace method[16].Specifically,in initial heading stage,rice from two clumps were collected according to average productive ear to explore differentiation and degradation of the 1stand 2ndbranches and glumous flowers.For the number of large vascular bundle,rice spike neck was cut to observe the number and chlorophyll content was measured on basis of randomly chosen 30 flag-leaf,which was measured with a SPAD-502 chlorophyll meter.In addition,roots wound flowing was measured as per gravimetric method and the samples were collected at 48:00,followed by weighing at 6:00 of the following day to compute roots wound flowing per hour(mg/h).

Data processing

The data were analyzed with Excel 2003 and analysis of variance proceeded with DPSv7.05.

Results and Analysis

Yield characteristics of doublecropping rice by mechanical transplanting

Yield components of early riceAs shown in Table2,with the number of rice by mechanical transplanting the same in the fixed area,for the same rice variety,the yield components by 2Z-455 rice transplanter performed higher compared with PF455S rice transplanter,and the yield improved by 2.90%.In the same treatment,however,the yield of Xinfengyou 22 was the highest followed by Lingliangyou 268,showing significant differences with other varieties.Besides,yields of Zhuliangyou 09 and Zhongjiazao 17 were the lowest by different mechanical methods; Zhongjiazao 17 and Zhuliangyou 819 kept the same in growth term,but the yields were significantly lower compared with Zhuliangyou 918,because Zhongjiazao 17 was normal rice,whose tillering capacity was poorer compared with hybrid rice,so that the number of productive ear was few.As for other rice varieties with the same growth term,yields showed little differences.In accordance with correlation analysis,rice yield showed significant correlation with the number of productive ear(r=0.461 1*).By the two mechanical transplanting methods,yields among varieties performed similar.Nevertheless,yield components tended to be volatile upon rice varieties.For example,the number of productive ear of Zhongjiazao 17 was few,but the number of kernel per ear was more; the number of kernel was the same of Zhuliangyou 819 and Jinyou 458,but setting percentage of the later kept higher; the number of productive ear of 03you 66 was more,but the number of kernel per ear and setting percentage were lower; the number of kernel per ear of Zhuliangyou 09 and Xiannong 25 was small,but setting percentage was higher; the number of relative productive ear of Xinfengyou 22 was more and the setting percentage kept higher; the yield components of Lingliangyou 268 kept balanced to certain extent.

Yield components of different later rice varietiesAs shown in Table3,later rice yield performed similar with that of early rice by different mechanical transplanting methods.By 2Z-455 rice transplanter,the yield was 2.73%higher compared with the treatment with PF455S rice transplanter.Considering from yield components,under influence of productive ear and the number of kernel per ear,the number of productive ear by 2Z-455 rice transplanter increased by 2.52%,and the number of kernel per ear increased by 2.95%.On basis of different varieties,the yield of Tianyouhuazhan was the highest,followed by Tianyou 998,and Fengyuanyou 299,and the treatments showed little differences of the same variety by different mechanical transplanting methods; the yields of Taifengyougan No.3,Wuyou 308 Rongyou 225 and Wufengyou T 025 ranked from the 4th to the 7th; yield of Shanyou 10 was the least.According to Table3,the variety with a high yield performed more in terms of productive ear and kernel per ear.As for Fengyuanyou 299,although the number of productive ear was small,the number of kernel per ear and kernel weight were higher compared with rest varieties.Hence,the yield showed little differences with that of Yianyouhuazhan and Tianyou 998.

Dynamics of leaf area of doublecropping rice by different mechanical transplanting methods

Dynamics of early rice leaf areaAs shown in Table4,leaf area index showed differences upon rice varietyand mechanical transplanting method.In tillering stage,leaf area by PF455S rice transplanter was larger compared with the treatment by 2Z-455 rice transplanter.After ear differentiation stage,leaf area in the treatment by 2Z-455 rice transplanter,however,was larger.Among different varieties of early rice,leaf area index of Zhongjiazao 17 was the least in different growth stages;leaf area index of Zhuliangyou 09 was a little higher than that of Zhongjiazao 17; leaf area indices of Xinfengyou 09,Lingliangyou 268,and 03you 66 were higher compared with rest varieties after differentiation stage;leaf area index of Zhuliangyou 819 was the highest and still kept higher than that of Zhongjiazao 17 and Zhuliangyou 09 after ear differentiation.It is notable that leaf area index in heading period and ripening period reflects photosystem and degradation in grainfilling stage,and correlation analysis indicated that leaf area index in later growth stage of early rice is of positive correlation with yield and accumulated dry matter.Specifically,the correlation coefficients of leaf area index with dry matter accumulation were 0.584 7*and 0.747 1**in heading and ripening stages,and 0.556 0*and 0.656 8**with yield.Therefore,leaf area index is of significance for improving rice yield after earing,which proves much better by 2Z-455 rice transplanter.

Table2 The yield components of different varieties in early season rice under the different mode of mechanical transplanting

Table3 The yield components of different varieties in late season rice under the different mode of mechanical transplanting

Table4 Leave area index of different early rice varieties under the different mode of mechanical mechanical transplanting in different growth period

Table5 Leave area index of different late rice varieties under different mode of mechanical mechanical transplanting in different growth period

Dynamics of leaf area of late riceAs shown in Table5,the differences of leaf area index of late rice were much similar to that of early rice in different treatments.In tillering stage,leaf area by PF455S rice transplanter was larger compared with the treatment by 2Z-455 rice transplanter.After ear differentiation stage,leaf area in the treatment by 2Z-455 rice transplanter,however,was larger.Among different varieties,leaf area tended to be volatile in later growth period,and the differences by two mechanical transplanting methods showed similar.Specifically,leaf area indices of Rongyou No.225 and Tianyou 998 were the highest,followed by Tianyouhuazhan,Shanyou 10,Wuyou 308,Wufengyou T025 and Taifengyougan 3.In the research,leaf of Shanyou 10 grew longer and shading became heavy.According to related analysis,leaf area index in heading and ripening stage showed positive correlation with dry matter accumulation and yield,with correlation coefficients of 0.447 6*and 0.592 2*with dry matter accumulation and 0.440 3*and 0.645 4**with yield.

Photosynthetic potential of different rice varieties by mechanical transplanting methods

Photosynthetic potential of early riceAs shown in Table6,average photosynthetic potential was higher by2Z-455 rice transplanter,which improved by 0.92%,3.99% and 5.64%from peak tillering ripening stages.Besides,photosynthetic potential showed significant differences among varieties of early rice.For example,photosynthetic potentials of Xinfengyou 22 and Lingliangyou 268 were the highest,and of Zhuliangyou 09 and Zhongjiazao 17 were the least.According to correlation analysis,yield components of early rice by mechanical transplanting were of positive correlation with photosynthetic potential.From peak tillering stage to ear differentiation stage,photosynthetic potential was of positive correlation with tillering peak of rice population,with a correlation coefficient (r) at 0.573 5*;from ear differentiation to heading stages,photosynthetic potential was of extremely significant positive correlation with the number of productive ear,with a correlation coefficient (r)at 0.795 0**; from heading to ripening stage,photosynthetic potential was of extremely significant positive correlation with rice yield,with a correlation coefficient (r)at 0.790 8**;from peak tillering to ripening stages,photosynthetic potential was of extremely significant positive correlation with dry matter,with a correlation coefficient(r)at 0.719 8**.The research indicatedthat high photosynthetic potential is a guarantee of high yielding of early rice by mechanical transplanting.

Table6 The photosynthetic potential of different of different early rice varieties under the different mode of mechanical transplanting in different growth period 104(m2/d)/hm2

Table7 The photosynthetic potential of different late rice varieties under the different mode of mechanical transplanting in different growth period 104(m2/d)/hm2

Photosynthetic potential of late rice varieties in different growth stagesAs shown in Table7,average photosynthetic potential was higher by 2Z-455 rice transplanter,which improved by 3.46%,7.09% and 6.79% from peak tillering ripening stages.Furthermore,photosynthetic potential showed significant differences among late rice varieties.For instance,photosynthetic potential of Tianyou 998 was lower than that of Shanyou 10 before ear differentiation,but kept higher thereafter.However,photosynthetic potentials of Shanyou 10,Wufengyou T025 and Taifengyougan 3 maintained lower.According to correlation analysis,photosynthetic potential of late rice population showed positive correlation with rice yield and dry matter.By mechanical transplanting,photosynthetic potential of late rice was abundant in different growth stages and increased by 74.26% and 77.79% by PF455S rice transplanter and 2Z-455 rice transplanter compared with early rice.

Differentiation and degradation of glumous flower of double-cropping rice by different mechanical transplanting

Differentiation and degradation of glumous flower of early riceRice branching and differentiation are closely related to the shape of ear,as well as cultivation conditions.With the number of ear the same,highly-qualified rice population is characterized by more differentiated branch and glumous flower and little degradation.As shown in Table8,mechanical transplanting had significant but varying effects on differentiation and degradation of branch and glumous flower.For example,with a 2Z-455 rice transplanter,the 1stand 2nddifferentiations of branch and glumous flower were higher,compared with the treatment with a PF455S rice transplanter,but degradation rate kept lower.What’s more,it can be concluded from Table8 that the 2ndbranching among treatments showed significant differences and the degradation rate of 2ndbranching was lower by 2Z-455 rice transplanter,suggesting that 2Z-455 rice transplanter is conductive to differentiation and development of branches.Among rice varieties,the number of the 1stbranch was of positive correlation with yield,with a correlation coefficient at 0.497 0*.In terms of degradation rate of the 2ndbranching,Zhuliangyou 09,Jinyou 458 and Xinfengyou 22 kept higher,and Zhongjiazao 17 and Zhuliangyou 819 were lower.According to the correlation analysis,the differentiation and growth number of the 2ndbranching of glumous flowers showed extremely significant differences,with correlation coefficients of 0.856 2**and 0.867 7**.

Differentiation and degradation of glumous flower of early riceAs shown in Table9,by PF455S rice transplanter,the number of differentiation and growth of the 1stbranching were higher compared with the treatment with 2Z-455 rice transplanter,and the degradation rate was also higher.As for the 2ndbranching and glumous flower,the differentiation and growth,the treatment by 2Z-455 rice transplanter was higher,but the degradation rate was lower,which were in consistent with that of early rice.In general,similar to early rice,mechanical transplanting promotes differentiation and growth of late rice.Besides,for late rice varieties,the number of the 1stbranching showed little differences and the 2ndbranching and the number of glumous flowers differed significantly.For instance,the number of the 2ndbranching kept higher of Tianyou 998 and Tianyouhuazhan,and of Shanyou 10 was the lowest.In accordance with correlation analysis,the number of 2ndbranching showed extremely significant differences with differentiation and growth of glumous flowers,with correlation coefficients of 0.953 4**and 0.947 7**; the number of 2ndbranching differentiation was of positive correlation with growth and yield,with correlation coefficients of 0.703 1**and 0.479 2*; Wufengyou T025 was the highest in the number of 2ndbranching and Tianyouhuazhan the most in glumous flower,and Shanyou 10 were the least of the indices.It can be concluded from Table10 that the number of differentiation and growth of the 2ndbranching and glumous flowers showed significant differences of Wuyou No.308,and more attention should be paid to the sensitivity of Wuyou 308 to growth environment.

The number of vascular bundle of double-cropping rice by different mechanical transplanting

Avascular bundle is a part of the transport system transporting water and nutrients for rice,reflecting the capacity of rice ear in transporting nutrients during grain-filling stage to certainextent.Related to rice characters,the number of vascular bundle is prone to influence from cultivation conditions.It can be concluded from Table10 that the number of vascular bundle was higher as per wide-narrow row compared with the treatment with equivalent row in an average way,with exceptions of Zhongjiazao 17,Xinfengyou 22,Xiannong 25,03you 66,Zhuliangyou 09,Fengyuanyou 299,Wufengyou T025 and Rongyou 225.According to correlation analysis,the number of the 1stbranching differentiation and growth showed significant positive correlation with the number of vascular bundle,with correlation coefficients of 0.466 9*and 0.468 9*for early rice and 0.452 2*and 0.421 2 for late rice.Moreover,thousand-seed weight was of significantly positive correlation with great vascular bundle,with correlation coefficients of 0.491 4*and 0.519 2*for early and late rice.It can be concluded that rice yield is closely related to the number of vascular bundle.of SPAD value after earing was of extremely significant differences with rice yield,with a correlation coefficient of-0.791 9**,which indicated that the content of chlorophyll of early rice dropped rapidly after earing,which would affect rice yield.

Dynamics of chlorophyll content of early riceAs shown in Table12,average SPAD values in different treatments of late rice showed much similar to that of early rice and the values in the treatment as per wide-narrow row maintained higher compared with the treatments as per equivalent row.Except of Fengyuanyou 299,SPAD values of the rest varieties all performed higher (2.37% in an average way) in the treatment as per equivalent row compared with the treatment as per wide-narrow row.Specifically,the value of Shanyou 10 differed by 4.08%by different mechanical transplanting methods and the differences of Wuyou 308 were small.Furthermore,SPAD values of Fengyuanyou 299,Tianyouhuazhan and Tianyou 988 kept

Dynamics of chlorophyll content of early rice

Photosynthesis of rice leaf is related to the content of chlorophyll which is under influence of rice characters as well as cultivation conditions.After heading stage,the dynamics of chlorophyll content reflect rice growth or aging.As shown in Table11,in the treatment as per wide-narrow row,SPAD value of early rice after full heading was higher compared with the treatment as per equivalent row.Among different rice varieties,SPAD value of Zhongjiazao 17 was the highest,followed by Xinfengyou 22,Zhuliangyou No.819 and Lingliangyou 268.Besides,as grain-filling stage continued,SPAD values of the rice varieties kept declining,and decrease rates reached 39.85% and 37.82% in the treatments as per equivalent row and wide-narrow row.On the other hand,SPAD value of 03you 66 was the highest,followed by Zhuliangyou 09 and Zhongjiazao 17.According to correlation analysis,the decrease rategenerally higher compared with rest varieties; the value of Shanyou 10 maintained higher than that of rest varieties 5 d after full heading,but declined thereafter,with the lowest 15 d after full heading.As shown in Table12,Shanyou 10 aged faster,and Wuyou 308 slower.It is concluded that the decrease rate of SPAD value of late rice showed extremely significant negative correlation with rice yield after full heading,with a correlation coefficient of-0.750 2**.

Table13 Root bleeding of different early rice varieties under the different mode of mechanical transplanting after heading

Table14 Root bleeding of different late rice varieties under the different mode of mechanical transplanting after heading

Root bleeding sap of rice after earing by different mechanical transplanting methods

Root bleeding sap of early riceRot bleeding sap reflects rice root activity and the higher root bleeding sap,the stronger root activity.As shown in Table13,from full heading to ripening stages,root bleeding sap in the treatment as per wide-narrow row kept higher compared with the treatment as per equivalent row.Among the rice varieties,root bleeding sap with a longer growth stage was higher,such as Xinfengyou 22,Lingliangyou No.268,and Jinyou 458,but root bleeding sap of Zhongjiazao 17 was lower,which proved similar by different mechanical transplanting methods.What’s more,it showed that the accumulation of dry matter and rice yield were of extremely significant positive correlation with root bleeding sap after full heading,with correlation coefficients of 0.830 8**and 0.870 2**(milk-ripening stage),indicating that root activity in later stage is of importance for improving yield.Although root bleeding sap in the treatment as per wide-narrow row is a little higher compared with the treatment as per equivalent row,the absolute value kept higher,which incorporated that the arrangement of wide-narrow row is conductive to improving root activity in later stage.

Root bleeding sap after earing of late riceAs shown in Table14,similar to early rice,root bleeding sap of late rice performed higher in the treatment as per wide-narrow row compared with the treatment as per equivalent row.However,the decrease rate in the treatment as per equivalent row kept higher.Still,in ripening stage,the root bleeding sap maintained higher in the treatment as per wide-narrow row.Moreover,root bleeding saps among rice varieties tended to be volatile.For example,root bleeding saps of Tianyouhuazhan,Tianyou 998,and Fengyuanyou 299 were higher,but of Shanyou 10 and Wufengyou were lower.It can be concluded that root bleeding sap of late rice were of extremely significant correlation with dry matter accumulation and yield in later stage,with correlation coefficients of 0.845 7**and 0.919 8**,which indicated that root activity after earing is crucial for rice yield,and the treatment as per wide-narrow row would improve root activity in later stage.

Conclusions and Discussions

High-yielding rice is characterized by high photosynthetic efficiency,highly-qualified morphological structure,the maximal photosynthetic capacity and colony growth quality index[17].Meanwhile,rice yield is of positive correlation with growth term[18-20].The research suggested that yield formation characteristics tend to be volatile upon rice varieties by mechanical transplanting,but the yield differences by the same transplanting mode indicate that mechanical transplanting is more suitable for high-yielding variety.In the research,of early rice,Zhuliangyou No.918 was more suitable to be transplanted by machines compared with Zhongjiazao 17 with growth term of 106 d,and Zhuliangyou 09 and 03 you 66,with growth term of 115-116 d,so that the varieties can be a priority in mechanical transplanting in Jiangxi Province.As for late rice,Fengyuanyou 299 and Taifengyougan 3,with growth term of 116 d,performed significantly higher in terms of yield compared with rest varieties with growth term of 115 -116 d,which,therefore,can be taken as priorities in mechanical transplanting.Furthermore,Jinyou 458 and Xinfengyou 22 were higher in yield,but the growth term kept longer,which might affect seedling transplanting of late rice.Besides,late rice Tianyouhuazhan and Tianyou 998 were higher in yield,but the growth terms also maintained longer.It is researched that rice yield is of close relationship to duration of photosynthetic function of leaf[21]and leaf source capacity of rice can be taken an a quantitative index for identifying individual rice yield[22].The research also incorporated that Zhuliangyou 819 and Fengyuanyou 299,with high yielding,performed well in physiological traits,such as high leaf area index,photosynthetic potential,chlorophyll content and root activity,and photosynthetic potential of rice population is of significant correlation with growth center in the term.

The research has demonstrated that mechanical transplanting has varying effects on yield and physiological traits of double-cropping rice.Specifically,mechanical transplanting as per wide-narrow row improved 2-3 points of rice yield compared with mechanical transplanting as per equivalent row,which actually optimized quality and physiological trait of double-cropping rice.Considering from leaf area index,mechanical transplanting as per wide-narrow row performed not so significantly in advantages in tillering stage and the number of tillers in the treatment as per equivalent row was higher.However,after tiller differentiation stage,leaf area index,photosynthetic potential,chlorophyll content,and root bleeding sap kept higher compared with the treatment as per equivalent row,as well as the number of differentiated branch and glumous flowers.The research proved that mechanical transplanting as per wide-narrow row performs better in ventilation,light transmitting,improving farmland transmitting,optimizing eco-environment and enhancing rice quality.Because double-cropping rice is short in growth term,attention should be paid to the effects of mechanical transplanting on yield and physiological trait.In addition to that,different chains of cultivation should be highlighted in mechanical production,and the mechanical transplanting and machine should be well considered as per specific rice cultivation mode.

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