To optimize the spatial distribution of cotton bolls and to increase the yield,the relationship between yield components and boll spatial distribution was investigated among different Bt(Bacillus thuringensis)cotton v...To optimize the spatial distribution of cotton bolls and to increase the yield,the relationship between yield components and boll spatial distribution was investigated among different Bt(Bacillus thuringensis)cotton varieties.A five-year field experiment was conducted to reveal the reasons for the differences in lint yield and fiber quality across three Bt cotton varieties with different yield formations from 2013 to 2017.The lint yield of Jiman 169(the average yield from 2013-2017 was 42.2 g/plant)was the highest,i.e.,16.3 and 36.9%higher than Lumianyan 21(L21)and Daizimian 99B(99B),respectively.And the differences in boll weight among the three cultivars were similar to the lint yield,while the others yield components were not.So the increase in lint yield was mainly attributed to the enlargement in boll weight.However,the change in fiber quality was inconsistent with the lint yield,and the quality of L21 was significantly better than that of Jimian 169(J169)and 99B,which was caused by the diversity of boll spatial distribution.Compared with 99B,the loose-type J169 had the highest number of large bolls in inner positions;the tight-type L21 had a few large bolls and the highest number of lower and middle bolls.And approximately 80.72%of the lint yield was concentrated on the inner nodes in Jiman 169,compared with 77.44%of L21 and 66.73%of 99B during the five-year experiment.Although lint yield was significantly affected by the interannual changes,the lint yield of J169 was the highest and the most stable,as well as its yield components.These observations demonstrated the increase in lint yield was due to the increase in boll weight,and the large bolls and high fiber quality were attributed to the optimal distribution of bolls within the canopies.展开更多
Increasing nitrogen(N)rate could accelerate the decomposition of crop residues,and then improve crop yield by increasing N availability of soil and N uptake of crops.However,it is not clear whether N rate and plant de...Increasing nitrogen(N)rate could accelerate the decomposition of crop residues,and then improve crop yield by increasing N availability of soil and N uptake of crops.However,it is not clear whether N rate and plant density should be modified after a long period of cotton stubble return with high N rate.This study seeks to assess the effects of N rate and plant density on cotton yield,N use efficiency,leaf senescence,soil inorganic N,and apparent N balance in cotton stubble return fields in Liaocheng,China,in 2016 and 2017.Three plant densities 5.25(D_(5.25)),6.75(D_(6.75))and 8.25(D_(8.25))plants m^(-2) and five N rates 0(N_(0)),105(N_(105)),210(N_(210)),315(N315),and 420(N420)kg ha^(-1) were investigated.Compared to the combination used by local farmers(D_(5.25)N_(315)),a 33.3%N reduction and a 28.6%increase in plant density(D_(6.75)N_(210))can maintain high cotton yield,while a 66.7%N reduction at 6.75 plants m^(-2)(D_(6.75)N_(105))can only achieve high yield in the first year.Biological yield increased with the increase of N rate and plant density,and the highest yield was obtained under 420 kg N ha^(-1) at 8.25 plants m^(-2)(D_(8.25)N_(420))across the two years under investigation.Compared to D5.25N315,N agronomic efficiency(NAE)and N recovery efficiency(NRE)in D_(6.75)N_(210) increased by 30.2 and 54.1%,respectively,and NAE and NRE in D6.75N105 increased by 104.8 and 88.1%,respectively.Soil inorganic N decreased sharply under 105 kg N ha^(-1),but no change was found under 210 kg N ha^(-1) at 6.75 plants m^(-2).N deficit occurred under 105 kg N ha^(-1),but it did not occurr under 210 kg N ha^(-1) at 6.75 plants m^(-2).Net photosynthetic rate and N concentration of leaves under N rate ranging from 210 to 420 kg ha^(-1) were higher than those under N rate of 0 or 105 kg N ha^(-1) at all three densities.The findings suggest that D6.75N210 is a superior combination in cotton stubble retaining fields in the Yellow River Valley and other areas with similar ecologies.展开更多
基金supported by the National Natural Science Foundation of China (31601253)the Modern Agroindustry Technology Research System, China (SDAIT-03)the Natural Science Foundation of Shandong Province, China (ZR2016CQ20)
文摘To optimize the spatial distribution of cotton bolls and to increase the yield,the relationship between yield components and boll spatial distribution was investigated among different Bt(Bacillus thuringensis)cotton varieties.A five-year field experiment was conducted to reveal the reasons for the differences in lint yield and fiber quality across three Bt cotton varieties with different yield formations from 2013 to 2017.The lint yield of Jiman 169(the average yield from 2013-2017 was 42.2 g/plant)was the highest,i.e.,16.3 and 36.9%higher than Lumianyan 21(L21)and Daizimian 99B(99B),respectively.And the differences in boll weight among the three cultivars were similar to the lint yield,while the others yield components were not.So the increase in lint yield was mainly attributed to the enlargement in boll weight.However,the change in fiber quality was inconsistent with the lint yield,and the quality of L21 was significantly better than that of Jimian 169(J169)and 99B,which was caused by the diversity of boll spatial distribution.Compared with 99B,the loose-type J169 had the highest number of large bolls in inner positions;the tight-type L21 had a few large bolls and the highest number of lower and middle bolls.And approximately 80.72%of the lint yield was concentrated on the inner nodes in Jiman 169,compared with 77.44%of L21 and 66.73%of 99B during the five-year experiment.Although lint yield was significantly affected by the interannual changes,the lint yield of J169 was the highest and the most stable,as well as its yield components.These observations demonstrated the increase in lint yield was due to the increase in boll weight,and the large bolls and high fiber quality were attributed to the optimal distribution of bolls within the canopies.
基金The study was supported by the National Natural Science Foundation of China(31601253)the Natural Science Foundation of Shandong Province,China(ZR2016CQ20)+1 种基金the China Postdoctoral Science Foundation(2017M610438)the Modern Agro-industry Technology Research System of Shandong Province,China(SDAIT-03-03/05).
文摘Increasing nitrogen(N)rate could accelerate the decomposition of crop residues,and then improve crop yield by increasing N availability of soil and N uptake of crops.However,it is not clear whether N rate and plant density should be modified after a long period of cotton stubble return with high N rate.This study seeks to assess the effects of N rate and plant density on cotton yield,N use efficiency,leaf senescence,soil inorganic N,and apparent N balance in cotton stubble return fields in Liaocheng,China,in 2016 and 2017.Three plant densities 5.25(D_(5.25)),6.75(D_(6.75))and 8.25(D_(8.25))plants m^(-2) and five N rates 0(N_(0)),105(N_(105)),210(N_(210)),315(N315),and 420(N420)kg ha^(-1) were investigated.Compared to the combination used by local farmers(D_(5.25)N_(315)),a 33.3%N reduction and a 28.6%increase in plant density(D_(6.75)N_(210))can maintain high cotton yield,while a 66.7%N reduction at 6.75 plants m^(-2)(D_(6.75)N_(105))can only achieve high yield in the first year.Biological yield increased with the increase of N rate and plant density,and the highest yield was obtained under 420 kg N ha^(-1) at 8.25 plants m^(-2)(D_(8.25)N_(420))across the two years under investigation.Compared to D5.25N315,N agronomic efficiency(NAE)and N recovery efficiency(NRE)in D_(6.75)N_(210) increased by 30.2 and 54.1%,respectively,and NAE and NRE in D6.75N105 increased by 104.8 and 88.1%,respectively.Soil inorganic N decreased sharply under 105 kg N ha^(-1),but no change was found under 210 kg N ha^(-1) at 6.75 plants m^(-2).N deficit occurred under 105 kg N ha^(-1),but it did not occurr under 210 kg N ha^(-1) at 6.75 plants m^(-2).Net photosynthetic rate and N concentration of leaves under N rate ranging from 210 to 420 kg ha^(-1) were higher than those under N rate of 0 or 105 kg N ha^(-1) at all three densities.The findings suggest that D6.75N210 is a superior combination in cotton stubble retaining fields in the Yellow River Valley and other areas with similar ecologies.
