Effects of DPC application on population plant type in direct seeding cotton after wheat harvest
In order to investigate the appropriate population plant type and the DPC manage strategy of cotton directly sown after wheat harvest for lint yield above 1 500 kg/hm2,'CCRI 425'was taken as the experimental material in Yangzhou University experimental farm from 2020 to 2021.Three DPC levels,0(A1),180(A2)and 360(A3)g/hm2 were set,and two DPC application stages were designed,which were at both peak squaring and early flowering stage(the ratio of dosage was 1∶2,B1)and at peak squaring,early flowering and peak flowering stage(the ratio of dosage was 1∶2∶3,B2),respectively.DPC level of 120 g/hm2 applied at early flowering was used as CK.The plant height,main stem internodes,fruit branch internodes,fruit branch orientation value,leaf angle and nodes to branches ratio were measured,and their correlations with lint yield were analyzed.The results showed that:DPC manage strategy significantly affected the plant type,boll formation and yield of cotton directly sown after wheat harvest(P＜0.05).Compared to CK,the plant height,main stem internodes and fruit branch internodes were significantly lower those in A2B1 and A2B2,whereas fruit branch orientation value,leaf angle and nodes to branches ratio were significantly higher(P＜0.05).The lint yield of A2B,was 1 628.04 and 2 085.02 kg/hm2 in 2020 and 2021,respectively,which increased 4.9％and 14.1％compared with CK(P＜0.05).The lint yield of A2B2 in both years was 1 553.97 and 1 999.97 kg/hm2,respectively,which increased 6.4％and 11.0％compared with CK(P＜0.05).In conclusion,with DPC at 180 g/hm2 applied at both full squaring and early flowering stage or at full square,early flowering and peak flowering stage for cotton directly sown after wheat harvest,the plant height could be kept at 60.63 to 77.80 cm,the internode length of main stem was at 4.2 to 6.0 cm,the internode length of fruit node was at 3.9 to 6.3 cm,the fruit branch orientation value was at 36.4 to 40.8,the leaf angle was at 45.0 to 46.7,and the ratio of fruiting nodes and fruiting branch was at 3.1 to 3.6.It is beneficial for cotton directly sown after wheat harvest in the middle and lower reaches of the Yangtze River cotton area to achieve concentrated boll formation,to be easy for mechanical harvesting,and to obtain high yields.
direct seeded cotton after wheat harvestyieldconcentrated boll retentionplant type
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