Studies On Canopy Structure Characteristics Of High-Yield Cotton And Fertlizer Nitrogen Regulation Under-Mulch-Drip Irrigation

The experiment been proceed 2003-2006 at 125 group No.7 agriculture division of Sinkiang producion and construction corps and Sinkiang Academy of agricultural and Reclamation Science Agricultural Techniques Extension Center experimental field,large field test combined with plot test in this experiment,New Large-scale popularizer precocious varieties of Xinluzao 10 and Xinluzao 12 in the north of Sinkiang selected as the experimental materials,the experiment based on canopy structure characteristics of high yield cotton drip-irrigated under the mulch in Sinkiang,and probe deeply into the regulation of nitrogen application modes on canopy structure and translocation and partitoning of photosynthates in cotton drip-irrigated under the mulch,Mostly findings as follows:1.Canopy structure characteristics of high yield cotton drip-irrigated under the mulchThe cotton canopy structure of lint cotton yield 2550 kg·hm^-2 varies by varieties.Max leaf area index(LAI) of Xinluzao 10 was 3.98 in full-boll stage,that retained was 3.25 in boll opening stage;The mean foliage inclination angle(MFIA) of Xinluzao 10 averages 41.66°during whole growing stage,Min transmission coefficient for radiation penetration(TRP) and min transmission coefficient for diffuse penetration(TDP) of Xinluzao 10 was 0.125 and 0.141 respectively in full-boll stage,TRP and TDP Slightly rised that over 0.153 and 0.172 in boll opening stage.Max LAI of Xinluzao 12 was 4.26 in full-boll stage,that retained 3.43 in boll opening stage;MFIA of Xinluzao 12 averages 51.24°during whole growing stage,Min TRP and min TDP of Xinluzao 12 was 0.115 and 0.112 respectively in full-boll stage,that over 0.168 and 0.186 in boll opening stage.Compare the cotton canopy structure of lint cotton yield over 2550 kg·hm^-2 with the cotton canopy structure of lint cotton yield 2000 kg·hm(-2) and 1500 kg·hm^-2,LAI of the smaller-leafed compact plant type varieties was 3.92-4.04 in full-boll stage,that retained 3.11-3.39 from full flowering and boll-setting stage to boll opening stage;MFIA averages 40.76-42.56°during whole growing stage,TRP and TDP was 0.120-0.130 and 0.129-0.153 respectively in full-boll stage,TRP and TDP Slightly rised that was 0.156-0.180 and 0.175-0.197 in boll opening stage.LAI of the large-leaved loose plant type varieties was 4.14-4.38 in full-boll stage,that retained 3.32-3.54 from full flowering and boll-setting stage to boll opening stage;MFIA averages 49.17-53.31°during whole growing stage,TRP and TDP was 0.113-0.117 and 0.139-0.171 respectively in full-boll stage,TRP and TDP Slightly rised that was 0.135-0.171 and 0.169-0.237 in boll opening stage.Accordingly,in order to achieve cotton output of high-yield and more high-yield in production,to prompt the rise of LAI steadily in the early growth period,the adoption of reasonable field management,well-shaped plant type,to improve interception photosynthetically active radiation of canopy in early growth period;LAI attained peak value in full-boll stage,a high level of LAI be retained in boll opening stage in order to improve the final output.2.Regulation of nitrogen application modes on canopy structure and translocation and partitoning of photosynthates in cotton drip-irrigated under the mulch.Studies on different nitrogen application modes effect on canopy structure in cotton drip-irrigated under the mulch show that LAI and MFIA was high-nitrogen in the early growth period＞equilibria nitrogen＞high-nitrogen in the late growing period respectively;TRP and TDP at high-nitrogen in the late growing periodshow that light damage at narrow-row in the early growth period and wide-row in the late growing period more than high-nitrogen in the early growth period and equilibria nitrogen.Cotton on high-nitrogen in the early growth period,so cotton plant well-developed and environment hige-adapted that leaf senescence and photosynthetic capacity decay were reduced;LAI was higher,MFIA was larger,light damage was lower,canopy structure in cotton was reasonable;but nitrogen in the late growing period,nutrient shortage of supply and all the indicator were reduced,that influence the well-canopy structural durative.Photosynthetic rate of cotton leaf in different regulation of nitrogen application modes show that high-nitrogen in the early growth period＞equilibria nitrogen＞high-nitrogen in the late growing period ahead of full-boll stage;high-nitrogen in the late growing period＞equilibria nitrogen＞high-nitrogen in the early growth period after full-boll stage,the individual photosynthate cumulant from full-bud stage to boll opening stage show that high-nitrogen in the early growth period＞equilibria nitrogen＞high-nitrogen in the late growing period;because nitrogen in the late growing period,the ¹⁴C ratio of distribution to boll has increased,the ¹⁴C ratio of distribution to stems and leaves has dropped,the ¹⁴C ratio of distribution to the function leaves of cotton and stems also increased,that indicate nitrogen in the late growing period to accelerate the export of assimilation substance,and increased the ratio of distribution to the reproductive organs;lint cotton yield in high-nitrogen during the early growth period with the highest weight,followed by the equilibria nitrogen,after the high-nitrogen in the late growing period.