| Drip irrigation under mulch film is an important measure of water-saving irrigation technology.With the change of climate,water resources are in short supply,which has restricted the development of cotton industry.Non-sufficient drip irrigation is put forward aiming at the shortage of water resources and the low efficiency of water use.The condition of drip irrigation under mulch film,it is important to study the sustainable development of cotton industry,which makes it possible to grow normally and yield no significant difference.“Xin Lu-zhong 54”as the experimental material,using a split plot experiment design,the main area for total irrigation is 2800 m~3/hm~2(non-sufficient drip irrigation)and 3800 m~3/hm~2(conventional drip irrigation),deputy area 4(pure N)levels of nitrogen,N0(0 kg/hm~2),N1(150 kg/hm~2),N2(300 kg/hm~2),N3(450 kg/hm~2)respectively.Through field plot experiment,research on compensation effect of nitrogen fertilizer on cotton growth and development,canopy structure,photosynthetic characteristics,accumulation and distribution of dry matter and nitrogen,water and nitrogen use efficiency and yield non-sufficient drip irrigation in drip irrigation under mulch film.The conclusions were as follows:1.Under the same nitrogen fertilizer treatment,non-sufficient drip irrigation treatment compared with conventional drip irrigation treatment,the growth stage was advanced;the plant height,the effective fruit branch number,the buds number,the bolls per plant,the boll weight and seed cotton yield were lower;but the fall four leaf width,the stem diameter and seed cotton yield increase rate were higher.With the increase of nitrogen fertilizer amount,the plant height were show N3>N2>N1>N0;the fall four leaf width,the stem diameter,the effective fruit branch number,the buds number,the bolls per plant,the boll weight,the seed cotton yield and seed cotton yield increase rate were show N2>N3>N1>N0.The compensation effect of increasing nitrogen fertilizer with the increase of nitrogen fertilizer amount was first increase and then decrease(in addition to cotton plant height),the compensation effect of N2 treatment was the most significant,compared with conventional drip irrigation treatment N2,the compensation effect mainly showed that the fall four leaf width,the stem diameter and buds number increased 2.91%and 3.73%and8.94%,the bolls per plant,the boll weight and seed cotton yield increase rate raised 6.82%and 15.67%and8.87%.2.Under the same nitrogen fertilizer treatment,non-sufficient drip irrigation treatment compared with conventional drip irrigation treatment,the cotton max LAI,the total fruit knots,the total boll number,the sink capacity load of unit leaf area(fruit knots,boll number and reproductive organ dry weight),the chlorophyll conten(a,b and a+b)and net photosynthetic rate were lower;but the cotton MTA were higher.With the increase of nitrogen fertilizer amount,the cotton max LAI were show N3>N2>N1>N0;the total fruit knots,the total boll number,the sink capacity load of unit leaf area(fruit knots,boll number and reproductive organ dry weight),the chlorophyll conten(a,b and a+b),the net photosynthetic rate and cotton DIFN were show N2>N3>N1>N0;the cotton MTA were show N0>N1>N2>N3.The compensation effect of increasing nitrogen fertilizer with the increase of nitrogen fertilizer amount was first increase and then decrease(in addition to cotton max LAI,the DIFN and MTA),the compensation effect of N2 treatment was the most significant,compared with conventional drip irrigation treatment N2,the compensation effect mainly showed that the sink capacity load of unit leaf area(reproductive organ dry weight)increased 6.58%,the chlorophyll conten(a,b and a+b)raised 30.92%and 18.24%and 3.58%;the net photosynthetic rate(Pn)increased 8.47%.3.Under the same nitrogen fertilizer treatment,non-sufficient drip irrigation treatment compared with conventional drip irrigation treatment,the maximum accumulation rate of dry matter and nitrogen occurrence time and duration and break point time were quicker;the dry matter and nitrogen maximum accumulation amount and accumulation rate,the dry matter and nitrogen to the reproductive organs allocation ratio and transfer efficiency of nitrogen to reproductive organs were lower;but the nitrogen agronomic use efficiency,the water and nitrogen use efficiency were higher.With the increase of nitrogen fertilizer amount,the maximum accumulation rate of dry matter and nitrogen occurrence time and duration and break point time were show N3>N2>N1>N0;the dry matter and nitrogen maximum accumulation amount and accumulation rate,the maximum growth characteristic value,the dry matter and nitrogen to the reproductive organ allocation ratio,the transfer efficiency of nitrogen to reproductive organs and water use efficiency were show N2>N3>N1>N0;the nitrogen agronomic use efficiency and nitrogen use efficiency were show N2>N3>N1.The compensation effect of increasing nitrogen fertilizer with the increase of nitrogen fertilizer amount was first increase and then decrease,the compensation effect of N2treatment was the most significant,compared with conventional drip irrigation treatment N2,the compensation effect mainly showed that the maximum accumulation rate of dry matter and nitrogen increased 0.88%and 3.12%,the dry matter to the reproductive organ allocation ratio and the transfer efficiency of nitrogen to reproductive organs raised 2.46%and 5.06%,water and nitrogen use efficiency enhanced 10.56%and 27.32%.To sum up,the non-sufficient drip irrigation and nitrogen application of 300 kg/hm~2 cotton can be normal growth and development,the photosynthetic performance was stronger,the canopy structure was reasonable,the accumulation amount of dry matter and nitrogen were suitable,the dry matter and nitrogen to the reproductive organ allocation ratio and the transfer efficiency of nitrogen to reproductive organs were higher,the water and nitrogen use efficiency were highest,has the largest yield compensation effect,and saving water 26.32%in the natural ecological conditions of the south of Xinjiang. |
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