Continuous Application Of Nitrogen Fertilizer On Dry Matter Accumulation & Distribution And Root Growth Of Potato Plants Under Film Mulching Culture Conditions

Gansu province is one of the main potato producing areas in China,but the overall low level of potato cultivation,especially potato fertilization exists blindness, most farmers still rely on the experience is not only caused by fertilization,fertilizer waste and environmental pollution,but also seriously affected the decline in yield and quality of Ma bell tuber. Therefore,we are in a stable area of main potato production areas in Gansu Province- Dingxi City,set up different field experiment of nitrogen level,continuous nitrogen conditions of different nitrogen levels on potato Qingshu 9 dry matter accumulation and distribution,effect of yield and quality,in order to provide scientific basis for.6 nitrogen levels were reasonable the application of nitrogen fertilizer in potato:T1:0kg N/hm2,T2:75kg N/hm2,T3:150kg N/hm2,T4:225kg N/hm2,T5:300kg N/hm2,T6:375Nkg/hm2.The main results are as follows:1 Under the condition of continuous nitrogen fertilization,different nitrogen levels had a significant effect on the accumulation of dry matter in potato plants and tubers.The test results show that the continuous nitrogen for third years,the lack of nitrogen can significantly influence the dry matter accumulation of potato plants, and potato harvest,all treatments,in order to control treatment without nitrogen(T1) dry matter accumulation was the lowest,only 178.82 g.plant-1,the highest in T2 and T3 treatment,respectively. 261.19 g.plant-1 and 259.85 g.plant-1,high N rate of T5 and T6 treatment dry matter accumulation was significantly lower than that of T2 and T3. The Logisit equation was found on the whole plant dry matter accumulation were fitted after nitrogen levels on dry matter accumulation duration tired(Δt) the impact of the most obviously, the accumulation of dry matter of maximum T2 and T3 treated T were 61 d and 57 d,T2 respectively compared with the,control without nitrogen more than 18 d,the highest T6 treatment than nitrogen application increased by 8d,indicating the amount of nitrogen deficiency and excess have obvious effects on Potato The plant dry matter accumulation period lasted for a long time.Continuous nitrogen in the third year,different nitrogen levels on potato tuber dry matter accumulation and the impact tendency of plant dry matter accumulation is basically the same, in the mature period of tuber dry matter accumulation amount of sequence T2>T3>T4>T1>T5>T6. In T2 treatment highest,192.72 g.plant-1 and high nitrogen application amount of T5 and T6 treatment of dry matter accumulation was significantly lower than that of T2 only for T2 of 72.79% and 72.80%.By the equation of Logisit in tubers of potato dry matter accumulation of fit is found,the different levels of nitrogen on tuber dry matter accumulation effect of different from the whole plant dry matter accumulation effect and nitrogen application amount is not sufficient and excess is mainly affected the potato growing period,the dry matter growth rate(Vmax) and potato dry matter fast accumulation of dry matter average growth velocity(vmean), Vmax and Vmea T2 treatment respectively for 3.85 g.plant-1.d-1 3.38 g.plant-1.d-1,significantly higher than other processing,than T1 increased 40.96% and 40.96%,than the T6 increased 29.90% and 29.90%.2 Under the condition of continuous nitrogen application,the distribution of stem and dry matter of potato was significantly affected by different nitrogen levels.Timely transfer to upper although the trend of continuous nitrogen 3 years,potato dry matter balance with nitrogen level increased significantly delayed,but "price scissors" with nitrogen levels were increased in first increased and then decreased trend,indicating that the application of nitrogen fertilizer to extend the "source" of the time,but nitrogen is excessive "source" of the growth period is too long,Wang long,the impact of the carbohydrate "library" and "library" of growth and source sink relationship coordination,thereby affecting yield. Nitrogen nutrient deficiencies, "source" of the accumulation of small,growth period in advance,not as a "library" to provide material source.Especially the improvement of continuous nitrogen 3 years,potato plants and tuber dry matter accumulation with nitrogen level increased first and then decreased trend. The amount of nitrogen fertilizer for potato tubers in the rapid accumulation period of accumulation,and excessive application of nitrogen will result in potato Tanqing late,thus leading to yield decrease. At the same time,potato dry matter in various organs in the distribution ratio is also affected by nitrogen application amount, the growth period of root,stem and leaf doing material in the proportion of overall performance with nitrogen application amount increased with increase in tuber dry matter allocation proportion with nitrogen level increased and decreased. It shows that appropriate N application to potato dry matter to tuber distribution.3 The effect of different nitrogen levels on root growth of potato under the condition of continuous nitrogen fertilizationContinuous nitrogen in the third year,T2(75kg N/hm2) processing of potato root growth has significant role,especially for root length,root surface area,root volume and root number increased. Potato yield formation in the critical period,T2 treatment root vigor has always maintained the highest level,under T2 treatment of nitrogen concentration,potato root has strong ability to absorb nutrients,so as to promote the root on soil nutrients and water to fully absorb the T2 treatment,the highest yield of potato.4 Under the condition of continuous nitrogen fertilization,the yield and yield components of potato were significantly affected by different nitrogen levels.Continuous nitrogen in the third year,all processing in T2 treatment(75kg N/hm2) tuber yield highest compared with no fertilizer control treatment(T1) increased by 16%; in T2 processing tuber reached the highest yield,tuber yield of potato was decreased with the increase of the amount of nitrogen fertilizer,the maximum application nitrogen T6 treatment 375 kg N/hm2 than T2 treatment 24.12% reduction, compared with no fertilizer control reduced by 12.21%. It indicated that applying nitrogen deficiency and excess are the potato tuber yield and yield decreased.From yield composition factors analysis showed that,the successive application of nitrogen in the third year,different nitrogen amount does not affect the potato tuber number per plant,but on tuber weight have a significant impact,especially excess nitrogen can significantly reduce the tuber weight per plant,this is mainly because the nitrogen excess,plant on the part of the leggy,T5、T6 treatment shipped to underground organs of dry mass reduction,resulting in tuber weight per plant decreased,indicating that lead to excessive nitrogen the tuber weight reduction is the main reason for the yield decreased significantly.The highest nitrogen application rate of third years was T2(75kgN/hm)and the yield was reduced when the amount of nitrogen applied was too high.5 Different nitrogen levels had significant effects on the main quality of potato under the condition of continuous nitrogen application.Excess growth of 3.67 percent. But the change with the change and improvement of continuous nitrogen 3 years,with no nitrogen treatment T1 compared to nitrogen treatments significantly increased the potato tuber protein content,and the nitrogen level increased. Reducing sugar,starch and Vc content of nitrogen levels showed a single peak trend to T2 treatment was the highest,but different is,and nitrogen fertilizer treatment compared to nitrogen treatment increased the reducing sugar and Vc content and higher nitrogen application level T6 tuber starch content reduces the excess nitrogen to aboveground vegetative organs,plant part and underground part growth is not coordinated,affected the starch accumulation.