Ammonia Volatilization Of Different Compatible Compound Fertilizers Under Facility Environment And Its Effect On Rape Growth

Nitrogen is an important factor in plant growth and yield formation.The application of nitrogen fertilizer can improve soil fertility.However,nitrogen in the soil will also be lost due to the physical,chemical or biological effects.One route of the losses is the ammonia evaporation.NH₃volatilization can also cause ammonia damage to plants.It can lead to the plants’fumigation.The volatilization of ammonia is particularly serious in the closed environment similar to the greenhouse,which also attracts people’s attention.Most researchers study the phenomenon when carrying out field fertilization operations.In this paper,the effects of different fertilizers on ammonia volatilization were studied under the simulated environment of facility cultivation.The inhibition effect of fertilizers prepared with different additives on soil ammonia volatilization was explored.On the basis of the experiment,the slow nitrogen compound fertilizers were prepared and its ammonia control effect were tested.Combined with the growth of rapeseed seedlings under ammonia volatilization and fumigation,the ammonia control effects were verified.The conclusions are as follows:1.The effect of the different compound fertilizers on ammonia volatilization（1）The ammonia volatilization of the compound fertilizers with different p H is different.The higher the alkalinity of fertilizer is,the greater the ammonia volatilization is.Reducing the acidity of the fertilizer could slow down the volatilization speed and delay the peak of ammonia volatilization.The total ammonia volatilization of the fertilizer with p H value of5.92 was 3.27 mmol more than that of the fertilizer with p H value of 2.61.（2）When compared the fertilizers powered by different forms of nitrogen,the amount of volatilization of fertilizers within ammonium nitrogen and nitrate nitrogen is the least,followed by the treatments of ammonium nitrogen and amidonitrogen and the treatments of amidonitrogen.What’s more,the ammonia volatilization is positively related to the content of nitrogen.And the fertilizers powered by low nitrogen content could slow down the ammonia volatilization under the same condition.It also could delay the ammonia volatilization peak.（3）When compared the fertilizers powered by different processes,urea formaldehyde fertilizers have the best inhibitory effects on ammonia volatilization.When using the urease inhibitor（UI）,the ammonia volatilization had the double peak trend.When using the urea sulfate（US）,the fertilizers inhibited it in the early stage.However,the inhibition weared off very quickly.And it reached the peak in about 12 days.The total amount of ammonia volatilization of formaldehyde fertilizers（UF）was 92.50%of that of urea sulfate compound fertilizers（US）and 70.11%of that of the stable fertilizers（UI）.2.Changes of ammonia volatilization in the compound fertilizers with different additivesWhen powered by biochemical potassium fulvate,the total amount of the volatilization of the compound fertilizers is the least.The results showed that there is no significant diff-erence in the ammonia release rate of the compound fertilizers powered with 10%humate,biochemical fulvic acid and mineral fulvic acid in about 12 days,and the ammonia release rate of them was relatively flat.The total amount of ammonia released by biochemical fulvic acid compound fertilizers was the lowest,which is about 5.304 mmol,the fulvate acid 8.403mmol,and the humic acid raw powder 8.739 mmol.When the addition increased from 10%to 20%,the inhibition effect of ammonia volatilization is not as good as it thoughts.The addition is positively relative to the soil addition amount.However,when nitrohumic acid was added,the results were reversed.The inhibition effect of 20%nitrohumic acid was lower than that of 10%.The ammonia release of potassium humate,biochemical fulvic acid and mineral fulvic acid fertilizers is gentle,and the total release amount is low.3.Appearance and physiological changes of rape seedlings exposed to NH₃The whole experiment shows that ammonia volatilization could inhibit the growth of rape,and rape gradually died with the increase of time.The higher the ammonia volatilization,the more serious the ammonia damage of basic fertilizers,amide nitrogen fertilizers,high nitrogen fertilizers（18%N,25%N）and stable fertilizers（UI）,the higher the soluble sugar content,the higher the MDA content and the lower the root activity.Appropriate control of ammonium nitrogen and nitrate nitrogen,or increase of urea formaldehyde fertilizers can be considered.4.Ammonia volatilization of different slow nitrogen compound fertilizers and its effect on rape growthBased on the above tests,the slow nitrogen compound fertilizers with different compatibility were prepared.The ammonia volatilization test showed that over 60%of the slow nitrogen compound fertilizers released ammonia at a gentle rate in the test cycle without any peak of ammonia volatilization.The addition of slow release nitrogen fertilizers such as urea and formaldehyde could play a corresponding inhibiting effect on ammonia volatilization.Under the experimental conditions,after 5 days fumigation with NH₃,the slow nitrogen compound fertilizer with 60%or less content appeared ammonia damage symptoms,but the ending showed that the growth rate of 80%and 100%is good.It is also confirmed that the slow nitrogen compound fertilizer with more than 60%content could effectively control ammonia volatilization and ammonia damage phenomenon.