The Effect Of Urea-Formaldehyde Fertilizer Application As Well As The Edible Safety In Leafy Vegetables And Environmental Security In The Soil

Pot experiments were applied to assess the effect of slow release urea-formaldehyde fertilizers(UF) which were developed in our laboratory on leaf vegetables growth which were Malabar spinach,lettuce,Chinese cabbage, mustard. Three seasons Malabar spinach continuous cultivation were adopted to study the effects of UF nitrogen uptake and nitrogen use efficiency(NUE).The UF formaldehyde residue were study by determination of formaldehyde content in lettuce and Chinese cabbage and potted and field soil.Discussed under the no leaching condition if UF still has nitrogen supply advantage than available nitrogen.UF whether impacted on the eating of leaf vegetables and soil environmental safety. In order to provide reliable theoretical basis for the application of the UF in the filed.The main research results are as followings.1.The growth and yield of lettuce and mustard significantly increased by applied UF separately. For mustard yields,when N application levels was 150 mg/kg soil there was no difference among the the UF that AI was 49%(UF9), AI was 60%(UF10), AI was 68%(UF11) and U treatment. However UF9 was significant higher 29% than UF10 treatment.The UF9,UF10,UF11 and U treatment were respectively significant higher 115%,67%,91%,83% than CK. When the N dosage increased to 200 mg N per kilogram soil,there was no difference between the UF9 and UF10 treatment. Also, no significant difference between U and UF10 treatment. UF11 was respectively significant higher 22%and 39% than UF9 and U treatment. The UF9,UF10,UF11 and U treatment were respectively significant higher 98%,77%,116%,56% than CK treatment. For lettuce yields,when N application levels was 200 mg/kg soil the UF that AI was 55%(UF6) were respectively significant higher 75%,23%, 47%, 27% than CK, the UF that AI was63%(UF7), AI was 72%(UF8), U treatment.However there was no significant differenceamong the UF that AI was 50%(UF9), the UF that AI was 68%(UF11) and U treatment.When the N dosage increased to 300 mg N per kilogram soil there was no significant difference between UF6, UF7, UF8 and U treatment, but respectively significant higher 47% to 69% than CK. The result shows that it was similar to the urea nitrogen and UF on leaft vegetables growth on pot experiments.2.The leaf vegetables growth and yield significantly increased by UF blended with urea(1:1) and urea no teaching condition. For lettuce yields, there was no significant difference between U+UF and U treatment when N application levels was 100 or 200mg/kg soil. When the N dosage increased to 300 mg N per kilogram soil, U was significant higher than the each UF + U treatment. For Chinese cabbage yields, there was no significant difference between U+UF and U treatment whatever the N dosage from 100 to300 mg N per kilogram soi but all nitrogen treatments were significant higher 35% to 58%than the CK. The result shows that it was similar to the urea nitrogen and U+UF on leaft vegetables growth on pot experiments.3.When three seasons Malabar spinach were planted continuously on the basis of the one season leaf vegetables cultivation. For Malabar spinach yields under N application level of 150 mg/kg soil, there was significant difference between each nitrogen treatment,however there was no significant difference between U and the UF that AI was 50%(UF2),so did AI was 61%(UF1) and AI was 41%(UF3), and the former group was higher20%~35% than last group in the first season. For UF after effect, there was no significant difference between each nitrogen treatment but all higher 68%~131% than CK in the second season. In the third season, UF1 treatment was respectively significant higher16%,31%,147% than UF3, U and CK, and there was also no significant difference between UF1 and UF2.The result of three seasons Malabar spinach total output shows that there was no significant difference between UF1 and UF2 but both were significant higher than UF3,U and CK treatment, and there was no significant difference between UF3 and U. The average three season cumulative production was up to 170g/pot, howeve it was 138g/pot.In addition, consists of two seasons yields shows that the second season was 42% of the total output which was the largest contribution to the outpu and the average production of UF treatment was up to 64g/pot, however U treatment was only 51g/pot. The result showsthat the yields of UF treatment was lower than U when in the first season. However, the UF after effect were played out in the latter two season especially in the third and the average production of UF treatment was up to 59g/pot which was the 2.23 times than U treatment,When N application levels of 200 mg/kg soil was the same as 100.4.The NUE of Malabar spinach under N application level of 150 mg/kg soil shows that there was significant difference between each nitrogen treatment and U was 26.58%which was the higher 0.3~1.2 times than each UF treatment in the first season.But there was no significant difference between each nitrogen treatment in the second season.However, UF was 0.91~1.15 times higher than U in the third season. Compared with three seasons NUE shows that the NUE of the two former season of UF treatment were both higher than the first season, but U treatment was in contrast to UF and the NUE of latter two season reduced gradually.It is mainly because Malabar spinach is of shorter growing duration in the first season, however there was more slow-release nitrogen in pure UF which could supply a long period fertilizer efficiency.So that nitrogen supply was relatively small.But UF could supply more slow-release nitrogen in the second and third seasons.There was no significant difference between the three season accumulation of NUE. When N application levels of 200 mg/kg soil was the same as 100.5、Compared with urea, whether application of UF individually or mixed with U, no matter the AI of the UF from 50% to 71.8% and whatever the N dosage from 100 to 300 mg N per kilogram soil, formaldehyde content of leafy vegetables will not be influenced. A maximum formaldehyde content was 5.36 mg/kg. The formaldehyde content of leafy vegetables are in the safe range.6、Formaldehyde residues of nitrogen treatment were significant higher than that of CK in potting soil.The treatment which added formaldehyde according to the production of UF was highest than any other UF treatment, it was 190.5mg/kg soil. There was also no siginificant difference between UF and U treatment in the field of soil and the mean was only 15.78mg/kg soil which was detected content greatly reducing to 13% of the UF that AI was 68% when was applied to the potting soil.