Pedosphere 13(4): 309--316, 2003
ISSN 1002-0160/CN 32-1315/P
©2003 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effects of N forms and rates on vegetable growth and nitrate accumulation |
WANG Zhao-Hui1 and LI Sheng-Xiu |
| College of Resources and Environmental Sciences, Northwestern Science and Technology University of Agriculture and Forestry, Yangling 712100 (China). E-mail: w-zhaohui@263.net |
| ABSTRACT |
| Experiments were carried out on a vegetable field with Peking cabbage (Brassica pekinensis (Lour.) Rupr.), cabbage (Brassica chinensis var. oleifera Makino and nemoto), green cabbage (Brassica chinensis L.), spinach (Spinacia oleracea L.) and rape (Brassica campestris L.) to study the effects of N forms and N rates on their growth and nitrate accumulation. The results indicated that application of ammonium chloride, ammonium nitrate, sodium nitrate and urea significantly increased the yields and nitrate concentrations of Peking cabbage and spinach. Although no significant difference was found in the yields after application of the 4 N forms, nitrate N increased nitrate accumulation in vegetables much more than ammonium N. The vegetable yields were not increased continuously with N rate increase, and oversupply of N reduced the plant growth, leading to a yield decline. This trend was also true for nitrate concentrations in some vegetables and at some sampling times. However, as a whole, the nitrate concentrations in vegetables were positively correlated with N rates. Thus, addition of N fertilizer to soil was the major cause for increases in nitrate concentrations in vegetables. Nitrate concentrations were much higher in roots, stems and petioles than in blades at any N rate. |
| Key Words: N form, N rate, nitrate accumulation, vegetable yield |
| Citation: Wang, Z. H. and Li, S. X. 2003. Effects of N forms and rates on vegetable growth and nitrate accumulation. Pedosphere. 13(4): 309-316. |
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