| Effects of elevated atmospheric CO2 and nitrogen fertilization on nitrogen distribution of “cotton-soil” in cotton field under drip irrigation |
|
View Fulltext View/Add Comment Download reader |
| |
| DOI：10.7606/j.issn.1000-7601.2014.06.016 |
| Key Words: elevated CO2 nitrogen fertilizer application cotton field with drip irrigation “cotton-soil” system N distribution |
|
| Hits: 1288 |
| Download times: 933 |
| Abstract: |
| Semi-open-top artificial climate chamber is designed to study the effects of elevated CO2 concentration (360, 540 μmol·mol-1 and 720 μmol·mol-1) and different nitrogen fertilizer application (0, 150, 300 kg·hm-2 and 450 kg·hm-2) on nitrogen distribution of bud stage “cotton-soil” system. The results showed that, when CO2 concentration elevated to 540 μmol·mol-1, the total N content of cotton leaves and buds decreased significantly under high nitrogen levels (300, 450 kg·hm-2), but the total N content of cotton stems and roots increased slightly at different nitrogen levels, the whole cotton N content decreased and the decline proportion of elevated CO2 (540 μmol·mol-1) treatment was greater than the elevated CO2 (720 μmol·mol-1). Under the same CO2 concentration, the total N content of cotton plant had an increasing tendency accompanied by increase of nitrogen application rate, and nitrogen accumulation in cotton buds and leaves was more than that in cotton stems and roots. This showed that elevated CO2 concentration interacted with nitrogen fertilizer application to promote underground nitrogen nutrients transporting to cotton leaves and buds. The determination of soil NH4+-N and NO3--N of cotton field found that the effects was significant with elevated CO2 concentration on soil nitrogen content (P＜0.05). Compared with the ambient CO2, when CO2 concentration elevated to 540 μmol·mol-1, cotton field soil NO3--N content decreased significantly at different nitrogen levels, but soil NH4+-N content increased slightly under low nitrogen levels (0, 150 kg·hm-2) and decreased under high nitrogen levels (300, 450 kg·hm-2); when CO2 concentration elevated to 720 μmol·mol-1, the soil NO3--N content still decreased but the decline proportion was lower than elevated CO2(540 μmol·mol-1), and soil NH4+-N content tended to increase. This study concluded that when CO2 concentration elevated to 500～700 μmol·mol-1, increasing nitrogen fertilizer application level (300 kg·hm-2) on cotton field could significantly promote cotton absorbing N especially NO3--N nutrient. |
|
|
|