Rice dry matter and nitrogen accumulation,soil mineral N around root and N leaching,with increasing application rates of fertilizer |
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| Institution: | 1. Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing 210008, China;2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China;3. School of Environmental Science & Engineering, Sun Yat-Sen University, Guangzhou 510275, China;1. MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, PR China;2. Hubei Collaborative Innovation Center for Grain Industry, Jingzhou 434023, Hubei, PR China;1. College of Agriculture, Henan University of Science and Technology, Luoyang, Henan 471023, China;2. Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA;1. State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China;2. University of Chinese Academy of Sciences, Beijing 100049, China;3. College of Resources and Environment, Chengdu University of Information Technology, China;1. Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Co-Innovation Centre for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China;2. College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, 225009, China |
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| Abstract: | Rice morphology and N leaching, together with mineral N in the soil and soil solution around root, were determined at different growth stages in a 3-year experiment located in the Taihu Lake region, China. The results showed that the N application rates had little impact on the soil mineral N around root, but increased the dry matter and N accumulation aboveground in the high fertility soil (55.3 mg kg−1 of soil mineral N before rice season in 2008). However, no significant difference in grain yield was observed in all N treatments in these 3 years. Path analysis showed that spikelet per panicle made the greatest direct contribution (0.781) and total contribution (0.309) to grain yield compared to other yield components. And a higher panicle per m2 and dry matter accumulation resulted in yield decline later in the season due to a decline in the percentage of filled grains.No significant increases in plant N uptake, regardless of N application rates, were observed at the seedling stage, which indicated that lower N application rates could suffice during the rice early growing stages. Nitrate contents, in spite of high N rates input, in the percolation water were all below 1.0 mg L−1 throughout the rice growing season. The increased N rates showed an increment of total N leaching through the percolation water, but not significant. The cumulative total N leaching only accounted for 1.86–4.96% of N fertilizer input, which suggested the N leaching should not be considered as main pollution resources in paddy filed in summer rice season. However, the evaluation of N leaching in different stages indicated that N leaching at seedling stage was larger in dominant (averaged 39.8% of total N leaching) than other stages. For the lower absorbing ability of rice seedling and more N leaching risk, suggestions on N fertilizer reduction should be made at rice early growing stage in this region. |
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| Keywords: | Rice Morphology N leaching Soil mineral N Grain yield |
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