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Tao Y.,China Agricultural University | Tao Y.,University of Gottingen | Qua H.,China Agricultural University | Lia Q.,China Agricultural University | And 10 more authors.
Field Crops Research | Year: 2014

The Ground Cover Rice Production System (GCRPS) is a promising technology for water-saving lowland rice cultivation. However, excessive vegetative growth and potential N shortages during reproductive stages might limit the grain yield potential, because all N fertilizer has to be applied before transplanting due to technical difficulties with later applications. A 10-year experiment was conducted, covering two experimental series, to evaluate the effects of controlled-release urea fertilizer and a nitrification inhibitor, as well as effects of combining organic manure and mineral nitrogen fertilizer. In the first experimental period (2003-2006), field trials included four treatments: (1) zero-N; (2) urea alone; (3) urea+nitrification inhibitor; (4) controlled-release urea. In the second period (2007-2012), the first two treatments were continued as before, and treatments 3 and 4 were replaced by either application of chicken manure alone, or a combination of urea and chicken manure. Compared to applying urea alone, controlled-release urea, or the combination of urea plus organic manure, significantly increased grain yield and nitrogen use efficiency, and enhanced the number of spikelets and the percentage of filled grains due to improved growth in the reproductive phase. Application of urea plus nitrification inhibitor did not enhance grain yield and nitrogen use efficiency because of high nitrogen uptake and biomass production in early growth stages and significantly lower N uptake at the later stages, which consequently also led to low spikelet numbers. Application of organic manure alone significantly decreased above-ground biomass production in early growth stages, and strongly reduced the number of productive tillers, indicating N shortages in the vegetative stage. Our results showed that, considering the present costs of controlled-release urea, the combination of organic manure with mineral N fertilizer is the most practical and most economical N fertilizer management for improving grain yield and nitrogen use efficiency, as well as the sustainability of water-saving GCRPS. © 2014 Elsevier B.V. All rights reserved.

Qu H.,China Agricultural University | Tao H.,China Agricultural University | Tao Y.,China Agricultural University | Liu M.,China Agricultural University | And 2 more authors.
Agronomy Journal | Year: 2012

Rice (Oryza sativa L.) production faces a worldwide challenge of severe water scarcity. The ground cover rice production system (GCRPS) is one alternative to the paddy system, using plastic-film covering and less irrigation water. As contradictory yield performances occurred throughout different regions, a general evaluation of GCRPS was seldom reported. Therefore, a 7-yr experiment was conducted in a mountainous area of the Hubei Province from 2003 to 2009. the paddy system and GCRPS were compared with 0 and 150 kg N ha-1, where crop growth, yield, plant N uptake, and soil C and N were measured to evaluate the adaptability, stability, and sustainability of GCRPS. Under GCRPS, grain yield was significantly higher than under the paddy system during the 7-yr period. Additionally, the interannual difference in grain yield under GCRPS was significantly lower than under the paddy system. Furthermore, vegetative growth of GCRPS plants was improved with a sufficient N supply, while reproductive growth was limited with N reduction, which led to low number of spikelets and filled grains. Soil organic C and total N (0-20-cm soil depth) were both significantly lower under GCRPS than paddy cultivation, while N fertilization slightly reversed organic C and N reductions. Hence, GCRPS is highly adoptable and stable in typical paddy areas where water scarcity and low temperature occur and high clay and organic matter contents prevail. Further research is needed to evaluate GCRPS in other related locations and to assess new techniques for achieving continuous soil N supply to the reproductive stage and increasing sustainability under GCRPS. Copyright © 2012 by the American Society of Agronomy.

Liu M.,China Agricultural University | Liu M.,Karlsruhe Institute of Technology | Lin S.,China Agricultural University | Dannenmann M.,Karlsruhe Institute of Technology | And 8 more authors.
Field Crops Research | Year: 2013

"Ground cover rice production system" (GCRPS) is an innovative production technique that uses significantly less water than traditional paddy cultivation (Paddy). Consequently, this system may allow for expansion of rice crops to regions with limited water availability. Earlier studies have reported contradictory grain yields and yield performances of GCRPS versus Paddy systems in experimental plots. However, the actual effects of using GCRPS on yields under real farming practices on heterogeneous environments are still unknown. In this study, we compared grain yields and yield components between GCRPS and Paddy systems by sampling paired adjacent farmer fields at 36 representative sites in the region of Shiyan, central China, which is typical for many mountainous areas across China. Furthermore, we characterized soil physico-chemical properties, soil redox potential, stable carbon isotopic composition of plant leaves, and monitored soil temperature during the growing season.Our study revealed the following findings: (1) Across all sites GCRPS significantly increased grain yield by on average 18%. Statistical analysis allowed us to classify three different groups of yield performance within the 36 paired sites: (a) group of significant increase (SI; n=22) with increases in yields on average 32%, (b) group showing no significant increase (NI; n=9), here yields increased on average 6%, and (c) sites with grain yields showing a small (-8%), but non significant decrease (ND; n=5). (2) Shoot dry biomass, number of productive tillers, spikelets per square meter and percentage of filled grains were significantly larger for GCRPS as compared to Paddy systems. (3) No significant differences in soil physical and chemical properties were found for the 0-20cm layer between GCRPS and Paddy systems. (4) Significantly higher soil temperatures observed in GCRPS during the first month after transplanting were only found in the SI sites, which showed that higher temperature during this critical period was the decisive factor for GCRPS-induced yield enhancement. (5) The average δ13C of plant leaves and soil redox potential were significantly higher in GCRPS than Paddy for the SI group only. In-detail analyses of the 5 pairs showing decreases in yields (ND) between GCRPS and Paddy systems revealed the lack of significant effects observed in some key parameters such as soil temperatures during the first month, δ13C of plant leaves and soil redox potential. These facts strongly suggested that unnecessary excess water was used, thus hampering GCRPS-induced increases in soil temperature and grain yields, and unequivocally signaling that appropriate water management by farmers is crucial for the successful implementation of GCRPS. Our study demonstrates the large potential of GCRPS to increase grain yields in regions where rice growth is both limited by low temperatures and water scarcity. © 2013 Elsevier B.V.

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