Abstract
The development of management techniques to improve the poor N use efficiency by lowland rice (Oryza sativa L.) and reduce the high N losses has been an important focus of agronomic research. The potential of an Azolla cover in combination with urea was assessed under field conditions in Laguna, Philippines. Two on-station field experiments were established in the 1998–1999 dry season and eight on-farm experiments per season were carried out in the 2000–2001 wet and dry seasons. Treatment combinations consisting of N levels applied alone or combined with Azolla were evaluated with respect to floodwater chemistry, 15N recovery, crop growth, and grain yield. A full Azolla cover on the floodwater surface at the time of urea application prevented the rapid and large increase in floodwater pH and floodwater temperature. As a consequence, the partial pressure of ammonia (ρNH3), which is an indicator of potential NH3 volatilization, was significantly depressed. 15N recovery was higher in plots covered with Azolla where the total 15N recovery ranged between 77 and 99%, and the aboveground (grain and straw) recovery by rice ranged between 32 and 61%. The tiller count in Azolla-covered plots was significantly increased by 50% more than the uncovered plots at all urea levels. Consequently, the grain yield was likewise improved. Grain yields from the 16 on-farm trials increased by as much as 40% at lower N rates (40 and 50 kg N ha−1) and by as much as 29% at higher N rates (80 and 100 kg N ha−1). In addition, response of rice to treatments with lower N rates with an Azolla cover was comparable to that obtained with the higher N rates without a cover. Thus, using Azolla as a surface cover in combination with urea can be an alternative management practice worth considering as a means to reduce NH3 volatilization losses and improve N use efficiency.
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References
Bronson K F, Hussain F, Pasuquin E and Ladha J K 2000 Use of 15 N labelled soil in measuring nitrogen fertilizer recovery efficiency in transplanted rice. Soil Sci. Soc. Am. J. 64, 235–239.
Cai G X, Freney J R, Humpreys E, Denmead O T, Samson M and Simpson J R 1987 Use of surface films to reduce ammonia volatilization from flooded rice fields. Aust. J. Agric. Res. 39, 177–186.
Cissé M and Vlek P L G 2003a Conservation of urea-N by immobilization-remobilization in a rice-Azolla intercrop. Plant Soil 250, 95–104.
Cissé M and Vlek P L G 2003b Influence of urea on biological N 2 fixation and N transfer from Azolla intercropped with rice. Plant Soil 250, 105–112.
Craswell E T and Vlek P L G 1979 Greenhouse evaluation of nitro-gen fertilizers for rice. Soil Sci. Soc. Am. J. 43(6), 1184–1188.
Damodar Reddy D and Sharma K L 2000 Effect of amending urea fertilizer with chemical additives on ammonia volatilization loss and nitrogen use efficiency. Biol. Fertil. Soils 32, 24–27.
De Datta S K, Buresh R J, Obcemea W N and Castillo E G 1989 Nitrogen-15 balances and nitrogen fertilizer use efficiency in upland rice. Fert. Res. 26, 179–187.
Denmead O T, Freney J R and Simpson J R 1983 Dynamics of ammonia volatilization during furrow irrigation of maize. Soil Sci. Soc. Am. J. 47, 618.
Dobermann A, Witt C, Dawe D, Abdulrachman S, Gines H C, Naga-rajan R, Satawathananont S, Son T T, Tan P S, Wang G H, Chieh N V, Thoa V T K, Phung C V, Stalin P, Muthukrishnan P, Ravi V, Babu M, Chatuporn S, Sookthongsa J, Sun Q, Fu R, Simbahan G C and Adviento M A A 2002 Site-specific nutrient manage-ment for intensive rice cropping systems in Asia. Field Crops Res. 74, 37–66.
Freney J R, Trevitt A C F, de Datta S K, Obcemea W N and Real J G 1990 The interdependence of ammonia volatilization and denitrification as nitrogen loss processes in flooded rice fields in the Philippines. Biol. Fertil. Soils 9, 31–36.
Freney J R, Keerthisinghe D G, Chaiwanakupt P and Phongpan S 1993 Use of urease inhibitors to reduce ammonia loss following the application of urea to flooded rice fields. Plant Soil 155/156, 371–373.
Gravois K A and Helms R S 1992 Plant analysis of rice yield and yield components as affected by seeding rate. Agron. J. 84, 1–4. IRRISTAT (version 3.1) Available Distributor: IRRI, Philippines.
Jayaweera G R and Mikkelsen D S 1990 Ammonia volatilization from flooded soil systems: A computer model. I. Theoretical aspects. Soil Sci. Soc. Am. J. 54, 1447–1455.
Keeney D R and Sahrawat K L 1986 Nitrogen transformations in flooded rice soils. Fert. Res. 9, 15–38.
Keepers A J and Zweers A 1986 Ammonium determination in soil extracts by salicylate method. Commun. Soil Sci. Plant Anal. 17(7), 715–723.
Kröck T, Alkamper J and Watanabe I 1988a Effect of an Azolla cover on the conditions in floodwater. J. Agron. Crop Sci. 161, 185–189.
Mae T and Shoji S 1984 Studies on the fate of fertilizer nitro-gen in rice plants and paddy soils by using 15 N as a tracer in northeastern Japan. Soil Sci. Plant Nutr. (special issue), 77–94.
Oliveros R, Ramirez C M and Watanabe I 1983 Dual culture of rice and Azolla. IRRI Sat. Sem. Los Banos, Philippines.
Parot V P 1991 Growth and nitrogen accumulation of four Azolla genotypes at different stages of rice canopy development and their efficiency as organic fertilizer. MS thesis. University of the Philippines Los Banos, Philippines.
Peoples M B, Freney J R and Mosier A R 1995 Minimizing gaseous losses of nitrogen. In Nitrogen Fertilization in the Environment. Ed. P E Bacon. pp. 565–590. Woodlots and Wetlands Pty. Ltd., Sydney.
Rao D L N 1987 Slow-release urea fertilizers-effect on floodwater chemistry, ammonia volatilization and rice growth in an alkali soil. Fert. Res. 13, 209–221.
Reddy K R, D'Angelo E, Lindau C and Patrick Jr W H 1990 Urea losses in flooded with established oxidized and reduced soil layers. Biol. Fertil. Soils 9, 283–287.
Roger P A and Ladha J K 1992 Biological N 2 fixation in wetland rice fields: Estimation and contribution to nitrogen balance. Plant Soil 141, 41–55.
Saito M and Watanabe I 1978 Organic matter production in rice field floodwater. Soil Sci. Plant Nutr. 24, 427–440.
Simpson J R, Freney J R, Wetselaar R, Muirhead W A, Leuning R and Denmead O T 1984 Transformations and losses of urea nitrogen after application to flooded rice. Aust. J. Agric. Res. 35, 189–200.
Simpson J R, Muirhead W A, Bowmer K H, Cai G X and Freney J R 1988 Control of gaseous nitrogen losses from urea applied to flooded rice soils. Fert. Res. 18, 31–47.
Simpson I C, Roger P A, Oficial R and Grant I F 1994 Effects of nitrogen fertilizer and pesticide management on floodwater eco-logy in a wetland ricefield. II. Dynamics of microcrustaceans and dipteran larvae. Biol. Fertil. Soils 17, 138–146.
Singh A L and Singh P K 1987 Comparative study of Azolla and blue-green algae dual culture with rice. Is. J. Bot. 36, 53–61.
Singh D P and Singh P K 1988 Influence of rice canopy on growth and nitrogen fixation of the water fern Azolla pinnata. Proc. Indian Acad. Sci. (Plant Sci.) 98(3), 209–214.
Soil and plant sampling and measurements 1994. IRRI, Philippines.
Thind H S and Rowell D L 1997 Effect of green manure and flood-water algae on diurnal fluctuations of floodwater pH and depth of aerobic soil layer under lowland rice conditions. Plant Soil 192, 161–165.
Villegas G G and San Valentin G O 1989 Effect of Azolla cover on nitrogen and rice in flooded Maahas clay. In Azolla: Its Culture, Management and Utilization in the Philippines. pp. 65–89. Na-tional Azolla Action Program, University of the Philippines Los Banos, Philippines.
Vlek P L G and Byrnes B H 1986 The efficacy and loss of fertilizer N in lowland rice. Fert. Res. 9, 131–147.
Vlek P L G and Craswell E T 1981 Ammonia volatilization from flooded soils. Fert. Res. 2, 227–245.
Vlek P L G and Fillery I R P 1984 Improving nitrogen efficiency in wetland rice soils. In Proceedings of the fertilizer society No. 230. December 13, 1984. London. pp. 3–28. Greenhill House, London.
Vlek P L G, Fugger W and Biker U 1992 The fate of fertilizer N under Azolla in wetland rice. In Proceedings of the 2nd ESA Congress. August 1992. Warwick University, UK.
Vlek P L G, Diakite M Y and Mueller H 1995 The role of Azolla in curbing ammonia volatilization from flooded rice systems. Fert. Res. 42, 165–174.
Vlek P L G, Eberhardt U and Aung M 2002 The role of Azolla in lowering the pH of simulated floodwater. J. Appl. Bot. 76, 1–7.
Watanabe I 1982 Azolla-Anabaena symbiosis-Its physiology and use in tropical agriculture. In Microbiology of Tropical Soil and Plant Productivity. Eds. Dommergues Y R andDiem H G. Martinus Nijhoff/Dr W Junk Publishers, The Hague.
Xing G X and Zhu Z L 2000 An assessment of N loss from agricul-tural fields to the environment in China. Nutr. Cycl. Agroecosyst. 57, 67–73.
Yanni Y G 1992 The effect of cyanobacteria and Azolla on the performance of rice under different levels of fertilizer nitrogen. World J. Microbiol. Biotechnol. 8, 132–136.
Zapata F 1990 Isotope techniques in soil fertility and plant relationships training course series No 2. Ed. G. Hardenson. International Atomic Energy Agency, Vienna.
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de Macale, M.A.R., Vlek, P.L. The role of Azolla cover in improving the nitrogen use efficiency of lowland rice. Plant and Soil 263, 311–321 (2004). https://doi.org/10.1023/B:PLSO.0000047742.67467.50
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DOI: https://doi.org/10.1023/B:PLSO.0000047742.67467.50