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Evaluation of Biofertilizers in Irrigated Rice: Effects on Grain Yield at Different Fertilizer Rates
International Rice Research Institute, Los Baños, Laguna 4030, Philippines
Crop Science Cluster, College of Agriculture (CA), University of the Philippines at Los Baños (UPLB), Laguna 4031, Philippines
Agricultural Systems Cluster, College of Agriculture (CA), University of the Philippines at Los Baños (UPLB), Laguna 4031, Philippines
* Author to whom correspondence should be addressed.
Received: 22 December 2011; in revised form: 23 February 2012 / Accepted: 28 February 2012 / Published: 14 March 2012
Abstract: Biofertilizers are becoming increasingly popular in many countries and for many crops, but very few studies on their effect on grain yield have been conducted in rice. Therefore, we evaluated three different biofertilizers (based on Azospirillum, Trichoderma, or unidentified rhizobacteria) in the Philippines during four cropping seasons between 2009 and 2011, using four different fertilizer rates (100% of the recommended rate [RR], 50% RR, 25% RR, and no fertilizer as Control). The experiments were conducted under fully irrigated conditions in a typical lowland rice environment. Significant yield increases due to biofertilizer use were observed in all experimental seasons with the exception of the 2008/09 DS. However, the effect on rice grain yield varied between biofertilizers, seasons, and fertilizer treatments. In relative terms, the seasonal yield increase across fertilizer treatments was between 5% and 18% for the best biofertilizer (Azospirillum-based), but went up to 24% in individual treatments. Absolute grain yield increases due to biofertilizer were usually below 0.5 t·ha−1, corresponding to an estimated additional N uptake of less than 7.5 kg N ha−1. The biofertilizer effect on yield did not significantly interact with the inorganic fertilizer rate used but the best effects on grain yield were achieved at low to medium fertilizer rates. Nevertheless, positive effects of the biofertilizers even occurred at grain yields up to 5 t·ha−1. However, the trends in our results seem to indicate that biofertilizers might be most helpful in rainfed environments with limited inorganic fertilizer input. However, for use in these target environments, biofertilizers need to be evaluated under conditions with abiotic stresses typical of such systems such as drought, soil acidity, or low soil fertility.
Keywords: Azospirillum; biofertilizer; grain yield; inorganic fertilizer; PGPR; plant growth-promoting rhizobacteria; rice; Trichoderma
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MDPI and ACS Style
Banayo, N.P.M.; Cruz, P.C.S.; Aguilar, E.A.; Badayos, R.B.; Haefele, S.M. Evaluation of Biofertilizers in Irrigated Rice: Effects on Grain Yield at Different Fertilizer Rates. Agriculture 2012, 2, 73-86.
Banayo NPM, Cruz PCS, Aguilar EA, Badayos RB, Haefele SM. Evaluation of Biofertilizers in Irrigated Rice: Effects on Grain Yield at Different Fertilizer Rates. Agriculture. 2012; 2(1):73-86.
Banayo, Niño Paul Meynard; Cruz, Pompe C. Sta.; Aguilar, Edna A.; Badayos, Rodrigo B.; Haefele, Stephan M. 2012. "Evaluation of Biofertilizers in Irrigated Rice: Effects on Grain Yield at Different Fertilizer Rates." Agriculture 2, no. 1: 73-86.