The Contribution of Chemical, Organic and Bio-Fertilizers on Rice Production in Iran: A Meta-analysis

Abstract

Rice (Oryza sativa L.) is an important global food crop and a main source of calories for about 60% of the world population. Fertilizers are essential components of modern agriculture and play a vital role in improving rice and other crops yield. We performed a meta-analysis to determine how different types of fertilizers including chemical (nitrogen (N), phosphorus (P), 18 potassium (K), silicon (Si), and micronutrients), organic (compost and manure) and bio-fertilizers (plant growth promoting rhizobacteria (PGPR) and fungi (PGPF)) influence on rice productivity in Iran. A significantly positive overall effect of fertilizers was noted on biological yield (28.39%), grain yield (26.02%), harvest index (3.17%) and 1000-grain weight (4.86%). Chemical, organic and bio-fertilizers positively influenced grain yield by 26.78, 15.20 and 26.61%, respectively. Among all types of fertilizers, N has the most important role in rice production and responsible for 38% of yield. For N and P, the most increase of yield (47.60 and 20.52%, respectively) had been calculated in high fertilization rates (>120 and >80 kg h–1, respectively), while the highest rice yield was obtained from moderate K and Si fertilization rates (40–80 and 250–500 kg ha–1, respectively). Therefore, it seems that lower rates of K and Si fertilizers could be used in paddy fields for reaching optimum yield. Overall, this meta-analysis indicated that about 27, 15, and 27% of rice yield is attributable to chemical, organic and bio-fertilizers, respectively.