Date of Publication

4-2026

Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Biology major in Medical Biology

Subject Categories

Biology

College

College of Science

Department/Unit

Biology

Thesis Advisor

Mark Christian Felipe R. Redillas

Defense Panel Chair

Yokimiko D. Torrejos

Defense Panel Member

Mr. Christian Jordan O. dela Rosa
John Paul S. Domingo

Abstract (English)

Rice (Oryza sativa L.) is a culturally and economically important crop in Southeast Asia. This systematic review aims to evaluate the effects of nitrogen-based synthetic, organic, and combined fertilizers on rice. A comprehensive search of databases including CrossRef, Google Scholar, OpenAlex, and PubMed identified published studies between 2014 and 2025 was accomplished using the Harzing Publish or Perish software. Out of 5,139 search results, a total of 88 studies were included in the review. Results show that synthetic fertilizers were most frequently studied, followed by combined treatments, while organic fertilizers were least represented. Grain yield responses to synthetic and combined fertilizers showed weak positive relationships with application rates, indicating only marginal yield gains at higher inputs. These weak correlations suggest the influence of confounding factors such as soil properties, rice varieties, climate conditions, and agronomic management across studies. Organic fertilizers showed little to no yield response, likely due to slower nutrient release and microbial dependency. PFP analysis revealed declining efficiency with increasing fertilizer rates across all treatments. Synthetic fertilizers produced the highest mean PFP but with high variability, while organic fertilizers showed consistently low productivity. Combined treatments exhibited highly variable outcomes. Overall, results highlight trade-offs between yield and efficiency, emphasizing the need for site-specific and balanced fertilizer strategies to improve rice productivity and sustainability.

Abstract Format

html

Abstract (Filipino)

Ang palay (Oryza sativa L.) ay isang mahalaga sa kultura at ekonomiya na pananim sa Timog-Silangang Asya. Ang sistematikong pagsusuri na ito ay naglalayong suriin ang epekto ng nitrogen-based na synthetic, organic, at combined fertilizers sa palay. Isang komprehensibong paghahanap sa mga database tulad ng CrossRef, Google Scholar, OpenAlex, at PubMed ang isinagawa gamit ang Harzing Publish or Perish upang makuha ang mga pag-aaral na nailathala mula 2014 hanggang 2025. Mula sa 5,139 na resulta ng paghahanap, 88 pag-aaral ang napili para sa pagsusuri. Ipinakita ng mga resulta na ang synthetic fertilizers ang pinakamaraming pinag-aralan, sinundan ng combined treatments, habang ang organic fertilizers ang may pinakakaunting pag-aaral. Ang tugon ng ani sa synthetic at combined fertilizers ay nagpakita ng mahihinang positibong ugnayan sa application rates, na nagpapahiwatig ng maliit na pagtaas ng ani sa mas mataas na input. Ang mahihinang ugnayang ito ay maaaring dahil sa mga confounding factors tulad ng kondisyon ng lupa, uri ng palay, klima, at mga pamamaraang agronomic sa iba’t ibang pag-aaral. Ang organic fertilizers ay nagpakita ng kaunti hanggang walang tugon sa ani, na maaaring dulot ng mabagal na paglabas ng sustansya at pagdepende sa microbial activity. Ipinakita rin ng PFP analysis ang pagbaba ng efficiency habang tumataas ang fertilizer rates sa lahat ng treatment. Ang synthetic fertilizers ang may pinakamataas na mean PFP ngunit may mataas na variability, habang ang organic fertilizers ay may tuloy-tuloy na mababang productivity. Ang combined treatments ay nagpakita ng mataas na variability ng resulta. Sa kabuuan, ipinapakita ng mga resulta ang trade-offs sa pagitan ng ani at efficiency, na nagbibigay-diin sa pangangailangan ng site-specific at balanseng fertilizer strategies upang mapabuti ang produksyon at sustainability ng palay.

Abstract Format

html

Language

English

Format

Electronic

Keywords

Rice; Fertilizers—Application; Plant nutrients; Crop yields; Grain

Upload Full Text

wf_yes

Embargo Period

4-14-2027

Download

Available for download on Wednesday, April 14, 2027

Share

COinS