Enhancing Nutrient Use Efficiency in Semi-arid Lowland Rice through Deep Placement of NPK Briquettes

Abstract

Background:  Global food security remains under increasing pressure due to rapid population growth and limited natural resources, particularly in developing regions reliant on staple crops such as rice. In Burkina Faso, low soil fertility, inefficient fertiliser use, and climate variability significantly constrain rice productivity, highlighting the need for more efficient nutrient management strategies such as deep fertiliser placement. Aims: This study aimed to evaluate the effect of deep placement of NPK briquettes on nitrogen and phosphorus use efficiency in lowland rice systems under semi-arid conditions in Burkina Faso. Study Design: A completely randomized experimental design with three replications was used to compare different fertilizer management practices. Place and Duration of the Study: The experiment was conducted in a lowland rice production area in the semi-arid zone of Burkina Faso during the 2022–2023 cropping season. Methodology: Five fertilizer treatments were tested: (i) control without fertilizer; (ii) farmer’s practice (150 kg ha⁻¹ NPK + 100 kg ha⁻¹ prilled urea); (iii) 150 kg ha⁻¹ NPK + 1.8 g urea super granule (USG); (iv) two 1.8 g NPK super granules (SG-NPK); and (v) two 1.8 g SG-NPK + 100 kg ha⁻¹ prilled urea. Agronomic efficiency (AE), internal efficiency (IE), physiological efficiency (PE), and partial factor productivity (PFP) were calculated for each treatment. Data were analyzed using ANOVA in GenStat (12th edition). Results: The combination of two SG-NPK with 100 kg ha⁻¹ prilled urea increased internal and physiological nitrogen use efficiency by 32.86% and 203.58%, respectively, compared with the farmer’s practice. The highest phosphorus agronomic efficiency (38.45 kg paddy kg⁻¹ P applied) was obtained with 150 kg ha⁻¹ NPK + 1.8 g USG. This treatment also produced the highest partial factor productivity (61.09 kg paddy kg⁻¹ N and 119.03 kg paddy kg⁻¹ P applied). Conclusion: Deep placement of NPK briquettes significantly improves nutrient use efficiency in lowland rice under semi-arid conditions, suggesting its potential as an effective strategy for optimizing nitrogen and phosphorus management.