TITLE:
Influence of Integrated Nutrient Management and Mulching on Fertilizer Use Efficiency Metrics and Yield Response of Dolichos Bean (Lablab purpureus L.) in Semi-Arid Areas of Nakuru County, Kenya
AUTHORS:
Okoth Paul Ogoye, Josphine P. Ouma, Joyce J. Lelei, Gezehegn Berecha
KEYWORDS:
Dolichos Bean, Fertilizer Use Efficiency, Agronomic Use Efficiency, Partial Factor Productivity, Yield Response, Relative Yield, Yield
JOURNAL NAME:
Agricultural Sciences,
Vol.17 No.8,
August
31,
2026
ABSTRACT: Efficient use of applied nutrients is essential for improving crop yield, particularly in low-fertility, moisture-limited environments. Fertilizer use efficiency metrics such as Agronomic Use Efficiency (AUE), Partial Factor Productivity (PFP), Yield Response (YR), and Relative Yield (RY) provide important insights into how effectively nutrients are converted into economic yield. These indices help to quantify the contribution of fertilizer inputs to yield improvement and assess the performance of different nutrient management strategies. Evaluating the metrics is critical for identifying practices that enhance productivity while optimizing input use in Dolichos bean production systems. Field experiments were conducted in Maai Mahiu (1˚1'17.2'' S, 36˚35'11.5'' E) and Lare (0˚25'45.2'' S, 36˚03'06.0'' E) Nakuru county, over two seasons (September 2024-January 2025) and (April 2025-August 2025) to evaluated the effect of integrated nutrient management and mulching on Dolichos bean yield and fertilizer use efficiency. Treatments included three rates of NPK 17:17:17 (0, 75, 150 kg ha−1), four rates of organic fertilizer (Griincom 2% N:4% P:5% K), 0, 200, 400, 600 kg ha−1 applied as dry matter, and two mulch levels of dry wheat straw (with mulch, without mulch). The highest AUE in Lare was observed in season 2 (382.93 kg kg−1 N) was recorded under 75 kg ha−1 NPK + 600 kg ha−1 organic fertilizer with mulch, while in Maai Mahiu the highest value (340.04 kg kg−1 N) was recorded under 0 kg ha−1 NPK + 200 kg ha−1 organic fertilizer with mulch in season 1. The highest PFP (468.24 kg kg−1 N ha−1) was observed at Lare season 2 under 200 kg organic fertilizer with mulch and no NPK, while the maximum RY (2495.13 kg ha−1) occurred under 150 kg ha−1 NPK + 600 kg ha−1 organic fertilizer with mulch at Lare season 1. The greatest YR (738.97%) was recorded at Maai Mahiu season 1 under the same treatment (150 kg ha−1 NPK + 600 kg ha−1 organic fertilizer with mulch). Mulching enhanced soil moisture retention and nutrient uptake, improving efficiency across sites. Economically, moderate N combined with organic fertilizer and mulch provided high yield per unit of nutrient applied, highlighting INM as a sustainable and cost-effective strategy for Dolichos bean production in semi-arid environments.