EFFECT OF INTEGRATED APPLICATION OF NAPHTHALENE ACETIC ACID, STAKING AND INORGANIC NITROGEN AND PHOSPHORUS ON NUTRIENT USE EFFICIENCY IN CLIMBING BEANS (Phaseolus vulgaris L.)

Abstract

In Kenya climbing beans (Phaseoulus vulgaris L.) are mainly grown by small-scale farmers under limited resources, such as limited land and high cost of inorganic fertiliser inputs. These have had led to declining trends and low productivity of climbing beans as well as increasing environmental concerns in cases of excess fertilizer inputs. To mitigate these problems there is need examine the factors that can lead to increased nutrient use efficiency (NUE) by climbing beans. A study was conducted at Kaguru Farmers Training Centre, Kenya, to determine the effect of integrating naphthalene acetic acid (NAA), staking, Diammonium phosphate (DAP) fertiliser on NUE in climbing beans. A 3x3x4 factorial experiment laid out in Randomised Complete Block Design was used. Treatments included NAA concentrations (0, 200 and 400 ppm), staking (no staking, staking with wooden stakes and maize plants as support), and DAP (0, 200, 250 and 300 Kg DAP ha^-1). The DAP was the source of both nitrogen and phosphorus. The yield data was used to calculate NUE. The obtained data was then subjected to analysis of variance using SAS version 9.4 and significant means separated using LSD at α = 0.05. There was significant difference (p < 0.05) in NUE amongst the different treatments. The integration of 200 ppm NAA, staking with wooden stakes and application of 250 Kg DAP ha^-1 resulted in the highest NUE (18.84 kg/kg). Though increase in NAA showed a general tread of increase in NUE, application of DAP fertiliser seems to have reached an optimum at around 250 Kg DAP ha^-1 The study demonstrate that integration of NAA, staking with wooden stakes and application of appropriate amount of DAP can lead to increased NUE by climbing beans. This study recommended use of appropriate agronomic practices that integrate 200 ppm of NAA, 250 Kg of DAP ha^-1 and staking with wooden stakes for sustainable climbing bean production.