Effect Of Fertilizer Microdosing And In Situ Moisture Conservation On Yield And Resource Use Efficiency Of Pearl Millet In Makueni County-Kenya

Abstract

Pearl millet productivity in semi-arid areas of Kenya is constrained mainly by moisture deficit and inherent low soil fertility. A field study was conducted in Makueni, Kenya during the 2014 short and long rains to determine the effect of in situ moisture conservation techniques and fertilizer microdozing on growth and yield of pearl millet and to quantify water, light and nutrient use efficiency of pearl millet as affected by fertilizer microdozing and in situ moisture conservation techniques. The treatments comprised of three moisture conservation techniques and three levels of fertilizer applications giving nine treatment combinations. Data was collected on soil moisture content, plant height, tiller numbers, root length density, leaf area index (LAI), photosynthetically active radiation (PAR), panicle length and number, 1000 grain weight, harvest index, water use efficiency and nutrient uptake. The data was subjected to Analysis of variance using GENSTAT statistical package (VSN International 2011). Highest plant heights (170.6-182.0 cm) were recorded in tied ridge-recommended rates while panicle length (8.5-10.2 cm) and tillers numbers (7.1-7.2) were recorded in tied ridge-micro dose rates. Maximum LAI ranged between 0.37 and 1.15 in flat-no fertilizer and tied ridge-micro dose respectively. Combination of tied ridge and micro dose fertilizer application increased pearl millet grain yields by 322.5 to 373.9 kg ha-1 and Stover yield by 844.9 and 1005 kg ha-1over flat-no fertilizer. Combination of tied ridge and recommended fertilizer rates recorded the highest water use of 140 mm in 2014 short rains and 200 mm in 2014 long rains. Pearl millet water use efficiency ranged between 2.13 and 3.98 kg ha-1mm-1 in flat-no fertilizer treatment and tied ridge-micro dose respectively indicating highest resource use efficiency of microdose application. Tied ridge-microdose provided the highest light use efficiency of 1.4 MJ PAR −1. Pearl millet subjected to combined application of tied ridge and micro dose fertilizer recorded the highest nutrient use efficiency of 16.98 kg N grain yield kg-1, 6.4 kg P grain yield kg-1, and 12.45 kg K grain yield kg-1. Overall soil moisture content was highest in tied ridge-no fertilizer (26.2 %) and lowest in flat-recommended fertilizer (17.6 %). Point application of fertilizer in microdose techinique promoted early lateral roots proliferation within the topsoil resulting into better exploitation of water and soil nutrients. These results demonstrate the potential use of integrated tied ridge and fertilizer microdosing in improving resource use efficiency and yield of pearl millet in semi-arid areas. Keywords: fertilizer microdosing; in situ moisture conservation; nutrient uptake; resource use efficiency.