Effect of maize-cowpea cropping patterns on soil moisture conservation in Meru and Tharaka nithi counties

Abstract

Given the frequent drought pressure caused by the unpredictable and limited precipitation concurrent with global climate change, highly efficient cultivation technologies have been increasingly recognized by various levels of scientific communities. Maize (Zea mays L.) based intercropping systems are widely practiced in Kenya, but only a few studies have focused on cowpea (Vigna unguiculata L.) as the companion intercrop in moisture conservatory strategy. This study was conducted during the 2018 long rains of March-April at the Kenya Agricultural and Livestock Research Organization (KALRO) Igoji Research Station and Magutuni Primary school in Meru and Tharaka-Nithi Counties, respectively. The objective of the study was to assess the effect of incorporating cowpea into the maize production pattern on crop cover and soil moisture content. The experiment was laid in a randomized complete block design with three replications in 3 x 4 m plots. The treatments comprised of pure maize stand, maize intercropped with inoculated cowpea, maize intercropped with non-inoculated cowpea and pure non-inoculated cowpea. A generalized linear model was used to determine the effects of cropping patterns on ground cover, leaf area index and soil moisture content, using GenStat 19th edition. Means were separated using Fischer’s protected least significant difference (LSD) test, with differences considered significant at P≤ 0.05. Significantly (P≤ 0.05) higher (82%) crop cover was exhibited at kernel development stage in maize intercropped with inoculated cowpea compared to 78, 64 and 53% in maize intercropped with non-inoculated cowpeas , sole stand of non-inoculated cowpeas and sole maize stand, respectively. Similarly, the highest soil moisture content was recorded at kernel development stage: 210.3, 209.3, 200.2 and 196.4 mm in maize

intercropped with inoculated cowpea, maize intercropped with non-inoculated cowpeas, sole stand of non-inoculated cowpeas and sole maize stand, respectively. Relative to sole maize stand and sole stand of non-inoculated cowpeas, maize intercropped with inoculated cowpea recorded the peak leaf area index of 3.75 at 70 days after planting at Igoji and 3.16 at 63 days after planting in Magutuni. The study showed that cowpea is a promising legume crop that could be integrated into maize cropping patterns to improve moisture conservation