EFFECT OF SELECTED ORGANIC MULCHES ON SOIL PROPERTIES, GROWTH AND YIELD OF AMARANTHUS IN KILIFI COUNTY

Abstract

Amaranthus is an indigenous vegetable which acts as a source of nutrition and income within Kilifi County. However, soil moisture stress due to unpredictable rains within the area is the major constraint to Agricultural production in the region. A study was carried out in Pwani University farm and Jaribuni secondary school farm to evaluate the effect of selected organic mulches on soil properties, growth and yield of amaranthus in Kilifi County. The experiment was laid out in randomized complete block design with three replications. The study was conducted from June 2nd 2018 to October 4th 2018. The selected organic mulches included; seaweed, neem leaves, cashew nut leaves, wood shavings and a control (no mulch). Data collected included; total nitrogen, exchangeable phosphorus, potassium, calcium and Magnesium, plant height, leaf length, leaf width, stem girth, number of branches, leaf number, chlorophyll content, leaf dry weight, soil temperature, soil moisture content and days to 50% flowering. Seaweeds increased soil pH in Jaribuni Secondary and Pwani University by 5.1% and 5.0%, respectively. Na content by 11% in both sites and Mn content by 113% in both sites. In Jaribuni Secondary and Pwani University, leaf number by 43% and 62% and chlorophyll content by 90% and 98% respectively. Seaweeds without amaranthus increased phosphorus in both sites by 90% and 100% in Jaribuni Secondary and Pwani University, respectively. Neem leaves and seaweeds mulches increased leaf area by 30% to 46%, stem girth by 32% to 40%, number of branches by 41% to 61%. Neem leaves mulch increased plant height by 70% to 76%, soil temp by 88% to 99%, fresh weight by 25% to 35% and dry matter by 8.4% to 8.5%. Neem leaves without amaranthus increased K by 23% and 25%, Mg content by 6% to 8% and Cu by 26 to 53%. Wood shavings with amaranthus increased Ca content by 23% and organic carbon by 8.3% and 10% in Jaribuni Secondary and Pwani University respectively. Cashew nut leaves lowered soil pH in both sites by 10.8% and 7.7%. Cashew nut leaves with amaranthus and seaweeds with amaranthus lowered the potassium in both sites by 40 % and 41%. Control without amaranthus had the highest Fe and Zn content. A clear indication that effects of mulches depends on the mulching material.