Abstract: This study was conducted in Naivasha, Kenya over a period of 15 weeks to determine the effect of manure or fertilizer application on height of Columbus grass (Sorghum almum). After field preparation, representative soil samples were taken for mineral profiling. Sixty plots of 2x2 sq. m size were then demarcated and further divided into 5 similar units comprising of 4 blocks of 3 plots each. The plots in each block were independently allotted to 3 treatments in a Randomized Complete Block (RCB) design. Treatments were T1-control (without fertilization), T2 and T3 received dry beef cattle manure and inorganic fertilizer, respectively. All the 4 blocks (weed free) in each of the five (randomly distributed) units were planted on the same day. Harvesting was done at 6, 8, 10, 12 and 14 weeks in a sequential manner starting with unit 1 to 5. All the blocks in each unit were harvested on the same day (at 5 cm height). Results showed that manure or fertilizer application had significant (p<0.0001; r2 = 0.9769) effect on height of Sorghum almum. ANOVA revealed high effect of cutting interval (p<0.0001) and cutting-treatment interaction (p<0.001). At 6 weeks the mean height in T2 (p<0.01) and T3 (p<0.001) were 12.74 and 19.05% higher than in T1. At 14 weeks T2 (p<0.01) and T3 (p<0.01) recorded 12.1 and 12.5% higher height than T1. At the same age however T2 and T3 were not different (p>0.05). The observed increases in the grass height between 6 and 14 weeks represented growth rate of 3.2, 3.6 and 3.5 cm d 1 for the 3 treatments respectively. Results further showed that height growth rates in T1, T2 and T3 were higher between 6 and 10 weeks (3.83, 3.77 and 3.95 cm d 1) compared to that recorded between 10 and 14 weeks (2.58, 3.4 and 3.12 cm d 1). The results also showed that height was strongly correlated with concentration of essential nutrients in the plant tissue. Gauging from the results of this study, availability and the known long-term residual effect, this study concluded that though both manure and fertilizer had significant effect on height, manure would be the best cost effective option for enhancing Sorghum almum growth rate and therefore yield on smallholder farms in Kenya.
T.P. Lanyasunya , H. Wang Rong , E.A. Mukisira and N.K. Kibitok , 2007. Effect of Manure or Fertilizer Application on Height of Sorghum almum Harvested at Different Maturity Stages. Agricultural Journal, 2: 82-86.