Effect of combined application of cattle manure and mineral fertilisers on the growth characteristics and quality of Pennisetum purpureum fodder

Abstract

Smallholder urban and peri-urban dairy farmers use elephant grass (Pennisetum purpureum) fodder on top of crop wastes for feeding livestock. However, with limited application of soil fertility management techniques, there has been progressive deterioration of soil fertility. Consequently, fodder yields have declined leading to reduced milk output, and in turn, to unstable household incomes and food insecurity. This study investigated whether composted cattle manure alone, or in combination with mineral fertilizers could improve fodder production. Application of cattle manure at low (ML), medium (MM) and high (MH) rates, or in combination with mineral fertilisers at medium (MFM) and high (MFH) rates significantly increased the leaf area indices (LAIs) and dry matter (DM) yields of Pennisetum purpureum fodder. The mean LAIs of treatments ML, MM, MH, MFM and MFH were 3.58, 3.69, 3.31, 3.28 and 3.56 respectively, and were significantly higher than 2.89 for the control which did not receive manure and fertilisers. Fodder yields from these treatments were 7.15, 6.99, 6.74, 6.80 and 7.01 ton ha-1. Fodder obtained from ML, MM and MFH contained greater proportions of leaf than fodder from the control, indicating that there was greater vegetative growth in these treatments than in the control. Since the leaves of plants usually contain less fibre and thus are more easily digested than stems, higher leaf content was an indication of improvement in fodder quality. The in vitro organic matter digestibilities of fodder from all treatments were similar but greater than that of the control