Effects of arbuscular mycorrhizal fungi and their combinations with nitrogen and phosphorus on grain yields of improved finger millet varieties

Abstract

Finger millet (Eleusine coracana (L.) Gaertn) is an important cereal crop commonly cultivated in both sub-humid and semi-arid regions of Africa and Asia. In Uganda, finger millet is the third ranked cereal after maize and sorghum in terms of production. It is grown mainly by subsistence smallholder farmers across regions of Uganda. It’s production in Uganda is low due to several abiotic and biotic factors. Among the abiotic factors, low soil fertility is the major constraint to production causing yields of less than 33% compared to that attained under research conditions. This can be addressed using fertilizers. The use of bio-fertilizers such as (AMF) which is defined as Arbuscular Mycorrhizal Fungi provides a cheap environmentally friendly sustainable option to improve crop yields by complementing fertilizers. AMF increases bio availability of phosphorus and nitrogen nutrients to the plant in the marginal soils or nutrient-depleted soils and minimizes leaching of N. This study aimed to assess how AMF singly and in a combination with low rates of mineral fertilizers (N and P) contributes to improved finger millet production in Uganda. The study was conducted at the national semiarid resources research institute (NaSARRI), Serere, and Bukedea districts located in eastern Uganda, being one of the major finger millet producing regions across the country. A completely randomized block design was used to attain all the objectives. For objective 1 a field experiment was laid and attaining both field and screen house experiments were used to attain objective 2. Data was analysed using excel and mean pair wise comparisons (T-tests) were done for grain yield, root length, root to shoot ratio and root length density at a significance level of 5%. Results showed that application of AMF alone caused no significant differences (p>0.05) in agronomic parameters and grain yield. However, there were significant statistical differences of grain yield realized between engeny combined with (AMF+20N+0P) and (NAROMIL5 combined with (AMF+0N+6P). The other interactions of variety and fertilizer treatments had no significant statistical difference for grain yield. The root to shoot ratio was statistically significantly different for NAROMIL2 and NAROMIL4 with AMF+20N+6P fertilizer combinations. The root length and root length densities were realized to be non-statistically significantly different among varieties, but significant statistical differences were noticed amongst fertilizer treatment combinations.