Nitrogen and arbuscular mycorrhizal fungi (AMF) effect on two commercial sweet potato clones on an inseptisol soil

Abstract

Sweet potato [Ipomoea batatas L. (Lam)], is the fifth most important food crop in developing countries due to its outstanding nutritional and culinary characteristics and it is also considered one of the two most important food crops along with cassava (Manihot esculenta Crantz). The response of various crops to inoculation with arbuscular mycorrhizal fungi is well known. The research was conducted at the The Research Institute of Tropical Root and Tuber Crops (INIVIT) on an inseptisol soil. The objective was to compare the effect of five nitrogen doses in the presence or absence of an effective AMF strain oin two sweet potato clones ‘INIVIT B2-2005’ and ‘CEMSA 78-354’. Yield, colonization rate and amount of spores were evaluated. Treatments inoculated with effective strains obtained higher yields of 35 to 37 t.ha-1 with a dose of 60 kg N ha-1; and chemical fertilizer nitrogen was reduced by 37.5 % in the form of N. A yield of 30 to35 t.ha-1 was obtained with a dose of 90 kg ha-1 of N and no AMF application. In all cases the best colonization values and spore numbers in 50 g soil coincide with optimal fertilization doses for the treatment inoculated efficiently. Colonization values were in the range of 71 to 76 % and 628-659 spores for the nitrogen dose of 60 kg ha-1.

Keywords

• Sweet potato
• efficient strain HMA