Mukhongo Ruth W, Tumuhairwe John B, Ebanyat Peter, AbdelGadir AbdelAziz H, Thuita Moses, Masso Cargele
Department of Agricultural Production, School of Agricultural Sciences, Makerere University Kampala, Uganda.
Department of Agricultural Production, School of Agricultural Sciences, Makerere UniversityKampala, Uganda; International Institute of Tropical AgricultureKampala, Uganda.
Front Plant Sci. 2017 Mar 13;8:219. doi: 10.3389/fpls.2017.00219. eCollection 2017.
Sweet potato [ (L) ] yields currently stand at 4.5 t ha on smallholder farms in Uganda, despite the attainable yield (45-48 t ha) of NASPOT 11 cultivar comparable to the potential yield (45 t ha) in sub-Saharan Africa (SSA). On-farm field experiments were conducted for two seasons in the Mt Elgon High Farmlands and Lake Victoria Crescent agro-ecological zones in Uganda to determine the potential of biofertilizers, specifically arbuscular mycorrhizal fungi (AMF), to increase sweet potato yields (NASPOT 11 cultivar). Two kinds of biofertilizers were compared to different rates of phosphorus (P) fertilizer when applied with or without nitrogen (N) and potassium (K). The sweet potato response to treatments was variable across sites (soil types) and seasons, and significant tuber yield increase ( < 0.05) was promoted by biofertilizer and NPK treatments during the short-rain season in the Ferralsol. Tuber yields ranged from 12.8 to 20.1 t ha in the Rhodic Nitisol (sandy-clay) compared to 7.6 to 14.9 t ha in the Ferralsol (sandy-loam) during the same season. Root colonization was greater in the short-rain season compared to the long-rain season. Biofertilizers combined with N and K realized higher biomass and tuber yield than biofertilizers alone during the short-rain season indicating the need for starter nutrients for hyphal growth and root colonization of AMF. In this study, N0.25PK (34.6 t ha) and N0.5PK (32.9 t ha) resulted in the highest yield during the long and the short-rain season, respectively, but there was still a yield gap of 11.9 and 13.6 t ha for the cultivar. Therefore, a combination of 90 kg N ha and 100 kg K ha with either 15 or 30 kg P ha can increase sweet potato yield from 4.5 to >30 t ha. The results also show that to realize significance of AMF in nutrient depleted soils, starter nutrients should be included.
在乌干达的小农户农场中，甘薯[（L）]目前的产量为每公顷4.5吨，尽管NASPOT 11品种的可实现产量（45 - 48吨/公顷）与撒哈拉以南非洲（SSA）的潜在产量（45吨/公顷）相当。在乌干达的埃尔贡山高农田和维多利亚湖新月形农业生态区进行了两个季节的田间试验，以确定生物肥料，特别是丛枝菌根真菌（AMF）提高甘薯（NASPOT 11品种）产量的潜力。将两种生物肥料与不同施用量的磷肥进行比较，同时设置了施氮和钾肥与不施氮钾肥的处理。甘薯对各处理的反应因地点（土壤类型）和季节而异，在铁铝土短雨季节，生物肥料和氮磷钾处理显著提高了块根产量（<0.05）。在同一季节，红壤性粘壤土中的块根产量为12.8至20.1吨/公顷，而铁铝土（砂壤土）中的块根产量为7.6至14.9吨/公顷。与长雨季节相比，短雨季节的根系定殖率更高。在短雨季节，生物肥料与氮钾肥结合比单独使用生物肥料实现了更高的生物量和块根产量，这表明AMF的菌丝生长和根系定殖需要起始养分。在本研究中，N0.25PK（34.6吨/公顷）和N0.5PK（32.9吨/公顷）分别在长雨季节和短雨季节产生了最高产量，但该品种仍存在11.9和13.6吨/公顷的产量差距。因此，每公顷90千克氮和100千克钾与15或30千克磷的组合可使甘薯产量从4.5吨/公顷提高到>30吨/公顷。结果还表明，为了在养分贫瘠的土壤中发挥AMF的作用，应包含起始养分。
