How does soil fertility affect yam growth?

Nitrogen Use by Yam as Affected by Mineral Fertilizer Application

“…The tuber yields produced in our study were lower than those produced in a nearby forest, where yields reached 50 Mg ha −1 in 2001 and 2003 (Diby et al, 2009). The yield difference between the two sites can be related to the low fertility of the savanna site (Diby et al, 2011).…”

“…Modeling crop growth based on rainfall, solar radiation, photoperiod, and temperature may improve these estimates (Marcos et al, 2009, 2011). A less sophisticated approach would be to measure the percentage of soil coverage as proposed by Diby et al (2011) because it correlates well with the leaf area index of creeping cultivars such as the one studied in this work. Based on improved yield estimates, it may be possible to improve fertilizer recommendations.…”

“…The yield potential and response to fertilizers of yam are influenced by the plant germplasm and local climatic and soil conditions (Ettien and Tschannen, 2003; Diby et al, 2011; Marcos et al, 2011). For example, for D. rotundata in Nigeria, <50 kg N ha −1 produced a yield ranging from 17 to 24 Mg fresh tubers ha −1 (Kayode, 1985; Law‐Ogbomo and Remison, 2008, 2009), while in Côte d'Ivoire, yields of 13 to 15 Mg ha −1 were produced when 120 kg N, 28 kg P, and 103 kg K ha −1 were applied (Ettien et al, 2009).…”

“…For example, for D. rotundata in Nigeria, <50 kg N ha −1 produced a yield ranging from 17 to 24 Mg fresh tubers ha −1 (Kayode, 1985; Law‐Ogbomo and Remison, 2008, 2009), while in Côte d'Ivoire, yields of 13 to 15 Mg ha −1 were produced when 120 kg N, 28 kg P, and 103 kg K ha −1 were applied (Ettien et al, 2009). For D. alata , the mineral fertilizer rates for maximum tuber yields varied from 75, 12, and 250 kg ha −1 of N, P, and K fertilizer in Puerto Rico, where the tuber yield reached 18.8 Mg ha −1 , to 240, 11, and 269 kg ha −1 of N, P, and K in Côte d'Ivoire, where the yield varied from 34 Mg ha −1 when the yam was planted in a less fertile savannah site to 50 Mg ha −1 when the crop was planted in a fertile forest site (Diby et al, 2011; Sotomayor‐Rodriguez et al, 2003). To resolve differences between optimum fertilizer rates, a better understanding of the relationships among soil, plant, and nutrient stress is needed.…”

“…Due to the long growing season of yam, we evaluated the effect of N fertilization added as two splits. The first split application was made at 90 d after planting to support leaf growth because maximal leaf area index is linked to tuber yield (Diby et al, 2011) and the second at 130 d after planting to support tuber growth.…”