Nutrient accumulation characteristics and quality differences of mineral nutrients of main yam cultivars in Hebei Province

Objectives We studied the relationship between mineral nutrient accumulation and the quality of local yam (Dioscorea oppositifolia L.) cultivars in Hebei Province to provide baseline information for efficient nutrient management in yam production in the study area.

Methods A field experiment was conducted in Lixian County, Hebei Province. The tested yam cultivars were Bangyao, Dahebaiyu, Ziyao, and Xiaobaizui, receiving the same amount of fertilizer. The whole plant was divided into above-ground and under-ground (tuber) parts to determine biomass and nutrient content (N, P, K, Ca, Mg, Fe, Mn, Cu and Zn). The mineral nutrient quality was assessed by principal component analysis.

Results The fresh tuber biomass was in the order Dahebaiyu>Bangyao>Ziyao>Xiaobaizui. Ziyao had the highest dry biomass, followed by Dahebaiyu and Xiaobaizui. Dahebaiyu tuber accumulated the highest N, Ca, Mg, Mn, Cu, and Zn, and distribution coefficient of K, Ca, Mg, Mn, Cu and Zn. Ziyao tuber had the highest accumulation of P and K, and the highest distribution coefficient of N and P. Bangyao tuber had the highest accumulation and distribution coefficient of Fe. The nutrients required to produce 1000 kg tuber yield of the different yam cultivars are K₂O>N>P₂O₅ for major elements, Mg>Ca for the intermediate elements, and Fe>Zn>Mn>Cu for micronutrients. The four yam cultivars were subjected to principal component analysis (PCA) to examine the nine mineral nutrition indicators for standard yam in China’s Food Composition (Standard Edition). Three PCAs with eigenvalues >1 were extracted. The PCAs had a cumulative contribution of 96.77% to the variation in the dataset. The first, second, and third PCA contributed 56.45%, 29.09%, and 11.22%. K and Zn were the representatives of the first PCA, Mg and Mn for the second, and Fe for the third. The principal component analysis showed that Dahebaiyu had the best comprehensive quality score of mineral nutrition, followed by Bangyao, Xiaobaizui, and Ziyao. Nevertheless, the qualities of the four tested varieties were all higher than the standard yam in China’s Food Composition (Standard Edition).

Conclusions Dahebaiyu has the highest mineral nutrition quality, classified as a high-zinc variety. Bangyao is a high-calcium and high-iron variety. The contents of K, Mg, Fe, Mn, and Zn in soil are the main elements affecting the differences in mineral nutritional quality of yam tubers. In the production of yam, the application of mineral fertilizer should consider the mineral element content in soil and the mineral element demand of different cultivars, and carry out scientific nutrient management to further improve the mineral nutrient quality of yam.