Causes and Prevention of Abnormal Root Tubers of Sweet Potato

In the process of sweet potato cultivation, we have encountered the phenomenon that sweet potato forms some abnormal root tubers. Some do not grow smoothly, some have a big head and a small tail, forming burdock roots, some have cracks, and some have hard roots, which seem to have "red blood" and so on. The occurrence of these phenomena has seriously affected the commodity value of sweet potato.

How are deformed potato blocks formed? To understand this, we might as well start with the formation of sweet potato roots. The young roots grown from potato seedlings or seed potato seedlings are called fiber roots, and the potato pieces are formed by the accelerated division, growth and expansion of the cambium cells under the skin of these fiber roots. However, the growth and development conditions of different fiber roots are different, and the roots formed are also different. Some are expanded to form tuber roots, some are not inflated and thickened, they are still fibrous roots, and those between the two form burdock roots (firewood roots). Whether fiber root can form tuber root is affected by many factors. under the conditions of sufficient sunshine, good soil ventilation and suitable conditions of fertilizer and water, it can enhance the cambium activity of fiber root and inhibit its Lignification, which is beneficial to the thickening of root and the formation of tuber root. On the contrary, high soil moisture, poor ventilation or excessive nitrogen fertilizer are beneficial to fiber root formation. In the process of potato tuber formation, if the soil is dry and hard, poor ventilation and other adverse conditions, it will hinder the expansion of the root tuber, thus forming burdock root. Therefore, in order to avoid this abnormal growth, it is necessary to adopt scientific and reasonable methods in soil selection, fertilization, irrigation and so on.

First, although the soil requirements of sweet potato are not strict, it is best to choose sandy loam and loam with loose topsoil, good drainage, rich organic matter and deep soil layer. The soil with too much sand should be improved by applying organic fertilizer and mixing clay. Although the land with heavy clay has strong water retention, it is not conducive to the formation and expansion of root tubers.

Second, it is necessary to apply fertilizer reasonably according to the fertilizer demand characteristics of sweet potato. In the lifetime of sweet potato, the demand of potash fertilizer is the largest, followed by nitrogen fertilizer, and phosphate fertilizer is the least. The water demand for nitrogen fertilizer is mostly concentrated before ridge sealing, and nitrogen fertilizer should not be applied in the tuber-forming period. at this time, if the content of available nitrogen in the soil is too high, the stele cells of young roots age to form fibrous roots, so it is difficult to expand into tuber roots. Therefore, when applying fertilizer, we must pay attention to diazo in the early stage and heavy potassium in the later stage.

Third, it is necessary to strengthen water management. Some deformed potatoes are caused by improper dry and wet soil, and some sweet potato roots crack in the process of expansion, which is often caused by watering or rain after drought. Therefore, maintain appropriate moisture in production, maintain 70-80% of the maximum field capacity in the branching stage, and 60-70% of the maximum field capacity in the rest of the period, so as to avoid the emergence of split potatoes and "red blood filaments". Get more "smooth" potato pieces.