When should potatoes be controlled for excessive vigor, and how?
As temperatures gradually rise and rain arrives, open-field potatoes have reached their peak growth period, which is precisely the critical time to control excessive vigor in potatoes. If excessive vigor is not controlled in time, it will cause the stems and leaves to grow excessively, reducing yield. So when is the best time to control excessive vigor in potatoes? How should it be done?
The benefits of controlling excessive vigor in potatoes
Timely control of excessive vigor can effectively curb above-ground growth, directing nutrients to the underground part to promote rapid tuber expansion, achieving the goals of increased yield and early maturity, and controlling excessive vigor can increase potato yield by 30-40%.
When is the best time to control excessive vigor in potatoes?
The best time to control excessive vigor is when the above-ground part of the potato has just closed the rows, with scattered flower buds appearing or flowers already blooming. It should not be too early or too late. If too early, the above-ground stems and leaves have not yet produced enough organic matter through photosynthesis needed for high yield, and the plant has not accumulated enough organic matter; if too late, the above-ground part shows a tendency toward excessive growth, consuming excessive photosynthetic products, weakening the nutrient supply capacity to the underground part, and causing yield reduction.
Techniques for controlling excessive vigor in potatoes
The vigor-control techniques currently promoted in production are quite diverse, with at least a dozen methods. Among these many techniques, only a small portion have been verified through production practice and are favored by farmers for being fast, effective, and non-rebounding. Some techniques take too long to control vigor, show results slowly, and the above-ground part easily rebounds, causing secondary excessive growth. Therefore, when controlling excessive vigor in potatoes, measures that are steady, accurate, and firm must be adopted. Do not blindly control vigor; it is best to complete vigor control and tuber expansion in one go. Production practice has verified: first remove potato flowers to inhibit reproductive growth, then spray the leaves with “triazole-based vigor-control agents + amino acid foliar fertilizers” for the best effect. Because potatoes are a fast-growing crop in North China, the yield formation period is only 10-15 days. If effective vigor-control measures are not taken in time before yield formation, reduced potato yield is unavoidable.
The best chemicals for controlling excessive vigor in potatoes
The use of foliar fertilizers is key to controlling excessive vigor in potatoes. Foliar fertilizers with vigor-control effects on the market include paclobutrazol, uniconazole, mepiquat chloride, tuber expansion agents, and other products. How should we choose?
As for paclobutrazol, its vigor-control effect is good, but because it leaves residues in the soil and has a relatively large impact on subsequent crops, especially since paclobutrazol residues are greater, it is not recommended for use on potatoes. Uniconazole is a broad-spectrum, high-efficiency plant growth regulator that also has fungicidal and herbicidal effects and is a gibberellin synthesis inhibitor; its activity is 6-10 times higher than paclobutrazol, but its soil residue is only 1/10 that of paclobutrazol, so uniconazole is quite good as a potato vigor-control agent. Mepiquat chloride is a new type of plant growth regulator with good systemic translocation in plants, inhibiting rampant stem and leaf growth, controlling lateral branches, shaping an ideal plant type, increasing root quantity and vitality, increasing fruit weight, and improving quality. As for tuber expansion agents, farmers should choose reliable brands with guaranteed quality. Improper use of tuber expansion agents will not only fail to increase yield but will also cause a decline in potato quality and may even cause fruit cracking, losing commercial value.