Detailed Explanation of Key Points of Scientific Fertilization Techniques for Daylily

Daylily (scientific name: Hemerocallis citrina Baroni), also known as golden needle vegetable or lemon daylily, belongs to the order Liliales, family Liliaceae, a perennial herbaceous plant, with roots nearly fleshy, often spindle-shaped and enlarged in the middle and lower parts. The scapes vary in length, the pedicels are relatively short, flowers are numerous, and the perianth is pale yellow, orange-red, or black-purple; the capsule is obtusely trigonous-elliptic, and the flowering and fruiting period is from May to September. Its nature and flavor are sweet and cool, and it has effects such as stopping bleeding, reducing inflammation, clearing heat, and draining dampness. It is rich in pollen, sugar, protein, vitamin C, calcium, fat, carotene, amino acids, and other nutrients essential to the human body. It is mainly distributed in China.

Growth Habits of Daylily

Daylily is tolerant of poor soil and drought, and has no strict requirements for soil; it can be cultivated at field edges or on hillsides. It has a wide adaptability to light and can be intercropped with relatively taller crops. The aboveground part of daylily is not cold-tolerant, while the underground part can withstand low temperatures of -10°C. It avoids overly wet or waterlogged soil. When the average ten-day temperature is above 5°C, seedlings begin to emerge, and the suitable temperature for leaf growth is 15°C-20°C; the flowering period requires a relatively high temperature, with 20°C-25°C being more suitable.

Distribution of Daylily

It is cultivated throughout northern and southern China, mostly distributed south of the Qinling Mountains in China, as well as in Hunan, Jiangsu, Zhejiang, Hubei, Jiangxi, Sichuan, Gansu, Shaanxi, Jilin, Guangdong, and the Inner Mongolia grasslands. Quxian County in Sichuan is known as the “Home of Chinese Daylily.” Shaodong County and Qidong County have been designated as “place of origin of daylily.” The daylily produced in Qingyang, Gansu, is of excellent quality and is exported overseas.

Scientific Fertilization Techniques for Daylily

1. Fertilization at planting. Daylily is a perennial crop, and after planting it takes a certain number of years before it is renewed and replanted, so applying sufficient base fertilizer before planting is very important. If the base fertilizer is insufficient when planting daylily, it will delay production after planting and result in low yield. Some high-yield experience is as follows: before planting daylily, open planting trenches 30 cm deep, apply 1000-1500 kg of decomposed pig and cattle manure, 2000-3000 kg of high-quality pond mud, field mud, or compost, and more than 50 kg of calcium magnesium phosphate fertilizer per 667 sq m, applying them in layers into the planting trench, then spread the original surface topsoil. When planting, also shallowly apply 1500-2000 kg of high-quality fertilizer ash per 667 sq m. After planting, immediately drench the root area with 100-200 kg of human excrement and urine per 667 sq m (which needs to be diluted with water), or 750-1000 kg of pig urine water, as press-root fertilizer. In this way, the upper, middle, and lower layers all contain fertilizer, and after the daylily roots become established, this ensures a continuous supply of fertilizer nutrients, laying a foundation for high and stable yield.

2. Fertilization during the harvest period. According to the different growth and development stages of daylily, it is required to apply sufficient winter fertilizer, apply seedling fertilizer early, apply heavy scape fertilizer, and supplement bud fertilizer.

1) Winter fertilizer. Winter fertilizer is the most important application during the growth period of daylily and has a great impact on the yield of daylily the following year. The time for applying winter fertilizer should be when the aboveground part of the daylily stops growing and withers after frost. Winter fertilizer should mainly be organic fertilizer and should be applied in a large amount. The amount of winter fertilizer should be determined according to soil fertility and the type of fertilizer. Generally, apply 1500-2000 kg of decomposed pig and cattle manure per 667 sq m, or more than 1000 kg of human excrement and urine, or 40-60 kg of cake fertilizer, or 2000-2500 kg of high-quality compost, combined with an appropriate amount of phosphate fertilizer. If conditions permit, multiple fertilizers can be mixed and applied, such as applying human excrement and urine first, then pig and cattle manure. As for the application method, between clumps or between rows, 10 cm from the plant clumps, open fertilization holes 15-20 cm wide and 15 cm deep (if there is more fertilizer, the fertilization holes should be made deeper and wider), apply deeply, and cover with soil after application to improve fertilizer efficiency.

2) Spring seedling fertilizer. From mid-February, when daylily seedlings emerge successively, to before the flower scapes are produced, this stage is the seedling stage. The nutrients supplied at this time are mainly used for emergence and leaf growth, promoting early and rapid leaf development, making the leaves grow robustly and have a strong assimilation area, thus laying the material foundation for striving for the quantity and quality of flower scape and flower bud differentiation. Spring seedling fertilizer should be applied early, generally when sprouting begins. Because the spring seedling stage of daylily is short, generally only 40-50 days, applying it too late will not only fail to promote early sprouting but will also cause leaves to appear later due to late fertilization. At the same time, the period during which leaves continue to appear is long, and when the later-emerging leaves are still relatively tender, leaf spot disease has already begun to flare up, making them prone to infection. If seedling fertilizer is applied early, the leaf tissue of the plant has already fully developed and the cuticle is thick, which can enhance disease tolerance. Spring seedling fertilizer can generally use a combination of quick-acting nitrogen, phosphorus, and potassium fertilizers, and the amount should be determined according to the amount of winter fertilizer applied and soil fertility. Generally, apply 100-200 kg of human excrement and urine per 667 sq m, or apply 10 kg of superphosphate combined with 5-10 kg of potassium sulfate or potassium chloride.

3) Scape fertilizer. After daylily passes through the vigorous vegetative growth stage, it enters the flower scape differentiation period, that is, from vegetative growth to reproductive growth. At this time, on the one hand, it must rapidly bolt and form buds; on the other hand, the leaves are still continuing to grow. Therefore, from scape pregnancy to bolting and bud formation, this period is the stage in the life of daylily when fertilizer demand is greatest. If nutrition is supplied sufficiently, the flower scapes can develop thick and strong, bolt neatly, and the flower buds can be plump, with a high rate of bud formation, and it can also enhance bud sprouting ability and prolong the picking period; otherwise, the flower scapes will be short and thin, uneven, the flower buds will have weak sprouting ability, a low rate of bud formation, short and thin buds, and low yield. According to the growth and development rules of daylily, in order to better exert fertilizer efficiency, generally fertilizer should be applied once each when the flower scape begins to differentiate and when the flower scape begins to emerge, mainly using quick-acting chemical fertilizers, and human excrement and urine as well as cake fertilizer may also be used. For the first application, it is best to use human excrement and urine mixed with cake fertilizer after fermentation, to promote the development of flower scapes and flower buds. If such fertilizers are lacking, chemical fertilizers can be used for both applications. In terms of amount, the amount of scape fertilizer should be greater than that of seedling fertilizer. The total fertilizer used for the two applications per 667 sq m is: 12.5-15 kg of urea, 10-15 kg of superphosphate, and 10-12.5 kg of potassium sulfate or potassium chloride. The first application should be slightly less than the second, because at the time of the first fertilization, the flower scape has just begun to differentiate, and more than half of the leaves have not yet grown out. If the amount applied is too heavy, it may promote vegetative growth, thereby inhibiting reproductive growth, and make the later-emerging leaves grow tender with loose tissue, making them susceptible to disease threats; at the time of the second fertilization, daylily is entering the peak reproductive growth period, with a large demand for fertilizer, while vegetative growth is in a subordinate position, the leaf age index has reached 100%, and the leaf tissue is substantial, so it can be applied heavily.

4) Bud fertilizer. Bud fertilizer is a supplementary measure and plays a certain role in increasing yield. Daylily has the characteristic of continuous picking and continuous sprouting, and the picking period is long. During the entire picking period, a large amount of nutrition is consumed. Bud fertilizer is intended to supplement the nutrition of daylily, prevent fertilizer deficiency and premature aging, and keep the leaves green, so as to promote buds and strengthen buds, increase the rate of bud formation, prolong the picking period, and thereby increase the yield of daylily. The time for applying bud fertilizer is generally 10 days after picking begins, that is, before entering the peak picking period, which is preferable. Apply 5-12.5 kg of urea per 667 sq m, diluted with water and drenched around the roots. In addition, during the entire bud-picking period, foliar fertilization and spraying of plant hormones can also be carried out multiple times. That is, use a mixed solution of 0.5%-1% urea, plus 2% superphosphate (soaked and filtered), plus 0.2%-0.3% potassium chloride, or use 0.1% potassium dihydrogen phosphate. To the above fertilizer solution, add 15-20 mg/L gibberellin, and spray after 5 p.m., which is very beneficial for strengthening buds and preventing bud shedding.