Bermuda grass

Bermuda grass, also known as iron coin grass and creeping grass. It is widely distributed in tropical, subtropical and temperate coastal areas, and is found in the southern United States, Africa, Europe and southern Asia. In China it is distributed in all provinces and autonomous regions south of the Yellow River basin, and has been promoted for planting in Guangdong, Guangxi and other provinces and autonomous regions. It usually grows on riverbanks, meadows and the edges and corners of fields, and can form single-dominant stands of a certain area.

I. Economic value

The greatest characteristic of Bermuda grass is its dual reproductive capacity through seeds and rhizomes. Its rhizomes have strong reproductive capacity, grow fast and yield high. It has abundant leaf mass, soft herbage, a mild taste, and slightly acidic stems; its palatability is good, and livestock such as yellow cattle, water buffalo, horses, goats and rabbits all like to feed on it, while pigs and poultry also like it when it is young and tender. In the young and tender stage, crude protein accounts for 17.58% of dry matter, crude fat 1.95%, crude fiber 29.64%, nitrogen-free extract 36.54%, and crude ash 14.29%. It can be cut 3--4 times a year, generally yielding 2250--3000 kg of hay per hectare; on fertile soil with good management conditions, it can yield 7500--11250 kg of hay per hectare. Bermuda grass has a well-developed root system and abundant roots, making it a good soil and water conservation plant; it is also a good plant for laying helicopter pads, sports fields, parks and courtyards, and for greening cities and beautifying the environment; its rhizomes can be used as medicine and have a blood-purifying effect.

II. Botanical characteristics

Bermuda grass is a perennial herbaceous plant of the genus Cynodon in the grass family. It has rhizomes and stolons, with internodes of varying lengths. The culms creep along the ground and can reach more than 2 m in length; any node touching the ground can take root, and each node can produce 1--5 tillers that reproduce into new plants; each node is formed by 2--3 nodes densely contracted into a "contracted node," so each internode can grow 2--3 leaves. The ligule is short, with small cilia; the leaf blade is linear, 2--10 cm long and 1--3 mm wide. The spike inflorescence consists of 3--6 spikes arranged digitately at the top of the culm; the spikelets are arranged on one side of the rachis, 2--2.5 mm long, containing 1 floret; the anthers do not dehisce, and most cannot set seed, so it mainly reproduces asexually by rhizomes; the glumes are equal in length, 1-nerved and keeled, shorter than the lemma; the lemma has 3 nerves and hairs on the keel; the lemma and palea are equal in length and have 2 keels. The 1000-seed weight is 0.25 g.

III. Biological characteristics

Bermuda grass is a spring-type grass that likes heat and cannot tolerate cold; it grows poorly in cold weather and is prone to frost damage. It grows well when the daily average temperature is above 24°C; growth slows when the temperature drops to 6--9°C; when the daily average temperature is -2-- -3°C, the stems and leaves fall to the ground and die. In southern China it generally germinates in March--April, grows vigorously from June--August, and gradually withers after November; the green-fodder period is more than 8 months, and the growth period is 250--280 days. It can resist relatively long periods of drought, but the yield is very low. It adapts to an extremely wide range of soils, growing from sandy soil to heavy clay, but grows best on moist, well-drained, moderately heavy clay soil. Under ordinary conditions, Bermuda grass has strong vegetative reproductive and competitive ability, spreading by stolons and rhizomes, and can spread rapidly under suitable soil conditions, with an average daily growth rate of 0.91 cm, reaching up to 1.4 cm, thus forming a plant community in which Bermuda grass is absolutely dominant.

IV. Cultivation techniques

The germination rate of Bermuda grass seed is very low, and few seeds can emerge, so land with deep, fertile soil should be selected for plowing and turning, with 60,000--70,000 kg of livestock pen manure and 150--225 kg of superphosphate applied per hectare as base fertilizer. Its main cultivation methods are as follows.

(1) Sowing method: propagation by seed. Bermuda grass seeds are small, so the land needs fine leveling to achieve a level surface and broken-up soil. Seed germination is best when the daily average temperature is 18°C, and the sowing rate is 3.75--11.25 kg per hectare. When sowing, the seed can be mixed with mud and sand and then broadcast, so that the seed and soil are in good contact, which is conducive to seed germination.

(2) Strip planting method: propagation by cuttings. Dig furrows with a row spacing of 0.6--1.0 m, place the chopped rhizomes into the furrows with the tips of the branches exposed above the soil surface, then cover with soil and tread firm.

(3) Division and transplanting method: dig up Bermuda grass turf and transplant the divisions into holes dug in the prepared land, taking care to keep the plants and buds facing upward.

(4) Block planting method: cut the dug-up turf into small blocks, dig holes larger than the turf blocks in the land to be planted, place the turf blocks into the holes, and fill them firmly with soil.

(5) Cut-stem broadcast pressing method: in early spring, dig up the stolons and rhizomes of Bermuda grass, cut them into 6--10 cm small sections, mix them with soil and broadcast them over the prepared land, then press them in promptly so that they contact the soil and can germinate and grow.

After cultivation by the above propagation methods, irrigate appropriately according to soil moisture conditions to facilitate survival. Whether or not Bermuda grass is fertilized makes a very large difference in yield, so the cultivation and management of Bermuda grass should pay attention to rational fertilization. Organic fertilizer can be applied as a base fertilizer before sowing, and nitrogen fertilizer should be applied as a top dressing after cutting.

V. Utilization methods

Bermuda grass has high yield and good quality and is most suitable for cutting as green fodder. When the grass canopy reaches 40--50 cm high, cutting and utilization can begin, with a stubble height of 2--3 cm. After cutting 1--2 times, quick-acting nitrogen fertilizer should be applied as a top dressing to promote the growth of regrowth grass. In the peak growing season, it can be cut once every 30--40 days, and 5--6 times in the whole year, with each cut yielding 15,000--23,000 kg of fresh grass per hectare and an annual yield of 110,000--150,000 kg of fresh grass per hectare, which can be used to make hay or silage. Because Bermuda grass is relatively tolerant of livestock trampling, it can also be used for grazing. If it is domesticated and attention is paid to increasing grass yield, it can serve as a cultivated grass species for permanent pastureland.