Cucurbit crops
Cucurbit crops — a group of agricultural crops of food, fodder, and industrial importance belonging to the Cucurbitaceae family (Cucurbitaceae).
Cucurbit growing — a branch of agricultural production concerned with growing cucurbit crops.
Cucurbit crops include:
- watermelon;
- melon;
- pumpkin;
- zucchini.
In private household plots, luffa can also be grown.
Sometimes cucurbit crops are classified as vegetable crops.
Economic importance
Table varieties of cucurbit crops are cultivated to obtain juicy fruits with high taste qualities.
Fodder varieties of watermelon, pumpkin, and zucchini are used as livestock feed and are distinguished by a milk-stimulating property. They can also be used as silage in a mixture with corn, beet or potato tops, and legumes.
Edible oil is obtained from the seeds of cucurbit crops, primarily pumpkin.
Due to the high sugar content in the fruits, cucurbit crops can serve as an additional raw material for sugar production.
Cucurbit crops have agronomic importance, since after them fields remain clean of weeds.
History
Cucurbit growing in Russia has been practiced since ancient times, as evidenced by archaeological finds of watermelon seeds near the Tsimlyansk Reservoir, dated to the 8th century CE. In Central Asia, melon seeds were found that were grown in the 3rd century CE.
Commercial cucurbit growing emerged in the mid-19th century, when cucurbit crops became widespread in the Lower Volga region, Kuban, Ukraine, and Central Asia. Now the cultivation boundaries of cucurbit crops have advanced significantly to the north and east.
Cultivation areas
The sown area occupied by cucurbit crops worldwide is over 1 million ha. The producing countries of cucurbit crops are China, India, Japan, countries of Africa, Central and South America, and Europe (Bulgaria, Hungary, Romania, Italy).
During the USSR, the sown areas of cucurbit crops were 201–224 thousand ha. In 1997, in Russia the areas were 170 thousand ha; in 2001–2005, 145 thousand ha. Russia occupies one of the leading places in the world in terms of sown area under cucurbit crops.
Conventionally, cucurbit-growing areas in Russia are divided into two zones:
- North Caucasus, Lower and Middle Volga region, where about 90% of all sown areas of cucurbit crops are concentrated, mainly watermelon;
- Central Chernozem zone, central regions of the Non-Chernozem zone, Trans-Urals, Siberia, and the Far East, where mainly early-ripening watermelon varieties and pumpkin are cultivated.
Russia’s conditions, where the share of arable land in the steppe and dry-steppe zones is large, make it possible to significantly expand commercial cucurbit growing, that is, not only to supply cucurbit crops to the domestic market but also to significantly increase the export share, taking into account quality control and environmental safety.
The highest yields of cucurbit crops on non-irrigated lands are obtained in the North Caucasus, and on irrigated lands in the Lower Volga region.
Botanical description
Cucurbit crops belong to the Cucurbitaceae family (Cucurbitaceae).
Four crops are cultivated in Russia:
- watermelon (Citrullous sp.);
- melon (Melo sp.);
- pumpkin (Cucurbita sp.);
- zucchini.
Crop rotation
Cucurbit crops are demanding regarding soil fertility and freedom of fields from weeds. They give good yields on virgin, floodplain, and fallow lands, after the sod and turnover of the sod of perennial grasses. After perennial grasses, cucurbit crops suffer less from fungal diseases and produce higher yields of better quality. For fodder purposes, they are recommended to be placed in near-farm crop rotations.
In field crop rotations, the best preceding crops are considered to be winter cereal crops, corn, annual grasses, and grain legumes.
For farms specializing in cucurbit crops, special crop rotations are recommended, for example, 1 — winter rye + grasses; 2 — first-year grasses; 3 — second-year grasses; 4 — third-year grasses; 5 — cucurbit crops; 6 — cucurbit crops; 7 — spring wheat; 8 — corn for silage. The share of cucurbit crops is 25%.
In Central Asia, a cucurbit–alfalfa–grain crop rotation is recommended: 1 — cucurbit crops; 2 — cucurbit crops; 3 — spring grains; 4 — cucurbit crops; 5 — first-year alfalfa; 6 — second-year alfalfa. The share of cucurbit crops is 50%.
Fields after preceding crops for which herbicides were used are unsuitable for cucurbit crops.
In crop rotation, cucurbit crops can serve as preceding crops for spring grain crops, and under conditions of sufficient moisture in the Kuban and Stavropol Krai, for winter wheat.
Fertilization
The use of mineral and organic fertilizers helps increase yield and fruit quality (sugar and dry matter content) and accelerate their ripening. Phosphorus and potassium fertilizers significantly accelerate development and ripening.
It is important to apply organic fertilizers to cucurbit crops on light soils. In autumn, for deep plowing, manure, compost, or other local organic fertilizers are applied. Optimal application rates of mineral fertilizers are N30-60P45-90K30-60.
For top dressing, slurry diluted with water at a rate of 3–4 t/ha or poultry manure at 300–500 kg/ha are suitable.
Soil tillage
Soil tillage for cucurbit crops is similar to that used for late-sown spring crops and includes stubble cultivation to a depth of 8–10 cm and plowing with moldboard plows with skimmers to 23–30 cm. They respond well to deep tillage.
In spring, harrowing and at least two cultivations followed by harrowing are carried out. In the northern cucurbit-growing regions, on heavily compacted soils, the first cultivation is usually replaced by replowing.
When the upper soil layer dries, rolling is carried out.
Sowing
Pre-sowing seed treatment
For sowing, seeds obtained from ripe healthy fruits are used. Seed germination must be at least 90%. 6–8 days before sowing, seeds are air-heat warmed in the sun for 3–5 days or heated at 50–60 °C for 4 h. Warming seeds helps increase watermelon yields by 11–20% (Donetsk Vegetable and Cucurbit Experimental Station, Ukrainian RI of Vegetable and Cucurbit Growing).
1–2 days before sowing, seeds are soaked in water at room temperature for 24 h.
Seeds are treated in advance with 80% TMTD at 5 g/kg of seeds or 65% fentiuram at 4 g/kg of seeds.
In practice, air-dried seeds 2–3 years old are usually used, since plants from them develop better and yields are often higher.
Sowing dates
Optimal sowing dates are determined by warming of the soil at a depth of 10 cm to 12–16 °C. If the optimal sowing dates for cucurbit seeds are not observed, that is, if they are sown in insufficiently warmed soil, they rot, producing sparse seedlings and reducing yield.
Sowing is carried out with cucurbit seeders of the SBN-3 and SZU-2.4 types. For hill and precision sowing methods, the SPCh-6M seeder can be used. Corn or cotton seeders can also be used.
The plant feeding area depends on the variety, climatic conditions, and soil fertility.
The Donetsk Vegetable and Cucurbit Experimental Station proposed a band-hill sowing method, which provides for sowing with a distance between bands of 2.1 m or 1.4 m, between rows in a band of 0.7 m, and in the row (line) between hills of 0.7–1.4 m. The method makes it possible to ensure optimal sowing density; yield increases by 26–29%.
On light soils, the seed placement depth for cucurbit crops is 5–6 cm; under dry spring conditions, 7–9 cm.
Crop care
Care of cucurbit crops consists of harrowing (before and after emergence) and loosening with rotary hoes before emergence to break the soil crust and destroy weed seedlings, as well as inter-row cultivation to a depth of 12–15 cm for the first and 8–10 cm for subsequent loosenings. In the 1–2 leaf phase, thinning of seedlings or replanting of sprouted seeds into empty hills may be carried out.
During inter-row cultivation, overgrown vines are moved aside so that they are not damaged by the wheels of the cultivating machinery; for this purpose, a vine-laying device is installed in the unit with the cultivator, which shifts the vines from the middle of the inter-row spaces by 50–60 cm.
For inter-row cultivation, KRN-4.2 and KRN-5.6 cultivators are used, as well as the KMB-5.4 cucurbit cultivator; for weeding in rows, the PAU-4 weeding unit is used.
To prevent vines from becoming tangled by wind, they are covered with moist soil, which also promotes the formation of additional adventitious roots to improve plant nutrition.
Pinching (topping) of the ends of vines up to the last developed leaf during the flowering phase of male flowers is effective. Topping of fodder watermelon helps increase yield by 6.7 t/ha (Voronezh Agricultural Institute).
To control anthracnose, cucurbit crops are treated with a 1% Bordeaux mixture solution; the working solution consumption is 600 l/ha. Against powdery mildew, ground sulfur is used at 15–20 kg/ha.
Harvesting
Fruit ripening of cucurbit crops occurs unevenly. For selective harvesting of cucurbit crops, the wide-span TShP-25 conveyor is used. Ripe fruits are picked and placed into cells of the conveyor belt, which directs and places them into vehicles.
When transporting fruits, it is recommended to use the container transportation method, which reduces manual labor in loading and unloading operations, improves product quality, and reduces transport downtime.
Cucurbit crops begin to be fed to animals from late autumn. For use in the winter for fodder purposes, cucurbit crops can be ensiled. For this, a layer of chopped legume or corn straw (30–40 cm) is placed on the bottom of the trench, and on top of it pumpkins, watermelons, or zucchini in a layer of 2–3 fruits. Then layers of chopped straw and fruits alternate. When compacted with heavy machinery, the fruits are well crushed and moisten the straw. The silage is readily eaten by all farm animals.
Irrigation
To obtain high yields when cultivating cucurbit crops, irrigation is used. Because of drought resistance, irrigations are carried out rarely. The effectiveness of irrigated cucurbit growing has been confirmed by many experimental institutions: the Bykovo Experimental Station of Cucurbit Growing (Volgograd Oblast), the Biryuchekut Vegetable Breeding Experimental Station (Rostov Oblast), the Moldavian RI of Irrigated Agriculture and Vegetable Growing, and the Crimean Agricultural Institute.
In the European part of Russia, 3–5 vegetative irrigations are carried out for cucurbit crops at intervals of 10–15 days. They begin long before flowering. During flowering, they are temporarily stopped and resumed when fruit set begins. Irrigation rate is 600–800 m3/ha.
In Central Asia, autumn moisture-recharging irrigations are most effective. They allow sowing without pre-planting irrigation and reduce the number of irrigations during the growing season. The first vegetative irrigation is carried out 20 days after emergence; subsequent ones at intervals of 10–15 days. Irrigations stop 15 days before the first fruit harvest. The number of vegetative irrigations is from 5 to 11. Irrigation rate is 500–700 m3/ha.
List of sources
- Vavilov P. P., Gritsenko V. V., Kuznetsov V. S. et al. (1986). Crop Production. Edited by Vavilov P. P. 5th ed., revised and enlarged. Moscow: Agropromizdat.
- Kolomeichenko V. V. (2007). Crop Production/Textbook. Moscow: Agrobusinesscenter.
- Niklyaev V. S. (2000). Fundamentals of Agricultural Production Technology. Agriculture and Crop Production. Moscow: Bylina.
