Spinach Cultivation

Source: www.bienniel plants.com Spinach

Spinach (Spinacia oleracea) is an edible flowering plant in the family of Amaranthaceae. It is native to central and southwestern Asia. It is an annual plant (rarely biennial), which grows to a height of up to 30 cm. Spinach can survive over winter in temperate regions. The leaves are alternate, simple, and ovate to triangular-based, very variable in size from about 2-30 cm long and 1-15 cm broad, with larger leaves at the base of the plant and small leaves higher on the flowering stem. The flowers are inconspicuous, yellow green, 3-4 mm diameter, maturing into a small, hard, dry, lumpy fruit cluster 5-10 mm across containing several seeds.

Introduction

Herbaceous plants harvested for their leaves are known as leafy vegetables including spinach, lettuce, cabbage, fenugreek and celery. Spinach (Spinacia oleracea L.) is native to Asia and is high value vegetable rich in vitamins, calcium, iron and fiber content in its leaves. China is leading in global spinach industry by producing 85% of total world's production followed by United States contributing 3% of total world crop production. Pakistan is producing 95.5 thousand tons of spinach with 1.2 tons / ha in yield.
Spinach (Spinacia oleracea L.) locally known as Palak, and it is an annual dioecious plant. Spinach is the most important highly nutritious green leafy winter vegetable grown in Pakistan on a large scale. It is one of the most common herbage vegetable grown for its greens or leaves. Spinach is a long-day plant that produces its best vegetative growth under cool temperature 116.18(°C) than short day length (Hartman at at, 1981). Long days especially coupled with high temperatures above 25°C cause the plant to bolt and flower, which is detrimental to the spinach production. Several factors are responsible for good spinach production but sowing time, plant spacing and numbers of cuttings are the most important. Spinach is generally grown by broadcast method in Pakistan. Close spacing between plants don't form a rosette of leaves and are to develop elongated shoots even at seeding stage. Planting in rows eases the weeding in the earlier stages of the growth. Plants within the rows are relatively close i.e. (15-10 cm). It was observed that spinach cultivar “Kandiairi” was sown at monthly intervals from 1st October to 1st January and leaves harvested once, twice and thrice. Maximum yield of spinach was gained in broadcast method as compared to any other method. Broadcast method showed the prominent results in all the parameters studied.
Spinach is important for skin and hair, bone health, and provide protein, iron, vitamins and minerals. Spinach is rich in flavonoids- a phytonutrient with anti-cancer properties. Thus, it has been found to be effective in slowing down cell division in human stomach and skin cancer cell. One cup of raw spinach contains 27 calories, 0.86 grams of protein, 30 milligrams of calcium, 0.81 grams of iron, 24 milligrams of magnesium, 167 milligrams of potassium, 2813 IUs of Vitamin A and 58 micrograms of folate. Spinach is also used for eating purpose as vegetable.

Venturing in Spinach Cultivation in Pakistan

Spinach is an excellent source of beta carotene, vitamin C, E, and K, potassium, iron, sulphur, sodium, folic acid and oxalic acid. It contains more protein than most vegetables. Spinach is one of the vegetables with the highest amount of chlorophyll, a fat-soluble substance that stimulates hemoglobin and red blood cell production.
Chlorophyll is known to have a chemical formula remarkably similar to that of hemoglobin, and it is said that the ingestion of chlorophyll will raise hemoglobin in blood without increasing the formed elements.
The exceptionally high antioxidant property of spinach is due to carotenoids, beta carotene and lutein, which are three to four times higher than in broccoli, for example. These naturally occurring fat-soluble pigments are most effective when eaten with some fat. Spinach also has plenty of potassium, which supports a healthy nervous system, aids proper muscle contraction, stabilizes blood pressure, regulates the transfer of nutrients through cell membranes and, together with sodium, controls the water balance of the body.
While spinach is known for its high iron content, recent studies have shown that the iron contained in spinach is not easy for the body to assimilate and only a very low percentage is used. The relatively high amount of oxalic acid in spinach interferes with the absorption of iron and calcium into the blood.
When eaten in large amounts, spinach could damage already impaired kidneys: oxalic acid removes calcium from the blood in the form of calcium oxalate, and calcium oxalate obstructs the kidney tubules. The fairly high concentrate of nitrogen compounds in spinach can be reduced up to 70% by blanching the vegetable.

Production Technology

Climate and Soils

This is an important vegetable of Rabi season and requires a cool and moist climate. Low temperature and high humidity helps in the development of succulent, tenders mild flavored foliage and quick growth. The plant prefers sunshine.
For seed development and maturity, plant requires long and warm days. Spinach germinates best at soil temperature below 10-12 °C. At high temperature, the seed fails to germinate because they enter into a dormant state which continues until the temperature again falls below 10-12 °C.
Spinach can be grown successfully on a variety of soils, but a fertile sandy loam high in organic matter is preferred. The use of cover crops and green manure crops is recommended to maintain the soil organic matter. The soil pH should range between 6.4 to 6.8. Spinach is very sensitive to acid soils, thus a soil test prior to planting this crop should be made. Low germination, yellowing and browning of margins and tips of seedling leaves, browning of roots, general slow growth and even death of plants, may indicate that the soil is too acid. If the pH is too high, leaves may have a yellow color referred to as chlorosis.

Land Prepration

A well-prepared seedbed that is free of large clods permits precision planting with rapid and uniform emergence of spinach seedlings. Uniform depth of seeding is critical when using pre-plant-incorporated herbicides because if spinach seeds are planted too deeply, seedlings may be killed by herbicide. Well-prepared seedbeds also permit proper and accurate incorporation of pre-plant-incorporated herbicides, leading to improved weed control and reduced phytotoxicity to seedlings.

Irrigation

Spinach requires abundant moisture to insure a high quality product. An application of one inch of water every seven to ten days, when rainfall is inadequate, is recommended. Keep soil moist until seedlings have emerged.

Time of Sowing

Winter spinach is best when sown in August. Summer spinach can be started in February and needs lot of water

Seed Rate

Around eight to ten kilo gram seeds per acre are recommended. Seeds are broadcast on the flat beds or in ridges and are mixed with fully prepared soil sans pressed with some hard material immediately after sowing seed, irrigation water is applied.

Varieties

    There are two local varieties of spinach in Pakistan.
  1. Local Sindhi
  2. Prickly Seeded

Fertilizers

Spinach requires a high level of fertility, especially nitrogen. Early spring spinach may require larger quantities of fertilizer than fall crops. Per acre requirements on sands and sandy loams are 85lb to 120 lb N; 75lb to 85 lb P2O5; and 85lb to 150 lb K2O. On heavier clay soils, 50 lb/acre of each nutrient should be adequate. Fertilizer is often broadcast and worked into the soil prior to seeding. If the fertilizer is banded at seeding, it should be placed along each side of the rows 2 to 3 inches below the level of the seed.

Weed Control

A healthy, vigorous crop provides substantial competition that suppresses weed growth and acts as part of the weed control programme. Therefore, proper fertilization, irrigation, and insect and disease control measures promote good crop growth and compliment other weed control measures. Hand-weeding is an expensive component of crop production budget. Ideally, good cultural practices and careful use of herbicides will result in minimal hand-weeding requirements. After planting the crop, there are two periods in which herbicides may need to be applied, depending on the weed species present. Post plant treatments are applied after planting but before the first irrigation and the emergence of crop; post emergent treatments are applied when spinach is in the seedling stage or older to the side of the row; fertilizer should never come in contact with the seed.

Marketing and Storage

Spinach is sold loose, in pre-packaged bags, or frozen. Fresh spinach loses much of its nutritional value with storage of more than a few days. While refrigeration slows this effect to about eight days, spinach will lose most of its folate and carotenoid content, so for longer storage it is frozen, cooked and frozen, or canned. Storage in the freezer can be for up to eight months.

Harvesting and Yield

The crop is ready for cutting within six to eight weeks after sowing. The cutting is done 2cm above the ground level when plants have put five to six leaves. New foliage is cut later with three to four cuttings.

Insects & Diseases

Spinach aphid and leaf miner are the two predominant insect pests of spinach.
Down Mildew (Blue Mold), bacterial soft rot, fusarium wilt, cucumber mosaic virus, carpospores spot, white rust and heterosporium spot can all be problems in spinach production.

Agri.Pedia

Pesticide: .a substance used for destroying insects or other organisms harmful to cultivated plants or to animals.

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