Hello Nature

Apr 17, 2023

No Comments Cotton is the most important natural vegetable fiber and the land devoted to its cultivation covers vast areas of the planet. The climatology limits the cultivation area in a range of 30° south and north of the equator. The most relevant production areas are in the United States, China, Paraguay, Mexico, Pakistan, Australia, Brazil, Turkey, Sudan and Egypt. Nor is it known exactly when cotton cultivation began. In the Indus River Valley of Pakistan, cotton was grown, processed, and woven into cloth as early as 3000 BC, or around the same time, the natives of the Nile Valley of Egypt made and wore cotton clothing. When Christopher Columbus discovered America in 1492, he found cotton growing in the Bahamas. By 1500 cotton was known throughout the world. The cotton (Gossypium spp.) belongs to the botanical family Malvaceae. It is an erect branched shrub, measuring up to 3 meters. The cotton plant has an indeterminate type of growth, since vegetative growth and reproductive development occur at the same time. The leaves are spirally arranged on the stems. They are generally webbed with 3-5 lobes, pubescent or glabrous. The flowers are solitary, pentamerous, white to pale yellow in color, rarely purple in the center. They are borne on pedicels 1-4 cm long and wrapped in three bracts that remain around the fruit after pollination. The fruit is a capsule, which opens when ripe. Each capsule contains many seeds, each of which is surrounded by a spongy, white, easy-to-spin fiber. Cotton has a tap root system and the roots can reach twice the length of the plant. Plant development takes place through several phenological phases that can be divided into vegetative and reproductive growth phases. After sowing, the seeds germinate in 5-10 days and the cotton plant begins its growth with two cotyledons until the plant forms true leaves. As the cotton plant begins to grow, it develops a series of nodes along the main stem. From the fifth or sixth node, the plant begins to form fruitful branches. Typically, a cotton plant grows to a total of 16-22 nodes, with 12-16 fruiting branches. After pollination, the flower petals wither and the capsule is formed, which is initially green in color. The capsule contains some sebaceous glands and many dark brown seeds that are wrapped in fluff. The fibers we know as “cotton” are represented by the fluff (called raw cotton) that is found around the seeds. When ripe, the capsule splits into four points, leaving the seeds and white fibers visible. The edges of the open capsule harden and become like spines around the cotton ball. If they are not harvested, the fibers and seeds are blown by the wind. Cotton is a permanent plant but is grown as an annual. The most cultivated cotton species are: Gossypium hirsutum – Upland Cotton: represents more than 90% of world production, normally supplies high quality cotton with high resistance and elasticity. Gossypium herbaceum – Herbaceous Cotton: It is native to Pakistan, India and some parts of Africa. Gossypium barbadense: cultivated in Egypt, Sudan, USA, Brazil and Peru. Gossypium arboreum: plant native to Pakistan, Sri Lanka and India. It is not widely cultivated, because it normally gives short fibers of poor quality. Cotton is a semixerophytic plant and is grown under tropical and subtropical conditions. A minimum temperature of 15°C is required for good seed germination. The optimum temperature for vegetative growth is 21-27°C and it can tolerate temperatures up to 43°C, but temperatures below 21°C are detrimental to cultivation. Cotton prefers soils with excellent water retention capacity. Aeration and good drainage are equally important, since it does not tolerate excessive humidity and stagnant water. The main types of soil suitable for growing cotton are alluvial, clayey or sandy-clayey. All the essential nutrients play an important role in the metabolism of the plant. A nutrient present in greater quantity cannot compensate for the lack of another nutrient, since they fulfill different functions. Plants manifest deficiency of one or more nutrients through symptoms on leaves, stems, and growth abnormalities. The crop also benefits from the application of biostimulant products, based on microorganisms and vegetable protein hydrolysates. These products can stimulate the emergence and development of roots in the early stages of seedling development, improve the availability of nutrients in the soil, increase yield from a quantitative and qualitative point of view, reduce the negative impact of climatic stress. and increase nutrient use efficiency (NUE). The application of biostimulants increases the environmental and economic sustainability of the productive system. Nitrogen (N) is the most important and most used element in cotton cultivation, but it is the most difficult to manage. Low N inputs can reduce yield and quality, while excessive N inputs can cause excessive tissue growth, boll rot, delayed maturation, and poor quality and yield. The N uptake rate is low early in the season, increases during the early fruiting phase, peaks at flowering, and gradually decreases as ripening approaches. Phosphorus (P) is important to promote root development in the early stages of seedling growth. Phosphorus can be applied with a starter fertilizer along with nitrogen, especially in heavy, low-phosphorus soils or cool soils. A starter fertilizer provides greater benefits in cooler, wet conditions than in warmer, dry conditions. P uptake by cotton is most critical early in the growing season because P is needed to stimulate root development and anticipate fruit set. Potassium (K) is essential for capsule formation. Like N, K is also required in large quantities after the first flowering and the demand for K can exceed that for N during this period. K uptake increases during boll formation, with approximately 70% of total uptake occurring after the first flowering. Soil application is the best method to manage K. 2023-04-16 10:39:40