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Vegetable Production Introduction : International rate of increase in the population is about 2% →2× each 30-35 years which is now about 7 Billion. This means that:
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Vegetable Production • Introduction: • International rate of increase in the population is about 2% →2× each 30-35 years which is now about 7 Billion. This means that: • Demand for food is increasing continuously while cultivated area or involvement of the area (old and new) is not proper with the increase in demand. Soil of very good properties is suitable for all sectors, so land involved in agriculture is of very low characteristics →which will increase the cost of cultivation. Total area is about 10% of the total. • Rich countries can either produce or import even if with high cost, while poor or developing countries are suffering from Hunger situations and malnutrition (in Asia, Africa, and Latin America). • Ref.: Table 1 and 2
The ratio of differences between rich and poor countries is about 20 years in life expectancies. متوسط العمر This is because of variation in Energy requirement/person and availability of fruits, vegetables (tubers, and or fruit nuts) which are important sources of high nutritional requirements (minerals, vitamins, proteins, starches, fats, and sugar), plus their importance for crude fibers → commercial sector → which is not possible by poor import or cultivate. One of the main reasons for hunger is the unbalance situation between number of people/km² area, and the arable land used for production. For example, Asia had reached saturation per km² → which means low food supply and low new land to be added, because of increasing in the number of people. Ref.: Table 1.1 and 1.2
Table1: Worldwide Production of Vegetables in 1993 in descending order.
Table 2: Major Vegetable Producing Countries*. * Vegetables (except roots and tubers) including carrot and melons. ** Commonwealth Independent States
Vegetable: A horticultural food crop, most grown as annuals and few as perennials. Most are herbaceous, edible part is either roots, stems, leaves, immature floral part, immature seeds and immature or mature fruits, where the edible part is highly rich with water which means the storage period is relatively short even under proper conditions, and can be eaten either raw or cooked.
Table 1.1. Some comparisons of developed and developing regions of the world. • Source: FAO data (1979). • low food supply in developing countries could be also related to the use of well fertilized land for export, activities. In addition to what mentioned before.
Table 1.2. Food producing capacity of some countries in relation to population density and arable land in 1979
Source: FAO data (1979). a Arable land: (a) If greater than 0.8 ha/person, food supply usually adequate; export of surplus. (b) If in range of 0.4-0.8 ha/person, country is 80% to completely self-sufficient. (c) If less than 0.4 ha/person, diet high in food of plant origin; import of food for adequate diet. b Developing nations.
Importance of Vegetable • The intake of proper nutrients is necessary for well being. • Proper food means different kinds of food with proper balance and optimal amounts. • The required amount of nutrients can vary with sex, age, size of the body, activity and environmental conditions. • The term under nourished means lack or inadequate caloric intake. • The term malnourished means lack of minimum daily intake of proper food that including essential amino acids, vitamins, minerals and others. • Both malnourished and undernourished can lead to diseases as marasmus disease, also it can increase susceptibility to infections and diseases, stunting of child’s growth even physical or mental →so it leads to reduction in intelligence level.
Importance of food components: Ref.: Table 3 1) Water: for dissolving minerals, maintain the osmotic balance in cells and drive out the metabolic waste. Daily intake is 1100ml from food and 1100ml from drinks and 250ml from metabolic water = 2450ml. Daily output of water is 1350ml as wastes and 1100ml as evaporation, and losses from skin and lungs, so the total daily output is 2450ml. - Metabolic water can be derived from carbohydrates (CHO), proteins, and fats, where: 1g of starch→ 0.6g of H2O 1g of protein→ 0.41g of H2O can be obtained from vegetables 1g of fats→1.07g of H2O
2) Energy: all foods released energy as they are broken in the body. Man needs about 2400-2500 kcal/day, where: 1g of CHO→4kcal as metabolic energy 1g of Fats→9kcal as metabolic energy 1g of Protein→4kcal as metabolic energy Can be obtained from vegetables 3) Carbohydrates (CHO): main CHO compounds in plants are starch, sugar (sucrose, glucose, fructose), for example, sun flower and onion are rich in fructose. 4) Lipids: fats and oils: adequate diets should have almost 15% of total calories derived from lipids. Fats of vegetables are generally oils while those of animal are solids. Vegetable fats are of less cholesterol in the blood. Also blood pressure and heart diseases are related to excess intake of fats (animal fats).
5) Proteins and amino acids: for building of body and enzymes formation which carry out the body functions. The 8 essential amino acids are not synthesized by body cells, so they are taken from food (plant and animal). • Protein quality: present of amino acids in proper proportion so as to be utilized effectively essential لأن غياب واحد يمنع تكوين الأخر • Net protein utilization: % of amino acids ingested as protein and retained in the body as protein. Vegetables show 50-70% متوسطه • Protein efficiency ratio: weight gained/unit of protein fed which is for vegetables =2.0 Protein malnutrition can cause kwashiorkor = nutritional disorder cause brain damage for ages from 6months-6years old. Ref.: =Tables 4.2+4.3
6) Vitamins: they are potent organic substances, need for normal body function. • Ref.: Table 4 • Fat-soluble vitamins: that can be stored by body. • Vitamin A: which is essential for vision in dim light and it’s deficiency cause abnormal dry skin. Highly found in green plants. • Vitamin E: which acts as antioxidant, it’s deficiency affects on the reproductive mechanism, but it's low in vegetables. • Vitamin K: which is important in coagulation of blood, found in fresh dark vegetables as spinach. • Daily intakes of vegetables is greater than animals
b. Water-soluble vitamin: can’t be stored by body in a significant amount, so we need continuous food sources. • Vitamin B1 (Thiamine): prevents Beriberi ضعف, cofactor in CHO metabolism. It’s deficiency prevents normal metabolism of pyruvic acid that come from CHO metabolism → brain and nerve which depends on CHO = as a source of energy will be affected negatively. Vegetables are good sources of B1. • Vitamin B2 (Riboflavin): it is a part of enzyme system to convert the food to chemical energy. Leafy vegetables are good sources even rich. • Vitamin C (Ascorbic acid): prevents scurvy مرض الاسقربوط =تورم اللثة ونزف الدم, it’s deficiency can cause anemia, poor wound healing and connective tissue formation. Green vegetables are high in vitamin C as pepper while tomato juice contain from 15-20mg (good), but potato has low vitamin C content, which by using sufficient amount → can be good source.
Vitamin B6 (Pyridoxine): has a role in nervous tissue metabolism and in anemia. Vegetables are high in this vitamin. • Folic acid (Tetra hydrfolic acid): important in nucleic acid and protein syntheses of the cell. Spanish, broccoli, cabbage and lettuce are good sources. • 7) Minerals (Table 5): They are required to support human biochemical processes by serving structural and functional roles, they are divided into two categories: • a. Macro-elements units: including: • Na, K, and Cl: important in maintaining osmotic balance of body fluid. • Ca, Mg, and P: important in blood and skeletal system, P also involved in many enzymatic reactions. • S: important in protein building throughout it’s role in enzyme system. • Fe: important in hemoglobin formation of the red blood cells.
b. Microelements units: including: • I: for thyroid activity. • Cu: for tyrosin activity, it’s lack block Fe metabolism and cause anemia. • Zn: involved in at least 8 enzymes systems. • Co: in vitamin B12 activity (anemia prevention). • Mn: cofactor in many enzyme reactions. • F: important to prevent dental decay. • All these can be obtained from vegetables.
Table 3: Proximate Composition (per 100g edible portion) of some important vegetables.
Table 4: Vitamin Content (per 100g edible portion) of some important vegetables.
IU: Vitamin A is formed of Isoprene units each has 5 carbon atoms.
Table 4.2: Minimum requirements of essential amino acids: national research council (g/day) ª Essential amino acids.
Table 4.3: Essential amino acid composition of some vegetables in comparison to hen’s egg and the limiting amino acid determining protein score.
Source: Kelley (1972) ª Limiting amino acids. b based on average figures.
Table 5: Mineral Content (per 100g edible portion) of Some Important Vegetables.
Factors affecting amounts of nutrients in vegetables: • Genetic make up of plant: under same growing conditions → you can see wide range of nutrient content in the same population. So selection and breeding program can be used to improve nutritional content of various vegetable spp. • Environmental conditions: • a. Seasonal factors: temp., moisture, and light, but excess or shortage of any factor negatively affects on nutrient content. • b. Atmospheric conditions and composition of toxicants and pollutants, also affects negatively on nutrient content. • c. Soil factors: chemical and physical properties of soil, and soil moisture content. • d. Cultural practices: fertilization, pests, diseases, weeds, competition and maturity aspect.
3) Losses during and after harvesting: • A . Harvest: volume of losses varies depending on spp. it self and its ability to resist braising and brake of cells. Mechanical induces more damage than hand harvest also transport could cause damage. • B .Holding and storage prior to processing: time and temp. can affect nutrient value. Content of Vitamin C is an index for proper storage condition since it is very labile. • C .Washing prior to processing: if you use recycled water which gets warmer and if you use detergents → some soluble substances can be leached and contamination with trace metals can occur while pesticides residues can be removed (non systemic pesticide). • D .Peeling and chopping: removal of peel even mechanical or by using soda → nutrients concentrated in skin can be removed especially Vitamin C because by oxidation which follows peeling or chopping or from tomato since concentrated under skin.
E .Blanching: exposing vegetables to steam or hot water to inactivate enzymes which may deteriorate the product. By this technique, water soluble vitamins and minerals can be exposed to losses. F .Processing: done by: 1) freezing; 2) dehydration; 3) canning; or 4) pickling. Thermal processing can induce major loss. G . Packaging and storage: depends on container to be used, storage temp., and duration of storage temp., and duration of storage. Low or no O2 by N2 replacing conditions, vacuum, low temp. and darkness to keep low temp., and no chlorophyll pigments, are best for nutrient retention. So, as temp. and/or storage time increase quality will decrease.
Vegetables can be grouped as a source of nutrients into: • High CHO as: white potato, sweet potato, sugar beet, sweet corn, dry beans, and cassava. • High in oils: legume seeds, and mature vegetables seeds. • High in proteins and amino acids: beans, peas, most leafy vegetables (cruciferous vegetables= Brassica spp.), and sweet corn. • High in Vitamin A: carrot, sweet potato, cucurbits, pepper, green leafy vegetables, green beans, and peas. • High in Vitamin C: crucifers, peppers, tomato, melon, most leafy vegetables, immature seeds of beans, and white potato. • Rich in minerals: most leafy vegetables especially crucifers and root crops.
So by under standing nutrient content of vegetables, it is possible to depend on plants when you take crops rich in protein in sufficient amounts. • So, what are the suggestions to improve vegetables situation? • A) Increase of food supply :by • Increase production: it is now about 2% per year to face the population growth, 20% from new areas involved and 80% due to Technology. As: new CVs, good cultural practices, fertilization, irrigation, plant population and regulators. This means better sustainability. • Development of new food forms from other resources using by-products, wastes and residues, (hydroponic) .
3)Increase the efficiency of nutrient production By eliminating animals from food chain a- plant →animal (excluded) →man Efficiency of land production will increase if we produce directly for human consumption, and concentrating on those that substitute low consumption from animals (valuable food = fats + protein of animals). Ref.: Figure 1.1. b- Selection of crops that produce highest quantity of nutrients as for example efficiency of producing the 8 essential amino acids to improve the nutritional status. Ref.: Figure 1.2
4)Multiple cropping: greater than cropping cultivation in one year a- sequential cropping: growing of two or more crops in a sequence/year, could be done by soil less cultivation. b- Inter cropping: growing of two or more crops simultaneously on the same land-either mixed or in alternative rows or strips. c- Ratoon cropping (to save all the time): cultivation of regrowth parts of the same crop after harvest (suckers and adventitious shoots). d- Relay cropping: the simultaneous growth between two or more crops, occurs in part of the growing period of each crop, normally the 2nd crop is seeded or transplanted when the first crop reaches the productive stage, as cucumber then tomato.
B) Improving the world vegetables: National • Improving efficiency, distribution, and conservation (in the same country) by cooperatives and institutions. Since single farmers can not if prices at producing sites are low, and costs of transport to areas that they need are high, so they can not control diseases, rodents, … during handling to decrease losses. • 2) Reducing losses and wastes during all production stages by: 1) Protect against diseases, insects, using immune cultivars; 2) Stop erosion and water wastes. • 3) Taking care of subsistence crops as much as the valuable exportable crops to achieve stability. • 4) Improving the use of wasted organic parts of vegetables.
C) Improving international trade of vegetables, • since the nature of vegetables is highly perishable → trade activity is very low. • The concentration should be directed towards processing, dehydration, freezing of products for longer distances, and improving means of transport either by air or seas, and using refrigerators for national transport of long distances. • - Also demand for vegetables increase during winter which can be by producing in tropical and subtropical regions, and forcing the vegetables. This needs programming, grading, and improving the quality of production. (Intrinsic and phenological characters).
Figure 1: Possible routes from production to consumption of vegetable. (from Ref. 5.) Storage Home Preparation Consumption
Fig. 1.2.: Efficiency of crops and animals in producing the essential amino acids on an area basis Vegetables are among those that produce the highest quantity of amino acids which also occurred in short period of time
In Jordan, major production areas of vegetables are: • Dry lands: were annual precipitation rate is 300mm or more, mainly in Irbid, Amman, Maa’daba, and Balka. That share with about 4.5 million J.D. of the total income, and represents about 1.6% of the total cultivated area. The production is changeable in relation to rainfall quantity. • Main crops are deep rooted ones as: tomato, okra, sweet melon, and snake cucumber. It is characterizing with low production because of: 1- Low plant density; 2- Rare treatments; 3- Low yielded cultivars are used. Since expected profit is low. • 2) Irrigated up lands: Beside lands irrigated by springs or by ground water, even protective and open field, both share with about 155 million J.D. of the total income, and represents about 53.8% of the total cultivated area. Mainly in Mafraq, Zarqa, Maa’daba, and Baqa. • Main crops are: tomato, eggplant, cucumber, cauliflower, sweet melon, and squash. Average yield is relatively low except when area is covered with plastic houses, because of low experience to fertilization, irrigation and pest or diseases management.
3) Jordan Valley Area: From north to south, the vegetables are planted from August to February, there are two planting times; in August and in Spring. In the southern regions spring planting time is of high risks because of many factors: 1) Water: it is a limiting factor; 2) Annual precipitation is decreasing from year to year; 3) High labor cost which represents about 50% of the total input cost; 4) Mechanization is not effectively used; 5) Land is divided to 30 donum areas between owners which means low technology implementation. Main crops during fall season are: tomato, potato, onion, squash, eggplant, and others as pepper, beans, and cucumber showing about 100,000 donum of cultivated area. Main crops during Spring are: Jews mallow, tomato, potato, musk melon, eggplant, onion, okra and water melon showing about 45,000 donum of cultivated area.
Factors influencing vegetables growth: 1- Climatic factors : Interaction of temp. x moisture x wind x solar radiation = atmospheric condition per period of time and summation of these atmospheric conditions, which determine the climatic conditions for many years, also, 2- Also, Soil conditions that depends on climatic factors, is another factor. For both climatic and soil factors appear the adaptation of plant spp. and ability to grow.
1) Climatic factors: • Temperature. • Moisture or precipitation rate • Light • Wind • CO2 concentration • A. Temp.: limits growth and distribution of plants, it is a result of solar energy that equals 2g cal/cm²/minute. Temp. distribution: equatorial zone is the hottest, while polar zones are the coldest with difference in solar energy received leading to seasons formation/year (summer, Autumn, Winter, and Spring). • - There is a 45ْC variation between winter and summer, while in equatorial is just 3ْC. • - Variation over continents is higher than that over oceans and seas because of larger heat capacity of water than soil.
- Day temp is higher than night temp. where maximum temp. is in the after noon and minimum temp. is at sunrise. • As the altitude increase, temp. will decrease in about 6ْC/1000 meter elevation. • Temp. in the southern side of the mountain is higher than that in the northern side during day. • All these are important factors in selection of adapted spp. Since for each spp. there is minimum, maximum, and optimum temp.) → temp. as cardinal. • Van Hoff's law (Q10 law): Every 10ْC rise→2x dry matter production in range of 5 ْC to 35ْC. • No. of frost-free days: average period between the last killing frost in spring and the first killing frost in the fall. • Heat units: degree-days.
Large diurnal range is favorable for net photosynthesis → growth and production. As night temp. increase it affects negatively on production. • Vernalization: exposing of seedlings or seeds to low temp periods (according to spp.) , it will induces or increases flowering. • Devernalization: reversal of Vernalization, when plant exposed to high temp. (30ْC or more) after low temp.
Fig. 1.3.: Different growth stages. Phase 1: vegetative growth; phase 2: vernalization; phase 3: floral initiation; phase 4: seed stalk development; phase 5: flowering and fertilization; phase 6: seed maturity.
If seeds are exposed to Vernalization, moistened seeds under low temp degrees will hinder radicle growth) → 1ْْْC-6ْC from 15-60 days. • Most vegetables are injured at temp slightly below freezing. • Freezing and chilling injury: Tropical and subtropical plants killed or damaged at temp. degrees below 10ْC as cucumber, tomato, and potato, especially for long period of time, this is called chilling injury. But if plants subjected to low temp degrees for a short period of time, then increase in temp degrees, the plants will not affect by low temp. before. So time-temp relationship is very important, also the growth stages from an thesis to shortly before flowering is the most sensitive period to cold. Hardening: Exposing plants to cold temp gradually but not suddenly as like cabbage. Also hardening can be done by exposing plants to water stress which can be more applicable.
High temp. injury: Increasing the temp. and increasing the percentage of relative humidity affects on leaf temp., it may reach 8 ْC higher than air temp., and if temp rises it results in protoplasm destruction in range of 45 ْC-50ْC. Also ↑ temp. during green fruits stage of tomato → sun-born and scalded of fruit as ripe. Also gradual exposure to raise in temp. with increasing hrs leads to acclimation of exposed plants.] Dormancy: Little or no growth at unfavorable environmental conditions, as decrease or increase in temp degrees, or lack or excess of moisture. Sometimes photoperiod is involved in dormancy all these + seed coat dormancy known as external dormancy, while if seed remain in rest period even with favorable conditions this is called internal or physiological dormancy which related to the changed in inhibitors and/or promoters rate that affected by temp variations. Storage temp. affects also in dormancy were as storage temp increase → duration of dormancy will decrease.
B. Moisture or precipitation rate: Tables 6.1 and 6.2 It is affected by geographical characters and it is important as much as temp. in determining the distribution of species. Relative Humidity (RH) = (quantity of water present in air divided on the quantity of water at saturation) multiplied by 100% at same temp. and pressure.
Dew point: Temp. of air at which the water vapor reaches saturation point, then as temperature drops down this lead to condensation and formation of dew. Dew + RH% can protect plants from severe transpiration and increase pollens viability but could be a cause of diseases and insect spreading. Amount of rain varies from area to another depending on far or close to equatorial, coasts, mountains, or valleys, also the distribution, If quantity fall in a longer period (up to late spring), there is no need for irrigation, but if all quantity during winter, we need irrigation in summer. Arid regions of less than 250mm/year, semiarid regions of 250-500mm/year, sub-humid of regions 500-100mm/year, humid regions of 1000-1500mm/year, and in wet regions of more than 1500mm/year as precipitation. Also dew is very important in arid regions, for example, in Palestine drops of dew equal to 25mm/year which is very important in summer, and that can be directly absorbed by leaves and release energy as condensate (540 cal/g of condensate water). But dew increase the infection by diseases as spores of late blight. The plant divided into 3v groups according to water requirement; They are hydrophytes, mesophytes and xerophytes. Water is very important for metabolic processes and its a medium for transport of minerals between cells + transpiration.