Soil Requirements for Horticultural Crops
Soil and climate are the important natural factors. Favorable combination of its, is essential for the production of Horticultural Crops. Little Human control is possible over unfavorable climatic and soil condition. All fruits and vegetables cannot be grown in all types of soil and climate. Hence zone wise cultivation is made.
A) Soil:
It may be defined as "Superficial earth crust" which functions as store house of reservoir of water and nutrient at the same time providing the necessary physical support to the plant".
A typical soil is heterogeneous mixture of different components which includes solids like minerals, living organism, water and air.
Properties of Soil:
Soil exhibits physical as well as chemical properties of which are mostly influenced by the mineral matter of the soil and by the size of soil particles i.e. Sand Silt and Clay.
Sand Particles:0.15 to 1 mm in diameter
Silty: 0.002 to 0.05 mm in diameter
Clay: 0.001 to 0.002 mm in diameter
On account of small size and relatively large surface area they exhibits colloidal property and are capable of increasing the water as well as nutrient retention capacity of the soil. In a typical soil there should be proper proportion of these soil particles. It is possible to alter the physical condition of the soil by adding organic to alter the physical condition of the soil by adding organic matters which improves the structure and texture of the soil. The soil which support the growth and production of perennial plants.
A) Physical Properties of Soil :
1. Soil Structure:
Soil structure should be uniform favorable for water penetration, soil aeration and drainage. Soil structure may be vary in different layers. Hence soil profile pits have to be taken and examined the structure.
2. Soil Aeration and Drainages:
Soil should provide good aeration and drainage. Soil aeration is necessary for growing aerobic organism in the soil to promote the metabolic activities of these organisms. Fruit and vegetable crops required well drained soils. Drainage is effected by the nature of sub soil. It affects the deep rooting capacity of the trees and drainage of the soil. In a good sub – soil trees can stand drought better, because of deeper root penetration on wet heavy soils with impermeable sub soil. Poor performance is observed due to poor aeration and inadequate drainage. Therefore, a well drained soil is essential. Extreme wet and dry soil should be avoided.
3. Water Table:
Availability of water at a certain depth in the soil that is called Water Table. High water table can give rise to water logging condition of the soil and ultimately the fruit and vegetable crops decline. Therefore, water table should be always below 2 meters throughout the year. High water table leads to por aeration and water logging condition. Rotting of roots may occurs due to prolonged water logging condition of the soil.
4. Soil Depth:
Extreme conditions of soils like very heavy (Clayey) and very light (highly sandy) with It accounts for at least half the action exchange capacity of soil. Whenever the soil contain more amount organic matter than there will be greater the yield of fruits and vegetables. Therefore soil should have more organic matters.
6. Soil Texture:
Fruits and vegetables crops generally required medium textured soil. Fine and coarse textured soil should be avoided.
7. Soil Temperature:
Soil temperature affects the root activity and is influenced by aeration and drainage. In cold soils, chemical and biological activities are slow and availability of nutrients like N.P.S. and Ca is limited. Nitrification would not start when the temperature is 40C. For successful growth of horticultural plants the soil temperature should be within the range of 26 to 320C. Due to low temperature absorption and transport of water and nutrient is adversely affected.
B) Chemical Properties of Soil:
1. Soil Fertility:
Moderate fertility in the soil is necessary with high amount of humus. Loam and sandy loan soils are not suitable for growing the plants. N, P, K, Ca, Mg, and S are important elements required for growth and development of plants. Micro – nutrients like Fe, Mn, Zn, Bo, Cu, MO etc. are also required. Premature decline of sweet orange in Punjab is associated with the micronutrient deficiencies predominated by Zinc.
2. Soil Reaction :
Soil analysis is important to find out the and Chemical composition. Neutral reaction is favorable. The safe pH range is from 6 to 8. Saline and alkaline soils should be avoided. In alkaline soils, concentration of sodium salts above 0.1% is harmful; Boron is deficient in alkaline soils and is unavailable in acidic soils. Iron is available in acidic soils. Calcium and Magnesium are deficient in acid soils. K, Mn, Fe, and BO are deficient in alkaline soils. pH above 8.7 is considered as critical High sodium content of soils with high pH may have direct toxic effects.
3. Soil Salinity:
Information on salt tolerance is necessary to select salt tolerant varieties and to adopt proper soil management practices.
i) Salt tolerant Crops (6-8 mmohs / cm) :
Date palm, phalsa, Guava, Sapota, Fig, Grape, Anola, Wood apple, Ber, Chicory, Potato, Sweet Potato, Watermelon etc.
ii) Moderate Salt Tolerant Crops (3 – 6 mmohs/cm) :
Pomegranate, Grape fruit, Lemon, Apple, Pear, Plum, Beans, Cucumber, Brinjal, Garlic, Radish, Pea, Tomato, Turneep.
iii) Salt Sensitive Crops (1.5 – 3 mmohs/cm) :
Orange, Peach Avocado, Straw berry, Asparagus, Beet, Cabbage, Cauliflower, Palak, Leek, Lettuce.
In general, it may be stated that soils for fruit growing should be porous, deep and aerated. They should not be water logged, marshy, saline or acidic and there should be no hard pan at the bottom layers.