Climatic Requirements of Horticultural Crops
Every fruit plant has a rarely well defined range of temperature to which it is tolerant and below or above which the plants of that variety are liable to be injured.
1. Minimum Temperature:
Plants cease to grow at the onset of sufficiently cold wealth or the exact temperature range varying with the kind of plant and its stage of growth and maturity. It is generally regarded that at stage of growth and maturity. It is generally regarded that at 320F or below the growth is suspended while above this it proceeds shed. The minimum temperature that one plant can endure maybe much lower than that which another will tolerate. Hardiness to the cold is not the absolute water content which brings about the hardiness but the latter is related to the form in which water is held by the tissues. The water in the plant tissues is usually held in three forms.
1. Fire water
2. Osatically held water and
3. Bend or colloidal held water
Plants containing larger amount of "bound water", are usually more resistant to cold is therefore, important for the grower not only to know what the minimum temperatures are in the region where he has to grow his fruit crops but also approximate minimum temperatures that the particular plant or crop will with and at different stages of growth.
It the minimum winter temperature in a region is expected to be very close to the freezing point, the grower should realize that though it is safe to grow all apples and pears an attempt to culture oranges and lemons is likely to be an utter failure. Similarly, if minimum temperature, is going to be low but not slow as to cause frost for a long period, he should understand that the culture of brings and Grape fruit would be safe but that of Mango will not be that safe.
2. Maximum Temperature:
Just like the minimum temperature, there is maximum temperature which the plant endures. This also various whith kinds of plant and its growth stage and maturity. Though the absolute minimum for the living protoplasm is very close to boiling point for most of the higher plants, the lethal point less some where between 110 to 1300F. A x number of growth processes are much retarded as temperature considerable under the so points. In tomatoes the flower fails to set fruits when the temperatures in shade rises above 90 – 1000F. It is also some times observed that if the flowering of Ambe Bahar in Santra is usually delayed i.e. sometimes the flowers appear in late February. The fruit set in these flowers is very low one account of higher temperature during that period.
It is somewhere between the minimum and the maximum temperature range, that plant or fruit can sustain its growth the range being usually narrower. This in known as Optimum Temperature.
3. Atmospheric Humidity :
Higher humidity and Higher temperature are favorable for growth of certain crops like Banana and Pineapple. It is usually observed that the Ambebahar fruits of santra and more juicy than these of Mrig Bahar probably due to the fact that the atmospheric humidity during the growing season of Ambebahar crop. Thus the atmospheric humidity effects that juiciness of the fruit. As regards to the fruits growing in higher humidity are less tasty and do not have good keeping quality, higher humidity, being congenial for growth of fungus bacteria and pests which may be harmful to the fruit trees.
4. Rain Fall:
The quantity of annual rainfall as well as its distribution plays an important role in the success of failure of fruit growing excessive rains occurring in short periods are generally unfavours to fruits as they load to water logging. Rains at the blooming period may was away pollens and thereby inhibit the pollination. In low rainfall regions to cultivation of fruits crops is difficult adequate and cheap irrigation facilities are not available.
5. Wind :
The wind causes damage to the fruit trees in several ways. High wind blow away the trees and break the branches. The situation exposed to wind causes a greater evaporation of soil moisture ant there by necessitating more irrigation. Hot winds at the time of blossoming may cause failure of pollination due to drying of stigmatic fluid and due to reduced activity of the pollinating insects. However, this damage can be reduced by planting wind breaks.
Hail storms are very rare in Maharashtra. However, in northern India, the fruit crops are greatly affected by hail. They causes shedding of young fruits and flowers while maturing fruits become almost unmarketable.
The sunlight is found to affect the quality of the fruit. Fruits exposed to sunlight are found to be better in quality as compared to those receiving loss of the sunlight. This is due to more quantities of carbohydrates prepared in the leaves. In Santra it has been observed that the fruits borne on upper half of the tree and consequently receiving more sunlight were found to be richer in Vitamins ‘C’ content. They also contained more sugars as compared to those on lower half of the trees. Fruits, constantly exposed to strong sunlight are likely to be ‘sunbrant’. In places where the summer temperatures are high as in Vidarbha. Region of the State, the stems of the plants are likely to suffer from sunburn and as a protection against this, an application of Bordeaux paste is recommended. In tropical regions the sunlight is not a problem but in temperate regions care has to be taken that the trees receive enough sunlight for which it is necessary to train and prune the trees in a particular fashion.