User manual HANNA INSTRUMENTS HI 993310

[. . . ] When shipping any instrument, make sure it is properly packaged for complete protection. TABLE OF CONTENTS PRELIMINARY EXAMINATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 SOIL ACTIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 WATER CONDUCTIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] HIGH SOIL ACTIVITY Soluble salts are indispensable for plant nutrition. However, when dosed in excess, they can cause various anomalies as toxicity, alteration of the nutrient absorption equilibrium, difficulty in absorbing water, changing of the pH value and damaging of the soil structure. For accurate pH measurements, use the Hanna HI 99121 pH meter, specially dedicated to soil application. Apart from these, an excessive use of fertilizers must be avoided and particular attention must be paid to the use of water with high salt concentration. If high values are detected, use the appropriate techniques to reduce the presence of salts (washing away irrigation, reduction of fertilizer dosages, addition of gypsum if the activity is caused by sodium, etc. ). In this case, add demineralized water to the soil, and then repeat the tests. Even soils rich in nutrients can give low values if they are not wet enough. In case of waterlogged soil, very high values indicate stressed plants. Find in the following pages a table with some indicative values for soil activity required by some common plants. 5 ORNAMENTAL PLANTS & FLOWERS Amaranthus Anthurium Azalea Begonia Chrysanthemum Croton Cyclamen Dahlia Dieffenbachia Dracaena Euphorbia Ficus Gerbera Kalanchoe Lilium Orchid Pelargonium Peperomia Philodendron Rose Saintpaulia Violet LAWN Lawn ORCHARD Apricot Orange Cherry Lemon Apple Walnut Pear Peach Plum Grapevine IDEAL VALUES 0. 4-0. 6 0. 2-0. 4 0. 3-0. 5 0. 3-0. 6 0. 4-0. 7 0. 2-0. 4 0. 4-0. 6 0. 4-0. 5 0. 4-0. 6 0. 2-0. 4 0. 4-0. 6 0. 4-0. 7 0. 4-0. 6 0. 2-0. 5 0. 3-0. 6 0. 2-0. 4 0. 2-0. 4 0. 3-0. 5 0. 4-0. 6 0. 2-0. 5 0. 3-0. 5 0. 2-0. 4 IDEAL VALUES 0. 1-0. 4 IDEAL VALUES 0. 2-0. 4 0. 1-0. 3 0. 2-0. 4 0. 1-0. 3 0. 2-0. 3 0. 2-0. 4 0. 2-0. 4 0. 2-0. 4 0. 2-0. 4 0. 2-0. 4 6 VEGETABLES & HERBACEOUS CULTIVATIONS Asparagus Sugar beet Carrot Cauliflower Cucumber Onion Watermelon Cotton Lettuce Maize Egg plant Melon Bean Strawberry Wheat Oat Potato Pepper Pea Tomato Soybean Spinach Tobacco IDEAL VALUES 0. 2-0. 4 0. 3-0. 5 0. 2-0. 4 0. 3-0. 5 0. 3-0. 5 0. 2-0. 5 0. 2-0. 4 0. 2-0. 4 0. 3-0. 5 0. 3-0. 5 0. 2-0. 4 0. 2-0. 4 0. 2-0. 4 0. 2-0. 4 0. 2-0. 4 0. 2-0. 4 0. 2-0. 5 0. 2-0. 4 0. 2-0. 3 0. 2-0. 6 0. 2-0. 3 0. 2-0. 4 0. 2-0. 4 7 WATER CONDUCTIVITY NUTRITIVE SOLUTIONS The nutritive solutions constitute one of the most important factors in determining the plant's growth and yield. Hence, putting the right solution at the plant's disposal is indispensable to get the best result. Conductivity (EC) of nutritive solutions must be checked regularly to ensure that it agrees with plant's requirements. The plants also have seasonal preferences, typically requiring lower concentrations in the summer. PLANT Asparagus Watermelon Carrot Cabbage Cucumber Chrysanthemum Onion Bean Strawberry Lettuce Egg plant Melon Potato Pepper Pea Tomato Celery Marrow PREFERRED EC VALUES 1. 50-2. 00 mS/cm 1. 50-2. 50 mS/cm 1. 50-2. 00 mS/cm 2. 00-3. 00 mS/cm 2. 00-3. 00 mS/cm 1. 50-2. 50 mS/cm 1. 50-2. 00 mS/cm 2. 00-2. 50 mS/cm 2. 00-2. 50 mS/cm 1. 00-1. 50 mS/cm 2. 50-3. 00 mS/cm 1. 50-2. 50 mS/cm 2. 00-3. 00 mS/cm 2. 00-3. 00 mS/cm 1. 00-1. 50 mS/cm 2. 50-5. 00 mS/cm 2. 00-2. 50 mS/cm 2. 00-2. 50 mS/cm 8 IRRIGATION WATER The irrigation water must be checked regularly, especially in the hydroponics industry. Conductivity is the most important parameter to check since plants can be seriously damaged by too high EC value. Water used for irrigation has been classified in four classes, depending on its conductivity: Class Class Class Class I II III IV EC < 0. 75 mS/cm EC = 0. 75 to 2. 50 mS/cm EC = 2. 50 to 4. 00 mS/cm EC > 4. 00 mS/cm Class I: This type of water can be used without any quantity limitation. Class II: Only a limited quantity should be used depending on the irrigation techniques and the crop. Class III: May be used occasionally, but only for tolerant plants and/or well-drained soils. Class IV: To be used only if there is no other alternative and as little as possible. SATURATED SOIL-PASTE CONDUCTIVITY The conductivity value of the saturated soil-paste can be used for classifying the salinity level of the soil and also provides indications about the soil productivity, depending on plants (see also the table on next page for reference). Response of cultivations depends also from different saturated soilpaste conductivity values. · EC = 2 mS/cm : the crop of the more sensible cultivations can be reduced. · EC = 8 mS/cm : only tolerant plants produce a satisfactory crop. · EC = 16 mS/cm : only a few very tolerant plants produce a satisfactory crop. 9 Tolerance of some common plants to the soil conductivity (Ayers & Westcot, 1976). [. . . ] To avoid electrical shock, do not use these instruments when voltages at the measurement surface exceed 24VAC or 60VDC. To avoid damage or burns, do not perform any measurement in microwave ovens. 16 BATTERY REPLACEMENT The instrument is powered by a 9 V battery and is provided with the Battery Error Prevention System (BEPS), which turns the unit off when a low battery signal is detected. When the remaining battery level is less than 10%, the "V" tag lights up on the display to indicate a low battery condition. It is recommended to replace the battery as soon as the low battery condition is detected. [. . . ]