The Miracle nutrient called Zinc

The same zinc that protects galvanized steel from rusting and the same zinc that is inside our pennies is the same zinc that is needed in infinitesimal amounts for all living things. An acre of healthy oats contains only one ounce. Yet, without this essential ounce of zinc no crop would grow at all! A grown man needs only seven one-thousandths of an ounce (25gm) of zinc per day. Yet this small amount helps build body protein, generate energy, promotes growth, and enhances taste and smell.

Only two ounces of zinc per ton of feed will prevent parakeratosis, or elephant hide, in hogs, promote hair growth on cattle, and generate healthy egg and chick development. Zinc is really a miracle micronutrient for plant life …an acre of corn needs only two ounces! But, this two ounces can increase yields by over 60 bu. per acre. Zinc is involved in most plant growth functions. Zinc helps produce auxins. Zinc is a growth promoting substance that controls the development of the shoot. Zinc also forms enzyme systems, which regulate plant life. Yet zinc is the most common micronutrient deficiency in agriculture today! Zinc deficiency can limit yields of corn, beans, wheat, cotton, sorghum, fruits, and vegetables.

The use of high yielding cereal varieties along with the increasing use of fertilizers containing major nutrients (N, P, and K) but without micronutrients through inorganic or organic fertilizers dramatically increased food production under intensified systems in early seventies. However, as a result of depleted Micronutrient reserves in the soil, this practice resulted in a number of nutrient disorders and associated nutrient imbalances. A sharp decline in the available micronutrient status of soil is reported in irrigated agricultural production systems in India under continuos cropping with recommended rates of only major nutrients.

Micronutrient deficiency in irrigated production and dry land systems:

For Example field scale deficiencies of Zinc in rice and wheat on alluvial soils, Fe deficiency in sugarcane, upland rice, chickpea and groundnut on sandy calcareous soils. Mn deficiency in rice-wheat systems on sandy soils and B deficiency in chickpea and rice on high pH, calcareous soil have been reported, mostly in intensified production systems. The deficiencies of micronutrients have assumed critical importance of sustaining high productivity in some areas of country. Among these Zinc deficiency is most prevalent in intensely cropped light textured alkaline soils. Boron deficiency has become more critical on highly calcareous soils, limed acid soils and reclaimed soils.

As an example, the Micronutrient requirement and removal of a few major cropping systems in intensified production systems are given below in Table 2. It is clear that micronutrient removal by various cropping systems varies from crop to crop {Source: Takkar (1996)}

Amounts of micronutrients (gm) removed by major intensified system in India

Under dry land agriculture, especially in the semi arid tropics with subsistence agriculture, the situation differs from the under irrigated intensified systems. In the first place soil erosion in some case, yields levels are low. Secondly soil erosion is severe resulting in the removal of top surface layers. Compounded with low use of organic manure, which were the dominant source of nutrients, micronutrients especially have dwindled in recent past.

Hence, there is a wide spread deficiency of Zn and B in watersheds of most parts of country. The deficiency is especially severe in Andhra Pradesh, MP and as indicated in table no. 1 intensive cropping area of Punjab, Haryana, West Bengal, UP and other states differing in severity. Hence, there is need for developing site specific nutrient management strategies for increasing the productivity of rainfed systems sustainability.

Confirmation of Zn Deficiency:

There are plant or soil tests to show Zinc deficiency .
The optimal ranges and critical levels of Zn in plant tissue are mm/kg:

On plant, the ranges of Zn deficiency in the whole shoot during vegetative growth (tillering) are as follows:

• < 10 mg kg -1 definite Zn deficiency
• 10-15 mg kg -1 very likely
• 15-20 mg kg -1 likely
• > 20 mg kg -1 unlikely (sufficient)

Problems with similar symptoms

The symptoms of Zinc deficiency may resemble those of Fe deficiency, which also occurs on alkaline soils. On alkaline soils, Zn deficiency is often associated with S deficiency. They may also resemble Mn deficiency and Mg deficiency.

Leaf spots may resemble Fe toxicity in appearance but the latter occurs on high organic status soils with low pH.

Why and where it occurs

One or more of the following factors can cause Zn deficiency particularly in paddy:

• Small amount of available Zn in the soil.
• Planted varieties are susceptible to Zn deficiency (i.e., Zn-inefficient cultivars).
• High pH (close to 7 or alkaline under anaerobic conditions). Solubility of Zn decreases by two orders of magnitude for each unit increase in pH. Zn is precipitated as sparingly soluble Zn(OH) 2 when pH increases in acid soil following flooding.
• High HCO 3- concentration because of reducing conditions in calcareous soils with high organic matter content or because of large concentrations of HCO 3- in irrigation water.
• Depressed Zn uptake because of an increase in Fe, Ca, Mg, Cu, Mn, and P after flooding.
• Formation of Zn-phosphates following large applications of P fertilizer. High P content in irrigation water (only in areas with polluted water).
• Formation of complexes between Zn and organic matter in soils with high pH and high organic matter content or because of large applications of organic manures and crop residues.
• Precipitation of Zn as ZnS when pH decreases in alkaline soil following flooding.

Mechanism of damage

Zinc is essential for several biochemical processes in the rice plant, such as:

• Cytochrome and nucleotide synthesis
• Auxin metabolism
• Chlorophyll production
• Enzyme activation
• Membrane integrity

Zn accumulates in roots and can be translocated from roots to developing plant parts. Because little retranslocation of Zn occurs within the leaf canopy, particularly in N-deficient plants, Zn deficiency symptoms are more common on young or middle-aged leaves.

Sources Of Zinc:

Some the sources of zinc are given as below:

Methods of application:

Options on Zn application include

• Soil application (broadcasting or band placement).
• Foliar Application as sprays,
• Dusting seeds with Zn powder or soaking them in Zn solutions.
• Swabbing foliage or pressing wounds with Zn paste or solution.
• Dipping roots of transplanted crops in solution or suspension of Zn salts and
• Pushing galvanized nails or pieces of metallic Zn into tree trunks (Katyal and Randhwa 1983)
• Of these, soil application and foliar spray are among the most extensively used. Soil application of Zn is preferred method over less efficient foliar sprays . Biweekly foliar sprays with 0.5 % ZnSO 4 +0.25 li m e suspension are recommended using 500 liters of water per hectare on crops exhibiting Zn deficiency symptoms, spraying continues until the disappearance of deficiency symptoms. Zn sprays are almost exclusively used to alleviate Zn deficiency in trees and Zn-sources are more effective if sprays are made before the spring flush of the growth.

We can summarize the method and mode of application as below:

• Basal application of Zn to soil through broadcast and mixed or its band placement below the seed proved superior to top dressing, side dressing or band placement, foliar sprays or soaking or coating of seeds/ seedlings in Zn solution/ slurry as well as transplanting Zn enriched nursery because of later application led delayed cure of Zn deficiency than basal use
• Foliar feeding of crops with application of 0.5 to 2.0 % ZnSO 4.7H 2O solution is the supplement of soil application but it is not a substitute . In field crops it is proved inferior in case of Zn and boron, however, in horticultural and plantation crops foliar feeding of crops with repeated foliar sprays or boron generally excelled to soil application.
• Seed coating of Zn materials like concentrated zinc, zinc phosphate was found good in correcting Zn deficiency in bold seed crops in marginally deficient soils. But in these areas ZnO proved superior but inferior to soil application of Zinc in highly Zn deficient soils. However seed treatment to potato with ZnSO 4.7H 2O solution proved equally effective as that of its foliar sprays or soil application.
• Dipping of rice seedlings in 2-4 % ZnO slurry before transplanting proved less effective with other sources in combating Zn deficiency or could not catch with farmers because of certain limitations of as that of zinc. Dipping of vegetable seedlings in ZnO suspension and sugarcane sets could not meet full Zn requirement of these crops.

Rate of Zinc Application:

• Rates of soil application of Zn vary with soil type. Amount of zinc required for alleviating zinc deficiencies that vary from severity of deficiency, soil type, nature of crop and cultivars.
• Alkali soils are generally deficiency in Zn and Ca. So higher yields of rice, wheat, berseem and other crops can not be achieved unless toxicity of Na /deficiency of Ca and Zn are corrected simultaneously. Use of 9-10 kg of Zn/ha to alkaline soils and 4.5 kg of Zn in reclaimed alkali soils for rice-rice, rice-wheat/mustard/barley was found optimum.
• Zinc requirement of crops in alkali soils is reduced substantially by 20-25%depending upon the levels of amendments added (25-100% GR) or reducing the levels of sodicities.
• Fertilizer Zn requirement of crops was found to be double in coarse textured sandy soils than in fine textured loam or clayey soil for wheat and rice.

USAGE INSTRUCTIONS :

For Paddy:

To control the zinc deficiencies in paddy crop use 300 gm of Mahazinc for one acre. Use 2gm of Mahazinc per litre of water and spray 15 days after transplantation in Paddy crop.

For Cotton, Mango & Oranges:

To control the Zinc deficiency in cotton & Oranges use 1.5 gm of Mahazinc per litre of water and spray when the first deficiency symptoms occurs. The 2 nd spray should be done 10 days after first spraying.

Mahazinc will supply zinc to the crops in two ways

• The leaves as well as roots will absorb the zinc.
• Mahazinc will supply more quantities of zinc to the crop. There will be very less wastage due to various activities. Hence value for your money.
• Mahazinc will control the zinc deficiency completely and within very less time.
• Mahazinc – Zinc Sulphate MonoHydrate, contains highest zinc –33 %.

Note: It is advisable to spray Mahazinc alone for better results.

RECOMMENDATION OF OUR PRODUCTS

Zinc Sulphate Tetra hydrate (21%) should be applied as basal @ 50 kg /ha to all the crops

Zinc Sulphate MonoHydrate (33%) should be preferably sprayed on the crops @ 300 grams per acre. The crop should be thoroughly drenched by using 200 litres of Water per acre.