Nutrient Management for Sunflower Production

Fertilizer management is an important part for sunflower production and one must know how input affects the crop and soil traits. Determination of optimum fertilizer rates is important because of increasing economic and environmental concerns. This study was therefore conducted to determine optimum fertilizer and manure requirement for sunflower production. In this regard, three field experiments were conducted at Students Farm, Sindh Agriculture University, Tandojam, Pakistan, located at 25o25’60’N 68o31’ 60E, altitude 19.5 m asl. In all the experiments sunflower variety HO-1 was sown in rows (75 cm spacing). The experiment-1, was meant to evaluate NPK, Zn and B requirements for sunflower production. The treatments consisted: Factor-A=Seasons (Spring and Autumn), Factor-B NPK Levels (0-0-0 NPK kg ha-1, 60-30-30 NPK kg ha-1 (N as broadcast), 90-45-45 NPK kg ha-1 (N as broadcast), 120-60-60 NPK kg ha-1 kg ha-1 (N as broadcast), 60-30-30 NPK kg ha-1 (N as fertigation), 90-45-45 NPK kg ha-1 (N as fertigation) and 120-60-60 NPK kg ha-1 (N as fertigation) and Factor-C (zinc and boron levels (0-0, 10.0-1.5, 10.0-2.0, 15.0-1.5, 15.0.2.0, 20.0-1.5 and 20.0-2.0 Zn+B kg ha-1). The results recorded taller plants (207.2 cm), maximum stem girth (12.2 cm), better head diameter (23.0 cm), more seeds head-1 (696.4), heavier seeds weight head-1 (49.0 g), bolder seed index (71.2 g), maximum seed yield (2743.0 kg ha-1) and higher dry matter (11666.7 kg ha-1), higher N-uptake (70.2 kg ha-1), P-uptake (19.1 kg ha-1), K-uptake (93.9 kg ha-1), Zn-uptake (335.8 g ha-1) and B-uptake (199.2 g ha-1) under application of 90-45- 45 NPK x 15-1.5 Zn-B kg ha-1 (N applied as fertigation). Similarly, higher values of physiological traits at flowering phase i.e dry matter (1353.0 g m-2), leaf area index (5.7), leaf area duration (55.6 days), crop growth rate (8.7 g m-2 day-1) and net assimilation rate (24.3 g m-2 day-1) were also noted for the same treatement.

However, oil content in this Interactive effect showed non-significant differences. The regression coefficient (b) revealed that a unit increase in various traits resulted in corresponding increase of sunflower seed yield by head diameter (101.2 kg ha-1) seeds head-1 (6.2 kg ha-1), seed weight head-1 (55.2 kg ha-1), seed index (58.2 kg ha-1), dry matter (0.3 kg ha-1), leaf area index (1108.3 kg ha-1), leaf area duration (113.4 kg ha-1), crop growth rate (378.4 kg ha-1), net assimilation rate (213.7 kg ha-1), nitrogen uptake (27.4 kg ha-1), phosphorus uptake (131.8 kg ha-1), potassium uptake (32.4 kg ha-1), zinc uptake (6.5 kg ha-1) and boron uptake (10.9 kg ha-1). However, a unit increase in seed oil content resulted corresponding decrease in seed yield by 1339.2 kg ha-1. The experiment-2, involved “Integrated use of organic manures and inorganic fertilizers nutrients for sunflower production” The treatments consisted: no manure, cattle manure (5, 10 and 15 tons ha-1) and poultry manure (5, 10 and 15 tons ha-1) with 90-45- 45 NPK + 15 Zn + 1.5 B (kg ha-1). The results of the study showed that the incorporation of fertilizers and manures significantly enhanced all the crop parameters. The taller plants (232.3, 231.2 cm), more stem girth (13.9, 13.9 cm), maximum head diameter (27.1 and 26.5 cm), higher number of seeds head-1 (801.9 and 797.9), heavier seed weight head-1 (66.6 and 65.9 g) bolder seed index (83.2 and 83.0), superior seed yield (3681.8 and 3643.2 kg ha-1) and higher dry matter at harvest (12859.3 and 12845.0 kg ha-1), higher Nuptake (80.7 and 82.2 kg ha-1), P-uptake (24.2 and 24.5 kg ha-1), K-uptake (114.2 and 114.0 kg ha-1), Zn-uptake (531.9 and 530.4 g ha-1) and B-uptake (320.4 and 314.9 g ha-1), higher dry matter (2075.0 and 2066.7 g m-2), maximum leaf area index (7.2 and 7.2), greater leaf area duration (67.4 and 67.3 days), more crop growth rate (10.3 and 10.2 g m- 2 day-1) and superior net assimilation rate (30.7 and 30.7 g m-2day-1) were recorded under cattle manure 10 t ha-1 + 90-45-45 NPK + 15-1.5 Zn-B kg ha-1 and poultry manure 5 t ha-1 + 90-45-45 NPK + 15-1.5 Zn-B kg ha-1, respectively, where N was applied as fertigation. Whereas, seed oil content showed inverse relationship under higher applications of inorganic fertilizers and manures. It was observed that application of poultry manure at 5 tha-1 or cattle manure at 10 t ha-1 with 90-45-45 NPK + 15-1.5 Zn-B kg ha-1 significantly enhanced all these traits and beyond these treatments no significant differences were exhibited even at higher levels of manures and were economically optimum levels for achieving satisfactory crop parameters. The regression coefficient indicates that a unit increase in various traits resulted in corresponding increase of sunflower seed yield by head diameter (150.0 kg ha-1) seeds head-1 (6.5 kg ha-1), seed weight head-1 (53.1 kg ha-1), seed index (62.8 kg ha-1), dry matter (0.4 kg ha-1), leaf area index (1027.5 kg ha-1), leaf area duration (116.0 kg ha-1), crop growth rate (469.9 kg ha-1), net assimilation rate (218.3 kg ha-1), nitrogen uptake (36.1 kg ha-1), phosphorus uptake (172.1 kg ha-1), potassium uptake (40.4 kg ha-1), zinc uptake (5.9 kg ha-1) and boron (9.5 kg ha-1). However, a unit increase in oil content resulted corresponding decrease in seed yield by (1546.3 kg ha-1). The experiment-3 entitled “residual effect of organic manures and supplemental inorganic fertilizers on sunflower production” revealed prolonged maturity (99.3 and 99.33 days), taller plants (258.1 and 256.9 cm), more stem girth (16.2 and 16.2 cm), maximum head diameter (31.1 and 31.0 cm), higher number of seeds head-1 (888.1 and 884.2), heavier seed weight head-1 (80.1 and 79.7 g) bolder seed index (90.9 and 92.0 g), superior seed yield (4420.2 and 4450.4 kg ha-1) and higher dry matter (14395.9 and 14381.2 kg ha-1), higher N-uptake (100.9 and 100.3 kg ha-1), P-uptake (33.9 and 33.7 kg ha-1), K-uptake (159.1 and 158.8, kg ha-1), Zn-uptake (603.0 and 605.1g ha-1), B-uptake (361.0 and 364.7 g ha-1), maximum leaf area index (7.9 and 7.9), greater leaf area duration (76.0 and 75.8, days), higher dry matter (2808.7 and 2740.4 g m-2), more crop growth rate (12.1 and 12.0 g m-2 day-1) and superior net assimilation rate (36.9 and 36.0 g m-2day-1) were recorded under residual cattle manure 10 t ha-1 + 90-45-45 NPK + 15-1.5 Zn-B kg ha-1 and residual poultry manure 5 t ha-1 + 90-45-45 NPK + 15-1.5 Zn-B kg ha-1 respectively where N applied as fertigation and beyond these treatments no significant increase in all the crop traits was noted. The regression coefficients indicate a unit increase in various traits resulted in corresponding increase of sunflower seed yield by head diameter (157.2 kg ha-1) seeds head-1 (7.3 kg ha-1), seed weight head-1 (53.7 kg ha-1), seed index (67.9 kg ha-1), dry matter (0.4 kg ha-1), leaf area index (1064.0 kg ha-1), leaf area duration (111.2 kg ha-1), crop growth rate (456.8 kg ha-1), net assimilation rate (195.3 kg ha-1), nitrogen uptake (36.0 kg ha-1), phosphorus uptake (143.0 kg ha-1), potassium uptake (33.3 kg ha-1), zinc uptake (6.5 kg ha-1) and boron (10.3 kg ha-1), however, a unit increase in oil content resulted in corresponding decrease in seed yield by 2037.6 kg ha-1. It is concluded that the fertilizers and manures enhanced all the crop traits, nutrient uptake and improved soil fertility. The application of NPK (90-45-45 kg ha-1, N applied as fertigation) + Zn+B (15+1.5 kg ha-1) with 10 t ha-1 of cattle or 5 t ha-1 poultry manure for their residual effect in the subsequent crop were superior and optimum fertilizer and manure doses for sunflower production without degrading fertility of soil. It is suggested that any source of well decomposed organic manures could be incorporated in the field to enrich the soil fertility on long term basis and higher sunflower production. Thus, it is recommended that sunflower crop should be fertilized with incorporation of NPK (90-45-45 kg ha-1, N as fertigation) + Zn+B (15+1.5 kg ha-1) with 10 t ha-1 cattle or 5 t ha-1 poultry manures for satisfactory yield and maintenance of soil fertility.

Source: SIDDIQUI, MUZZAMMIL HUSSAIN (2010) Nutrient Management for Sunflower Production. PhD thesis, Sindh Agriculture University, Tando Jam

Nutrients availability at different pH value

The pH value measures the ratio of H+ ions to OH-base ions in the soil. If the soil solution has more H+, the soil is acidic. If the OH-dominates, the soil is alkaline. The equal balance between them is neutral and its value 7.0. The soil pH value interacts with the mineral nutrients. Availability is determined by the soil pH and varies for each nutrient. High or low pH causes toxicity and decreases microbiological life in the soil.

Sodium raises pH and destroys soil structure. High pH makes elements such iron zinc and manganese less soluble. Low pH leads to continuous acidification in the soil. Acidification can be the result of the excessive use of fertiliser, or it can also occur naturally. For example, a mass of vegetation in a warm and moist condition during decomposition produces high quantities of carbon dioxide. In another instance, acidic  cations in large amounts replace the natural nutrients and cause acidity in the soil. Strong and extremely acidic soils are deficient in calcium and magnesium. Alkaline and strong alkaline soils contain high levels of free limes. Extremely alkaline soils are usually sodic soils. The positively charged sodium ions attract the negatively charged soil particles. The soil particles move close to each other, which creates a soil compaction. As a result, the water infiltration into the soil is slow and organic matter dissolution is possible. Root penetration is also extremely difficult.

The Role Of Nitrogen In Plants

Nitrogen is an essential macronutrient needed by all plants to thrive. It is an important component of many structural, genetic and metabolic compounds in plant cells. It is also one of the basic components of chlorophyll, the compound by which plants use sunlight energy to produce sugars during the process of photosynthesis.

Increasing the levels of nitrogen during the vegetative stage can strengthen and support your roots, enabling plants to take in more water and nutrients.  This allows a plant to grow more rapidly and produce large amounts of succulent, green foliage, which in turn can generate bigger yields, tastier vegetables, and a crop that is more resistant to pests, diseases, and other adverse conditions.

A nitrogen-deficient plant is generally small and develops slowly because it lacks the nitrogen it requires to manufacture adequate structural and genetic materials.  Older leaves become yellow or pale green due to the lack of chlorophyll, beginning in the tips of the lower leaves and eventually spreading throughout the plant.  In extreme deficiencies, the affected leaves become brownish, wither, die and hang down around the lower stem.

Using too much nitrogen, however, can be just as harmful to plants as too little. When there are high levels of nitrogen present, plants may not produce flowers or fruit. As with nitrogen deficiency, the leaves may turn yellow and drop. Too much nitrogen can result in plant burning, which causes them to shrivel and die.  If plants show any signs of nitrogen burn, immediately flush them with clean water.

It’s relatively normal for leaves to start turning yellow towards the end of the flowering cycle, as the plant uses excess nitrogen reserves for fruit and flower development instead. However, if you notice leaves turning yellow in the vegetative stage or during the beginning parts of the flowering stage, your plant may be experiencing a nitrogen deficiency, which should be treated.

All plants need nitrogen for healthy growth. Understanding the nitrogen requirements for plants makes it easier to meet their supplement needs. Use House & Garden’s Nitrogen Boost to raise nitrogen levels for your garden crops, helping to produce greener, more vigorous plants.

Source: House & Garden

Role of Potassium in Crop Yield

Potassium is vital to many plant processes. A review of its role involves under-standing the basic biochemical and physiological systems of plants. While K does not become a part of the chemical structure of plants, it plays many important regulatory roles in development.

Enzyme Activation

Enzymes serve as catalysts for chemical reactions, being utilized but not consumed in the process. They bring together other molecules in such a way that the chemical reaction can take place.

Potassium “activates” at least 60 different enzymes involved in plant growth. The K changes the physical shape of the enzyme molecule, exposing the appropriate chemically active sites for reaction. Potassium also neutralizes various organic anions and other compounds within the plant, helping to stabilize pH between 7 and 8...optimum for most enzyme reactions.

The amount of K present in the cell deter-mines how many of the enzymes can be activated and the rates at which chemical reactions can proceed. Thus, the rate of a given reaction is controlled by the rate at which K enters the cell.

Stomatal Activity (Water Use)

Plants depend upon K to regulate the opening and closing of stomates...the pores through which leaves exchange carbon diox-ide (CO 2), water vapor, and oxygen (O2) with the atmosphere. Proper functioning of stomates is essential for photosynthesis, water and nutrient transport, and plant cooling. When K moves into the guard cells around the stomates, the cells accumulate water and swell, causing the pores to open and allowing gases to move freely in and out.

When water supply is short, K is pumped out of the guard cells. The pores close tightly to prevent loss of water and minimize drought stress to the plant. If K supply is inadequate, the stomates become sluggish – slow to respond – and water vapor is lost. Closure may take hours rather than minutes and is incomplete. As a result, plants with an insufficient supply of K are much more susceptible to water stress.

Accumulation of K in plant roots produces a gradient of osmotic pressure that draws water into the roots. Plants deficient in K are thus less able to absorb water and are more subject to stress when water is in short supply.

Photosynthesis

The role of K in photosynthesis is complex. The activation of enzymes by K and its involvement in adenosine triphosphate (ATP) production is probably more important in regulating the rate of photosynthesis than is the role of K in stomatal activity.

When the sun’s energy is used to combine CO2and water to form sugars, the initial high-energy product is ATP. The ATP is then used as the energy source for many other chemical reactions. The electrical charge bal-ance at the site of ATP production is maintained with K ions. When plants are K deficient, the rate of photosynthesis and the rate of ATP production are reduced, and all of the processes dependent on ATP are slowed down. Conversely, plant respiration increases which also contributes to slower growth and development.

In some plants, leaf blades re-orient toward light sources to increase light interception or away to avoid damage by excess light, in effect assisting to regulate the rate of photosynthesis. These movements of leaves are brought about by reversible changes in turgor pressure through movement of K into and out of specialized tissues similar to that described above for stomata.

Transport of Sugars

Sugars produced in photo-synthesis must be transported through the phloem to other parts of the plant for utilization and storage. The plant’s transport system uses energy in the form of ATP. If K is inadequate, less ATP is available, and the transport system breaks down. This causes photosynthates to build up in the leaves, and the rate of photosynthesis is reduced. Normal development of energy storage organs, such as grain, is retarded as a result. An adequate supply of K helps to keep all of these processes and transportation systems functioning normally.

Water and Nutrient Transport

Potassium also plays a major role in the transport of water and nutrients throughout the plant in the xylem. When K supply is reduced, translocation of nitrates, phosphates, calcium (Ca), magnesium (Mg), and amino acids is de-pressed. As with phloem transport systems, the role of K in xylem transport is often in con-junction with specific enzymes and plant growth hormones. An ample supply of K is essential to efficient operation of these systems.

Protein Synthesis

Potassium is required for every major step of protein synthesis. The “reading” of the genetic code in plant cells to produce proteins and enzymes that regulate all growth processes would be impossible without adequate K. When plants are deficient in K, proteins are not synthesized despite an abundance of avail-able nitrogen (N). Instead, protein “raw materials” (precursors) such as amino acids, amides and nitrate accumulate. The enzyme nitrate reductase catalyzes the formation of proteins, and K is likely responsible for its activation and synthesis.

Starch Synthesis

The enzyme responsible for synthesis of starch (starch synthetase) is activated by K. Thus, with inadequate K, the level of starch declines while soluble carbohydrates and N compounds accumulate. Photosynthetic activity also affects the rate of sugar formation for ultimate starch production. Under high K levels, starch is efficiently moved from sites of production to storage organs.

Crop Quality

Potassium plays significant roles in enhancing crop quality. High levels of avail-able K improve the physical quality, disease resistance, and shelf life of fruits and vegetables used for human consumption and the feeding value of grain and forage crops. Fiber quality of cotton is improved. Quality can also be affected in the field before harvesting such as when K reduces lodging of grains or enhances winter hardiness of many crops. The effects of K deficiency can cause reduced yield potential and quality long before visible symptoms appear. This “hidden hunger” robs profits from the farmer who fails to keep soil K levels in the range high enough to supply adequate K at all times during the growing season. Even short periods of deficiency, especially during critical developmental stages, can cause serious losses.

Nutrient Deficiencies Symptoms in Plants

Following Chart Show Nutrient Deficiencies Symptoms in Plants, simple and easy way to understand nutrient deficiency in Plants.

Nutrient Deficiency Symptoms

By: Dave Franzen
NDSU Extension Soil Scientist

HTML Editors: Jochum Wiersma & Tracy Allrich

The preferred way to handle nutrient deficiencies is to identify annual crop needs with soil testing, perennial crop needs with plant analysis, and to correct the deficiencies before the crop is established or deficiency symptoms appear. However, soils are very variable in nutrient levels. Portions of fields low in a certain nutrient may not show up in a normal composite soil sample. The chemistry of some nutrients, such as iron and manganese, is very complex and difficult to predict with a simple soil test. Thus, deficiencies of some nutrients can sometimes appear even with a good soil testing program. Certain nutrient problems are sometimes so rare that regular soil analysis requests do not include testing for those nutrients. Nutrient deficiency symptoms are often the first clues to a nutrient problem within a field.
Plants which are under stress show unusual growth patterns or coloration. These visual symptoms are called deficiency symptoms. Deficiency symptoms can sometimes be confused with other complex field events, such as high water tables, salt damage, disease, drought, herbicide stress and varietal differences. Deficiencies can also be so slight that they are confused with other problems. If more than one deficiency is present, one can be more dominant in its symptoms, obscuring the symptoms of the other element.

Terminology of nutrient deficiencies

Chlorosis

General yellowing of the leaf tissue. A very common deficiency symptom, since many nutrients affect the photosynthesis process directly or indirectly.

Coloration abnormalities

Some deficiencies lower the amount of photosynthesis and chlorophyll which is produced by the plant. Other colored compounds can then become dominant. When normal nutrient sinks are not available, the plants can store up excess sugars within other compounds which have distinct colors of red, purple, or sometimes brown. The absence of chlorophyll altogether causes the plant to turn white.

Firing

Yellowing, followed by rapid death of lower leaves, moving up the plant and giving the same appearance as if someone touched the bottom of the plants

Interveinal Chlorosis

Yellowing in between leaf veins, but with the veins themselves remaining green. In grasses, this is called striping.

Necrosis

Severe deficiencies result in death of the entire plant or parts of the plant first affected by the deficiency. The plant tissue browns and dies. This is called necrosis. The tissue which has already died on a still living plant is called necrotic tissue.

Stunting

Many deficiencies result in decreased growth. This can result in shorter height of the affected plants.

Functions of the 13 soil supplied essential elements

Nitrogen

An essential component of amino acids, and therefore all proteins. An essential component of nucleic acids, and therefore needed for all cell division and reproduction. Enzymes are specialized proteins, and serve to lower energy requirements to perform many tasks inside plants. Nitrogen is contained in all enzymes essential for all plant functions.

Phosphorus

A component of the compound within plants which supply the energy to grow and maintain the plant. Part of cell membranes, the structures which selectively keep out unneeded compounds and allow in those compounds which are needed for the plant cells to function correctly. A part of DNA and its relatives. Needed for cell division and for reproduction.

Potassium

Activates certain enzymes. It regulates stomate opening, which in turn regulates air flow into the leaf and transpiration of water out of the leaf. it acts to balance charge between negatively and positively charged ions within plant cells. It regulates turgor pressure, which helps protect plant cells from disease invasion. In certain plants, potassium can be replaced by sodium.

Sulfur

Sulfur is a part of certain amino acids and all proteins. It acts as an enzyme activator and coenzyme (compound which is not part of all enzyme, but is needed in close coordination with the enzyme for certain specialized functions to operate correctly). It is a part of the flavor compounds in mustard and onion family plants.

Calcium

Calcium is a part of cell walls and regulates cell wall construction. Cell walls give plant cells their structural strength. Enhances uptake of negatively charged ions such as nitrate, sulfate, borate and molybdate. It balances charge from organic an ions produced through metabolism by the plant. Some enzymes are regulated by Ca-calmodulin.

Magnesium

Magnesium is the central element within the chlorophyll molecule. It is an important cofactor the production of ATP, the compound which is the energy transfer tool for the plant.

Boron

Boron is important in sugar transport within the plant. It has a role in cell division, and is required for the production of certain amino acids, although it is not a part of any amino acid.

Molybdenum

Molybdenum is needed for the reduction of absorbed nitrates into ammonia prior to incorporation into an amino acid. It performs this function as a part of the enzyme nitrate reductase. In addition to direct plant functions, molybdenum is also essential for nitrogen fixation by nitrogen-fixing bacteria in legumes. Responses of legumes to Molybdenum application are mainly due to the need by these symbiotic bacteria.

Iron

Iron is a component of the many enzymes and light energy transferring compounds involved in photosynthesis.

Zinc

Zinc is a component of many enzymes. It is essential for plant hormone balance, especially auxin activity.

Manganese

Manganese is a cofactor in many plant reactions. It is essential for chloroplast production.

Copper

Copper is a component of enzymes involved with photosynthesis.

Chlorine

Plants use chlorine as chloride ion. Chloride is useful as a charge balancing ion and for turgor regulation, keeping plant cells more free of infection by disease organisms. It is essential for photosynthesis.

Mobility of plant nutrients

Plant nutrients which can move from places where they are stored to places where they are needed are called plant mobile. Nitrogen, phosphorus and potassium are always plant mobile nutrients. Deficiencies are noticeable first on older tissue. Plant immobile element deficiencies are noticeable first on younger tissue. Calcium and boron are always plant immobile nutrients. Sulfur, chloride, copper, zinc, manganese, iron and molybdenum are intermediate in plant mobility. Under certain circumstances the intermediate elements are mobile. Mobility in intermediate elements may be linked to the breakdown under low nitrogen conditions of amino acids and proteins in older parts of the plant, and the mobility of these organic compounds to younger parts of the plant in the phloem stream. Under good nitrogen availability, these elements are mostly immobile.

Value of plant nutrient deficiency keys

Use of this plant nutrient deficiency key should be considered first as the first step toward understanding deficiency symptoms in the field secondly as an educational tool to be used in conjunction with soil testing and plant analysis. Environmental stress such as drought, wet conditions, disease, heat and agchemical interactions can easily be misinterpreted as deficiency symptoms. Photographs of nutrient deficiencies are useful in diagnosis, but field experience and a knowledge of field history based on local experience is the best diagnostic aid.