Potassium Management Studies in Spring Maize under different Irrigation Regimes

The Management of Potassium in Spring Maize Under Different Irrigation Systems

Sixty chemical elements are absorbed by plants including maize. The most likely to be

depleted are nitrogen (N), phosphorus(P) and potassium (K), which can be restored by

the use of organic or chemical fertilizers. These are available in balanced formulas

including all three elements or as a single nutrient. Nitrogen is needed for the production

of stems and leaves, especially in spring when growth is rapid, while phosphorus is

vital for flower and fruit production and root and bulb formation. Potassium is connected

with overall plant health. Plants suffer less from insect attack, disease and frost damage

when there is a balance of nitrogen and potassium. Potassium aids in low light level

photosynthesis, internal water regulation, and in the flavor and color improvement of

fruits and vegetables.[1]

Potassium (K) deficiency symptoms in corn can appear even if K in the soil is adequate

for crop production because K uptake is limited if the soil zone is dry. Root growth

limiters like compacted soil layers and root pruning also reduce K uptake in the corn

plant. Such symptoms appear first on the lower leaves, the outer leaf margins of which

become yellowish, and begin at the leaf tip and progress down the margin toward the

leaf base. Both adequate rainfall and K level in the soil are necessary for the uptake of

K in the corn plant. The discernment of true soil deficiency effects from climatic ones

may be obtained from soil tests from good and affected field areas.[2] Fertilization without

soil testing may result in excessive and/or sub-optimum application of nutrients. A 200

bushel crop of corn can take up to 250-300 pounds of potassium fertilizer.[3]

A corn grower’s most difficult problem is a prolonged period of dry weather because

corn yields will be limited by lack of water without irrigation. Adequate rainfall every 10

to 14 days is needed to prevent damage to the corn crop. The highest yields in corn

production can only be accomplished if environmental conditions are favorable at all

stages of growth. Since potassium impacts water movement within the corn plant as

well as its stalk and root health, the inadequacy of K often makes managing drought

more difficult.[4]

Irrigation if combined with other good production practices and favorable weather

should result in corn yields of 150 bushels or more per acre. Non-irrigated corn yield

is only 5 to 75% of irrigated corn yield. Corn crop may need water in the range of 20 to

24 inches during a season and to produce one bushel of corn grain, 5,000 gallons of

water is necessary. Depressions in corn fields need adequate drainage that will route

water off the field in 24 hours or less and coarse textured soil will need more frequent

irrigation than fine textured soil. Corn requires water most from tasseling through ear

filling, with moisture stress prior to tasseling being able to reduce yield from 10 to 40%,

and moisture stress between tasseling and soft dough stages being able to reduce yield

from 20 to 50%.[5]

Based on recent laboratory investigations and field experiments in different regions in

Iraq, various crops including corn responded well to the application of potassium (K)

fertilizers, in spite of the belief that Iraqi soils are rich in K. Potassium chloride (KCl)

and potassium sulfate (K2SO4) fertilizers were tested in different crops using

conventional, sprinkler and drip irrigation systems and traditional irrigation systems as

well.[6]

Studies of corn production for three plant populations in Kansas, USA, over four

years, using conventional, strip and no tillage systems for irrigation, indicated a 6.4 to

10% general increase of yield, with strip and no tillage performing better than

conventional tillage.[7]

[1] “The Effects of Fertilizers on Plant Growth”, eHow home, 2011, <http://www.ehow.com/about_5403919_effects-fertilizers-plant-growth.html> [accessed 6 June 2011]

[2] John E. Sawyer, “Potassium Deficiency Symptoms in Corn”, Integrated Crop Management, 26 June 2000, <http://www.ipm.iastate.edu/ipm/icm/2000/6-26-2000/kdef.html> [accessed 6 June 2011]

[3] David Wright et al, “Field Corn Production Guide”, EDIS, 2009, <http://edis.ifas.ufl.edu/ag202>

[accessed 7 June 2011]

[4] Roy Robertson, “Corn Yields will be Limited without Irrigation”, Southeast Farm Press, 10 June 2008,

<http://southeastfarmpress.com/corn-yields-will-be-limited-without-irrigation> [accessed 7 June 2011]

[5] David Wright et al

[6] A.Al-Zubaidi, “Potassium Behavior and Response under Different Methods of Irrigation and

Management”, pdf, November 2004, <http://www.ipipotash.org/udocs/Potassium Behavior and Response under Different Methods of Irrigation and Management> [accessed 7 June 2011]

[7] F. R. Lamm et al, “Effect of Tillage Practices and Deficit Irrigation on Corn”, pdf, February 2007,

<http://www.ksre.ksu.edu/pr_irrigate/Reports/Lamm08b.pdf> [accessed 7 June 2011]

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