Crop Physiology Crop Water Usage and Fertilizer Uptake. Charles Stichler Professor Emeritus

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1 Crop Physiology Crop Water Usage and Fertilizer Uptake Charles Stichler Professor Emeritus

2 Crop Management Without knowing how a plant grows and develops, it is impossible to make wise decisions Water, fertilizer uptake and plant growth all effect the response of the other they work together Crop production is NOT a series of cook book steps It s the eye of the feeder that fattens the calf Each field must be managed separately Water is the single most important factor related to production Fertility is second most important factor

3 Function of Water Water is the blood of a plant Cool the plant transpiration Nutrient uptake from soil Cell elongation Cell function and enzyme activity Photosynthesis Nutrient and photosynthate transport

4 C0 2 + H 2 O = C 6 H 12 O 6 1. Makes Food 2. Energy Stored 3. Occurs in chloroplasts 4. Oxygen is released 5. Water is used 6. Carbon dioxide is used 7. Occurs in light

5 Leaves are solar collectors Yield is the result of photosynthetic conversion The more leaf area the more carbohydrates are produced The more water use from more leaves The more fertilizer needed to grow the leaves and roots What is the yield goal of a field????

6 General Water and Nutrient Use Curve for All Crops Inches of water per day 0.3 Bloom and seed fill 0.1 Planting Harvest

7 0.3 Roots pick up ions (nutrients) Inches of water per day as they Bloom pick and seed up water fill - the more water the plant picks up - the more nutrients it also picks up. 0.1 Planting Harvest

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9 Soil Microbes are like cattle in a feedlot 1. They cannot move 2. Heat 55 F 3. Water 4. Oxygen 5. Carbohydrates 6. N-P-Nitrogen - protein In the soil microbes get the nitrogen FIRST after decomposition and the microbes die and decompose the nitrogen is available. If you plant into a lot of residue you have to feed the microbes FIRST before the crop gets some of the N

10 98% of Nutrients are absorbed from the soil solution only about 2% are absorbed directly from soil particles Root Hairs do almost all the absorption of nutrients and water Root hairs are short lived often only a few days

11 Black dot represent nitrogen or soluble nutrients Washington State University

12 Black dot represent nitrogen or soluble nutrients Washington State University

13 Black dot represent nitrogen or soluble nutrients Washington State University

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15 8 week old corn plant

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18 Corn root development 1. Plant deep enough 1 ½ Side dress fertilizer away from crown roots. 3. Do not cultivate too close to the plant 4. Dirt the base of the plant 5. Apply lay-by herbicides after dirting

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21 V-7 tassel V-6 plant ears begin to develop

22 About 35 days after emergence, the head begins to form.

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24 Cotton AT EARLY BLOOM 80-90% OF THE CROP TO BE HARVESTED IS ALREADY ON THE PLANT.

25 Water and Fertility Stress Corn Abortion of ovules on the end of the cob Abortion of ovules from failure to pollinate 40 DAP stress causes charcoal 70 ovule abortion lack of exertion Cotton flower/fruit abortion

26 Cotton Nutrient Uptake 2 Bale Crop Nitrogen Pounds % Phos. Pounds % Potassium Pounds % Seedling Early Sq Bloom Boll Boll- Maturity Totals

27 Nutrient Requirement for 7,500 Sorghum Stage DAP N P K Seedling Rapid Growth E. Bloom Grain Fill Maturity Total Harvest

28 Nutrient Usage in 180 Bushel Corn Stage Days #/N % #/P % #/K % Early Rapid Growth Silk Grain fill Mature > Totals

29 Stichler Grain in Corn Growth Percent of Total Wt Early Dent Days After Silking Average of 3 varieties 1/2 Milk Line Black Layer Top of Cob

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31 Yield is a measure of how much water a crop uses

32 Average Yield/Inch of Water Cotton lbs of lint/inch 15 inches X 50 = 750 lbs. of lint Corn - 7 bushels/inch 15 inches X 7 = 105 bushels Sorghum lbs/inch 15 inches X 300 = 4,500 lbs Wheat bu/inch 15 inches X 3.5 = 52.5 bushels

33 Corn High Plains Seed 0.25 Emerg leaf leaf leaf leaf leaf leaf leaf 1.25 Tassel 1.25 Silk 1.30 Blister 1.30 Milk 1.30 Dough 1.20 Dent 1.00 ½Milk 0.90 Blk Lyr 0.70 Corn Uvalde Seed 0.20 Emerg leaf leaf leaf leaf leaf leaf leaf 1.15 Tassel 1.20 Silk 1.25 Blister 1.35 Milk 1.35 Dough 1.35 Dent 1.35 ½Milk 1.30 Blk Lyr 1.30 Cotton HP Seed st Sq st Blm 0.44 Peak B st OB % O % O % O 0.44 Sorghum HP Seed 0.40 Emerg leaf leaf leaf 0.70 Hd. Init 0.80 Flg Lf 0.95 Boot 1.10 Heading 1.10 Bloom 1.00 Sft Dgh.95 Hd Dgh 0.90 Blk Lyr 0.85 Crop Coefficient X ET = Water Used 1.35 X =.390 Inches/day

34 Cotton Calculated water need in Applied + rainfall in Yield lbs of lint/inch Average of lbs/inch

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36 Total water 14.2 inches Yield 130 bu = 9.15 bu/in Average of 7 bu/inch

37 Field Capacity can be thought of as all the water a soil can hold against the pull of gravity Available Water

38 Summary Crop production is a balance of water, fertility, temperature, sunlight and crop development The amount of water and nutrients applied is not as important as timing Understand when the crop needs what and apply it according to the developmental stage of the crop