Soil fertility management for pepper production

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<ul><li><p>Soil fertility management for </p><p>pepper production</p></li><li><p>lbs per acre</p><p>20 - 30</p><p>40 - 60 </p><p>P2O5</p><p>120 - 18080 - 110fruit content</p><p>240 - 320 200 - 260total plant content</p><p>K2ON</p><p>Typical nutrient uptake by a bell pepper crop</p><p>producing 50,000 lb of fruit/acre :</p></li><li><p>Common soil tests for P availability :</p><p>Olsen (bicarbonate) test - extraction in sodium bicarbonate at pH 8.5</p><p>best method if soil pH &gt; 6.5</p><p>Bray test - extraction in dilute acid</p><p>useful in acidic soil (pH &lt; 6.5)</p><p> Represents available P, not total P</p><p> Bray values higher than Olsen in most cases</p><p>Phosphorus requirement for pepper :</p></li><li><p>Does the Olsen test measure plant-available P ?</p><p>Bio-available P (anion membrane) technique</p></li><li><p>0.0</p><p>2.0</p><p>4.0</p><p>6.0</p><p>8.0</p><p>0 50 100 150 200</p><p>Olsen P (PPM)</p><p>Anion resin P</p><p> (ug/cm2)</p><p>r = 0.89</p><p>Bio-available P vs. Olsen P :</p><p>30 California soils in vegetable rotations</p></li><li><p>Temperature affects soil P bioavailability :</p><p>0</p><p>1</p><p>2</p><p>3</p><p>4</p><p>5</p><p>6</p><p>7</p><p>8</p><p>29 76 85 142 177</p><p>Soil Olsen P level (PPM)</p><p>Anion resin extractable P</p><p>(ug/cm2)</p><p>5 C = 41 F</p><p>15 C = 59 F</p><p>25 C = 77 F</p><p>On average, each 10 oF increase in soil temperature increases </p><p>bioavailable P by 20%</p></li><li><p>High Low</p><p>Lettuce</p><p>Potato</p><p>Pepper?</p><p>Tomato</p><p>Soil P availability requirement :</p><p>Is P application always necessary ?</p><p>What application rate is reasonable ?</p></li><li><p>Soil P availability requirement :</p><p>Is P application always necessary ?</p><p>What application rate is reasonable ?</p><p>Agronomic threshold</p><p>(Olsen test)</p><p>High Low</p><p>Lettuce</p><p>Potato</p><p>Pepper?</p><p>Tomato</p><p>60 PPM 20 PPM</p></li><li><p>positive crop response unlikely&gt; 40 PPM</p><p>positive response likely, especially</p><p>in cold soil</p><p>20 - 40 PPM</p><p>positive response guaranteed &lt; 20 PPM</p><p>Pepper response to applied POlsen P level</p></li><li><p>positive crop response unlikely&gt; 40 PPM</p><p>positive response possible, especially</p><p>in cold soil</p><p>20 - 40 PPM</p><p>positive response guaranteed &lt; 20 PPM</p><p>Pepper response to applied POlsen P level</p><p>Application rate ? limit application to crop removal rate in fields with high soil P</p><p> rates &gt; 120-150 lb P2O5/acre questionable, regardless of </p><p>soil test level</p></li><li><p>Nitrogen management :</p><p> Crop N uptake is predictable by growth stage</p><p>lb N per acre per day:</p><p>&lt; 1 4 - 5 &lt; 3</p></li><li><p>Nitrogen management :</p><p> Crop N uptake is predictable by growth stage</p><p>lb N per acre per day:</p><p> Not all N needs to come from fertilizer application:</p><p>- residual soil NO3-N can be substantial</p><p>- soil N mineralization can be up to 1 lb / acre / day</p><p>&lt; 1 4 - 5 &lt; 3</p></li><li><p>Irrigation efficiency and N management : at common soil NO3-N levels during the season, one inch of</p><p>leaching may carry 20-30 lb NO3-N/acre out of the root zone</p></li><li><p>Potassium management :</p><p> Crop K uptake is predictable by growth stage</p><p>lb N per acre per day:</p><p>&lt; 1 4 - 7 &lt; 4</p></li><li><p>Potassium management :</p><p> Crop K uptake is predictable by growth stage</p><p>lb N per acre per day:</p><p>&lt; 1 4 - 7 &lt; 4</p><p> pepper has a moderately high K requirement (240 - 320 lb K2O/acre)</p><p> majority of K ends up in fruit</p><p>leaf K declines to feed the fruit; thats why deficiency shows late</p></li><li><p>Evaluating soil K supply :</p><p> exchangeable K, usually expressed as PPM</p><p> K as a % of base exchange</p><p>[milliequivalent of K / (meq Ca + Mg + Na + K)] x 100</p></li><li><p>Soil test K interpretation :</p><p> fields &gt; 200 PPM exchangeable K, and &gt; 3% of base exchange, </p><p>do not require K fertilization</p><p> soils &lt; 150 PPM, or &lt; 2% of base exchange, should be fertilized</p><p> K fertilization is most effective during fruit set and </p><p>early fruit development</p></li><li><p>http://vric.ucdavis.edu/veg_info_topic/fertilization.htm</p></li><li><p>Crop monitoring options In-season soil nitrate testing :</p><p> high root zone soil NO3-N concentration (&gt; 20 PPM) indicate</p><p>that additional N application can be postponed</p><p>Soil nitrate testing most useful early in the season</p></li><li><p>Petiole testing as a management tool ? high NO3-N or PO4-P concentration guarantees current sufficiency,</p><p>but does not project far into the future</p></li><li><p>Petiole testing as a management tool ? high NO3-N or PO4-P concentration guarantees current sufficiency,</p><p>but does not project far into the future</p><p> lower NO3-N or PO4-P concentration does not prove deficiency</p></li><li><p>2004-05 survey of 75 coastal lettuce fields</p></li><li><p>0.0</p><p>1.0</p><p>2.0</p><p>3.0</p><p>4.0</p><p>5.0</p><p>6.0</p><p>7.0</p><p>2 4 6 8 10 12 14 16 18 20</p><p>Field</p><p>% leaf N Current</p><p>sufficiency</p><p>threshold</p><p>at early heading stage :</p><p>Leaf total N of the 20 highest yielding fields</p></li><li><p>0</p><p>3,000</p><p>6,000</p><p>9,000</p><p>12,000</p><p>15,000</p><p>2 4 6 8 10 12 14 16 18 20</p><p>Field</p><p>Midrib NO3-N</p><p> (PPM)</p><p>Current</p><p>sufficiency</p><p>threshold</p><p>Midrib NO3-N of the 20 highest yielding fields</p><p>at early heading stage :</p></li><li><p>Tissue sampling in processing tomato :</p><p> 4 high yield commercial fields</p><p> UCD fertilizer trial</p></li><li><p>Tissue sampling in processing tomato :</p><p> 4 high yield commercial fields</p><p> UCD fertilizer trial</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>200 400 600 800 1000 1200</p><p>Growing degree days</p><p>Leaf N (g kg-1)</p><p>field 1</p><p>field 2</p><p>field 3</p><p>field 4</p><p>UCD deficient</p><p>UCD adequate</p><p>UCD excessive</p></li><li><p>Tissue sampling in processing tomato :</p><p> 4 high yield commercial fields</p><p> UCD fertilizer trial</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>200 400 600 800 1000 1200</p><p>Growing degree days</p><p>Leaf N (g kg-1)</p><p>field 1</p><p>field 2</p><p>field 3</p><p>field 4</p><p>UCD deficient</p><p>UCD adequate</p><p>UCD excessive</p><p>0</p><p>3,000</p><p>6,000</p><p>9,000</p><p>12,000</p><p>15,000</p><p>200 400 600 800 1000 1200</p><p>Growing degree days</p><p>Petiole NO3-N (PPM) field 1</p><p>field 2</p><p>field 3</p><p>field 4</p><p>UCD deficient</p><p>UCD adequate</p><p>UCD excessive</p></li><li><p>Does petiole testing indicate recent nutrient uptake ?</p><p>2007 UC Davis processing tomato trial</p></li><li><p>Conclusion :Most petiole NO3-N is already in cell vacuoles, and therefore the</p><p>concentration is affected by the rate at which the plant converts</p><p>nitrate to organic N; factors other than soil nitrate supply</p><p>govern that rate</p><p>0</p><p>200</p><p>400</p><p>600</p><p>800</p><p>1,000</p><p>1,200</p><p>1,400</p><p>1,600</p><p>4 6 8 10 12 14</p><p>Weeks after transplanting</p><p>NO3-N</p><p>(mg liter-1)</p><p>sap</p><p>xylem</p></li><li><p>Calcium disorders : symptoms develop because insufficient Ca is moved into </p><p>actively growing cells during fruit development </p></li><li><p>Calcium disorders : symptoms develop because insufficient Ca is moved into </p><p>actively growing cells during fruit development </p><p> origin of the problem is the inefficient way plants move Ca into fruit;</p><p>soil Ca limitation seldom the primary problem</p></li><li><p>Calcium disorders : symptoms develop because insufficient Ca is moved into </p><p>actively growing cells during fruit development </p><p> origin of the problem is the inefficient way plants move Ca into fruit;</p><p>soil Ca limitation seldom the primary problem</p><p> control by soil or foliar Ca application is minimally effective</p></li><li><p>How much plant-available calcium</p><p>do California soils have ?</p><p>15 representative California soils tested</p></li><li><p>y = 0.20x</p><p>r = 0.72</p><p>0</p><p>50</p><p>100</p><p>150</p><p>200</p><p>250</p><p>300</p><p>0 200 400 600 800 1000 1200</p><p>Soil solution Ca (PPM)</p><p>Saturated paste Ca</p><p> (PPM) </p><p> most California soils have 100 - 200 lb/acre Ca in solution in the</p><p>top foot; as plants remove it, more becomes available </p><p> at normal application rates, fertilizer Ca only marginally increases</p><p>soil Ca supply</p></li><li><p>0.00</p><p>0.10</p><p>0.20</p><p>0.30</p><p>0.40</p><p>0 2 4 6</p><p>Leaf Ca (%)</p><p>Fruit Ca (%)</p><p>Processing tomato fruit quality survey, 140 fields :</p><p>Calcium doesnt move into fruit easily :</p><p> Ca moves in transpirational flow in xylem, so leaf Ca is high </p><p> Ca does not move in phloem, so fruit Ca is low; surface wax</p><p>on fruit makes foliar application questionable</p></li><li><p>What can be done to minimize calcium disorders ?</p><p> prevent water stress</p><p> choose adapted varieties</p><p> avoid high ammonium levels during early fruit development</p></li></ul>

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