Phosphorus deficient soils

Extensive areas of phosphorus-deficient soils occur throughout the world, especially in tropical and subtropical areas, and a deficiency of phosphorus can be regarded as the most widespread and economically important of all the mineral disabilities affecting grazing livestock. 

Phosphorus deficiency of vegetarians on a high fiber diet produced on phosphorus-deficient soils—Presently, this is without proof in humans, but there is abundant evidence that this condition occurs in animals. 

Phosphorus (P) is one of the major limiting factors for plant growth in many soils. Plant availability of inorganic phosphorus (Pi) can be limited by formation of sparingly soluble Ca phosphates, particularly in alkaline and calcareous soils by adsorption to Fe- and Al-oxide surfaces in acid soils and by formation of Fe/ Al-P complexes with humic acids (94). Phosphorus deficiency can significantly alter the composition of root exudates in a way that is, at least in some plant species, related to an increased ability for mobilization of sparingly soluble P sources (29,31,71). 

M. Li, T. Shinano, and T. Tadano, Distribution of exudates of lupin roots in the rhizosphere under phosphorus deficient conditions. Soil Sci. Plant Nutr. 43 237 (1997). 

G. Neumann and V. Romheld, Root excretion of carboxylic acids and protons in phosphorus-deficient plants. Plant Soil 2// 121 (1999). 

Purchase (153, 154), using root washings of H. filipendula, found no evidence of toxicity to Nitrobacter and Nitrosomonas. Since Nitrobacter is more sensitive to phosphorus deficiency than Nitrosomonas, and because phosphorus deficiency is sufficiently severe in some soils to restrict growth, its ability to compete for nitrogen is diminished. Inhibition was found in the root extract... 

Miiller R, Morant M, Jarmer H, Nilsson L, Nielsen TH (2007) Genome-wide analysis of the ara-bidopsis leaf transcriptome reveals interaction of phosphate and sugar metabolism. Plant Physiol 143 156-171. doi http //www.plantphysiol.org/cgi/content/abstract/143/l/156 Neumann G, Romheld V (1999) Root exudation of carboxylic acids and protons in phosphorus-deficient plants. Plant Soil 211 121-130... 

Brandon AM, Mikkelsen DS. 1979. Phosphorus transformations in alternately flooded California soils. I. Cause of plant phosphorus deficiency in rice rotation crops and correction methods. Soil Science Society of America Journal 43 989-994. 

Phosphorus deficiency (on tomato leaves), often seen in acidic soil. 

Deficiencies of available phosphorus in soils are a major cause of limited crop production. Phosphorus deficiency is regarded by some authorities as the most critical mineral deficiency in grazing livestock. 

PHOSPHORUS (In Biological Systems). Phosphorus is required by every living plant and animal cell. Deficiencies of available phosphorus in soils are a major cause of limited crop production, Phosphorus deficiency is probably the most critical mineral deficiency in grazing livestock. Phosphorus, as orthophosphate or as the phosphoric acid ester of organic compounds, has many functions in the animal body. As such, phosphorus is an essential dietary nutrient. 

When phosphorus fertilizers are added to soils deficient in available forms of the element, increased crop and pasture yields ordinarily follow. Sometimes the phosphorus concentration in the crop is increased, and this increase may help to prevent phosphorus deficiency in the animals consuming the crop, but this is not always so. Some soils convert phosphorus added in fertilizers to forms that are not available to plants. On these soils, very heavy applications of phosphorus fertilizer may be required. Some plants always contain low concentrations of phosphorus even though phosphorus availability from the soil may be good. See also Fertilizer. 

Leaves with purplish patches. Cause Phosphorus deficiency. This is common in cool spring soils. Plants usually outgrow problem when soils warm. Spray leaves with seaweed extract to speed up recovery. 

Roots poorly formed or pale. Causes Nutrient deficiency extreme temperatures. Spindly, short roots can be caused by potassium deficiency or excessive heat. Poor color and taste are caused by magnesium deficiency, phosphorus deficiency, and low or high temperatures. Copper deficiency can also cause poor root development. Spray foliage with seaweed extract to prevent deficiencies. Do a soil test and amend soil as needed. 

Celery is a heavy feeder. Boron deficiency causes brown, mottled leaves and horizontal cracks on stalks. Florida 683 is tolerant of low boron. Calcium deficiency causes the center of the plant to blacken and die. Utah 52-70R Improved is tolerant of low calcium. Magnesium deficiency causes yellow leaves. Discolored streaks on stalks are a symptom of potassium deficiency. Phosphorus deficiency causes plants to form rosettes. Prevent problems by adding plenty of compost to the soil and by spraying plants with seaweed extract every 2 weeks. Check suspected deficiencies with soil tests and amend soil as needed. 

Seedlings purplish. Cause Phosphorus deficiency. See page 77 for an illustration of this condition. Phosphorus is not readily available in cool soils. Spray plants with seaweed extract or compost tea to alleviate symptoms. 

Ears with bare, undeveloped tips can also be caused by potassium deficiency. Phosphorus deficiency also causes small, irregular ears. See page 77 for an illustration of this condition. If ears are misshapen and kernels have corky, brown bands at their bases, suspect boron deficiency. Spray young plants with seaweed extract or compost tea to help prevent deficiencies. Confirm deficiencies with a soil test and amend soil as needed. 

Fruit dull bronze. Cause Phosphorus deficiency. Spray plants with compost tea to correct possible nutrient deficiency. Check with a soil test and amend soil as needed. 

Various nutrient deficiencies can affect lettuce. Boron or phosphorus deficiency causes malformed plants. Calcium deficiency causes browning of young leaves. Poor heart formation is a symptom of molybdenum deficiency. Copper deficiency prevents heads from forming. Spray seedlings with seaweed extract to help prevent nutrient deficiencies. Continue to spray plants with seaweed extract or compost tea every 2 weeks to boost plant health. Do a soil test to confirm the deficiency, and amend soil accordingly. 

Phosphorus or potassium deficiency can cause spots or patches of dark flesh. Oversize tubers with hollow centers may also indicate potassium deficiency. If deficiencies are suspected, have soil tested and amend as needed. If plants show symptoms of phosphorus deficiency, raise soil pH to 6.0 so the mineral will be more available to the plants. 

Leaves of young plant purple. Causes Phosphorus deficiency lack of dark period. Phosphorus is unavailable in cool soil symptoms usually fade as soil warms. Spray plants with seaweed extract to alleviate symptoms. 

Time garden tasks. Optimizing growing conditions for a plant is not only a question of what to do, but of when to do it. Corn or bean seeds planted before the soil has warmed sufficiently do not germinate rapidly and are susceptible to damping-off. Tomatoes set out too early in the spring may succumb to frost or show phosphorus deficiency until their roots become active. 

Prevention and Control Phosphorus deficiency symptoms develop fairly frequently in transplants set out in early spring. Unlike some other nutrients, phosphorus does not move through the soil roots must grow to reach it. Until the soil warms sufficiently to stimulate root growth, plants may not be able to take up enough phosphorus. 

That such soils. should be phosphorus deficient is a prediction from pedogenic theory (Walker and Syers, 1976). This is because, in contra.st to carbon, nitrogen, and sulfur, P is cycled mainly on geological time scales. That is to say, the only substantial primary source of P for plants is from the weathering of parent material at the base of the soil. As soil development proceeds, there is a loss of this weathered P as a consequence of leaching. The rate of leaching is quite small on an annual basis, even in the tropics (typically 0.1-1 mmol P m year Bruijnzeel, 1991) but it occurs over. several thousand years. Moreover, as soils become older, not only does the total amount of phosphorus decline, but there is also a transfer of phosphate from labile pools to nonlabOe pools (Walker and Syers, 1976). 

---