Long-term Organic Production Systems in Northern Highbush Blueberry: Placing Weed Mat over Existing Organic Mulches and Changing to Nitrogen-only Fertilizer Sources Increased Yield

In long-lived organic blueberry production systems, nutrient imbalances caused by some fertilization and mulching practices can reduce plant growth and yield. The ability to balance nutrient levels and thus improve productivity over time was evaluated in a mature planting of ‘Duke’ and ‘Liberty’ that had been used to study different mulching practices [sawdust (9-cm deep), yard-debris compost (4-cm) topped with sawdust (5-cm), and weed mat] and various rates and sources of N fertilizer (feather meal or fish solubles, each applied initially at “low” or “high” rates of 29 and 57 kg·ha−1 N in 2007–08 and then increased incrementally as the planting matured to 73 and 140 kg·ha−1 N in 2013–16). In Winter 2016–17, existing weed mat was removed and replaced where it was present, and new weed mat was installed on top of any existing organic mulches, thus changing the mulch treatments to weed mat (over bare soil), weed mat over sawdust, and weed mat over compost + sawdust from 2017 to 2020. A hydrolyzed soy-protein–based fertilizer containing essentially only N was applied at a moderate rate (106 kg·ha−1 N) relative to prior treatments. Plants grown on flat and raised beds were evaluated separately. From 2016 to 2020, yield of ‘Duke’ and ‘Liberty’ increased by an average of 19% and 56%, respectively, on flat beds and 8% and 42%, respectively, on raised beds. On flat or raised beds, plants that had weed mat placed over the existing sawdust or compost + sawdust mulch had a greater increase in yield (averaging 41%) than those with weed mat alone (over bare soil; averaging 12%). Soil under weed mat alone continued to have the lowest organic matter content (averaging 3%) throughout the study. Prior fertilization source and rate had no impact on the increase in yield of ‘Duke’, whereas ‘Liberty’ plants previously fertilized with feather meal had a larger increase in yield through 2020 than those fertilized with fish solubles. Fertilizing with an intermediate rate of N from 2017 to 2020 increased yield regardless of whether plants received the low or high N rate from 2007 to 2016, confirming our previous conclusion that the low rate provided sufficient N. Soil K and leaf %K declined after discontinuing fertilization with fish solubles and use of yard-debris compost, likely a factor in yield improvement. However, there were still negative correlations between yield and leaf %K in multiple years. This study illustrated that changing mulch and fertility practices in established organic blueberry to mitigate prior applications of high K can improve plant performance, nutrient imbalances, and yield within a relatively short period of time.

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Colored Plastic Mulch Effects on Plant Performance and Disease Suppression in Organically Grown Bell Pepper (Capsicum annuum)

Journal of Agricultural Science ◽

10.5539/jas.v13n6p11 ◽

2021 ◽

Vol 13 (6) ◽

pp. 11

Author(s):

Leopold M. Nyochembeng ◽

Regine N. Mankolo

Keyword(s):

Soil Temperature ◽

Bare Soil ◽

Organic Production ◽

Fruit Yield ◽

Bell Pepper ◽

Disease Suppression ◽

Plant Performance ◽

Growth And Yield ◽

Plastic Mulch ◽

Southeastern Us

Weeds and diseases are major biological competitors that pose significant threats to organic production of vegetables in southeastern US during the summer. We evaluated plasticulture as an alternative weed and disease management strategy for open field organic production of bell peppers. The objective of the research was to assess the effects of four colored plastic mulches on soil temperature, moisture, fruit yield and suppression of weeds and diseases on bell pepper. Bell pepper cv ‘King Arthur’ was planted on raised soil beds covered with colored (olive green, black, white and silver) mulch treatments including a control (bare soil). The experimental design was a randomized complete block with four replications. Soil temperature and moisture, disease incidence and severity, and fruit yield were determined. Plant performance (growth and yield) varied with mulch type. The black and olive plastic mulches warmed the soil significantly more than the reflective silver and bare soil. Bell pepper plants across all mulch treatments exhibited susceptibility to bacterial leaf spot (BLS). However, the incidence and severity of BLS varied with mulch type. Plants on reflective silver plastic displayed significant BLS incidence and severity compared to the olive plastic and bare soil. The black, white, and reflective silver plastic mulches significantly increased fruit yields, while the olive mulch and bare soil exhibited poor crop performance. These results suggest that the black and white plastic mulches retain the potential to be used in organic vegetable production in Alabama and the southeastern US.

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Weed Management, Training, and Irrigation Practices for Organic Production of Trailing Blackberry: I. Mature Plant Growth and Fruit Production

HortScience ◽

10.21273/hortsci.50.8.1165 ◽

2015 ◽

Vol 50 (8) ◽

pp. 1165-1177 ◽

Cited By ~ 6

Author(s):

Emily K. Dixon ◽

Bernadine C. Strik ◽

Luis R. Valenzuela-Estrada ◽

David R. Bryla

Keyword(s):

Weed Management ◽

Management Practices ◽

Production Systems ◽

Management Training ◽

Bare Soil ◽

Fruit Production ◽

Organic Production ◽

Growth And Yield ◽

Training Time ◽

Irrigation Practices

Weed management, training time, and irrigation practices were evaluated from 2013 to 2014 in a mature field of trailing blackberry (Rubus L. subgenus Rubus Watson) established in western Oregon. The field was planted in 2010 and certified organic in 2012, before the first harvest season. Treatments included two cultivars (Marion and Black Diamond), three weed management practices [nonweeded, hand-weeded or bare soil, and weed mat (black landscape fabric)], two irrigation strategies (irrigation throughout the growing season and no postharvest irrigation), and two primocane training dates (August and February). When averaged over the other treatments, ‘Marion’ and ‘Black Diamond’ had similar yields in both years. However, the presence of weeds reduced vegetative growth and yield, especially in ‘Black Diamond’, while weed mat increased growth and yield over hand-weeded plots by 13%. Withholding irrigation after harvest reduced water use by an average of 44% each year without adversely affecting yield in either cultivar. The effects of training time were primarily seen in 2014 after a cold winter. August-trained ‘Marion’ plants had more cold damage than February-trained plants and, consequently, had fewer and shorter canes, less biomass, fewer nodes, and 1 kg/plant less yield than February-trained plants. ‘Black Diamond’ was cold hardier than ‘Marion’, but was more readily infested by raspberry crown borer (Pennisetia marginata Harris). As the planting reached maturity, yields in the best performing organic production systems (both cultivars under weed mat and ‘Marion’ that was February-trained) averaged 11 and 9 t·ha−1, for ‘Black Diamond’ and ‘Marion’ respectively, similar to what would be expected in conventional production.

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Fertilizer integration on cacao cum rubber: implications on cacao growth, yield, disease occurrence and profitability

American Journal of Agricultural Science, Engineering and Technology ◽

10.54536/ajaset.v5i2.93 ◽

2021 ◽

Vol 5 (2) ◽

pp. 169-196

Author(s):

Noe S Mamon Jr

Keyword(s):

Block Design ◽

Organic Matter Content ◽

Growth Yield ◽

Leaf Nitrogen ◽

Matter Content ◽

Leaf Length ◽

Growth And Yield ◽

Leaf Nitrogen Content ◽

Dry Bean ◽

Disease Occurrence

This study was conducted to enhance the growth and yield performance of cacao trees under mature rubber for one (1) fruiting season through the integration of urea and vermicompost. The experimental design was set in factorial Randomized Complete Block Design with a total of 15 treatment combinations. The treatments were three rates of urea (0, 100 and 200 g/tree) and five rates of vermicompost (0, 1.5, 3.0, 4.5 and 6.0 kg/tree). The trunk circumference, leaf length and width, number of pods developed and harvested, pod and bean character, soil OM%, leaf Nitrogen content and prevalence of pest and diseases were evaluated. The application of 200g urea per tree produced significant increase from 4.86 to 8.44 kg (73.66% increase) in weight of harvested pods and from 23.32 to 26.40 g/pod (13.21% increase) dry bean weight and significant decrease in the pod index from 43.39 to 38.45 (11.36% decrease). Moreover, the heaviest and thickest pod husk was obtained from plants applied with 100 grams urea + 1.5 kg vermicompost. The highest mean number of beans/pod was obtained from trees applied with 100 – 200 g urea + 1.5 – 3.0 kg vermicompost. The soil organic matter content (%) and leaf N was slightly increased by application of fertilizer treatments. Pod borer infestation and nematode population were significantly affected by application of urea and vermicompost. Application of 100 g urea/tree or 3.5 bags/ha gave the highest return of investment and was the most profitable source of nutrient.

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Hardsetting in the surface horizons of sandy soils and Its implications for soil classification and management

Soil Research ◽

10.1071/sr9940603 ◽

1994 ◽

Vol 32 (3) ◽

pp. 603 ◽

Cited By ~ 13

Author(s):

RJ Harper ◽

RJ Gilkes

Keyword(s):

Organic Matter Content ◽

Sandy Soils ◽

Clay Content ◽

Soil Classification ◽

Matter Content ◽

Arid Area ◽

Plant Performance ◽

Classification Schemes ◽

Surface Conditions ◽

Measured Strength

Marked variations in hardsetting occur in the sandy surface horizons of duplex deep sandy soils in a semi-arid area of Western Australia. Hardsetting by definition only occurs in dry soils and increases with field texture. Soil strength measured on remoulded samples in the laboratory conformed with field assessments of strength (consistence). Most (79%) of the variation in strength between Ap horizon samples was explained by clay content, with small differences in clay content resulting in large differences in strength. Half of the maximum measured strength in the Ap horizons was achieved at a clay content of only 8%. The A2 horizons were markedly stronger than corresponding Ap horizons, despite similar clay contents, and this difference in strength is related to the larger organic matter content of the Ap horizons. Hardsetting of these sandy soils may be explained in terms of the cementing action provided by clay which forms bridges between particles. Organic material weakens these bridges. Hardsetting may affect the wind erodibility of sandy soils, through differences in surface conditions (i.e. loose v. compact) and by increasing the resistance to abrasion by saltating sand. It is not clear what effect it will have on plant performance. Hardsetting is a continuous, rather than discrete soil attribute, and if it is to be described in the field, and used in soil classification schemes, objectives class limits should be defined, perhaps using dry consistence ratings.

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Organic Production Systems in Northern Highbush Blueberry: I. Impact of Planting Method, Cultivar, Fertilizer, and Mulch on Yield and Fruit Quality from Planting through Maturity

HortScience ◽

10.21273/hortsci12179-17 ◽

2017 ◽

Vol 52 (9) ◽

pp. 1201-1213 ◽

Cited By ~ 2

Author(s):

Bernadine C. Strik ◽

Amanda Vance ◽

David R. Bryla ◽

Dan M. Sullivan

Keyword(s):

Production System ◽

Production Systems ◽

Organic Production ◽

High Rate ◽

Highbush Blueberry ◽

Feather Meal ◽

Cumulative Yield ◽

Planting Method ◽

Flat Ground ◽

Low Rate

A long-term trial was established in Oct. 2006 in western Oregon to identify organic production systems for maximum yield and quality in highbush blueberry (Vaccinium corymbosum L.). The planting was transitional during the first year after planting and was certified organic during fruit production (2008–16). Treatments included planting method (on raised beds or flat ground), fertilizer source (granular feather meal or fish solubles), and rate (“low” and “high” rates of 29 and 57 kg·ha−1 N during establishment, increased incrementally as the planting matured to 73 and 140 kg·ha−1 N, respectively), mulch [sawdust, yard debris compost topped with sawdust (compost + sawdust), or black, woven polyethylene groundcover (weed mat)], and cultivar (‘Duke’ and ‘Liberty’). Mulches were replenished, as needed, and weeds were controlled throughout the study. Raised beds resulted in greater yield than flat ground during the establishment years but had less effect on yield once the plants were mature. After 9 years, cumulative yield was 22% greater on raised beds than on flat ground in ‘Liberty’ but was unaffected by planting method in ‘Duke’. Cumulative yield was also 10% greater with feather meal than with fish solubles, on average, and 4% greater with the low rate than with the high rate of fertilizer. ‘Duke’ was particularly sensitive to fertilizer source and produced 35% less yield overall with fish solubles than with feather meal. By contrast, there was relatively little effect of fertilizer source or rate on yield in ‘Liberty’. In five of 9 years, yield was 8% to 20% greater with weed mat than with sawdust or compost + sawdust. Mulch type had no effect on cumulative yield of ‘Duke’, but cumulative yield of ‘Liberty’ was 11% greater with weed mat than with sawdust or compost + sawdust. Soil temperature was warmer under weed mat than under sawdust, and plants on raised beds covered with weed mat required more irrigation than those grown on flat ground mulched with sawdust. ‘Duke’ produced heavier, larger, and firmer berries with lower total soluble solids (TSS) than ‘Liberty’. However, other treatment effects on berry quality were relatively small and inconsistent. For example, berry weight was greater on raised beds than on flat ground, on average, but only by 3% (0.06 g/berry). Plants on raised beds also produced berries with slightly lower TSS than those on flat ground (15.2% and 15.7%, respectively, in ‘Liberty’, and 13.1% and 13.3%, respectively in ‘Duke’). There was no effect of fertilizer source or rate on TSS in ‘Liberty’ (15.5% on average), whereas in ‘Duke’, TSS was highest when fertilized at the high (13.7%) or low (13.4%) rate of fish, and was lower when using feather meal (12.9% and 13.1% for low and high rate, respectively). Plants fertilized with fish produced firmer fruit than with feather meal in five of the 7 years in which the measurements were taken. Also, fertilization with the higher rate of either product increased berry firmness compared with the low rate in six of the 7 years. The impact of mulch was inconsistent through the study period. On average, ‘Duke’ berries were softest when fertilized with the low (173 g·mm−1 deflection) and high (176 g·mm−1) rates of feather meal and were the firmest with the high rate of fish (182 g·mm−1). In ‘Liberty’, the low rate of feather meal produced softer fruit (157 g·mm−1) than the other fertilizer treatments (162 g·mm−1 on average). When this study was initiated in 2006, the most common organic production system in this region was raised beds with sawdust mulch and fertilizing with a high rate of fish solubles. For this production system, yield for mature plants in our study (2014−16) was the equivalent of 8.9−12.3 t·ha−1 in ‘Duke’ and 11.8−23.7 t·ha−1 in ‘Liberty’. However, when plants were grown on raised beds with weed mat and fertilized with the high rate of feather meal, yield increased to 10.2−19.3 t·ha−1, depending on year, in ‘Duke’. By contrast, there was little effect of production system on yield of mature ‘Liberty’ plants. These yields, particularly for the best-performing treatment combination in ‘Duke’, are similar to what are observed in commercial conventional fields or organic farms using similar management practices. Our results showed that choice of organic production system can have significant impact on yield and economic costs and returns.

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Effect of Mycorrhizal Inoculation and Compost Supply on Growth and Nutrient Uptake of Young Leek Plants Grown on Peat-based Substrates

HortScience ◽

10.21273/hortsci.41.3.628 ◽

2006 ◽

Vol 41 (3) ◽

pp. 628-632 ◽

Cited By ~ 26

Author(s):

Henrike Perner ◽

Dietmar Schwarz ◽

Eckhard George

Keyword(s):

Plant Growth ◽

Production Systems ◽

Mycorrhizal Fungus ◽

Nutrient Deficiency ◽

Am Fungi ◽

Organic Production ◽

Growth And Yield ◽

Mycorrhizal Symbiosis ◽

Test Plant ◽

Substrate Quality

Organic horticultural production systems often are characterized by the use of beneficial soil microorganisms because the application of soluble inorganic P or N fertilizers is not endorsed. Due to the limited supply of soluble nutrients in organic production systems, nutrient deficiency may limit plant growth and yield. The sole use of peat for pot-based cultures is also discouraged in organic production systems. Therefore, we have studied viable alternatives for highly soluble fertilizers and pure peat substrates using leek [Allium ampeloprasum L. var. Porrum] as a test plant. Plants were grown on peat-based substrates with different rates of compost additions, and with and without inoculation with arbuscular mycorrhizal (AM) fungi. Inoculation with a commercial AM fungus inoculum resulted in colonization rates of up to 70% of total root length, whereas not inoculated plants remained free of root colonization. Mycorrhizal fungus colonization increased shoot Zn and K concentrations, but did not significantly affect shoot dry matter or shoot N and P concentrations. In contrast, compost addition increased plant growth, and also increased P and K concentrations in plants. We conclude that plants with high rates of mycorrhizal colonization can be obtained on peat-based substrates, but that under these conditions plants may not consistently benefit in growth from the mycorrhizal symbiosis. In contrast, additions of compost are a possible means to improve the substrate quality in organic horticultural production.

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Effect of Biostimulants on Yield and Quality of Cherry Tomatoes Grown in Fertile and Stressed Soils

HortScience ◽

10.21273/hortsci15568-20 ◽

2021 ◽

pp. 1-10

Author(s):

Metin Turan ◽

Ertan Yildirim ◽

Melek Ekinci ◽

Sanem Argin

Keyword(s):

Plant Growth ◽

Mineral Content ◽

Organic Matter Content ◽

Growth Yield ◽

Matter Content ◽

Growth And Yield ◽

Cherry Tomato ◽

Negative Effects ◽

Positive Effects ◽

Different Characteristics

Plant biostimulants are microorganisms (PGPR) and/or products obtained from different organic substances that positively affect plant growth and efficiency and reduce the negative effects of abiotic challenges. Effects of biostimulants on the plant growth, yield, mineral content, antioxidant enzyme activity, H2O2, malondialdehyde (MDA), sucrose, and proline contents of cherry tomato (Solanum lycopersicum var. cerasiforme L.) grown in soils with two different characteristics were investigated during a pot study under greenhouse conditions. Soil I was a fertile routinely vegetable-cultivated soil. Soil II had high salinity, high CaCO3 content, and low organic matter content. Commercial biostimulant products Powhumus® (PH), Huminbio Microsense Seed® (SC), Huminbio Microsense Bio® (RE), and Fulvagra® (FU) were used as seed coatings and/or drench solutions. All biostimulant treatments improved the plant growth and yield compared with the control in both soils. All biostimulant applications were more effective in soil II than in soil I. RE was the most effective application for mineral content in soil I, whereas FU was the most effective in soil II. Antioxidant activity, H2O2, MDA, and proline contents were decreased in both soils when biostimulants were used compared with the control. Peroxide (POD) activity was greater with SC1 in soil II. The RE treatment increased the sucrose content in soil II. In conclusion, single and combined use of high-purity fulvic acid and PGPR had positive effects on the growth of cherry tomato in fertile soil and under stressed conditions.

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An evaluation of a no-tillage, unfertilised, direct-sown, wheat - rice cropping system in Korea

Australian Journal of Experimental Agriculture ◽

10.1071/ea00060 ◽

2001 ◽

Vol 41 (1) ◽

pp. 53 ◽

Cited By ~ 13

Author(s):

Y. S. Cho ◽

B. Z. Lee ◽

Z. R. Choe ◽

S. E. Ockerby

Keyword(s):

Organic Matter ◽

Time Course ◽

Crop Yields ◽

Cultural Practices ◽

Organic Matter Content ◽

Cropping System ◽

Matter Content ◽

Growth And Yield ◽

No Tillage ◽

Rice Growth

A no-tillage, direct-sown, unfertilised, wheat–rice relaying cropping system has major advantages over a conventional transplanted-rice system. For example, when rice is sown simultaneously with the wheat harvest, there are savings in labor and costs as a result of eliminating the tillage required to prepare the seedbed and for transplanting. A field experiment was conducted between 1996 and 1998 at Hadong, Korea. The experiment compared the soil microbial-N status, the soil physical and chemical characteristics, and rice growth and yield in a long-term conventional rice system with those in a no-tillage, unfertilised, direct-sown, wheat–rice, relay cropping system. The wheat–rice system was imposed for 2, 4 and 7 years to identify the time course of responses in the soil and crop. Agricultural chemicals including fertilisers were not applied in the wheat–rice cropping system. Rice crop yields after 2, 4 and 7 years of a direct-sown, wheat–rice cropping system were similar to those in the conventional rice system. Rice yields were high, ranging from 4.7 to 6.9 t/ha. Since 110 kg N/ha was applied to the conventional rice system, a large amount of N was mineralised during the wheat–rice system. The pattern of rice growth and yield formation, however, differed between the 2 systems. Rice in the wheat–rice system generally had more panicles, fewer spikelets per panicle and heavier grains. These responses reflected temporal changes in the N content and greenness of the rice leaf and were related to soluble N levels in the soil. Generally the soil was fertile with a high initial organic matter content. Organic matter increased by 30% during the 7 years of wheat–rice cropping. Other soil physical measures, bulk density and permeability to air and water, indicated that soil structure improved in response to wheat–rice cropping. Problems of pathogens and perennial weeds associated with new cultural practices in the wheat–rice cropping were minor; however, a higher rate of seeding was necessary to achieve satisfactory seedling establishment. Benefits to weed control and soil moisture conditions during crop establishment were derived from the increased level of crop mulch. The wheat–rice cropping system was found to be high yielding and sustainable over the 7-year period of experimentation.

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Effects of integrated nutrient management in early season cauliflower production and its residual effects on soil properties

Journal of Agriculture and Natural Resources ◽

10.3126/janr.v3i2.32548 ◽

2020 ◽

Vol 3 (2) ◽

pp. 353-365

Author(s):

Babita Neupane ◽

Krishna Aryal ◽

Lal Bahadur Chhetri ◽

Shishir Regmi

Keyword(s):

Soil Properties ◽

Nutrient Management ◽

Particle Density ◽

Organic Matter Content ◽

Poultry Manure ◽

Matter Content ◽

Growth And Yield ◽

Residual Effects ◽

Available Phosphorus ◽

Integrated Nutrient Management

This experiment was conducted in the farmer’s field at Khajrauta, Gadhawa-4, Dang, Nepal to evaluate the effect of integrated nutrient management on growth and yield of cauliflower as well as their residual effects on soil properties. The cauliflower variety silvercup-60 was grown under eight different treatments; T1: 50% N through RDF + 50% N through FYM; T2: 50% N through RDF + 50% N through PM; T3: 50% N through RDF + 50% N through VC, T4: 50% N through RDF + 25% N through FYM + 25% N through PM; T5: 50% N through RDF + 25% N through VC + 25% N through PM; T6: 50% N through RDF + 25% N through VC + 25% N through FYM; T7: 50% N through RDF + 25% N through VC +25% N through FYM; T8: 50% N through RDF + 50% N through FYM,VC and poultry manure. The experiment was laid out in RCB design with three replications. The result revealed that the highest plant height (36.40 cm), number of leaves (15), plant spread (31.72 cm), leaf area (526.5 cm2), curd weight (207.3g) and curd yield (12.85 t/ha) were found under 50% N through RDF +50% N through VC. The root length, root diameter and root density were better under all INM treatments as compared to 100% N through RDF. INM treatments showed lesser bulk density, lesser particle density, greater infiltration rate and greater organic matter content than application of 100% N through RDF. Soil total nitrogen was increased in all INM treatments while soil available phosphorus decreases in all treatments except 100% N trough RDF and 50% N through RDF +50% N through PM. Thus, farmers are suggested to apply 50% N through VC along with 50% N through RDF to increase cauliflower yield.

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Research Proposal : Growth and yield components of wheat as affected by integrated use of oxalic and phosphoric acid in calcisol

10.31219/osf.io/4u5jv ◽

2021 ◽

Author(s):

S M Nazmuz Sakib

Keyword(s):

Oxalic Acid ◽

Phosphoric Acid ◽

Agricultural Soils ◽

Phosphorus Deficiency ◽

Organic Matter Content ◽

Calcareous Soils ◽

Wheat Plant ◽

Matter Content ◽

Growth And Yield ◽

The World

Wheat is a cereal crop that is mainly used by humans as a source of starch and energy and is also used for livestock around the world. Wheat straw is rich in cellulose fibers, hemicellulose, protein and ash. Wheat is the most cultivated crop in the world and especially in Pakistan. As the population grows rapidly, wheat production needs to be increased to bridge the gap between growth and consumption. The amount of phosphorus required for wheat is much higher than for other crops. It is the most important nutrient needed by the wheat plant and it is important for the development of wheat from seedling to adulthood. Farmers add phosphorus to obtain high yields of wheat on phosphorus-deficient soils. Most of these soils are calcareous and its availability in wheat is due to its reaction with various heavy metals present in the soil. Low molecular weight organic acid oxalic acid in combination with phosphoric acid plays an important role in the mobilization of phosphorus in the soil. Oxalic acid secreted from the roots plays an important role in preventing phosphorus deficiency as it plays an important role in phosphorus mobilization. Agricultural soils of Pakistan are generally calcareous soils with high pH and low organic matter content usually less than one percent and more phosphorus fixation capacity and it has been reported that phosphorus is not sufficient to support prosperous agriculture. These calcareous soils contain more calcium carbonate, so when phosphate is applied, it binds to the soil and is not available to plants.

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