Peach orchard studies utilizing fluidized bed material

Abstract

Fluidized bed material (FBM, a coal/limestone combustion byproduct) was used as a lime substitute prior to establishment of a peach (Prunus persia L.) orchard. Growth and nutrition of the trees were generally unaffected by applied FBM, either broadcasted or incorporated, at rates up to three times the soil lime requirement. Leaf and fruit Ca concentration were not significantly effected by FBM additions when compared to limestone or a fertilized control. Minor differences between treatments were noted for some elements. The applied FBM was found to be a suitable substitute for limestone in establishing a peach orchard from the aspects of tree nutrition and expected effects in the soil; elevated pH and higher extractable Ca status.     

Utilization of fluidized bed material as a calcium and sulfur source for apples

Abstract

Fluidized bed material (FBM), a dry, high Ca, alkaline waste product which results from combining coal and limestone, was used as a Ca or S source or lime substitute in an established apple orchard (Malus domestica Borkh., cv. ‘York Imperial') over a four year period. Treatment comparisons were made between FBM applied at one or two times (1x or 2x) the soil lime requirement and CaCO, applied at the lime requirement (lx). Additionally, FBM lx was compared to a combination treatment consisting of CaCO₃ plus gypsum to apply similar amounts of Ca and S. All treatments were also compared to an untreated control.

No significant treatment comparisons were noted on leaf Ca levels however leaf Mg significantly decreased when FBM applied at the 1x or 2x level compared to CaCO₃ 1x. When FBM was compared with CaCO. plus gypsum there was a significant decrease in leaf Ca with FBM but no difference in leaf Mg. These effects were probably due to either a solubility difference between nutrients or to actual amount of Mg applied by the different sources. Leaf S levels were unaffected by treatments. Yields, fresh fruit weight and the incidence of cork spot were little affected by treatments.

Soil extractable Mg, 1N NH₄Ac, was not a good prediction of leaf Mg content or Mg added to the soil. Only soil Al was significantly reduced, compared to the control, by the treatments among the metals studied (Zn, Mn, Cu, Cd, Pb and Al). FBM applied at twice the lime requirement (wt. basis) resulted in similar soil pH to CaCO₃ applied at the lime requirement.     

Evaluation of three calcium extractants for coastal plain soils

Abstract

Mehlich 1‐Ca is used as an index to predict the Ca requirement for peanut (Arachis hypogaea L.) fruit development in major peanut growing states. Recently, some concern has been raised about the inadequacy of Mehlich 1 extractable Ca for that purpose. Possible use of alternative extractants for soil Ca has been suggested. In this study, relationships among Mehlich 1, 0.2 M NH₄Cl and 0.01 M NaNO₃ extractable Ca were examined in several Coastal Plain soils to which gypsum or lime had been applied. Variability in extractable Ca was much greater following lime treatment than following gypsum treatment. In Bonifay soil, the quantity of Ca extractable by the three extractants was similar in a gypsum treatment, but in a lime treatment (at an application rate equivalent to the gypsum treatment) Mehlich 1‐Ca was 2 and 5‐fold greater than NH₄Cl‐ and NaNO₃‐Ca, respectively. In Greenville soil, Mehlich 1‐Ca was 3 to 4‐fold greater than NaNO₃‐Ca regardless of gypsum or lime amendment.

For soil samples from a field experiment on Lakeland sand, where lime or gypsum was applied prior to planting, Mehlich 1‐Ca was 7.5 and 2.2‐fold greater than NaNO₃‐Ca for the lime and gypsum treatments, respectively. Greater variability in Mehlich 1‐Ca in lime than in gypsum treatments was due to possible inclusion of undissolved limestone in the soil samples, resulting in overestimation of Ca available for peanut fruits. Mehlich 1‐Ca appears to be an adequate index of soil Ca for prediction of supplemental Ca requirement for peanut if lime has not been applied or has been applied well in advance of planting, thus minimizing the inclusion of undissolved limestone with the soil sample taken from the fruiting zone (0–8 cm depth) 10–14 d after planting.     

Effects of liming on yield,forage cation composition,and tetany potential of wheat in Kansas

Abstract

We studied the effects of liming on dry matter production, nutrient composition, and grain yields of wheat in field experiments conducted on two soil types at three locations during the 1976–77 and 1977–78 growing seasons. Lime sources were commercial agricultural lime, finely divided stack dust, and dolomitic limestone (which contained 10.6% Mg). Lime applied at 2,800 kg/ha in the 1976–77 and 10,750 kg/ha in the 1977–78 experiments provided Mg from the dolomite at rates of 300 and 1,140 kg/ha, respectively.

Soil pH was significantly increased by liming, but Mg saturation percentages were significantly greater only at the 1,140 kg/ha rate. Forage dry matter and grain yields were not increased by lime applied at the lower rate, but significant increases were found in dry‐matter production in the late fall and spring samplings of the 1977–78 experiment. Those increases in plant growth and dry matter production were probably due to reductions in the soluble Mn and Al concentrations in the soil. Forage N and P concentrations were generally not influenced by liming. Potassium concentrations in forage from the limed plots were usually equal to or greater than those in forage from unlimed plots. Calcitic limestone sources generally increased forage Ca concentrations, but liming with dolomite more often than not depressed Ca concentrations below levels found in the check plots. Dolomite, when applied at the 1,140 kg/ha rate, effectively increased the forage Mg concentration, although the concentration exceeded 0.2% only during the early growth stages. Liming generally showed no significant reduction in the tetany potential of the wheat forage as predicted by the equivalent ratio K/(Ca + Mg).     

Paper pulp as an amendment to a tropical acid soil: Effects on growth of rye grass

Abstract

Paper pulp was evaluated, with reference to lime, as a soil amendment to a tropical acid soil (typic Kandiudult). Rye grass (Lolium perenne L.) was grown under greenhouse conditions. Amendments were applied at rates to attain target pH values of 5.5,6.0, and 6.5. Paper pulp and lime were equally effective in increasing dry matter production. Similar to lime, paper pulp provided high calcium (Ca) inputs and alleviated aluminum (Al) and manganese (Mn) toxicity. Paper pulp can be applied to a tropical acid soil as a lime substitute.     

Comparative study of selected lime requirement methods for some acid Ghanaian soils

Abstract

The acid soils of the western region of Ghana which hitherto have been relegated to forest and tree crops production are becoming increasingly important for agricultural food crop production in the country. However, on account of their strongly acidic properties, there is the need to apply agricultural lime to the soils to improve upon their productivity. At present, however, information on the lime requirement and appropriate liming practice for these soils is lacking. The objective of this study was to compare the suitability of selected chemical methods for the determination of the lime requirement to predict lime needs of these naturally occurring acid soils. The lime requirement of six acid soils were determined by calcium hydroxide [Ca(OH)₂] titration, exchangeable aluminum (Al), and Shoemaker, McLean, and Pratt (SMP) buffer methods. Correlation analysis showed that all the methods were highly correlated with one another. The SMP method was found to be somewhat better than either exchangeable Al or Ca(OH)₂ titration method for estimating the lime requirement of the soils. Hence, the SMP method is recommended for use as the diagnostic index of lime requirement of these soils because of its speed and simplicity. Regression studies on the lime requirement values by the three methods and selected soil properties showed that exchangeable Al and organic carbon were the most important soil factors contributing to the lime requirement of these soils. Clay content was significantly correlated only with the Ca(OH)₂‐based lime requirement values (r = 0.81*).     

Effects of limestone and phosphorus on nutrient availability and coastal bermudagrass yield on an ultisol

Abstract

This field study was conducted to evaluate nutrient availability and Coastal bermudagrass [Cynodon dactylon (L.) Pers.] yield response to factorial combinations of applied limestone and P in a strongly acid (pH 4.7), infertile soil. Limestone was applied at rates of 0, 672, and 3808 kg ha^‐1 to a Lilbert loamy fine sand (loamy, siliceous, thermic, arenic Plinthic Paleudult). Phosphorus was applied at rates of 0, 30, 60, 90, 120, 240, and 480 kg P ha^‐1. Soil pH in the surface 15 cm initially increased to 6.2 in response to the high limestone rate, but subsequently declined due to N fertilization. Lime increased soil test P, Ca, and Mg and decreased K and Al. The efficiency of increasing soil test P with fertilizer P was low, but improved as a consequence of liming. Coastal bermudagrass yield increased by as much as 37 percent from P application. Maximum yield coincided with 10 to 15 mg kg^‐1 or greater soil test P and tissue P concentrations that ranged from 1.6 to 2.2 g kg^‐1. Lime Increased tissue Ca and Mg, but had no effect on plant P concentrations. Yield was unaffected by lime despite its positive effect on soil P and an apparent K‐Mg antagonism. Plant nutrients obtained from deep rooting of the bermudagrass into an argiilic horizon may have precluded any positive effect of lime on Coastal bermudagrass yield.     

Factors associated with annual ryegrass yield response to limestone

Abstract

Quantifying the effects of soil acidity on plant growth remains a challenging research topic as numerous soil and plant growth factors are influenced by pH and lime. In the field, annual ryegrass (Lolium multiflorum Lam. ‘Marshall') responded positively to the application of 3.8 Mg lime/ha on a strongly acid (pH 4.7) Lilbert loamy fine sand (loamy, siliceous, thermic, arenic Plinthic Paleudult) over three growing seasons. Dry matter yield in some cuttings, however, was better correlated with soil Al, P, Ca, Mg, and K than with pH. A greenhouse study was undertaken to quantitatively determine the effects of these five minerals plus Mo on ryegrass yield in limed and unlimed Lilbert soil material. Three ryegrass cuttings were obtained from unlimed (pH 4.8) or limed (1000 mg CaCO₃/kg) Lilbert soil which was also amended with five rates of Ca, K, Mg, Al, P, and Mo in combinations stipulated by central composite design methodology. Response surface models that fit yield to the applied treatments and soil test data were complex because all factors and many interactions were significant. Furthermore, the models were transformed as the plants matured and element availability changed due to mineral uptake. Most yield improvement derived from liming occurred as a result of the elimination of exchangeable Al with a concomitant increase in P efficiency. Applied Ca did not alleviate Al toxicity in unlimed soil. Chlorotic plants developed in all pots where Mg was excluded. Yield was increased by applied Mg and Mo in unlimed soil, but not in limed soil. Applied K improved yield only in limed soil. Although regression accounted for a large portion of the yield variability (R² values ranged from 0.75 to 0.95), these models were unable to accurately predict yield in control treatments.     

Response of Mature Phosphorus-Deficient Apple Trees to Phosphorus Fertilization and Liming

ABSTRACT

The aim of the study was to examine response of mature phosphorus (P) deficient apple (Malus domestica Borkh.) trees to phosphorus fertilization and liming. The experiment was carried out during 2003–2005 in a commercial orchard in Central Poland on ‘Jonagold’ apple trees/M.26 planted in 1996 on a coarse-textured soil with low both pH (4.6) and organic matter (1.2%). Calcium-lactate soluble phosphorus concentration in the soil was within an optimal range despite appearance of leaf phosphorus deficiency symptoms. Soil and foliar applications of phosphorus, and soil liming were applied. Soil phosphorus fertilization was made in the first year of the experimental at a rate of 100 kg P per ha as triple superphosphate. Foliar sprays of a soluble compound containing organic phosphorus were performed 5 times per season at 2-week intervals, starting 4 weeks after full bloom. Soil liming was applied in the fall 2002 at a rate of 1100 kg Ca ha^?1 as hydrated lime. Additional combination as soil phosphorus fertilization plus liming was also applied. Plots unsupplied with phosphorus and lime served as a control. The results showed that liming and liming plus soil P application increased soil pH, and phosphatase activity in the soil, and improved phosphorus nutrition, tree vigor, yield, fruit color, and firmness after storage; effect of these treatments was not found only in the first year of the study. In all years foliar phosphorus sprays improved phosphorus nutrition of apple trees, and fruit color and firmness after storage. In 2 out of 3 years foliar phosphorus application increased yield. The vegetative and reproductive responses of ‘Jonagold’ apple trees did not depend on soil phosphorus fertilization. It was concluded that maintaining an optimal pH of soils for apple trees limits the incidence of orchard phosphorus deficiency and that foliar phosphorus sprays should be applied in phosphorus-deficient apple orchards to improve yield, and fruit appearance and storability.     

Effects of soil acidity and phosphorus on the yield and chemical composition of tall fescue

Abstract

Tall fescue (Festuca arundinacea) is assuming increasing importance as a pasture species in South Africa. Many of the soils on which fescue is grown are inherently high in exchangeable Al and are characterized by high P‐immobilization capacities. The responses of fescue to dolomitic lime and P were examined in a factorial field trial on a red clay (Kandiustalfic Eustrustox) having a pH(KCl) and acid saturation [100(Al+H)/(Al+H+Ca+Mg+K)] in the unlimed state of 4.1 and 48%, respectively. A significant, though very limited, dry‐matter yield response to lime was evident (yields in the absence of lime were approximately 80% of the yields obtained at high lime levels). This pattern in the response to lime remained consistent over the three seasons of experimentation, despite soil acidity levels being substantially increased through the periodic use of ammonium sulphate as the N source in the trial. A significant response to P was evident at the first harvest after establishment; thereafter, P treatments had no effect on yield. The lime and P response data obtained in this investigation indicate that tall fescue is much more tolerant of soil acidity and has substantially lower soil P requirements than other important crop and pasture species in this country, such as maize (Zea mays) and Italian ryegrass (Lolium multiflorum). Lime significantly increased herbage Mg levels yet, in general, did not influence Ca levels in the herbage. Concentrations of Mg in the herbage exceeded Ca concentrations at all lime rates. Luxury uptake of K resulted in the K/(Ca+Mg) equivalents ratio in the herbage frequently exceeding the tetany hazard threshold of 2.2.     

Evaluation of liming and magnesium materials for increasing soil pH and available magnesium

Abstract

Four liming and Mg materials were compared in a greenhouse experiment with soybeans for their ability to raise soil pH, supply Mg, and their effect on the availability of Mn, Cu, Fe, and Zn. Three materials were added at rates of 0, 1, and 2 times the lime requirement, calcitic lime, dolomitic lime, and Hydra‐Mag (an industrial by‐product containing 20% Mg). Sul‐Po‐Mag was the fourth material added as a plus Mg check at a rate based on an equivalent amount of Mg to that supplied by Hydra‐Mag. Plant growth, plant tissue element content and extractable soil elements were determined after growing the soybeans for 5 weeks. Plants in treatments where no lime/Mg materials were added were very small due possibly to Mg deficiency and Al toxicity. The 1 and 2 times rates of the materials gave about equal growth except that the high Sul‐Po‐Mag rate caused salt injury. Hydra‐Mag increased soil pH more than calcitic lime which increased soil pH more than dolomitic lime. Soil and plant Mg levels were increased more by Hydra‐Mag than dolomitic lime when applied at equivalent rates based on the lime requirement. Dolomitic lime gave very good plant growth indicating that it made adequate amounts of Mg available. Hydra‐Mag reduced plant and extractable soil Zn, Cu, and Fe but no more so than calcitic or dolomitic lime. Hydra‐Mag reduced plant Mn more than for the other limes.     

The response of fruit trees in Michigan to trickle irrigation

Abstract

Trickle irrigation was evaluated in 2 seasons on sour cherry, plum, peach, and apple. Rates of water applied were 0, 1.9, 3.8, and 7.6 liters per hour (LPH) in 1975, and 0, 3.8, 7.6, and 15.2 LPH in 1976. Peach yields were increased both years. Apple yields were increased in 1976. Leaf content of Na, Ca, Mg, Mn, and Al in sour cherry; P, Cu, B, and Al in peach; and P, Na, Fe, Cu, and Al in plum was increased by irrigation.     

Annual ryegrass response to limestone and phosphorus on an ultisol 1

Decreasing winter pasture productivity in unlimed Ultisols has been associated with increased soil acidity due to fertilizer N application. The susceptibility of cool season grasses to soil acidity and associated infertility factors that result in reduced forage yield are not well understood. This field study was undertaken to evaluate the effects of factorial combinations of limestone and P applications on annual ryegrass (Lolium multiflorum Lam. ‘Marshall') dry matter production and tissue mineral concentrations on a strongly acid (pH 4.7), sandy soil. Limestone was applied to a Lilbert loamy fine sand (loamy, siliceous, thermic, arenic Plinthic Paleudult) at rates of 0, 672, or 3808 kg ha^‐1. Phosphorus was applied to split plots at rates of 0, 30, 60, 90, 120, 240, or 480 kg P ha^‐1. Over three harvest years, ryegrass yields increased 90 to 750% and 25 to 80% at the highest lime and P rates, respectively. In the second year, yield response to applied P was significantly less at the high lime rate which indicated that liming made soil P more plant available. Lime and applied P increased plant tissue P, Ca, and Mg concentrations. Yield was positively correlated with soil pH, P, Ca, and Mg and negatively related to soil K and Al. Clear relationships between individual soil test levels and leaf mineral concentrations with yield fluctuations could not be established because these variables were inextricably related to the lime and P rates. Nevertheless, excessive soil Al, coupled with inadequate P, Ca, and Mg availability, were indicated as important nutritional factors limiting annual ryegrass growth in unlimed soil.     

Growth dynamics and calcium content in mcintosh and Spartan apples

Abstract

The growth dynamics and Ca content of apple fruit were investigated over three growing seasons for the cultivar Spartan and two seasons for the cultivar McIntosh. Calcium content per fruit increased from fertilization to harvest, with some fluctuations during the season. The final Ca content ranged from 8 to 11 mg per fruit. Calcium concentration diminished markedly as a function of dilution during the first few weeks of growth after which it decreased less rapidly until reaching minimum values at 100 and 110 days after bloom for Mclntosh and Spartan respectively     

Limestone and gypsum effects on calcium nutrition of ‘Florunner’ and ‘NC‐7’ Peanuts

Abstract

Minimum sufficiency levels of hull and seed Ca for maximum yield and grade of runner or Virginia type peanuts (Arachis hypogaea L.) have not been established and there is limited information on single and combined effects of limestone and gypsum on production and quality of peanuts. Field experiments were conducted on runner and Virginia type peanuts to study single and combined effects of limestone and gypsum on yield and grade, and to attempt to establish minimum sufficiency levels of hull and seed Ca for maximum yield and grade of each type. Gypsum treatments, O, low, medium, and high rates, were superimposed on residual limestone rates on three sites with ‘Florunner’ (runner type) and on one site with ‘NC‐7’ (Virginia type) peanuts. Yield and grade of Florunner peanuts were not increased by limestone or gypsum treatments on any site even though soil Ca concentrations (Mehlich 1) ranged from 152 to 200 mg/kg among the sites. These levels were lower than the Georgia recommended minimum sufficiency value of 250 mg/kg. However, yield and grade of ‘NC‐7’ peanuts were increased by limestone or gypsum, but maximum yield occurred only where gypsum was applied even with soil Ca levels of 682 mg/kg. The minimum hull Ca level of 1.2 g/kg and seed Ca of 0.42 g/kg were sufficient for Florunner peanuts since yields and quality were not increased by limestone or gypsum application. Maximim yield and grade were achieved with Florunner at leaf, hull, and seed Ca concentrations of 13.2, 1.2, and 0.42 g/kg as compared with 26.0, 1.9, and 0.58 g/kg for NC‐7, respectively. These data show that NC‐7 has a higher Ca requirement than Florunner.     

Yield of sugar beet,soybean, corn,field bean,and wheat as affected by lime application on alkaline soils

Abstract

Environmental regulations and limited storage space compel processors to remove spent limestone and not stockpile it on site. This material is often used as a liming material to control pH on acid soils, but in some cases may have to be applied to alkaline soils. This study was undertaken to evaluate the effect of applying sugar beet processing lime on soils with an alkaline solum. Studies were conducted at seven sites representing four soil series. Lime was applied at rates of 0,1.4, 2.8, and 5.6 magnesium (Mg) ha^‐1. Sugar beet (Beta vulgaris L.), soybean (Glycine max L.), cora (Zea mays L.), field bean (Phaseolus vulgaris L.), and wheat (Triticum aestivum L.) were used as test crops. Yield of sucrose and roots of sugar beet as well as yield of soybean, corn, field bean, and wheat were not affected by lime application. Manganese (Mn) and zinc (Zn) concentration in leaves of sugar beet and soybean, and whole field bean plants decreased with increasing lime rates. These results show this lime may be applied at rates up to 5 Mg ha^‐1 once every three years on these alkaline soils without negatively affecting the yield of sugar beet, soybean, corn, field bean, and wheat. Nutritional status of these crops should be carefully monitored after lime application.     

Chemical and organic immobilization treatments for reducing phytoavailability of heavy metals in copper‐mine tailings

This study was conducted to evaluate the efficiency of diammonium phosphate (DAP), agricultural limestone (lime), and green‐waste compost mixed with 30% treated sewage sludge (GCS) applied alone or in combination as chemical immobilization treatment using tomato as a test crop. Mine waste was collected from an abandoned copper‐mine tailing site at Mynydd Parys, Anglesey (UK). Lime was applied at the rate of CaCO₃ equivalent (CCE, pH = 7), DAP at the rate of 23 g P per kg substrate, and 10% by weight, GCS as sole application. Half rate of each amendment was also tested as a combined treatment and an untreated substrate (control). Plant‐available metals (Cd, Cu, Fe, Pb, and Zn) were measured in substrate with conventional diethylenetriaminepentaacetic acid (DTPA) and sequential Ca(NO₃)₂ extraction. Plant–dry biomass yield was significantly (p < 0.001) increased by the combined application of all the three amendments while sole application of DAP reduced yield by 4‐fold compared to unamended soil probably due to P toxicity. Addition of lime reduced the DTPA‐extractable Cu, Fe, and Zn by 75%, 81%, and 85%, respectively, while Pb availability was reduced by 88% in combined DAP + lime + GCS treatment compared to control. The extraction capacity of DTPA was higher than that of Ca(NO₃)₂ by 3‐fold for Cu and Fe, 8‐fold for Pb, and 2‐fold for Zn. The leaf‐tissue concentrations of Cu and Fe were reduced by 77% and 83% in the lime + GCS amendment, respectively, while both Pb and Zn were reduced by 89% and 33%, respectively, in substrate treated with the combined application of all three amendments. These results suggest that alkaline amendments (both lime and GCS) were effective in reducing the phytoavailability of Cu, Fe, and Zn while DAP mixed with either GCS or lime was effective in reducing Pb availability.     

Response of eleven forage species to treatment of acid soil with calcitic and dolomitic lime

Abstract

The cost and difficulty of applying lime on hilly pastures or small forage fields makes it appropriate to devote attention to efficiency of lime utilization. This study evaluated effects of calcitic and dolomitic lime on yield and mineral composition of 11 forage species grown on soil with a low base status of 0.46 cmol_c as Ca and 0.18 cmol_c as Mg kg^‐1. Both lime types increased dry matter production, but only Lolium multiflorum responded more positively to dolomitic lime. The low Mg level in the soil was not a major factor limiting yield. Increase in yield was mainly attributed to the increase in pH with the concurrent decrease in Al level and to an increased Ca availability to plants. The species ranked as follows according to the magnitude of yield increase due to calcitic liming: Trifolium fragiferum > Trifolium pratense > Vicia sativa > Vicia villosa > Trifolium repens > Lolium perenne > Lolium multiflorum > Festuca arundinaceae = Lolium (multiflorum x perenne x perenne) > Trifolium subterraneum > Dactylis glomerata. The most responsive, Trifolium fragiferum, did not grow without lime. The least responsive, Dactylis glomerata, showed a yield increase of 36%. A similar ranking was obtained when all species were evaluated for Al tolerance using a 48 hour root elongation bioassay. In both unlimed soil and soil limed with calcitic lime, Mg concentrations of all species were relatively low. Although they were generally not low enough to have an effect on yield, they barely met the Mg nutritional requirement of cattle. By adding dolomitic lime, Mg content increased in grasses an average of 3.7 fold and in legumes by 2.4 fold. Grasses were similar in Ca, Mg, and K concentrations within a soil treatment. Legumes showed a greater range with the two vetches having the lowest Ca and Mg concentrations and red clover the highest.     

Influence of FGD Gypsum on the Properties of a Highly Erodible Soil under Conservation Tillage

Surface application of agricultural lime and fertilizers in no-till (NT) systems can be inadequate because of the excess time required for slowly soluble lime to improve soil aggregation such that water and nutrients move more rapidly into and down the soil profile. This study used fluidized gas desulfurization (FGD) gypsum as an alternative to lime because of its greater solubility and calcium (Ca) and sulfur (S) contents. Gypsum was applied to NT cotton (Gossypium hirsutum L.) plots at rates of 0, 2.24, 4.48, and 6.72 Mg ha^?1 for 3 years. After 1 year, Ca, S, and soil aggregation increased significantly (P ≤ 0.05) while exchangeable aluminum (Al) activities were reduced. These results indicate that FGD gypsum can increase NT cotton yields by increasing infiltration and soil water contents, reducing runoff, ameliorating exchangeable Al problems, and by providing a readily available source of S, a limiting nutrient in many cotton soils.     

Response of grass leys to applications of calcified seaweed

Abstract

Calcified seaweed has long been used as a soil conditioner in northern Europe, but supposed beneficial responses have not been experimentally substantiated. Field and glasshouse studies examined treatment responses on the characteristics of sandy silt loam Hapludalf soils and on the growth and elemental composition of Loliumperenne. Agricultural lime was a treatment in both experiments, being chemically similar to calcified seaweed. Calcified seaweed was applied at 2 t ha^‐1 and produced small increases in soil pH and extractable calcium (Ca). Significant increases in Lolium perenne growth were found in field studies after both calcified seaweed and lime applications. Smaller, but consistent, increases in growth were found in glasshouse pot studies. However, only one harvest showed a significant dry weight yield increase after calcified seaweed application compared with the untreated control. In pot studies, increases in soil extractable Ca were associated with increases in shoot elemental Ca. Decreases in shoot zinc (Zn) and manganese (Mn) concentrations were found after both calcified seaweed and lime applications. Total shoot element accumulation of Zn and Mn after calcified seaweed application were similar to those produced by the control, suggesting that decreases in shoot Zn and Mn concentrations resulted from dilution after increased shoot growth. However, total Zn and Mn accumulation decreased after lime application compared to the control and calcified seaweed treatments, probably resulting from fixation of available soil Zn and Mn through greater increases in soil pH.