Lime Rates Research Articles

Lime application effects on soil aggregate properties: Use of the mean weight diameter and synchrotron-based X-ray μCT techniques

The hierarchical organization of aggregates in soil is responsible for the presence of inter and intra-aggregate pores. This research aimed to investigate effects of soil surface liming, considering lime rates of 0, 10 and 15 t ha−1, on the intra-aggregate porous system of soil aggregates with equivalent diameters of 2–4 and 1–2 mm, from 0 to 10 (A) and 10 to 20 cm (B) soil layers. These aggregates were selected by the wet sieving method carried out for determination of the mean weight diameter. Synchrotron-based computed microtomography (μCT) of aggregates was analyzed in terms of porosity, connectivity, tortuosity, and fractal dimension. Additionally, X-ray fluorescence was used to evaluate the elemental composition of the soil aggregates. All liming effects were concentrated at layer A, where calcium percentage was elevated in aggregates from 1–2 mm class as compared to those from 2–4 mm class. Accordingly, the physical parameters studied were generally more affected in the case of smaller aggregates (1–2 mm). Liming decreased total porosity, increased tortuosity of pores, and decreased fractal dimension for 1–2 mm aggregates, which was in line with the fact that larger pores were replaced by smaller ones in 1–2 mm aggregates, as found via both quantitative and qualitative analyses. On the other hand, liming did not affect pore connectivity under any of the circumstances.

LIME AND GYPSUM APPLICATIONS ON SOIL CHEMICAL ATTRIBUTES AND INITIAL GROWTH OF EUCALYPTUS

Eucalyptus crops in Southern Brazil are generally conducted in acidic soils, thus their yield can be increased by lime and gypsum applications. The objective of this study was to evaluate the effect of lime and gypsum applications on soil chemical attributes and initial growth of Eucalyptus benthamii and Eucalyptus dunnii in a Humic Cambisol (Inceptisol). The experiment was conducted in a greenhouse, with seedlings of both species of eucalyptus grown in soil treated with different rates of lime (0, 3, 6, and 12 Mg ha-1), and gypsum (0, 6, 3, 12.6, and 25.2 Mg ha-1). At 90 days after application of the treatments, the soil chemical attributes and growth components of eucalyptus seedlings. The lime increased the production shoot dry weight, however, the response to gypsum was negative. The lime increased the soil pH, exchangeable calcium (Ca), base saturation (V %), and slightly the soil electrical conductivity, decreased the soil aluminium saturation (m %), and promoted little reduction in the exchangeable potassium (K) and magnesium (Mg) contents. The gypsum didn't alter the soil pH, but decreased the m%, increased soil phosphorus (P) contents, and expressively increased the electrical conductivity, which may have had a negative effect on the eucalyptus growth. In conclusion, the addition of limestone decreases the soil acidity and benefits the growth of eucalyptus seedlings. However, the addition of gypsum has no expressive effects upon those variables, but it can decrease the growth of seedlings when the rates are excessive.

Cadmium Uptake by Ryegrass and Ryegrass-Clover Mixtures under Different Liming Rates.

Cadmium accumulates in soils that receive repeated applications of Cd-rich superphosphate fertilizers. There is evidence that adding clovers to a crop solubilizes soil Cd, increasing the bioavailability of Cd. This can lead to high plant Cd concentrations. This research aimed to test whether liming-induced increases in pH in mixed crops of clovers and ryegrasses reduced forage Cd concentrations. A greenhouse pot trial applied lime at three rates (0, 1, and 2% of soil dry weight) to eight different plant treatments-four as monocultures (perennial ryegrass [ L.], Italian ryegrass [ Lam.], white clover [ L.], and red clover [ L.]) and four as ryegrass-clover mixtures (two plant types in each treatment)-in soil (initial soil pH = 5.1, initial soil Cd concentration = 1.31 mg kg) with added Cd (CdSO ∼ 1 mg kg). Adding lime increased soil pH in both mono- and mixed crops and, in most treatments, increased forage yields. However, the relationship between forage Cd and soil pH differed between plant treatments. In mono- and mixed crop treatments containing perennial ryegrass, adding lime increased the forage yield but did not increase the mass of Cd in the plants compared with the no-lime treatment. However, adding lime to treatments that included Italian ryegrass increased both the forage yield and the Cd compared with the no-lime treatment. The results show that a combination of certain plant species composition and lime rates can optimize forage yields without increasing forage Cd concentrations.

Liming effects on soil pH and crop yield depend on lime material type, application method and rate, and crop species: a global meta-analysis

The aim of this meta-analysis was to investigate the interactive effects of environmental and managerial factors on soil pH and crop yield related to liming across different cropping systems on a global scale. This study examined the effects of liming rate, lime application method, and liming material type on various soil chemical properties and crop yield based on data collected from 175 published studies worldwide since 1980. The most important variables that drive changes in soil pH and crop yield were liming rate and crop species, respectively. Soil conditions, such as initial soil organic matter and soil pH, were more important for increasing soil pH in field-based experiments, while lime material type and application method were more important for improving crop yield. To effectively neutralize soil acidity, the optimum liming duration, rate, and material type were < 3 years, 3–6 Mg ha−1, and Ca (OH)2, respectively. Averaged across different crop species, the application of CaO, CaCO3, Ca (OH)2, and CaMg (CO3)2 increased yield by 13.2, 34.3, 29.2, and 66.5%, respectively. This meta-analysis will help design liming management strategies to ameliorate soil acidity and thus improve crop yield in agroecosystems.

Lime or Phosphorus: Which is Best to Limit Broomsedge in Tall Fescue Pastures?

Core Ideas Broomsedge increases in low‐fertility tall fescue pastures. Phosphorus fertilization limits broomsedge increase in tall fescue pastures. Lime application limits broomsedge increase in tall fescue pastures. Applying recommended rates of lime and phosphorus increases tall fescue and limits broomsedge. Most Missouri tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) pastures grow on acidic, low‐phosphorus (P) soils. These conditions favor increases in broomsedge (Andropogon virginicus L.), a grass that is unpalatable for livestock. Three management strategies, 1) liming, 2) P fertilization, and 3) liming plus P fertilization, were evaluated for limiting broomsedge in tall fescue pastures. An established tall fescue pasture containing broomsedge was selected in southwest Missouri (soil pH 4.6, 6 lb/acre Bray I P). Lime was applied at 0x, 0.5x, 1x, and 2x the soil test recommendation (x = 3.67 ton/acre). Plots were treated with 0 or 50 lb P/acre. Plant counts for tall fescue and broomsedge were estimated over the next 3 years. Without P fertilization, broomsedge doubled over a 3‐year period. Phosphorus fertilization effectively maintained broomsedge at the initial level. The P treatment doubled the tall fescue count in 3 years following treatment, but without P, tall fescue counts remained at the initial level. Broomsedge increased nearly threefold without lime. Tall fescue more than doubled with the two highest lime treatments in 3 years. The 0x lime treatment resulted in no increase in tall fescue. Lime and P combined limited broomsedge increase to the greatest degree and produced the greatest increase in tall fescue. Increased vigor of tall fescue resulting from improved soil fertility likely influenced the increase in tall fescue and limited further encroachment of broomsedge. Applying lime and P could improve pastures by encouraging growth of desirable grasses and discouraging increases in common weeds like broomsedge.

Determination of Critical Soil Silicon Levels for Rice Production in Louisiana Using Different Extraction Procedures

ABSTRACTWhile silicon (Si) fertilization is widely practiced in rice production, establishing critical soil Si levels has remained understudied. Field trials were established at 12 sites across Louisiana from 2013 to 2015 to determine critical soil Si for rice cultivation. Five silica slag (14% Si) rates at 0, 1, 2, 4, 6, and 8 Mg ha−1 and two lime rates (2 and 4 Mg ha−1) were arranged in randomized complete block design with four replications. Post harvest soil samples were analyzed for Si using seven extraction procedures. The critical soil Si levels established by the linear plateau model using 0.5 M acetic acid-1 hr (OAc-1) extraction procedure were 36, 41 and 50 mg kg−1 for plant Si uptake, grain yield, and relative yield as response variables, respectively. Generally, soils having high initial Si and pH had minimal responses to Si fertilization, whereas Si content of soils with low initial Si was significantly increased.

Effects of Lime, Vermicompost, and Chemical P Fertilizer on Selected Properties of Acid Soils of Ebantu District, Western Highlands of Ethiopia

Soil acidity is one of the major factors limiting soil fertility and crop production in large areas of Ethiopia. A two-month incubation experiment was conducted to evaluate the effects of lime, vermicompost (VC), and chemical phosphorus (P) fertilizer on selected chemical properties of Dystric Nitisols in Ebantu District, Western Ethiopia. The treatments comprised of three rates of lime (2, 4, and 6 tons CaCO3·ha−1), VC (2.5, 5, and 7.5 tons·ha−1), and mineral P fertilizer (20, 40, and 60 kg·P·ha−1) each applied alone and in various combinations. The experiment was laid down in a completely randomized design with two replications. The results showed that the highest increment of pH from 4.83 at the control to 6.05 and reduction of exchangeable Al from 1.70 to 0.09 cmolc·kg−1were obtained from combined application of lime at 4 tons CaCO3·ha−1and VC at 7.5 tons·ha−1. The most significant decrease in exchangeable acidity (0.17 cmolc.kg-1) was observed in soil that was treated with 6 tons CaCO3·ha−1lime applied alone (93%) and combined application of lime at 4 tons CaCO3·ha−1with VC at 7.5 tons·ha−1by (81%). The highest contents of OM (4.1%) and total nitrogen (0.29%) were obtained from combined application of lime at 4 tons CaCO3·ha−1and VC at 7.5 tons·ha−1. Integrated application of chemical P (60 kg·P·ha−1) with lime (2 tons·ha−1) plus VC (7.5 tons·ha−1) resulted in Bray-II P increased by 45% relative to control. The various combinations of the treatments also improved exchangeable Ca2+and Mg2+. The results indicate that integrated use of lime, vermicompost, and chemical P fertilizer can improve soil acidity and availability of nutrients. However, the real potential of the amendments used in this experiment should be further assessed under field conditions using a test crop.

&lt;b&gt;Application of lime, phosphogypsum and fertilization rates affect soil fertility and common bean development in no-tillage system in a Cerrado Oxisol

There is a lack of information about the effects of interactions among lime, phosphogypsum (PG) and fertilization on soil fertility and their effects on common bean yields in the tropics. This study aimed to determine the effects of annual application of PG and limestone and rates of fertilization on the chemical attributes of soil, fertilization efficiency, yield components and the grain yield of the common bean. The study was performed for three growing seasons in an acidic Oxisol. The experimental design was randomized blocks in a 4x4 factorial scheme. The treatments consisted of lime, lime + PG, PG, and control (without corrective application) with four fertilization rates. In an acidic and low-fertility Cerrado soil, limestone or limestone + PG applied annually at 1/3 of the total rate in a no tillage system increased the common bean yield and the efficiency of the fertilization, although the improvement of the soil acidity indicators did not reach the desired levels. The application of soluble fertilizers to provide adequate and balanced amounts of nutrients provided greater yield gains and improved soil fertility compared to surface liming without fertilization, but the combination of the two practices resulted in the greatest benefits to both plant and soil fertility.

Weeds on Soybeans Crop After the Application of the Association of the Herbicides Imazapic + Imazapyr on Different Liming Rates in a No-till Cropping System

The repeated use of the herbicide glyphosate has selected weed resistant species to this molecule. The combination of the tank-mix imazapic + imazapyr (Cultivance® technology) turns out being an alternative on the management of glyphosate resistant weeds. The interaction of these molecules with the soil’s chemical properties with the spraying frequency, and the weed diversity are yet unknown. This study evaluated the effects of liming at the weed incidence on the soybeans crop treated with the association of herbicides imazapic + imazapyr in a no-till cropping system. The experiment was installed at the field in a RCBD with four replications. The experiment was conducted in a factorial arrangement 5 × 2 with five rates of calcitic limestone (0, 2.5, 5, 12.5, and 30 ton/ha) and two corresponding to the presence or absence of the herbicides imazapic + imazapyr (rate of 100 g/ha of the commercial product Soyvance®) sprayed in a spray-plant system. After 40 months of surface-liming, the soybean cultivar Lancer® was planted in a no-till field, and it was evaluated: frequency and abundance of weeds, and the chemical soil parameters: pH, Ca, H+Al, and Mg at the depth of 0-10 cm. The most abundant weeds observed were: Desmodium spp., Schlechtendalia luzulifolia, Digitaria horizontalis, Raphanus sativus and Cyperus spp., with predominance of dicot species. In conclusion, as the surface-liming rate was increased, the greater the frequency of dicot weeds, and the lesser the monocots were found in the area.

Vegetation and Soil Responses to Concrete Grinding Residue Application on Highway Roadsides of Eastern Nebraska.

As a precautionary principle, the National Pollutant Discharge Elimination System (NPDES) permit establishes that the primary pollutant in concrete grinding residue (CGR) is its alkalinity and restricts CGR roadside discharge to 11 Mg ha or the agronomic liming rate, whichever is lower. We evaluated the effect of CGR application on roadside soil chemical properties, existing vegetation, and rainfall runoff. Five CGR rates (0, 11, 22, 45, and 90 dry Mg ha) were tested on roadsides slopes at two different locations in eastern Nebraska. Vegetation, soil, and runoff characteristics were evaluated before CGR application and 30 d and 1 yr after CGR application. Soil pH of control plots averaged 8.3 and 8.5 for each site respectively, across depths and slope positions, thus not requiring any liming for agronomic purposes. Soil electrical conductivity (EC, 1:1) averages of control plots were 0.79 and 1.24 dS m across depths and slope positions. In the short term (30 d) the highest CGR application affected the 0- to 7.5-cm soil depth by increasing soil extractable Ca (21 and 25% for each site, respectively), soil pH (0.2, south site), and soil EC (0.2 dS m) compared with the control. However, these changes in soil did not persist 1 yr after CGR application. The pH buffering capacity of soil prevented post-CGR-application pH from exceeding 8.9, even at the highest application rate. Application of CGR did not produce any differences in biomass production, botanical composition, and runoff characteristics at either site. From our study, CGR up to ?90 dry Mg ha-about the amount produced during diamond grinding operations-can be one-time applied to roadside soils of similar characteristics on already established vegetation.

Accuracy of methods to estimate potential acidity and lime requirement in soils of west region of Santa Catarina

ABSTRACT: The objective of this study was to compare two methods of evaluation of potencial acidity (H+Al) and two methods to estimate liming requirement (LR) for soils from the west region of Santa Catarina State, Brazil. Fourteen soils were incubated with 7 lime rates for 120 days, obtaining the real values of H+Al at pH 7.0 and LR. These values were used as reference to evaluate the accuracy of two H+Al estimating methods: SMP buffer and calcium acetate at pH 7.0, and to evaluate the accuracy of two LR methods: base saturation (BS) and SMP index. On average, H+Al was underestimated in 6 and 40% by SMP and calcium acetate methods, respectively, especially in soils with high buffer capacity. The LR was underestimated in 20 and 30% by SMP index and BS, respectively. The SMP Index showed a better LR estimative than BS, especially in soils with high buffer capacity.

Application of different lime rates and phosphorus on soil physico-chemical properties of acid soils in western Ethiopia

Soil acidity and phosphorus deficiency are the major yield limiting factors to crop production in Haro Sabu area, western Ethiopia. Thus, a field experiment was carried out in 2014 main cropping season from the end of June to the end of November at Haro Sabu to assess the effect of lime and phosphorus rates on soil physico-chemical properties of the experimental soil . The treatments were factorial combination of five rates of phosphorus (0, 11.5, 23, 46, 57.5 kg P2O5) and four rates of lime (CaCO 3 ) (0, 2.25, 3 and 3.75 tons ha-1) in randomized complete block design and replicated three times. The pre soil analysis indicated that the soil of experimental area was acidic (pH = 5.31) and low in available P (2.34 mg kg -1 ). The soil textural class was sandy clay loam with constituents of sand (53%), clay (19%) and silt (28%). Application of both lime and phosphorus to the experimental plot increased exchangeable Ca, available phosphorus and total nitrogen while decreased exchangeable aluminum. Therefore, application of lime and phosphorous on acid soil improves the pH of the soil, there by the availability of phosphorous and cations.

English

Integrated use of lime with organic and chemical fertilizers is considered as a good approach for sustainable crop production under acidic soils. Vermicompost (VC) and chemical phosphorus (P) fertilizer when used with lime play a vital role in enhancing productivity of acidic soils. Field experiments were conducted for two consecutive cropping seasons of 2015 and 2016 to evaluate the effects of lime, VC and chemical P fertilizer on yield and yield components of maize in Ebantu District, Western highlands of Ethiopia. The experiments were laid out in a randomized complete block design as a factorial combination of two lime rates (0, and 4 t CaCO3 ha-1), three VC rates (0, 2.5 and 5 t VC ha-1) and three chemical P rates (0, 20 and 40 kg P ha-1) which were replicated three times. Relevant crop parameters were measured following standard procedures. Tasseling days (102), silking days (109), highest leaf area index (5.91), plant height (3.48 m), cob length (47.83 cm), number of grain per cob (644) and above ground dry biomass yield (22 t ha-1) were exhibited by 5 t ha-1 VC and 40 kg ha-1 chemical P fertilizer with lime of 0 and 4 t ha-1 while the highest 1000-seed weight (508 g), grain yield (4.87 t ha-1) and harvest index (24%) were obtained at 2.5 t ha-1 VC and 40 kg P ha-1 with lime. Integrated application of organic and chemical fertilizers with lime amended the acidic soils and improved its fertility which in turn increased crop yields. Combined use of VC at 2.5 t ha-1 and chemical P fertilizer at 20 kg ha-1 with lime at 4 t ha-1 is economically optimum and could be recommended for reclaiming soil acidity and improve nutrients for maize as it enhanced grain yield and yield components of maize plant in strongly acidic soils for the two consecutive years pooled together. Key words: Maize yield, lime, Vermicompost (VC), phosphorus (P), integrated application.

Morphogenetic and structural characteristics of signal grass in response to liming and defoliation severity

ABSTRACT The control of soil acidity through liming and the adoption of adequate management are essential to the maintenance of pastures productivity. The morphogenetic and structural characteristics of Urochloa decumbens cv. Basilisk, in canopies with (0.7 t ha-1 and 1.0 t ha-1) or without liming and subjected to severe or lenient cuttings (stubble corresponding to 40 % or 60 % of the pre-harvest height, respectively), were evaluated throughout regrowth, during late spring and summer. Treatments were distributed in a 3 x 2 factorial arrangement, in a completely randomized block design, with 3 replications (80 m2 plots). Increased liming rates do not result in benefits to the herbage mass, tiller population density or a faster canopy recovering. The average tiller weight decreases, while the duration of regrowth linearly increases, with increasing liming rates, particularly in late spring. Stem elongation and leaf senescence rates increase and leaf elongation rates decrease from the 15th day of regrowth, regardless of the liming rates or defoliation severities. Post-harvest heights ranging from 40 % to 60 % of the pre-harvest height showed to be within the tolerance limits to defoliation of U. decumbens. The liming rates adopted had only marginal impacts on the morphogenetic characteristics of U. decumbens.

Effects of Fertilizer, Rhizobium Inoculation and Lime Rate on Growth and Yields Field Pea in Horro and Gedo Highlands

Effects of Fertilizer, Rhizobium Inoculation and Lime Rate on Growth and Yields Field Pea in Horro and Gedo Highlands

Changes in Soil Physical Properties and Carbon Protection Mechanisms by Surface Application of Lime in a Tropical No‐Tillage System

Core Ideas Liming helped avoid structural degradation. Liming effectively increased the stabilization of soil organic matter. More stable soil structure was achieved by liming. Long‐term no‐till soils often have layers that are severely affected by physical and chemical degradation. Soil acidity is associated with physical problems, such as higher bulk density, that restrict root growth and crop production, especially in tropical regions with dry seasons. Liming is the most common practice adopted to alleviate soil acidity, but limited information is available regarding the long‐term effect of lime applied superficially on soil physical attributes and the distribution of organic C in different aggregate size groups. In an Oxisol managed under a no‐tillage system for 12 yr, a trial was established with four lime rates (0, 1000, 2000, and 4000 kg ha–1) estimated using the base saturation method. The results showed that among the treatments, the rate calculated to increase the base saturation at 70% (2000 kg ha–1) provided a higher formation of water‐stable (WS) macroaggregates of &gt;2.00 to 8.00 mm size class at 0‐ to 0.40‐m depth, and a significant decrease in the stability of the largest aggregates when the highest rate was applied. Increased values of mean weight diameter (MWD) and geometric mean diameter (GMD) were estimated with the application of rates varying from 1500 to 2500 kg ha–1. Liming increased carbon‐protection mechanisms, resulting in an accumulation of organic C in all aggregate size classes, mainly in the &gt;0.105 to 0.25 and &gt;0.25 to 2.00 mm size classes. Improving the formation of WS aggregates and total organic carbon (TOC) content with liming influenced positively the total porosity, macroporosity, and soil bulk density in the deepest soil layers (0.20–0.40 and 0.40–0.60 m).

Increased lucerne nodulation in acid soils with

Acidic conditions with damaging levels of available aluminium (Al3+) currently limit lucerne (Medicago sativa) production on soils in the New Zealand high country and in large areas of Australia. Increased lucerne nodulation could be achieved by using an Al3+-tolerant strain of Sinorhizobium meliloti to inoculate an Al3+-tolerant lucerne line. The Al3+ tolerance of the current commercial Australasian inoculant strain for lucerne, S. meliloti RRI128, was compared with strain SRDI736, selected in Australia for tolerance to low pH. Four Al3+ levels (0, 2, 4 and 8 µm) were created at pH 5.1 in a hydroponic system. The rhizobial strains were evaluated on SARDI AT7, a lucerne line selected for improved growth and nodulation in acidic solution culture with Al3+, and on Stamina 5, a commercial cultivar commonly grown in Australasia. SARDI AT7 when inoculated with strain SRDI736 produced more nodules per plant (3.6 vs 2.4) and had higher nodulation percentage (&gt;80% vs &lt;50%) at all Al3+ levels than when inoculated with RRI128. The percentage of nodulated Stamina 5 plants after inoculation with the commercial strain was lower than after inoculation with strain SRDI736 (10–16% vs 25–70%) at all Al3+ levels. The potential of S. meliloti strains SRDI736, SRDI672 and RRI128 and rates of lime to increase lucerne nodulation and dry matter production in soils of low pH (&lt;5.5, in water) and high Al3+ (&gt;3 mg kg–1 soil) was also investigated in a pot trial. Lime had a more consistent effect than inoculant strain for increasing nodulation. At 0.5 and 2 t lime ha–1, plants inoculated with strains SRDI672 and SRDI736 had more nodules per plant than plants inoculated with the commercial strain. At 4 t lime ha–1, the number of nodules per plant was highest for all three inoculants, and there were no differences among them. This confirms the importance of lime to increase lucerne nodulation in low-pH, high-Al3+ soils. However, where liming is uneconomic or impractical, the results show that it was possible to select rhizobial strains to increase lucerne nodulation in acidic soils with damaging levels of available Al3+.

Effect of Lime Addition to CaSO 4 Oxygen Carrier in Chemical Looping Combustion

Abstract Chemical-looping combustion (CLC), which has the characteristic of greenhouse gas CO2 inherent separation, is a novel combustion technology. In this study, CLC experiments of methane using CaSO4 oxygen carrier with lime addition were carried out in a batched fluidized bed reactor, where the sample was exposed to alternate oxidizing and reducing conditions. The influences of temperature, calcium-to-sulphur ratio and lime particle size on the conversion of CaSO4 and sulfur capture were investigated and a suitable operation condition was determined. Under the optimal operation condition, a multi-cycle test was performed to evaluate the cyclic redox behavior of the lime-promoted CaSO4 sample. X-ray diffraction and a field emission scanning electron microscope were used to characterize the phase and surface morphology of the samples used. The results show that the addition of lime could improve the conversion rate of CaSO4 and the capture efficiency of sulfur-containing gases. The operation conditions of calcium-to-sulfur ratio 0.8, lime particle size of 180-250 μm and operation temperature of 900 °C turned out to be the optimal conditions. Besides, the average desulphurization rate of lime was up to 78.77% during the cyclic test.

Phosphorus availability in low phosphorous acidic soils as affected by liming and phosphorous addition

An incubation study was conducted to determine the effect of lime (L) as CaCO3, and phosphorus (P) as triple super phosphate (TSP) on soil pH, available P, organic matter decomposition, inorganic nitrogen content, and calcium (Ca) content of soil. Three rates of lime equivalent to 0, 1 000, 2 000 kg (CaCO3) ha-1 and three rates of TSP equivalent to 0, 50 and 100 mg (P) kg-1 were applied in combination as treatments with three replicates. With the increasing rate of lime, soil pH was significantly (p < 0.001) increased. Both lime and TSP had significant effects (p < 0.001) on P availability at three different soil test P extraction methods. Two thousand kg (CaCO3) ha-1 with 100 mg (P) kg-1gave the highest available P irrespective of extractant used. Bray and Kurtz-1 method extracted the largest amount of P (5.63- 66.69 mg kg-1) while Borax method extracted the smallest amount (3.42 – 42.42 mg kg-1). Despite the varied ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3 --N) contents, the NH4+-N content decreased and NO3- - N content increased in the all treatments when incubation progressed. With the increasing rate of liming, the decomposition of organic matter and the Ca content also increased.

Interaction of soil pH and phosphorus efficacy: Long-term effects of P fertilizer and lime applications on wheat, barley, and sugar beet

Phosphorus (P), a plant macronutrient, must be adequately supplied for crop growth. In Germany, many soils are high in plant-available P; specifically in arable farming, P fertilizer application has been reduced or even omitted in the last decade. Therefore, it is important to understand how long these soils can support sustainable crop production, and what concentrations of soil P are required for it. We analyzed a 36-year long-term field experiment regarding the effects of different P application and liming rates on plant growth and soil P concentrations with a crop rotation of sugar beet, wheat, and barley. Sugar beet reacted to low soil P and low soil pH levels more sensitively than wheat, which was not significantly affected by the long-term omitted P application. All three crop species showed adequate growth at soil P levels lower than the currently recommended levels, if low soil pH was optimized by liming. The increase in efficacy of soil and fertilizer P by reduced P application rates therefore requires the adaptation of the soil pH to a soil type-specific optimal level.