Soil phosphorus availability and dry bean yield as affected by the application of liquid calcium carbonate micron particles on the furrow

The application of calcium carbonate micron particles in the planting furrow, because of the reduced particle size may favor a faster reaction in the soil and could provide increased pH and P availability for plants such as dry bean (Phaseolus vulgaris L.), potentially increasing yield. A field experiment was conducted for two consecutive years with the objective to evaluate the effect of the liquid calcium carbonate micron particle application in the planting furrow on soil properties (Ph, P, Ca, K and Al content and V) and on the yield components, grain yield, and concentration and content of P in dry bean. The experimental design was a randomized complete block scheme. The treatments consisted of six rates of calcium carbonate micron particles, that is, 0, 1.05, 2.10, 4.2, 8.4 and 12.6 kg ha -1 applied in the furrow at sowing of dry bean. Calcium carbonate increased the pH (from 4.8 to 5.3 at 0 to 0.10 m deep layer) and the P concentration in the soil (from 70 to 80 mg dm -3 at 0 to 0.10 m deep layer) until 30 days after application. The concentration of Ca, K and the base saturation of the soil were not affected by the addition of calcium carbonate. The concentration (from 4 to 4.3 g kg -1 ) and content (from 1,500 to 1,870 g ha -1 ) of P in the grain and grain yield (from 3,500 to 4,100 kg ha -1 ) of the dry beans increased with increasing concentration of calcium carbonate. The use of calcium carbonate micron particles in the sowing furrow is a new and effective practice that could increase crop yield in no-tillage system (NTS).

The application of calcium carbonate micron particles in the planting furrow, because of the reduced particle size may favor a faster reaction in the soil and could provide increased pH and P availability for plants such as dry bean (Phaseolus vulgaris L.), potentially increasing yield.A field experiment was conducted for two consecutive years with the objective to evaluate the effect of the liquid calcium carbonate micron particle application in the planting furrow on soil properties (Ph, P, Ca, K and Al content and V) and on the yield components, grain yield, and concentration and content of P in dry bean.The experimental design was a randomized complete block scheme.The treatments consisted of six rates of calcium carbonate micron particles, that is, 0, 1.05, 2.10, 4.2, 8.4 and 12.6 kg ha -1 applied in the furrow at sowing of dry bean.Calcium carbonate increased the pH (from 4.8 to 5.3 at 0 to 0.10 m deep layer) and the P concentration in the soil (from 70 to 80 mg dm -3 at 0 to 0.10 m deep layer) until 30 days after application.The concentration of Ca, K and the base saturation of the soil were not affected by the addition of calcium carbonate.The concentration (from 4 to 4.3 g kg
irrigation, crop rotation, pest management) during this harvest, especially in the first (Nov-Feb) and second (Feb-May) seasons, which is cultivated mainly by smallholders, resulting in a low productivity average of 1,050 kg ha -1 . The third season (May-Aug), cultivated in the center of Brazil normally by middle to big farmers, is characterized by high use of technology such as irrigation, liming application, certified seeds and more input of fertilizers (Nascente et al., 2012), in 2012, as a result there was a yield average of 2,529 kg ha -1 .Based on these results it can be concluded there is big yield gap between use of low and high technology.
One of the factors that is important for highly yield of dry beans is the development of root system which is maximum in a pH range of 6.0 to 6.5 to achieve maximum yield potential (Silva et al., 2004;Fageria et al., 2011).Tropical soils such as the Brazilian Cerrado or the African Savannas are naturally acidic because high levels of rainfall, which over many years has leached basic ions resulting in reduced soil fertility (Caires et al., 2008).According to Souza et al. (2006), tropical soils are highly weathered and are dominated by 1:1 clay minerals such as kaolinite and iron oxides (hematite and goethite) and Al (gibbsite), which have a high P adsorption capacity.In these areas satisfactory cash crop grain yields are dependent on proper liming and soil fertilization (Rosolem, 1994;Caires et al., 2001;Alleoni et al., 2009;Souza et al., 2011).An adequate and balanced supply of nutrients provides suitable crop development with a positive impact on grain yield (Fageria et al., 2011;Mallarino and Pagani, 2012;Crusciol et al., 2013).
Soil acidity limits crop production in many areas of the world due to Al toxicity, phosphorus deficiency, and low base saturation (Fageria and Baligar, 2008;Fageria, 2008).In Brazil, the most common material used for acidity correction is limestone while Ca and Mg silicate is rarely used (Camargo et al., 2007).The application of dolomitic limestone is effective at raising the soil pH, the calcium and magnesium concentration, and the base saturation and at reducing the levels of exchangeable aluminum in the soil (Caires et al., 2003).In tropical areas soil acidity affects land area of about 2.27 billion ha, which is more frequent in Oxisols (South America and Africa) and Ultisols (South America) (Fageria and Nascente, 2014).In these areas, normally the use of dolomitic lime required large amount to increase desired soil pH for dry bean production.Fageria (2008) reported that optimum soil pH for dry bean was 6.5 in no-tillage system (NTS) in Brazilian Oxisol and to achieve this pH an average of 10 Mg lime ha -1 is required.In most grain producing areas under a NTS, in the beginning of the system it is recommended to make the soil correction with incorporation.Then, in the following growing seasons when necessary, soil acidity correction is achieved by applying limestone on the soil surface without incorporation (Soratto and Crusciol, 2008a;Alleoni et al., 2009).However, the reaction of limestone is Nascente and Cobucci 1841 generally limited to the location of application/ incorporation due to its low mobility in soil.Results of field studies show that the movement of lime in the soil profile varies according to timing and rates of liming, lime application forms, soil type, weather conditions, addition of acidic fertilizers, and cropping systems (Oliveira and Pavan, 1996;Gascho and Parker, 2001;Conyers et al., 2003;Tang et al., 2003;Caires et al., 2008;Sorrato and Crusciol, 2008a,b;Churka et al., 2013).According to Caires et al. (2003), liming, whether surface applied or incorporated into the soil (layer 0 to 0.02 m), provided a more accentuated soil acidity correction in the superficial layer (0 to 0.5 m).However, there was a stronger reaction in the 0.05 to 0.10 and 0.10 to 0.20 m layers when lime was incorporated into the soil.Caires et al. (2005) adds that the effects of surface liming on all three acidity-related variables (pH, Al, and basic cations) were significant at 0 to 0.05 and 0.05 to 0.10 m depths beginning in year 1 and also at the 0.10 to 0.20 m depth only after 2.5 years from application.As a result, there is further delay in the reaction of lime in the soil, especially soon after its application (Caires et al., 1998;Fageria and Baligar, 2008;Soratto and Crusciol, 2008b).Thus, the development of technologies that provide a better environment for crop development may soon complement the application of lime on the soil surface.The use of nano particles or micron particles could be quite significant, allowing the development of new methods and techniques in various industrial, agricultural, cosmetic, pharmaceutical, textile, and other processes (Lêdo et al., 2007;Siqueira-Batista et al., 2010).However, there is a lack of information regarding the use of small particles of lime in the planting furrow on soil chemical properties and crop response.In Brazil the lime requirement (LR) of soils is calculated for given values of base saturation, using the equation: In which CEC is the cation exchange capacity, V 1 is the base saturation of the soil, V 2 is the expected value upon liming and ENV is the effective neutralizing value (Quaggio et al., 1985).The amount of limestone applied will depend on the desired saturation bases, but it usually ranges from 1 to 22 Mg ha -1 (Miranda et al., 2005;Caires et al., 2,008;Briedis et al., 2012;Pagani and Mallarino, 2012).While the conventional liming has a particle size of 50% < 0.3 mm and 50% > 0.3 mm the micron particle has a size between from 0.0001 to 0.0002 mm.The intent of limestone broadcast is to correct the whole soil area.With the application of limestone micron particle the intent is to effect only on the sowing furrow which equates to one tenth of the soil area.Further, the intention of applying limestone as micron particle is not to have total soil correction nor to substitute the traditional limestone, but only to have better conditions to the early plant development.Because of the smaller size it is likely that the liquid liming application will provide faster soil reaction in the soil furrow than the traditional liming.However, to the best of our knowledge there is limited research about the use of liquid liming in sowing furrow.The objective of this study was to evaluate the effect of the liquid application of calcium carbonate micron particles in the sowing furrow on the pH, the concentrations of Al, P, K, and Ca, and the base saturation in the soil and on the yield components (number of pods per plant, number of seeds per pod, and mass of 100 seeds), grain yield, concentration, and grain content of dry bean.
The experimental area was grown for four years as NTS, with corn cultivated in summer and dry beans in the winter season.The soil was a sandy clay loam (kaolinitic, thermic Typic Haplorthox) with 500 g kg -1 clay, 300 g kg -1 silt, and 200 g kg -1 sand.Before initiating the experiment, the soil chemical characteristics were determined (0 to 20 cm), with the following results: a pH of 4.6; a total soil organic matter content of 15 g kg -1 ; a P (Mehlich 1) of 12.1 mg kg -1 ; exchangeable K (0.51 mmolc kg -1 ), Ca (2.4 mmolc kg -1 ), Mg (0.9 mmolc kg -1 ), and Al (0.3 mmolc kg -1 ), with a total acidity at pH 7.0 (H+Al) of 3.6 mmolc kg -1 ; and a base saturation of 51.4%.The aluminum saturation was 3.45%.The soil analysis was performed according to Embrapa (1997).The soil pH was determined in a 0.01 mol L -1 CaCl2 suspension (1:2.5 soil/solution).Exchangeable Ca, Mg, and Al were extracted with neutral 1 mol L -1 KCl in a 1:10 soil/solution ratio and determined by titration with a 0.025 mol L -1 NaOH solution.Phosphorus and exchangeable K were extracted with a (Mehlich 1) extracting solution (0.05 M HCl in 0.0125 M H2SO4).The extracts were colorimetrically analyzed for P, and flame photometry was used to analyze K.The base saturation values were calculated using the results of the exchangeable bases and total acidity at pH 7.0 (H + Al).Aluminum saturation was calculated by dividing the Al concentration by the CEC.Using the Equation (1) and aiming a base saturation of 60%, and having an ENV of 70% the LR will be 911 kg ha -1 .For micron particles on the sowing furrow we calculate an application of 9.11 kg ha -1 .

Experimental design and treatments
The experimental design was a randomized complete block design with four replications in both years, which we have new plots each year.The treatments consisted of six rates of liquid calcium carbonate, CaCO3 (0, 1. 05, 2.10, 4.20, 8.40, and 12.60 kg ha -1 ) applied in the sowing furrow (0.03 m deep together with the dry bean seed).The plots were 40 m 2 (10.0 m x 4.0 m).The useful area of each plot was the two central rows, disregarding the 0.50 m on each end totalizing 9 m².

Dry bean management
The seeding of the dry bean cultivar Pérola was performed mechanically on May 12, 2010, and May 16, 2011, using no-till seeding (Semeato, model Personale Drill 13, Passo Fundo, RS, Brazil) with a row spacing of 0.50 m and density of 8 pure live seeds m -1 .The sowing fertilization consisted of 30 kg ha -1 N as urea, 39.3 kg ha -1 P + 10 kg ha -1 N as MAP, monoammonium phosphate and 50 kg ha -1 K as potassium chloride and an application of 60 kg N ha -1 (urea) at topdressing fertilization at 18 days after emergence (DAE) in both seasons, following recommendation of Sousa and Lobato (2003).The plant management was performed according to the crop needs.The plant emergence occurred at 7 days after sowing in both years.The full flowering stage occurred at 35 and 31 DAE in 2010 and 2011, respectively.The harvest was performed manually after physiological maturation.The dry bean season length was 104 and 101 DAE in the first and second years, respectively.
Liquid calcium carbonate solution (at a size of 0.0001-0.0002mm and a density of 2,711 g cm -3 ) was applied via a spray directly on the dry bean seeds in the sowing furrow with a StandMax Hunter CS applicator coupled to the planter during the same operation of sowing.The liquid calcium carbonate solution was acquired from a private company, which was created by suspending very finely ground limestone in water.The chemistry of liquid liming materials is the same as that of conventional liming and the rate of reaction and the neutralizing power for liquid lime are the same as for dry materials when particle sizes are the same.Each rate had a different batch of water and lime made up with the appropriate amount of lime in 60 L ha -1 of water.The machine used to apply the liquid liming has an agitator to keep the solution in suspension during the application.The area was sprinkler irrigated (center pivot) and the irrigation was schedule based on soil water content (Reichardt, 1987;Doorenbos and Pruitt, 1976).

Characterization of soil
A 4.5 cm diameter galvanized-steel auger was used for sampling at depths of 0 to 0.10 and 0.10 to 0.20 m at 15 and 30 days after calcium carbonate application.For each soil horizon, eight subsamples were collected from under the dry bean plant rows and in the middle of the inter-rows (0.25 m from the plant row) of each plot.For each location (in-row and between rows), the eight subsamples were combined into a composite sample.The composite samples were air dried and sieved to pass a 2 mm mesh and later analyzed to determine the pH (CaCl2 0.01 mol L -1 ), P, Al, Ca, and exchangeable K, as well as the calculated base saturation (V%) and aluminum saturation (%), according to the methodology proposed by Embrapa (1997).

Yield components and grain yield
The following variables were determined: a) Number of pods per plant: The number of pods contained in 10 plants randomly collected in each experimental unit at harvest was counted.Next, number of pods per plant was transformed to pods m -2 .b) Number of seeds per pod: The number of beans on the 10 plants used to count pods and then the seed number was divided by the number of pods per plant.c) Mass of 100 seeds: Determined by randomly collecting and weighing 100 seeds from four samples of each experimental unit, seed weight was corrected for moisture to 130 g kg -1 (wet basis).

Concentration and content of P in dry bean seeds
After the seed harvest, 10 random samples of 100 g of seeds were collected to determine the P concentration.The material was dried in forced ventilation at a temperature of 65°C until it reached constant weight.Then, the grain was ground and analyzed according to the methodology proposed by Malavolta et al. (1997).
Briefly, P was extracted with a nitro-perchloric solution and determined by atomic absorption spectrophotometry.We calculated P content (kg ha -1 ) in the seed by multiplying P concentration times the bean yield at 100% dry matter.

Statistical analysis
The data were subjected to analysis of variance (ANOVA).If F test was significant for calcium carbonate rates then a regression analysis was performed.We used the SAS statistical package (SAS, 1999).

RESULTS
There was no interaction between years and calcium carbonate among any of the variables evaluated (Tables 1 and 2).The application of calcium carbonate in the sowing row did not affect soil properties between rows at either sampling (15 and 30 days after lime application).However, there were significant differences (P<0.05) in pH, P, and Al% at 0 to 0.10 m 15 and 30 days after liquid liming application in the evaluations done in the row.The pH data from within the row sampling were fitted to quadratic equations of two depths evaluated at 15 (Figure 1A) and 30 (Figure 1B) days after calcium carbonate application.Moreover, it was verified that in-row lime application increased the amount of P in the soil up to a rate of 3,793 and 4,926 g calcium carbonate ha -1 , respectively in the layers 0 to 0.10 and 0.10 to 0.20 m in the evaluation performed 15 days (Figure 2A).When sampled at 30 days (Figure 2B) after liming application P content increased up to a rate of 1,360 and 3,532 g calcium carbonate ha -1 , respectively in the layers 0-0.10 and 0.10-0.20 m.The Al saturation data were fit to a linear equation at the 0-0.10 m depth in the evaluation performed 15 days, from 2,12 to 0,11% (Figure 3A) after calcium carbonate application.There was a linear effect in both layers (0 to 0.10, from 4.37 to 1.53% and 0.10 to 0.20 m, from 4.31 to 1.73%) at 30 days after liming application (Figure 3B).
Regarding yield components, only the number of pods m -2 was affected by calcium carbonate application (Figure 4).The grain yield was fitted to a second-degree polynomial equation, with higher values (4,147 kg ha -1 ) at a rate of 8.02 kg ha -1 of calcium carbonate (Figure 5).In the P concentration (Figure 6) and P accumulation (Figure 7) variables in the dry bean seeds, the data fit to a quadratic plateau model.For P concentration the highest value (4.38 g kg -1 ) was achieved at rate 4.99 kg ha -1 of calcium carbonate and for P accumulation the highest value (18,686 kg ha -1 ) was obtained at rate 6.59 kg ha -1 of calcium carbonate.

DISCUSSION
The variable analyzed in soil samples between the plant rows was unaffected by the application of calcium carbonate and also Ca, K, Al saturation, and base saturation at both layers in rows.These results indicate that the action of the calcium carbonate in micron particles occurred only near the application area.Furthermore, the low amount of liming material applied (12.6 kg ha -1 at the maximum rate used) was not enough to cause significant changes in these nutrients, which usually ranges from 1 to 22 Mg ha -1 (Miranda et al., 2005;Caires et al., 2008;Briedis et al., 2012;Pagani and Mallarino, 2012).
There was a greater P availability in the sowing furrow in the two periods after the calcium carbonate application, which may be due to the release of P fixed to Al or Fe (Souza et al., 2006).Fageria (2009) reported that Mehlich 1 extracting P increased significantly in no-tillage system when soil pH was raised from 5 to 7.5 in the Brazilian Oxisol.Lopes and Cox (1979) add that the process of P adsorption by the oxides, hydroxides and oxyhydroxides of iron and aluminum is among the main factors involved in the insolubilization of this nutrient in tropical soils.Thus, it is likely that the application of lime in the planting furrow caused the precipitation of Al and Fe in the forms of AlOH 3 and FeOH 3 and provided the increased availability of P in the early crop development only in this sowing furrow, which provided better condition to the plant development.The increase in the soil pH by liming increases the activity and concentration of the OH -ion in the soil solution, and it promotes the precipitation of Fe and Al, reducing the precipitation of P-Fe and P-Al (Mendez and Kamprath, 1978;Mcbride, 1994;Alleoni et al., 2009).It is noteworthy that the calcium in high pH (above 6.0-6.5)can form compounds with the phosphorus and precipitate it, which made P unavailable to plants.However, the pH values for the occurrence of these reactions are rarely found in soils under Cerrado (Malavolta et al., 1997).These results (precipitation of Fe and Al) were confirmed when it was found that increasing the rate of limestone in the furrow provided increases in the pH and reduced Al saturation in the 0 to 0.10 m layer.Davenport and Bair (2012) also reported an increased P     availability with increasing pH when the initial pH is low.Our results allow us to conclude that the application of calcium carbonate micron particles can provide a faster reaction in the planting furrow than the traditional liming applied at the soil surface without plowing, which normally take one year to correct the soil acidity at the depth 0 to 0.05 m (Caires et al., 2003(Caires et al., , 2005)).The liquid liming provided a greater availability of P in the furrow in the early stages of plant development.As a suggestion for new research application of conventional lime to the surface and liquid lime in the sowing furrow until the conventional lime has a chance to increase pH is a potential area of study.Thus, this combination with traditional liming and liquid liming can provide more promising results than simply applying liming on the soil surface, which, in NTS, takes even longer to react with the soil (Caires et al., 2008;Briedis et al., 2012).
Increasing the amount of lime increased the number of pods produced and as a result increased the grain yield.The number of pods is the yield component that most affects the grain yield (Valderrama et al., 2009;Nascente et al., 2012).Furthermore, the increase in grain yield may have been due to the greater P availability for the dry bean crop at the early development stage.Phosphorus  availability in dry bean crops has shown significant positive responses in grain yield (Miranda et al., 2000;Silva et al., 2001;Zucareli et al., 2011). Valderrama et al. (2009), working with dry bean cv.Perola at NTS, reported a crop response to a rate of 120 kg ha -1 of P.However, in our trial there are others factors that influenced the dry bean yield once the P data showed that the highest P levels occurred near the 2.1 kg rate.On the other hand, the highest yield of the pods and grain were at the 8.4 kg rate.It could be the decrease in soluble Al or the increase in the availability of Ca, Mg and K to the soil or other not evaluated causes.According to Caires et al. (2008) the liming application provides increasing in the soil availability of P, Ca, Mg and K, which causes reduction in the Al content and increases pH levels.

Conclusions
The application of small amounts of lime in the form of micron particles was efficient at increasing the availability of P, raising the pH of the soil, reducing the saturation of

Figure 1 .
Figure 1.pH values within the rows at 0-0.10 and 0.10 to 0.20 m soil layers as affected by the calcium carbonate rates at 15 (A) and 30 (B) days after application.Average of two growing seasons (2010 and 2011).

Figure 2 .
Figure 2. P values within the rows at 0-0.10 and 0.10 to 0.20 m soil layers as affected by the calcium carbonate rates at 15 (A) and 30 (B) days after application.Average of two growing seasons (2010 and 2011).

Figure 3 .
Figure 3. Al saturation values within the rows at 0-0.10 and 0.10 to 0.20 m soil layers as affected by the rates of calcium carbonate at 15 (A) and 30 (B) days after application.Average of two growing seasons (2010 and 2011).

Figure 4 .
Figure 4. Number of pods m -2 of dry bean as affected by calcium carbonate rates.Average of two growing seasons (2010 and 2011).

Figure 5 .
Figure 5. Grain yield of dry bean as affected by calcium carbonate rates.Average of two growing seasons (2010 and 2011).

Figure 6 .
Figure 6.Phosphorus concentration of dry bean grains as affected by calcium carbonate rates.Average of two growing seasons (2010 and 2011).

Figure 7 .
Figure 7. Phosphorus content of dry bean grains as affected by calcium carbonate rates.Average of two growing seasons (2010 and 2011).