Status assessment of macronutrients in banana leaves and its associated soil in Thatta , Sindh , Pakistan

Macronutrients are critically essential for successful plant growth and are consumed in larger quantities from fertile soils. Most of the soil conditions all over the world can support plants with sufficient nutrition and do not need fertilizer to complete life cycle. In the meanwhile, soils have manipulated through anthropogenic means through the addition of fertilizer to promote vigorous growth and increase yield. This study was aimed to assess the status of macronutrients in the agricultural soils of District Thatta, Sindh, Pakistan. A total of 33 composite soil samples at the depths of 0-15 and 15-30 cm including exact number of banana leaves were also collected from different study sites. The macronutrients i.e. NPK, Ca, Mg, Zn and Cl were assessed their status in the soils. In addition, organic matter, Electrical Conductivity, pH and lime (CaCO3) also analyzed. Results showed that physicochemical properties of surface and sub-surface soils were heavy in texture, non-saline, medium alkaline and moderately calcareous in nature. The analysis of soluble anions indicated that carbonates were absent and chlorides were dominant as compared to bicarbonates. Concentrations of nitrogen and zinc were remained below stipulated levels of soil standards. Whereas, phosphorus, potassium, manganese and chloride ions were recorded above critical limits. This study recommend that fertilizers dosage of nitrogen and phosphorous should be increased to get maximum banana yield.


Introduction
Banana holds a high position in fruit and food crops of the tropical and sub-tropical regions.Being a cash crop of high value, it catches growers heed to be a good source of agricultural income, and its fine taste and high nutritive value keep it in great demand throughout the year [1].The global banana production estimates 42 million tons/year [2].Major Banana growing counties are America, Brazil, Australia, Bangladesh, and Philippines etc. [3,4].In Pakistan, the area planted to banana has shown progressive increase over the time.In 1989 the area under banana was 23.5 thousand hectares and yielding 209 thousand tons/year [5].Sindh is the leading banana producing province of Pakistan having share of 86.42% in total Banana production [6].Main banana growing districts of Sindh province are Hyderabad, Mirpurkhas, Badin, Thatta, Nawabshah, Nausharo Feroze and Khairpur etc. [7].Banana requires more nutrients than any other commercially important crops which must be supplied through giving fertilizers to obtain maximum yields [8].This crop requires all the essential nutrients in adequate quantity for successful growth and yield.The macronutrients i.e. nitrogen, phosphorus, and potassium are required in large quantities and soils are usually deficient of these nutrients due to excessive use of croplands [9].Nitrogen is critically essential nutrient for banana growth due to its biochemical function in the plant body.Nitrogen participates in photosynthesis through a series of enzymes reactions as well as being part of chlorophyll molecule [10].Phosphorus is a part of nucleic acids, phospholipids, and energy storing and transferring system in the plant.It is required high concentration at the growing points of roots and shoots [11].Potassium is considered the most important nutrient in Banana production because; it is required for at least 60 different enzymes evolved in plant growth.Potassium is not a constitute of any plant structure or organic compound, but it is essential in nearly all the biological processes needed to sustain plant life and catalyze important metabolic reaction such as respiration, photosynthesis, starch synthesis, regulation of stomata and regulation of nutrients and water intake [12].
Different research studies have revealed that soils of banana growing areas in Sindh province are relatively deficient due to inadequate required fertilizer dosage to sustain its fertility.Therefore, this study was planned to assess the status of macronutrients in Thatta district of Sindh province and suggest the growers to provide required nutrients to deficient soils.

Soil Sample Collection
The study was conducted at privately owned different agricultural farms in Thatta district.A total of 18 soil samples at the depth of 0-15 and 15-30cm including 33 banana leaves samples were collected randomly from the selected areas.A total 50 gm soil was collected from four corners and one from centre then mixed together to get bulk sample.Soil and banana leaves samples were put in polyethylene plastic bags, labelled and preserved according to standard procedures.Soil samples were brought to laboratory on the same day and stored in the refrigerator at 4 0 C prior to analysis.Soil samples were sieved 2mm using mechanical shaker.Analysis were carried out in the analytical labs in the Department of Soil Science, Sindh Agriculture University, Tando Jam, Sindh, Pakistan.

Experimental Design
The physicochemical properties of soil samples were analyzed i.e. soil texture, organic matter, pH, EC, lime (CaCO3), carbonates, bicarbonates, macronutrients (NPK, Ca & Mg.) and micronutrient (Zn).Soil texture was determined using Hydrometer method [13].40 g air-dried soil (2 mm) was taken and 60 ml of dispersing solution (Dissolve 40 g sodium hexametaphosphate [(NaPO3)13], and 10 g sodium carbonate (Na2CO3) was added in DI water, and final volume was raised upto 1000 ml.The solution was shacked using orbital shaker (SCILOGEX Analog Orbital Shaker SK-O180-E) for 30 minutes.Then solution was transferred into 1000 ml measuring cylinder and inserted hydrometer.Sample was stirred and noted first reading and left for 2 hrs for second reading.Soil texture was calculated using soil textural triangle.50 g air-dried soil (< 2-mm) was taken and added 250 ml DI water and put for vertical shaker (THZ, China) for 2 hrs.EC and pH reading was noted using pH/EC Meter (2182A, Spectrum Technologies, Inc.) Organic matter was determined using Walkley-Black method [14].Weighed 1 g air-dry soil (0.15 mm) and.added 10 mL 1 N potassium dichromate then added 20 mL concentrated H2SO4 using a dispenser, and swirl the beaker to mix the suspension, added 200 mL Distil water, added 10 mL concentrated H3PO4 and allow the mixture to cool, added 10 -15 drops diphenylamine indicator, titrate with 0.5 M ferrous ammonium sulfate until the color changes from violet-blue to green.Prepared two blanks, containing all reagents but no soil, and treat them in exactly the same way as the soil suspensions Organic matter was calculated using formula.

Phosphorus was analyzed using Olsen techniques
[15].Exchangeable K, Ca and Mg was determined by using flame photometer (Cole-Parmer Four-Element Flame Photometer, WU-02655-15).10 g air-dried soil (< 2-mm) was taken and put into a 250-mL flask, pour 50 mL 1 N NH4OAc solution (ratio 1:5), shacked for 30 minutes using reciprocal shaker (Model E5850) at 200-300 rpm, filter suspension using a Whatman No.1 filter paper to exclude any soil particles, and brought the extract to a 50-mL volume with 1 N NH4OAc solution.Readings were expressed in mg/kg.Carbonate, bicarbonate and chlorides were determined using titration method.Pipette out 10 -15 mL soil saturation extract in a wide-mouthed porcelain crucible or a 150-mL Erlenmeyer flask, added 1 drop phenolphthalein indicator, If pink color develops, added 0.01 N H2SO4 by a burette, drop by drop, until the color disappears, take the reading for carbonate, continue the titration with 0.01 N H2SO4 after adding 2 drops 0.1 % methyl orange indicator until the color turns to orange noted the reading for bicarbonate.Now for chlorides added 4 drops 5 % K2CrO4 solution in sample and titrate against 0.01 N AgNO3 until a permanent reddish-brown color appears.Calcium carbonate was also analyzed using titration method. 1 g of air-dried soil (0.15mm) was taken into a 250-mL Erlenmeyer flask, added 10 mL 1 N HCl solution to the flask with a volumetric pipette, swirled and left the flask overnight, or heat to 50 -60 °C, and let the flask cool, added 50 -100 mL DI water using a graduated cylinder, and add 2 -3 drops phenolphthalein indicator, titrate with 1 N NaOH solution while swirling the flask.Continue the titration until a faint pink color develops, and take the reading, R. 0.5-1.0g air dried and ground plant material (0.15 mm) into a 300-mL calibrated digestion tube (or into a 150-ml conical flask), added 5 mL concentrated H2SO4 (in the fume hood), and swirled carefully and then placed tubes in the rack, placed the tubes rack in the blockdigester (or hot plate), and then place a glass funnel in the neck of the tubes, slowly increase temperature setting to about 145 °C for 1 hour, added 5 mL tri-acid mixtures and heat it to 240 o C for to further 1 hour, and if possible, keep overnight to prevent excessive foaming, lift the tubes rack out of the blockdigester, carefully place on a rack holder, and let tubes cool to room temperature, filter through Whatman No. 42 filter paper and bring to 50-mL volume, determined Fe, Mn, Cu, Zn, Cd, Ni, Pb, Co, and Cr using AAS (Varian Spectra AA 240, USA).

Result and Discussion
Soil texture is a qualitative classification tool used in both the field and laboratory to determine classes for agricultural soils based on their physical texture [16,17].Results of soil textural analysis (Table 1) showed that surface and sub-surface soil samples were alluvial contained a high amount of clay particles and heavily compacted in nature [18,19].EC (Figure 1), pH (Figure 2), organic matter (Figure 3) and CaCO3 (Figure 4) were observed that mostly of the soil samples were medium to strongly alkaline in reactions, medium to adequate in organic matter and moderately calcareous in nature respectively and investigated results also compared with soil standards, it was also investigated banana plant required more water and salt can easily leach down or due to the effect of the dolomite clay mineral in soils near coastal regions [20,21].Nitrogen (Figure 5), available Phosphorous (Figure 6) and exchangeable potassium (Figure 7) were analyzed in soil and plant samples and it was observed that soil samples were poor to medium in N at the surface and subsurface soil layer, low to optimum in phosphorous but optimum in exchangeable potassium, same result were also reported by [22][23].
The concentrations of Ca.Mg and available Zn in the soils samples are shown in figure (8, 9 & 10).The concentrations of bicarbonates (Figure 11) and chlorides (Figure 12) showed that mostly bicarbonates were present in minute quantitative whereas chlorides were dominates ion at both the soil layer.The concentrations of NPK and Zn in the banana leaves (Figure 13) showed that mostly N and available Zn were below the critical level whereas P and K were above the critical levels and as suggested by lava and turner.With an average value of 2.29% and 2.40%, 0.48 and 0.38%, 6.1 and 6.9 respectively, whereas analysis results of Ca, Mg and Cl (Figure 14 & 15) in the banana leaves leaf concentration of banana leaves and were above the critical levels as suggested by lava and turner with an average value of 0.68% and 0.75%, 0.67% and 0.77%, 0.83% and 0.836% respectively.

Conclusion
This study revealed that soils of studied area were heavily compact in structure which may effect on the internal drainage of soil.Results showed that physicochemical properties of surface and sub-surface soils were nonsaline, medium alkaline and moderately calcareous in nature.Concentrations of nitrogen and zinc were remained below stipulated levels of soil standards.Whereas, phosphorus, potassium, manganese and chloride ions were recorded above critical limits.This study recommend that fertilizers dosage 20 tons/ha -1 of farmyard manure should be provided to deficient soils of

Figure 1 .
Figure 1.Electric Conductivity of the agricultural soils of District Thatta, Sindh, Pakistan.The blue represents particle size of 0-15 and orange 16-30.

Figure 2 .
Figure 2. The pH of the agricultural soil particles of District Thatta, Sindh, Pakistan.The blue represents particle size of 0-15 and orange 16-30.

Figure 3 .Figure 4 .
Figure 3. Organic matter concentration of the agricultural soils of District Thatta, Sindh, Pakistan.The blue represents particle size of 0-15 and orange 16-30.

Figure 14 .Figure 15 .
Figure 14.Calcium and Magnesium concentration in the Banana Leaves.