Potassium is most of import macro-nutrient for harvest growing. More than 30 Pakistani dirts are low in available K and is inevitable for maximal harvest output. The methods for calculating the K fertiliser recommendations, theoretical account based ( Langmuir and Freundlich isotherms ) recommendations are best for crop-specific and site-specific intents under different textures. Therefore, a field experiment will be conducted to find the K demand of rice by analyzing the K keeping capacity of dirt utilizing Freundlich and Langmuir surface assimilation theoretical account, in small town Boopra Khird, District Gujranwala. The interventions will be: Control ( recommended doses of K ) , Freundlich calculated K dosage ( F-K ) and K dosage calculated through Langmuir theoretical account ( L-K ) . Treatments will be replicated thrice following randomized complete block design ( RCBD ) . Composite dirt samples will be collected from each secret plan at 0-15 centimeter dirt deepness for finding assorted chemical features ( ECe, United States Public Health Service, OM, CaCO3, soluble cations and anions ) . The harvest will be harvested at adulthood phase and different growing parametric quantities will be recorded. Plants and dirt samples will be analyzed to calculate external and internal K demand.
Rice ( Oryza sativa L ) is considered one of the most of import cereals of Pakistan and occupies 2nd place after wheat. It is the most of import summer cereal harvest of traditional rice turning countries of the Punjab ( 61 % ) , Sindh ( 31 % ) , Baluchistan ( 4 % ) and high height vales in the North ( 4 % ) ( Awan et al. , 2007 ) . It is an of import beginning of gaining foreign exchange. Area under rice cultivation in Pakistan is 2571 1000 hectares with one-year production of 6160 1000s tones and mean output is 2396 kilogram ha-1 ( Economic Survey of Pakistan, 2011-12 ) .
Potassium is a critical component for works growing and is an exceptionally dynamic ion in the dirt system. As an ion, K is extremely nomadic in the works system but, merely reasonably nomadic in the dirt system. Potassium is a cardinal food and makes the workss tolerant to emphasiss such as cold / heat emphasiss, drouth, diseases, and pest onslaught. Potassium catalyzes many of the enzymatic procedures that are taking topographic point in the workss ( Ujwalaranade, 2011 ) .
In Pakistan, largely dirts are sufficient in entire K as Mica is the dominant clay mineral in most of dirts ( Soil Survey, 1985 ) . Potassium is present as constituent of comparatively indissoluble mineral, nevertheless merely a little fraction is present in available signifier to workss. In the dirt, there is the equilibrium among soluble, exchangeable, non-exchangeable and fixed signifiers of the K and therefore responsible for the K handiness. Among these signifiers, soluble and exchangeable K is thirstily available to workss whereas the signifier which is easy available is the non-exchangeable K. Due to less application of K fertiliser and extended remotion of rice straw from the Fieldss, Pakistani dirts are confronting a K-depletion of 8.8 mg kg-1 dirt on an one-year footing and a entire shortage of 0.27 million tones yearly ( Bajwa, 1994 ; Malik et al. , 1989 ) .
For the rice, the husbandmans use merely N fertiliser and really frequently P and K fertilisers are applied at sub-optimal degree. This pattern of instability and unequal fertiliser application affects the dirt productiveness and depletes the indispensable foods ( Cassman et al. , 1996 ) . It is hence pre-requisite to apologize the usage of fertilisers peculiarly the K. Oftenly ; response to K fertiliser in Pakistan is sporadic which necessitates the site-specific recommendations for K.
Different surface assimilation equations/models are traditionally used for recommendation of fertilisers while maintaining in position harvest demand and surface assimilation capacity of dirts. Among these theoretical accounts Freundlich and Langmuir theoretical accounts are widely used for site-specific recommendations. These involve monitoring of surface assimilation of the food in dirt, development of the sorption isotherm which accounts for strength, sum and competency factors which have much importance for foretelling the sum of food required for the maximal growing of the works.
The present survey will be conducted:
Apply and compare the K degrees in the field determined by Freundlich and Langmuir theoretical accounts.
V. REVIEW OF LITERATURE
Hannan et Al. ( 2007 ) conducted a research lab survey to happen out the K surface assimilation features of four dirts under potato-maize cultivation system in Punjab. Adsorption isotherm of Potassium were constructed by equilibrating 2.5 g dirt samples with 11 degrees of K ( 0- 250mg L-1 ) as KH2PO4 in 25 milliliter of 0.01M CaCl2 solutions. Then surface assimilation informations were fitted to the Freundlich, Langmuir and the Temkin surface assimilation equations. Loam, flaxen clay loam and silt loam dirts arrived at equilibrium after 12 hours while clay loams soil reached in steady province after 18 hours of equilibrium period. On an mean sum of K adsorbed ranged from 30.10 to 37.67 % of added K. The Freundlich equation explained the surface assimilation behaviour of K better than the other two equations as higher correlativity values runing from 0.95 to 0.99 is evidenced. All the four dirts with about similar clay contents differed in their surface assimilation features.
Hannan et Al. ( 2011 ) conducted an experiment to look into K-adsorption in the dirt. For this, dirt sample from the major murphy turning countries of Pakistan was collected. The Freundlich and Langmuir are the surface assimilation theoretical accounts in which surface assimilation informations were fitted. The consequences showed that the Freundlich surface assimilation theoretical account ( R2= 0.96** ) explains the informations better than the Langmuir surface assimilation theoretical account. On the footing of Freundlich theoretical account fertiliser rates were calculated and the K degrees of the dirt solution were targeted at 0, 3, 6, 9, 12, 15, 18, 21, 24, and 27 milligram K L?1. Then on the dirt a field survey was conducted to find the consequence of assorted K degrees ( 0-27 milligram L?1, holding K fertiliser rates of 0, 24, 49, 75, 101, 128, 155, 182, 210, and 237 kilograms ha?1 ) in the dirt solution on the output and quality of murphy tuber. At the clip of seeding N and P2O5 are applied at the rate of 300 kilograms and 250 kilograms ha?1 severally. Yield response theoretical accounts ( additive plus tableland, quadratic, square root, quadratic plus tableland, and exponential ) were used to gauge the fertiliser rate optimal for murphy harvest. Linear plus plateau theoretical account fit the information with less favouritism than the other output response theoretical accounts. It was seen that there was a considerable consequence of K usage on the output and quality of murphy tubers. Application of K fertiliser @ 130 kilogram K ha?1, which is equal to the degree 12 milligram K L?1 in the dirt solution, maximized the output of murphy tubers.
Hannan et Al. ( 2012 ) Different dirts have different surface assimilation capacity due to which an single critical degree of K is in sufficient for different textured dirts every bit good as truth of harvests. In a state, fertilizer recommendations for a specific part required drawn-out investigational trails. Bing a good index of dirt birthrate, sorption isotherm provides dependable fertiliser recommendations. Freundlich and Langmuir surface assimilation isotherms are worldwide used to mensurate the behaviour of food in dirt and fertiliser recommendation for a specific site and harvest. A few experimental trails required for this sort of attack. Initially within research lab, mark dirt solution degrees to be set with the aid of antecedently discussed surface assimilation theoretical accounts. At the terminal of trail, a precise targeted output to be achieved through rating of output informations by utilizing assorted theoretical accounts ( quadratic, exponential/Mitscherlich, Boltzman sigmoid, Extended logistic, additive plus plateau theoretical accounts ) .Maize fodder harvest tested by utilizing above said attack. As a consequence of 14.50 milligrams L?1 dirt solution degree which is equal to 144 kilograms K ha?1, the entire fresh fish output was 61.91 Mg ha?1.The consequence indicates that a higher dirt solution degree required for upper limit and better quality fodder trait end product.
Doula et Al. ( 2008 ) studied the dynamicss of K surface assimilation from solution to exchangeable stages on bentonite samples. First, bentonite was saturated with Ca in the signifier of CaCl2. Potassium surface assimilation clip was evaluated on Ca-saturated samples utilizing 125, 150, 200, and 250 ?g K mL-1 solutions equilibrated for 10, 15, 20, 30, 35, 45, 60, 75, 80 and 120 proceedingss. Samples pH varied between 4.0 and 9.0. Equilibrium in K exchange was reached faster in lower concentrations and higher pH values. First order rate, parabolic diffusion, Elovich and modified Freunlich equation were used to depict K sorption. Comparison of coefficients of findings ( r2 ) secret plans indicated that modified Freunlich and parabolic diffusion theoretical accounts provided the best tantrums of the surface assimilation informations ( r2 & A ; gt ; 0.979 ) Constants for the Freunlich equation were estimated and the theoretical account was expressed as a map of pH.
Choudhury et Al. ( 2003 ) investigated the K lack in different rice turning countries of Malaysia. So a survey was carried out on K surface assimilation in three Malayan rice dirts ( Guar, Hutan and Kangar series ) . They used six degrees of K ( 0.00, 28.77, 33.57, 38.37, 43.16 and 47.96 mmol kg-1 ) . The information on the K surface assimilation were fitted into Langmuir, Freundlich, and Temkin surface assimilation equations. Adsorption informations were besides correlated with pH, cation exchange capacity and organic affair content of the dirts. Potassium surface assimilation increased linearly with increasing degrees of added K in all the three dirts. The rate of addition was the highest in Guar series followed by Kangar and Hutan series, severally. Potassium surface assimilation in two dirts ( Hutan and Kangar ) fitted into Langmuir equation while the surface assimilation informations in Guar series did non suit into this equation. Adsorption informations in none of the dirts fitted good in Freundlich and Temkin surface assimilation equations. Correlation between K surface assimilation and pH was important ( r = 0.881 ) , whereas, correlativity of K surface assimilation with either organic affair content or cation exchange capacity was non-significant. The consequences of this survey indicated that K surface assimilation is chiefly dependent on dirt pH. In dirts with higher surface assimilation capacity, more potassium fertiliser may be needed to acquire immediate harvest response.
Jibrin ( 2010 ) conducted an experiment to mensurate the position of K ( K ) and adsorption behaviour of 12 cultivated Fadama surface dirts across Nigeria. The dirts had 0.01- 0.23 ( average 0.07 ) , 0.21-6.83 ( average 2.70 ) , 0.20 – 1.73 ( average 0.91 ) and 0.09-0.26 ( average 0.14 ) cmolc kg-1, H2O soluble, 0.5 M NaHCO3 extractible, 1 N HNO3 extractible, and exchangeable K concentrations, severally. Five of the dirts were low in exchangeable K, while the staying Seven had average scope of exchangeable K concentration. The Freundlich sorption theoretical account conformed to the K features of the dirts with R2 values runing from 0.630 to 0.852 and had in the scope of 54.1 to 71.8 L kg-1 KF ( Freundlich coefficients ) value. The dirts had several types of sorption sites confirmed by the hapless fit indicant of the Langmuir theoretical account. The consequences of this survey indicated that exchangeable K pools in the dirt respond to high nutrient-demanding harvests, such as rice with K fertiliser application.
Y.J. Dua et Al. ( 2004 ) presented a survey in the geographic expedition of some factors commanding the surface assimilation of K+ onto two dirts ( Ariake clay and Akaboku ) . The man-made leachates were used i.e solution holding KCl salt and the solution incorporating multi-salts of KCl, NaCl and CaCl2. For both soils the K surface assimilation depends upon solid/solution ratio but in instance of Ariake clay soil the consequences were more important as comparison to Akaboku dirt. The K+ surface assimilation decreased with the increased ratio of soild/solution. The dirts were equilibrating before the preordained clip of standard batch-type trials and the Freundlich isotherm equation was used to find the relationship between adsorbed and equilibrium concentration. In instance of KCl solution conditions, both dirts were adsorbed larger sum of K+ comparative to multi-salt conditions.