Cation - Exchange

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higher, ie 9.62-13.80 meq/100 g and 9.81- 13.82 meq/ 100 g at flowering stage of rice ... exchangeable Na 14.50 meq/100 g, Ca+ Mg 2.50 meq/ 100 g, K 0.50 ...
Indian Journal of Agricultural Sciences 62 (3): 200-4, March 1992

Cation- exchange capacity of roots in relation to response of fertilizer nutrients in salt- affected soil A K SRIVASTAVA1 and O P SRIVASTAVA2 Banaras Hindu University, Varanasi, Uttar Pradesh 221 005 Received: 4 March 1991

ABSTRACT An experiment was conducted during 1998 at Varanasi to study the cation- exchange capacity of roots as affected by N, P, K, Fe, Mn, Zn and farmyard manure + N in gypsum- amended, salt-affected soil (Typic Natraqualf) and its relationship with dry-matter accumulation and nutrients uptake at different physiological stages of rice (Oryza satiwa L.) and wheat (Triticum aestivum L. emend. Fiori & Paol.). The application of N and Zn significantly Increased the cation-exchange capacity of roots as flowering stage of rice respectively from 6.21 to 9.62 meq/100 g and 9.90 to 12.20 meq/100 g and of wheat from 5.80 to 9.81 meq/100 g and 8.96 to 13.82 meq/100 g. The magnitude of response with combined application of farmyard manure and N was much higher, ie 9.62-13.80 meq/100 g and 9.81- 13.82 meq/ 100 g at flowering stage of rice and wheat respectively. The nutrient uptake also followed a similar trend of nutrient response, indicating no necessity of Zn application where farmyard manure is adequately used.

Cation-exchange capacity of roots varies widely with the nature of species, variety, time of sampling, age of crop, growth conditions, root zone, soil- nutrient level and soil type (Chamuah and Dey 1987). High exchangeable sodium percentage and sodium-adsorption ratio in association with extremes of pH of these soils are the chief factors that govern the nutrient imbalances and their deficiencies (Yadav 1980). Under these condition the response of application of some of the nutrients on cation-exchange capacity of roots is highly imperative, which eventually may affect the crop yield. Since information on cationexchange capacity of roots in salt- affected soil is scanty, and experiment was conducted to find out the cation- exchange capacity of roots at different physiological stages of rice (Oryza sativa L.) and wheat (Triticum aestivum L. emend. Fiori & Paol.) and total cation uptake. MATERIALS AND METHODS

A pot experiment in completely randomized block design with 4 replications was conducted during 1988 under greenhouse condition in a bulk of heterogeneously- processed, salt- affected soil (Typic Natra- qualf). The soil was loam and had pH 10.30, electrical conductivity 18.80 dS/m, exchangeable sodium 82.80%, sodium-adsorption ratio 133.60, exchangeable Na 14.50 meq/100 g, Ca+ Mg 2.50 meq/ 100 g, K 0.50 meq/100 g and cationexchange capacity 17.50 meq/100 g. The fertility status of the soil was: available N 30.0 ppm, P28.0 ppm, K 266.0 ppm, Fe 0.98 ppm, Mn 1.1 ppm and Zn 0.2 ppm. Eight treatments consisted of the control, N, P, K, Fe, Mn and Zn @ 60,30,30,10,10 and 5 ppm respectively, and farmyard manure @ 0.5 % of soil (20 tonnes/ha) + N @ 60ppm. These were supplied through ammonium sulphate, diammonium phosphate, potassium dihydrogen phosphate,

ferrous sulphate, man-ganous sulphate, Zinc sulphate and dried cow-dung powder respectively to each of the 32 pots with open bottom, having 10 kg soil as per treatment. All the pots were initially treated with 75% gypsum requirement (Richards 1954), kept waterlogged for 4 weeks and finally leached thoroughly. The leached soil had pH 9.4, electrical conductivity 10.50 dS/m, exchangeable sodium 50.67%, sodium-adsorption ratio 85.28, exchangeable Na 7.50 meq/100g, Ca + Mg 8.00 meq/100 g, K 0.32 meq/100 g and cation- exchangeable capacity 14.80 meq/100 g. Seedlings of ‘Saket4’ rice at 5 weeks were transplanted in pots, whose bottom was closed after leaching, and ‘HUM 205’ wheat was raised soon after the harvesting of rice. Water- logged condition for rice and field- capacity moisture level for wheat were maintained by frequent irrigations. Plant roots and shoots were sampled at different physiological stages, viz tillering, flowering, ripening and maturity of the crops. The plants were taken out of pots with their root system. The roots were separated and cleaned. Dry matter was recorded at tillering, flowering and ripening stages, and the straw and grain yield at maturity stage. These were finally correlated with cation-exchange capacity of the roots. The values of different cations (Na, K, Ca and Mg) determined in plant tops were added and multiplied with dry-matter content to ex-press the total cation uptake. Nitrogen content in root was also determined. Root-N content and total cation uptake were finally correlated with cation-exchange capacity of the roots of both the crops. Cation-exchange capacity of roots was determined titrimetrically ( Crooke 1964). Plant tops were digested in nitric acid and perchloric acid mixture in the ratio of 10:4 according to procedure described by Johnson and Ulrich (1959), whereas roots were digested in perchloric and sulphuric acid in 4:1 ratio. The cations (Na; K, Ca and Mg) in plant tops and N in roots were determined as per the methods described by Richards (1954) and Jackson (1973) respectively. RESULTS AND DISCUSSION Effect of N Application of N Significantly increased the cation-exchange capacity of root in rice and wheat compared with the control with N application from tillering to flowering stages of crops (Table 1). Thereafter a decreasing trend was noticed up to the maturity stage of crops. It may be attributed to the concentration of most effective physiological activities of crops for formation of pectin of cell walls at this stage of growth. The exchange properties of roots are largely due to free carboxyl groups of uronic acid of pectin (Knight et al. 1961). Since the salt-affected soil was low in available N, application of N increased the soil cation uptake from 36.20 to 39.10 meq/ 100g dry matter and from 37.20 to 41.20 meq/100 g dry matter from tillering to flowering stage, which positively correlated with cation-exchange capacity of rice and wheat roots (fig 1).

Effect of P and K The application of P and K showed no significant response on cation-exchange capacity of rice and wheat roots and total cation uptake. It may be attributed to the presence of available P and K well above the critical level in the experimental soil due to the formation of sodium phosphate and release of non-exchangeable K from secondary mineral lattices respectively. Kansal et al. (1974) reported no response of P and Paliwal and Subramanian (1964) of K in the normal soil under rice – wheat crop sequence. Effect of fe, Mn and Zn As rice was grown under waterlogged condition and addition of gypsum further increased the intensity of reduction, the soil was adequately supplied with available Fe and Mn Hence there was no response of their application on cation- exchange capacity of rice and wheat roots (Table1). Soil is critically low in available Zn due to its immobilization and formation of calcium zincate under saline- Sodic conditions ( Sakal et al. 1988). Shukla and Mukhi (1985) reported that application of Zn is more Important than application of gypsum in saltaffected soil. Zinc application in association with N ,P and K significantly increased the cation- exchange capacity of rice roots at tillering flowering, ripening and maturity stages respectively, compared with the application of N, P and K alone, Similar trend was observed in wheat (Table 1). The Increase in cation-exchange capacity of roots with Zn application may be attributed to its role in auxin metabolism, which induces cell division in the underground parts of crop plants, helping in the production of more exchange sites on root tips. Table 1 Effect of various fertilizer nutrients on cation- exchange capacity (meq/100g) of roots and total cation uptake (meq/100 g dry matter) a different growth stages of rice and wheat.

Treatment

Rice

Tillering Flowering Ripening Maturity Tillering 5.10 6.21 5.82 4.13 5.21 (32.10) (32.40) (31.80) (28.40) (33.12) N60 7.41 9.62 8.80 7.22 7.41 (36.20) (39.10) (38.00) (32.80) (37.20) N60 +P30 7.60 9.91 8.93 7.80 7.90 (37.62) (38.00) (38.12) (33.72) (38.10) N60+P30+K30 7.62 9.90 9.40 8.07 8.00 (38.21) (41.16) (40.16) (34.00) (38.81) N60+P30+K30+ 8.00 10.52 9.64 8.61 9.21 Fe10 (39.11) (41.70) (39.82) (35.26) (42.00) N60+P30+K30+ 8.62 10.80 9.20 8.81 10.42 Mn10 (39.70) (41.82) (41.90) (35.66) (45.16) N60+P30+K30+ 10.11 12.20 11.00 9.00 12.41 Zn5 (42.32) (46.28) (44.86) (38.18) (49.10) N60+ FYM 0.5 11.80 13.80 12.60 10.64 14.20 (47.31) (51.25) (48.21) (45.24) (53.20) Mean 8.28 10.37 9.42 8.03 8.00 (39.07) (41.46) (40.36) (35.41) (42.08) CD(P=0.05) 1.20 1.50 1.40 0.90 1.70 (3.20) (4.30) (3.20) (3.96) (3.20) Data in parentheses indicate total cation uptake FYM, Farmyard manure Control

Wheat Flowering 5.80 (36.12) 9.81 (41.20) 9.40 (39.90) 8.96 (42.82) 10.00 (44.12) 11.11 (45.80) 13.82 (51.26) 16.12 (55.10) 10.63 (44.54) 2.20 (3.80)

Ripening 5.20 (36.00) 9.00 (40.00) 8.96 (37.20) 8.88 (41.74) 9.80 (42.80) 10.80 (44.20) 13.21 (48.82) 15.71 (51.10) 10.20 (42.73) 2.80 (3.85)

Maturity 4.00 (33.16) 7.00 (35.70) 8.45 (36.21) 8.62 (36.34) 8.91 (37.20) 9.30 (37.94) 10.81 (42.50) 12.76 (47.10) 8.73 (38.27) 1.70 (4.20)

Effect of farmyard manure The maximum cation-exchange capacity of root and uptake of cations were observed with farmyard manure + N application compared with NPK + Zn treatment at flowering stage of rice. In wheat also, maximum values of cation- exchange capacity of roots and cation uptake were noted with combined application of farmyard manure and N compared with NPK + Zn at flowering stage. These values were more in wheat than in rice. The saltaffected soils possess poor physical condition in the form of poor water-transmission characteristics (Richards 1954), which restricts the root growth. Application of farmyard manure in gypsum-amended soil creates highly conducive soil micro-environment (Dargan1979) for root proliferation due to increased dispersion, dissolution and alkaline hydrolysis of farmyard manure under saline-sodic condition. These processes help in maintaining high fertility status of soil, which paves the way for better mining capacity of roots and hence ensures high rate of nutrient uptake. Application of farmyard manure fulfils the Zn requirement of crop by making native Zn available through its solubilization (Sinha 1972). Effect of cation-exchange capacity of roots on crop yield The cation- exchange capacity of roots had significant impact on dry –matter accumulation of rice and wheat throughout their growth period, as evident from their degree of correlations in rice (r= 0.900, 0.870, 0.890 and 0.964) and wheat crop (r= 0.957, 0.988, 0.931 and 0.976) at tillering, flowering, ripening and maturity stages respectively. Significant and positive correlation of cation- exchange capacity of root was observed with straw and grain yields of rice increased@ 7.30 and 4.55 g/pot respectively with unit increase in the cation- exchange capacity of roots. In wheat, Straw and grain yields increased @ 4.10 and 2.46 g/pot respectively with unit increase in cation-exchange capacity of roots. The results support the findings of Singh and Singh (1980). REFERENCES Chamuah. G S and Dey J K. 1987. Root cation exchange capacity in relation to nutrient uptake of rice. Journal of Indian Society of Soil Science 35: 113-4. Crooke W M. 1964. The measurement of the cation exchange capacity of plant roots. Plant and soil 21: 43-9. Dargan K S. 1979. Agronomic and cultural practices for crop production in salt affected soils. Current Science 3: 1-20. Jackson M L. 1973. Soil Chemical Analysis, edn 2, pp 111-83. Prentice Hall of India Pvt Ltd, New Delhi. Jhonson C M and Ulrich A. 1959. Analytical method for use in plant analysis. Bulletin 766, California Experimental Station, California, USA, pp 25-78. Kansal B D, Bhumbla D R and Kanwar JS. 1974. Variations in fertilizers response of different varieties of wheat and rice. Indian Journal of Agricultural Sciences 44(1): 55-9. Knight A H, Crooke W H and InKson RHE. 1961. Cation exchange capacity of tissues of higher and lower plants and their related uronic acid contents. Nature, London 192 : 142-3.

Paliwal K V and Subramanian T R. 1964. Constancy of cation exchange capacity of plant roots. Current Science 33: 463-4. Richards L A. 1954 Diagnosis and improvement of saline and alkali soil, pp 83-106, 1-5, Handbook 60, United States Department of Agriculture, Washington DC. Sakal R. Singh A P and Singh S P. 1988. Distribution of available zinc, copper, iron and manganese in old alluvial soils as related to certain soil characteristics. Journal of Indian Society of Soil Science 36: 59-63. Shukla U C and Mukhi A K. 1985. Ameliorative role of zinc growth on maize (Zea mays L.,) under salt affected soil conditions. Plant and soil 87: 423-32. Singh L. and Singh S. 1980. Cation exchange capacity of plant roots in relation to yield of rice and wheat. Journal of Indian Society of Soil Science 28: 242-4. Sinha M.K 1972. Organic matter transformation in soils. I Humification of the 14C tagged out roots. Plant and soil 36: 283-93. Yadav JSP. 1980. Effcacy of fertilizers used in saline and alkali soils for crop production. Fertiliser News 25: 19-27.