Loss of soil organic matter following cultivation of long-term pasture: effects on major exchangeable cations and cation exchange capacity
D. Curtin A B , P. M. Fraser A and M. H. Beare AA The New Zealand Institute for Plant and Food Research Limited, Private Bag 4704, Christchurch, New Zealand.
B Corresponding author. Email: denis.curtin@plantandfood.co.nz
Soil Research 53(4) 377-385 https://doi.org/10.1071/SR14173
Submitted: 8 July 2014 Accepted: 2 February 2015 Published: 30 June 2015
Abstract
Cultivation of grassland is known to lead to the depletion of soil organic matter (SOM), but the effect on the size and composition of the exchangeable cation suite has not been documented. We measured cation exchange capacity (CEC) and exchangeable cations (calcium, Ca; magnesium, Mg; potassium, K; sodium, Na), as well as soil carbon (C) and nitrogen (N) (0–7.5, 7.5–15, and 15–25 cm), 8 years after conversion of long-term ryegrass–white clover pasture (grazed by sheep) to annual crop production. The trial was near Lincoln, Canterbury, New Zealand. The trial included three tillage treatments: crops established using intensive cultivation (mouldboard ploughing), minimum tillage (shallow cultivation, ~10 cm), or no-tillage. The 8-year rotation was barley, wheat, pea, barley, pea, barley, barley, barley. A sheep-grazed pasture was maintained as an experimental control. The experiment also included a permanent fallow treatment (maintained plant-free using herbicides; not cultivated). After 8 years under arable cropping, soil C stocks (0–25 cm) were 10 t ha–1 less, on average, than under pasture. The vertical distribution of soil organic matter (SOM) was affected by tillage type, but the total amount of organic matter in the top 25 cm did not differ (P > 0.05) among the tillage treatments. Under permanent fallow (C loss of 13 t ha–1 relative to pasture), total exchangeable cation (Ca + Mg + K +Na) equivalents declined by 47 kmolc ha–1, a 20% decrease compared with pasture. Loss of exchange capacity resulted in the selective release of cations with lower affinity for SOM (K, Na, Mg). Smaller losses of exchangeable cations were recorded under the arable cropping rotation (average 31 kmolc ha–1), with no differences among tillage treatments. Effective CEC (at field pH) decreased under permanent fallow and cultivated treatments because of: (1) depletion of SOM (direct effect); and (2) soil acidification, which eliminated some of the remaining exchange sites (indirect effect). Acidification in the permanent fallow can be attributed to the N mineralisation process, whereas in the cropped systems, excess cation removal in harvested straw and grain accounted for about half of the measured acidification. There was evidence that the organic matter lost under arable cropping and fallow had lower CEC than SOM as a whole.
Additional keywords: acidification, arable cropping, cation exchange capacity, land use change, pasture, soil C, tillage intensity.
References
Baldock J, Beare M, Curtin D (2011) Modelling measurable pools of carbon in New Zealand soils: A case study. In ‘3rd International Symposium on Soil Organic Matter: Organic Matter Dynamics—From Soils to Oceans’. 11–14 July 2011, Leuven, Belgium. p. 65.Bolan NS, Hedley MJ (1991) Processes of soil acidification during nitrogen cycling with emphasis on legume based pastures. Plant and Soil 134, 53–63.
Bolan NS, Curtin D, Adriano DC (2005) Acidity. In ‘Encyclopaedia of soils in the environment’. (Ed. D Hillel) pp. 11–17. (Elsevier: Oxford, UK)
Bouman OT, Curtin D, Campbell CA, Biederbeck VO, Ukrainetz H (1995) Soil acidification from long-term use of anhydrous ammonia and urea. Soil Science Society of America Journal 59, 1488–1494.
| Soil acidification from long-term use of anhydrous ammonia and urea.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2MXotFOnsrs%3D&md5=75563f65f6d17233ef5c520c90c2401eCAS |
Cornforth IS (1998) ‘Practical soil management.’ (Lincoln University Press and Daphne Brasell Associates Ltd: Lincoln, New Zealand)
Curtin D, Rostad HPW (1997) Cation exchange and buffer potential of Saskatchewan soil estimated from texture, organic matter and pH. Canadian Journal of Soil Science 77, 621–626.
| Cation exchange and buffer potential of Saskatchewan soil estimated from texture, organic matter and pH.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXhslWrsL8%3D&md5=b3f9654eafac2743b5264b39c2950d3cCAS |
Curtin D, Selles F, Steppuhn H (1995) Sodium-calcium exchange selectivity as influenced by soil properties and method of determination. Soil Science 159, 176–184.
| Sodium-calcium exchange selectivity as influenced by soil properties and method of determination.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2MXkslWltbs%3D&md5=a1ab0b796d909df8997c3b301afb7402CAS |
Curtin D, Selles F, Steppuhn H (1998) Estimating calcium-magnesium selectivity in smectitic soils from organic matter and texture. Soil Science Society of America Journal 62, 1280–1285.
| Estimating calcium-magnesium selectivity in smectitic soils from organic matter and texture.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXmvVOqtLo%3D&md5=fbab0f7f61c570f0281951f95ce7450dCAS |
de Klein CAM, Monaghan RM, Sinclair AG (1997) Soil acidification: a provisional model for New Zealand pastoral systems. New Zealand Journal of Agricultural Research 40, 541–557.
| Soil acidification: a provisional model for New Zealand pastoral systems.Crossref | GoogleScholarGoogle Scholar |
Fraser PM, Curtin D, Beare MH, Meenken ED, Gillespie RN (2010) Temporal changes in soil surface elevation under different tillage systems. Soil Science Society of America Journal 74, 1743–1749.
| Temporal changes in soil surface elevation under different tillage systems.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXht1CmsrrL&md5=dcd7bbca87f94dc8ab5d15e5cfb2b0a6CAS |
Fraser PM, Curtin D, Harrison-Kirk T, Meenken ED, Beare MH, Tabley F, Gillespie RN, Francis GS (2013) Winter nitrate leaching under different tillage and winter cover crop management practices. Soil Science Society of America Journal 77, 1391–1401.
| Winter nitrate leaching under different tillage and winter cover crop management practices.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhtFOjsr%2FJ&md5=9a53ef88e343d7d21e6a5c58808e65faCAS |
García-Gómez A, Bernal MP, Roig A (2005) Organic matter fractions involved in degradation and humification processes during composting. Compost Science & Utilization 13, 127–135.
| Organic matter fractions involved in degradation and humification processes during composting.Crossref | GoogleScholarGoogle Scholar |
Gregorich EG, Beare MH, McKim UF, Skjemstad JO (2006) Chemical and biological characteristics of physically uncomplexed organic matter. Soil Science Society of America Journal 70, 975–985.
| Chemical and biological characteristics of physically uncomplexed organic matter.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XksVyks7w%3D&md5=77b01b18d7a357bdb373c57415b9e4a4CAS |
Haynes RJ (1986) Nitrification. In ‘Mineral nitrogen in the plant-soil system’. pp. 127–165. (Academic Press: Orlando, FL, USA)
Helling CS, Chesters G, Corey RB (1964) Contribution of organic matter and clay to soil cation-exchange capacity as affected by pH of the saturating solution. Soil Science Society of America Proceedings 28, 517–520.
| Contribution of organic matter and clay to soil cation-exchange capacity as affected by pH of the saturating solution.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaF2cXks1yhtr0%3D&md5=696f61d3473e2345252244c70388c1dbCAS |
Hunsaker VE, Pratt PF (1971) Calcium–magnesium exchange equilibria in soils. Soil Science 35, 151–152.
| Calcium–magnesium exchange equilibria in soils.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaE3MXls1aksw%3D%3D&md5=5c264c911173017a9773b7e5169a94f7CAS |
Nelson PN, Oades JM (1998) Organic matter, sodicity, and soil structure. In ‘Sodic soils: distribution, properties, management, and environmental consequences’. (Eds ME Sumner, R Naidu) pp. 51–75. (Oxford University Press: New York)
Nicholls A (2009) ‘Managing soil fertility on cropping farms.’ (New Zealand Fertilisers Manufacturers’ Research Association: Auckland, NZ)
Parfitt RL (1992) Potassium-calcium exchange in some New Zealand soils. Australian Journal of Soil Research 30, 145–158.
| Potassium-calcium exchange in some New Zealand soils.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK38XitlCmt7g%3D&md5=d1ded2c44f7bf8753bb0c6e661d9d6a3CAS |
Pierre WH, Banwart WL (1973) Excess-base and excess base/nitrogen ratio of various crop species and parts of plants. Agronomy Journal 65, 91–96.
| Excess-base and excess base/nitrogen ratio of various crop species and parts of plants.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaE3sXht1eiu70%3D&md5=799959baf7c183c584078a5ddd178a63CAS |
Suarez DL, Simunek J (1997) UNSATCHEM: Unsaturated water and solute transport model with equilibrium and kinetic chemistry. Soil Science Society of America Journal 61, 1633–1646.
| UNSATCHEM: Unsaturated water and solute transport model with equilibrium and kinetic chemistry.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXnvFWhs78%3D&md5=2318debc01582d1881939d67630b906bCAS |
Tang CT, Rengel Z (2003) Role of plant cation/anion uptake ratio in soil acidification. In ‘Handbook of soil acidity’. (Ed. Z Rengel) pp. 57–81. (Marcel Dekker: New York)
Thomas GW (1982) Exchangeable cations. In ‘Methods of soil analysis. Part 2’. 2nd edn (Eds AL Page, RH Miller, DR Keeney) pp. 159–164. (American Society of Agronomy: Madison, WI, USA)
Thomas GW, Hargrove WL (1984) The chemistry of soil acidity. In ‘Soil acidity and liming’. 2nd edn. Agronomy No. 12. (Ed. F Adams) pp. 3–56. (American Society of Agronomy, Crop Science Society of America, Soil Science Society of America: Madison, WI, USA)
Tiessen H, Stewart JWB (1983) Particle-size fractions and their use in studies of soil organic-matter. 2. Cultivation effects on organic-matter composition in size fractions. Soil Science Society of America Journal 47, 509–514.
| Particle-size fractions and their use in studies of soil organic-matter. 2. Cultivation effects on organic-matter composition in size fractions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL3sXks12ntb4%3D&md5=f2799b519c1cbaf62fd5a8ce3030639bCAS |
Tiessen H, Stewart JWB, Bettany JR (1982) Cultivation effects on the amounts and concentration of carbon, nitrogen, and phosphorus in grassland soils. Agronomy Journal 74, 831–835.
| Cultivation effects on the amounts and concentration of carbon, nitrogen, and phosphorus in grassland soils.Crossref | GoogleScholarGoogle Scholar |
Williams PH, Haynes RJ (1992) Balance sheet of phosphorus, sulphur and potassium in long-term grazed pasture supplied with superphosphate. Fertilizer Research 31, 51–60.
| Balance sheet of phosphorus, sulphur and potassium in long-term grazed pasture supplied with superphosphate.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK38XitFemtLk%3D&md5=92c39ab3dba129c24bd9f7b5eee03446CAS |
