Abstract
Intensively managed grasslands are occasionally chemically killed with herbicide and ploughed in order to grow an arable crop. After this management, large N mineralization rates with large losses to the environment are commonly observed. However, it remains to be determined to what extent the chemical killing contribute to increased N mineralization. In this study the potential nitrogen (N) mineralization from grasslands, that were killed with herbicides but otherwise undisturbed, was investigated in a laboratory experiment with undisturbed soil columns. Subsequently we assessed the predictive value of several laboratory indices for N mineralization after chemically killing of the grass. Mineralization rates varied from 0.5 to 3.0 g N m−2 wk−1. The contents of total N, total C, dissolved organic carbon (DOC) and hot-KCl extractable NH +4 were best related to N mineralization rates (R2 = 50, 48, 38 and 47%, respectively). In combination with information on the N content of the roots and stubble and the age of grassland at destruction, up to 62% of the variation in N mineralization rates could be explained. Although previous studies suggested that dissolved organic nitrogen (DON) is a good indicator for mineralization rates, this was not the case after chemically killing grass in the current study.
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Introduction
European intensive dairy production systems are often based on rotations of grasslands and arable crops (Taube and Conijn 2004). In these systems, grasslands are occasionally treated with herbicides and ploughed in order to grow an arable crop or for reseeding with high yielding grass varieties. As result of grassland destruction, the content of mineral N in the soil strongly increases (up to more than 200 kg N ha-1) (Besnard et al. 2007; Bommelé 2007; Davies et al. 2001; Eriksen and Jensen 2001; Johnston et al. 1994; Nevens and Reheul 2002). This increase in mineral N content is caused by a combination of mineralization of the grass biomass (stubbles and roots) and by enhanced mineralization of organic N that accumulated under the forage grass. When periods with high soil mineral N contents coincide with wet conditions, the risk on NO −3 leaching, denitrification losses and the emission of the greenhouse gas nitrous oxide (N2O) is high (Adams and Jan 1999; Ball et al. 2007; Hansen et al. 2007; Lloyd 1992; Shepherd et al. 2001).
As ploughing generally has a strong effect on the soil mineral N content through mineralization of soil organic matter, chemically killing of grassland without ploughing may be a strategy to decrease the risk of N losses. Fine-tuning the rates and timing of N fertilizer applications to the following crop, taking into account predicted N mineralization of the killed sward, might help to reduce N losses. For example, Aarts et al. (2001) and Nevens and Reheul (2002) showed that N fertilizer can be withheld without yield loss for maize in the first year after grassland ploughing. However, this requires quantitative insight in the N mineralization rates after killing the sward and the availability of N in the soil, both directly after the sward has been killed and later on.
There are several options to gain this insight in mineralization rates. Published studies on predicting plant available N in the soil focus either on biological (incubation) or chemical (extraction) laboratory indices (Keeney 1982), on models (Bhogal et al. 2001; Thornley and Verberne 1989), or on field methods (Bhogal et al. 1999; Hatch et al. 2000; Wienhold 2007; Besnard et al. 2007). Field methods have the advantage that they may determine the N mineralization rates under realistic conditions, but their results may be difficult to generalize. Moreover, these methods are much more time consuming than laboratory indices that can be implemented as routine analyses in laboratories. Published laboratory indicators for N mineralization rates in permanent arable and grassland soils include total N and C contents (Accoe et al. 2004; Hassink 1995), hot KCl extractable NH +4 (Gianello and Bremner 1986), and soluble organic N (DON) (Groot and Houba 1995). DON has shown to be a promising indicator in other studies (Murphy et al. 2000). However, these studies used mixed soil material. To study the effects of chemically killing the sward, the soil should not be disturbed or mixed. However, it is unknown to what extent the known methods predict N mineralization rates in undisturbed soils containing large quantities of plant residues. Therefore the predictive value of the indices has to be determined in this study.
The main objective of our study is to quantify the potential N mineralization rates in grasslands on a range of grassland soils that were chemically killed with herbicide but otherwise undisturbed. As fine-tuning N fertilizing in the subsequent crop to N mineralization rates may contribute to reducing N losses, our second aim is to assess a series of laboratory indices as predictors of N mineralization rates in the same set of soils.
Materials and methods
Field selection and sampling
In the Netherlands, grassland renewal occurs on both clay soils and sandy soils and includes grasslands of different ages (Schils et al. 2002). Grasslands on sandy soils are on average ploughed every 5 years and grasslands on clay soils every 10 years. A total of 42 grassland fields, varying in soil organic matter content and grassland age, were selected within 13 dairy farms where management records were accurate and easily available. Seven farms were located on sandy (to sandy loam) soils and the other six on clayey (silt loam to heavy clay) soils. Grassland ages were recorded, except for a few old grassland fields (>20 years old) where the exact age was not known and therefore estimated. For statistical analysis, grassland ages for the old fields were set to 30 years. The texture of the soils was estimated based on the guidelines for soil description (FAO-ISRIC 1990).
As our study was on chemically killed, but otherwise undisturbed swards, our experimental set-up differed markedly from most of previous studies quantifying mineralization rates in sieved soil after removal of fresh crop residues. In each field, two undisturbed soil columns of 19.5 cm diameter and 15.0 cm height (including the grass/sward that remained after cutting) were sampled within 15 cm from each other. Sampling was performed immediately after the first grass cut in April and before application of fertilizers. Destruction of grasslands in the Netherlands generally takes place in this period. Six of the farms were sampled in May 2005, the rest in May 2006. In both years, an identical sampling procedure was followed.
Experimental set-up
One of the two soil columns per field was used for soil and plant analyses and was vertically divided in two halves. This was done within one or 2 days after sampling. One half, used for measuring soil parameters at the start of the experiment, was dried at 40°C, weighed and ground after biomass (stubbles and roots) was removed from soil by sieving over a 2 mm sieve. The other half, used for measuring and analyzing plant biomass, was rinsed with water in order to remove all soil particles from grass stubbles and roots. The biomass was dried at 70°C, weighed and ground.
The remaining column for each field was stored in a 6-liter Mitscherlich pot for determination of net N mineralization in undisturbed soil. In all columns, moisture contents were kept below field capacity during the incubation (gravimetric soil moisture 0.20–0.40 g g−1 corresponding to water-filled pore space (WFPS) of 24–29% and 29–35% for the sandy and clayey soils, respectively). Samples were gravimetrically adjusted to a soil moisture content of 0.20 g g−1.
The grass in the columns was chemically killed using glyphosate, which is the common chemical used for grassland destruction in the Netherlands. The columns were kept at 15°C for 2 weeks and were exposed to light during this period, in order to facilitate the initial enhanced growth of grass after glyphosate that is usually observed. After this period of 2 weeks, when the grass was dead, three small soil cores (1 cm diameter and 15 cm length) were sampled and combined. These soil samples were analysed for contents of NO −3 , NH +4 , DON and DOC, using the methods as described below. The columns were subsequently incubated at 20°C for 12 weeks. Sampling and soil analysis was repeated after 2, 6 and 12 weeks, using the same procedure of taking small cores. The holes were filled with plastic tubes to prevent the soil from drying.
Laboratory analyses on indicators in soil and biomass
Several indicators were quantified on all soil samples. Total N contents were measured spectrophotometrically after digestion with a mixture of sulphuric acid, salicylic acid, Se and H2O2; total C contents were determined spectrophotometrically according to Kurmies (Houba et al. 1997; Temminghoff 2000). The contents of NH +4 , NO +3 , soluble organic C (DOC) and soluble organic N (DON) in soil were analysed after extraction in a 1:10 (v/v) ratio with 0.01 M CaCl2 (Houba et al. 2000). The NO −3 and NH +4 concentrations were determined using standard segmented-flow analysis. Total content of DON was calculated as the difference between total dissolved N and mineral N (i.e. NH +4 -N + NO −3 -N). The release of NH4 during boiling of soil at 100°C in KCl has shown to be a promising indicator for N mineralization rates (Curtin et al. 2006; Gianello and Bremner 1986; Smith and Li 1993). Hot KCl extraction was carried out on soil and biomass through a 4 h extraction of 6 g air dry soil with 40 ml 2 M KCl in 100 ml incubation bottles placed in a water bath of 100°C The bottles were regularly stirred during the extraction. The extraction solution was filtered over a 5-µm filter and analysed for NO −3 and NH +4 using standard segmented-flow analysis techniques. The hot KCl extractable NH +4 was calculated as the difference between NH4 after boiling with 2 M KCl and the NH +4 content derived from the 0.01 M CaCl2 extraction data.
Data analyses
A t-test showed no significant differences in N mineralization rates between the samples of both years. All samples were therefore treated as one population and jointly analyzed. To determine the net N mineralization rate during the 12 week incubation period, a linear regression line was fitted through the mineral N after 0, 2, 6, and 12 weeks. Data analyses were both performed per soil type and on all data combined. Correlations among soil parameters were determined by Pearson’s correlation analyses. In order to find an indicator that predicts total net mineralization after 12 weeks, single and multiple linear regression analyses were performed with all measured soil and biomass parameters (total C, total N, DOC, DON, Hot-KCl extractable NH4 in soil and total N in crop). The age of grassland and soil type were also included in the multiple regression analysis,. All statistical analyses were carried out with SPSS 15.0.
Results
N mineralization rates
The mineral N contents during the 12 weeks of incubation could be modelled using linear regression (Table 1). Mineralization rates varied from 0.5 to 3.0 g N m−2 week−1. Mineralization rates did not differ significantly (p = 0.066) between sandy soils (mean 1.2 ± standard deviation of 0.5 g N m−2 wk−1) and clay soils (1.5 ± 0.6 g N m−2 wk−1), and were not related to the soil textural classes (Table 1). Though very variable inside a class of age, the mineralization rates tended to increase from short term- (1–2 years) to mid term (3–5 years and 6–10 years) grasslands, but decreased in long term grasslands (10–19 years) and were highest after destruction of old grasslands (≥20 years) (Table 2). When all samples were used, a significant positive relationship between N mineralization and grassland age was observed. This relation was not significant when only grassland younger than 20 years were considered.
Biomass parameters
Grass biomass (roots and stubbles combined) after cutting varied widely among fields (Table 1). However, this might partly have been caused by differences in the height of the stubble (which was not recorded). On average, the amount of N in the biomass equalled 11 and 13 g N m−2 in clay soils and sandy soils, respectively. C:N ratios of the biomass (Table 1) varied widely (between 13 to 39). This might have been caused by different stubble to root ratios (not analysed, as stubbles and roots were processed jointly). There was no clear effect of grassland age or soil type on the C:N ratio of the remaining biomass (Table 2).
Soil parameters
Organic matter content of the soil varied from 10 to 77 g C kg−1 (Table 1) Although C contents of the old grasslands on clay soil were relatively high (>67 g kg−1), there was in general no relation between C content and age of the grassland. In clay soils initial DOC was strongly related to total C, and DON to total N, while in sandy soils these relationships were less pronounced. In sandy soils the C:N ratios was generally higher (average of 18) than in clay soils (on average 11).
Contents of DON and DOC were lower in the sandy soil than in the clay soil (Table 1). During the 12 week incubation, DON and DOC content in the sandy soils did not change. In clay soils, DOC slightly decreased during the first 2 weeks while the grass died, but remained constant during the incubation period. DON decreased from 36 mg N kg−1 (±18 mg N kg−1) in the non-treated samples to 26 mg N kg−1 (±14 mg kg−1) after 12 weeks of incubation.
Indicators for net N-mineralisation
Soil and plant biomass parameters were tested as possible indicators for mineralization, both for the complete data set and for sandy soils and clay soils separately (Table 3 and Fig. 1). The regression lines for clay soils showed a better fit (i.e. higher R2) than for sandy soils. When data of both soil types were combined, all indicators in Table 3 were significantly related to net N-mineralization, although there was a large difference in fit between the indicators. Total C, total N, DOC and hot-KCl extractable NH +4 were considered good predictors, as these indicators were significantly related with N mineralization for both soil types (Table 3). Total N appeared to be the best indicator for both soil types and the combined data. Total C and hot-KCl extractable NH +4 performed second best. DON was significantly related with N mineralization for clay soils and the combination of both soil types, but not for sandy soils.
Since correlations among soil parameters were significant (data not presented), only one soil parameter at a time was included in the multiple regression analyses. So several stepwise multiple regressions were conducted, each with a combination of one soil parameter and either biomass N, age (log transformed), texture or soil type were tested (Table 4). Total soil N again gave best results. Including grassland age and plant biomass N improved the fit of the model, but hardly decreased the standard error of the estimate. With total N in soil, grassland age and N contents in the remaining biomass after cutting (roots and stubbles), 62% of the variance in N mineralization rate could be explained. Including soil type or texture class in the multiple regression analyses did not improve the results.
Discussion
Nitrogen mineralization
The first aim of this study was to quantify the potential mineralization after the grass was chemically killed. Nitrogen mineralization ranged from 59 to 361 kg N per ha in 12 weeks. Possible differences in moisture contents were not expected to cause differences in N mineralization since N mineralization is at maximum at a relatively broad range of moisture contents around field capacity (e.g. Antonopoulos 1999) and as long moisture content is at least 50% of field capacity, it is not a major factor controlling the mineralization rates (Gonçalves and Carlyle 1994). Only at dry or very wet conditions, a significant decrease in N mineralization may occur and those conditions were avoided. Mineralization rates were obtained at relatively high temperatures (20°C). The average temperature in the period half May to half August in the Netherlands is 16°C. In this period N uptake by the crop is highest. For a good comparison of the laboratory results with field conditions a correction factor of about 0.75 is appropriate, assuming a Q10 relationship of 2 (i.e. the mineralization increases with a factor 2 when temperature increases with 10°C; Stanford et al. 1973). Thus, the N mineralization corrected for field temperature ranges from 45 to 275 kg N ha−1 in the 12-week period of the incubation experiment.
Since we found no other studies on mineralization rates in chemically killed but otherwise undisturbed swards, it is not possible to compare these figures to other studies that were comparable in setup. However, N mineralization rates in our study were in range of data from studies where grasslands were ploughed (Aarts et al. 2001; Johnston et al. 1994; Vertès et al. 2007; Whitehead et al. 1990). Those studies report a wide range of annual N mineralization rates (100 to 400 kg N ha−1 yr−1) in the first year after grassland ploughing. This wide range may be due to large differences in experimental conditions (soil type, soil organic matter content, N management, sward age, crop type and management) and in the method of estimation of N mineralization (N balance, models, N uptake, and in-situ or laboratory incubations). High mineralization rates in our study and the linear increase in mineral N during the incubation period may indicate that we only determined the peak of N mineralization during several months after killing the sward. This is comparable to Vertès et al. (2007), who indicated that the N mineralization kinetics after ploughing of grassland consists of a first phase of several months with rapid and high N mineralization, followed by a period with much smaller N mineralization rates. This effect remained significant for several years, depending on the age the grassland.
It was assumed that only chemically killing the grass might reduce the risk of N losses, since ploughing is omitted. The effect of ploughing may be described as a combination killing the sward, chopping of the sward residues into smaller pieces, better mixing the sward residues in the soil and better aeration of the soil, but also disturbance of macro- and micro aggregates (Six et al. 2004). However, the high N mineralization rates in our experiment suggests that killing of the sward is a major factor controlling N mineralization in destroyed grasslands. This last assumption is supported by results of Velthof et al. (2009), who showed that mineral N contents in the soil were similar or higher after only chemically killing of the swards than after chemically killing and ploughing of the sward. Arnott and Clement (1966) found that N yields of crops following grassland that was chemically killed (and not ploughed) were similar to those obtained by ploughing (and not chemically killed). Both studies suggests that soil cultivation after chemically killing of the sward does not further enhance N mineralization.
Relation between indicators and N mineralization
The results show that the contents of total N, total C, DOC and hot KCl NH +4 were the best indicators of the N mineralization. Accoe et al. (2004) in Belgium and Hassink (1995) in the Netherlands showed that total N is also a good predictor of N mineralization of undisturbed, but intensively managed grassland. It is therefore used in N fertilizer recommendations for grassland in the Netherlands. In a simple regression model for predicting the N off take in newly resown grassland (Hatch et al. 2004), total N content was also a significant parameter, the other parameters being hot KCl NH +4 , the clay content and the accumulated daily temperature. Like Accoe et al. (2004) we found a negative relationship between the C:N ratio and the N mineralization, for the clay soil and the combined data. In this study we only tested rapid chemical methods as indices for mineralization. Our results and conclusions only apply to these methods and not to other measurements (e.g. on soil microbial biomass).
The results of the multiple regression analysis showed that when the N content of the roots and stubbles and the number of years since sowing is known, the prediction of N mineralization could be improved up to 62%. (Table 3). Although Johnston et al. (1994) and Vertès et al. (2007) also reported a tendency that N mineralization increases with increasing age of ploughed grassland, we have to note that this only applied when all samples were included. In field situations it is unlikely that those very old grassland will be destroyed for renovation. Although we found that the prediction of N mineralization, could be improved when the N content of the biomass (both roots and stubbles) is known, it is a too difficult and time-consuming method to suggest its determination as a standard and rapid method in laboratories to provide farmers fertilizer recommendations on basis of soil and plant tests.
Performance of DON as indicator for N mineralization
Based on many studies (Appel and Mengel 1990, 1998; Bregliani et al. 2006; Groot and Houba 1995) and an experiment in permanent (not killed) grasslands on sandy soils in the Netherlands (Velthof 2003), we expected DON (i.e. 0.01 M CaCl2 extractable organic N) to be a good index for mineralizable N. However, the exact role of DON in mineralization is not clear. Mengel et al. (1999) indicated that determination of the N compounds in CaCl2-extractable organic N may improve its use as an index, because amino N and the amino sugar N were positively correlated with N mineralization. In our experiment DON was significantly related with N mineralization in the clay soil and the overall dataset, but not for the sandy soil. We also expected that DON and DOC contents would temporary increase, because of decaying grass residues like in studies of Bhogal et al. (2000) and Murphy et al. (2007), who showed flushes of DON after residue incorporation. In our experiment, the DON contents in sandy soils remained constant during the incubation and decreased slightly in the clay soils.
Obviously, the role of DON in mineralization and processes controlling DON contents in the soil are yet unclear. Possibly, DON is a better predictor for N mineralization in sieved soil samples as in the study of Velthof et al. (2009), than in undisturbed samples containing crop residues. Because of the promising results of DON as indicator for mineralization in many studies and the fact that measurement of DON is a rapid and easy method, further study on this topic is needed.
Variability in mineralization and indices
Although total N, total C, DOC and hot KCl NH +4 were significantly related to the N mineralization, the R2 of 40–60% indicated that a considerable part of the variance in N mineralization is not explained. Even when some additional indicators like age or biomass N were included, the explained variance never exceeded 62%. There are several possible causes for this. First, N mineralization is a complex process in which many biological, chemical, physical factors play a role. A practical (and therefore necessarily simple) mineralization index can never account for all these factors and thus part of the variance in N mineralization will always be unaccounted for. Secondly, spatial variability of N parameters may have played a role. Since we measured the N indicators in one column, they may not always apply to mineralization rates derived from measurements in the other column. A third complicating factor may be the variability within the columns. We used undisturbed sward samples where the killing of the grass sward may have introduced a significant source of variability by mineralization of crop residues. Since determination of N mineralization was based on small soil cores samples, the results may deviate from studies in which incubations are carried out with well mixed composite soil samples.
Some studies report higher correlations (up to 85%) between mineralization indices and measured soil mineralization (e.g Gianello and Bremner 1986; Groot and Houba 1995; Mengel et al. 1999), but in those studies the effects of small scale spatial variability are minimized by sieving and mixing the soil, which is by definition impossible in undisturbed soil cores. In some studies, the N yield from unfertilized grassland is used as an indicator of mineralization. The percentage of the variance in the N off take explained by mineralization indices is somewhat higher (60–90%) compared to our study (Hassink 1995: total N; Hatch et al. 2004: hot KCl NH +4 ). This is mainly because the N off take is measured by mowing of a relatively large grassland area, which reduces spatial variability of N mineralization compared to the small samples in our study. However, it must be noted that grass growth may be limited by climatic factors and that the N yield of grassland is only an indicator for part of the N mineralization. Large amounts of N (more than 100 kg N ha−1; Whitehead et al. 1990) needed for the establishment of roots and stubbles are not taken in account.
Conclusion: To a field indicator for mineralization?
In our study we focussed on rapid chemical indicators for N mineralization in a laboratory experiment. Tested indicators can be used to predict N mineralization in order to better fine-tune N applications in crops after chemically killing the grass. The laboratory study showed that contents of total N, total C, DOC and hot KCl NH +4 , whether or not in combination with the N content of the biomass and the number of years since sowing, are promising indicators for mineralization in these grasslands. Studies are needed to test the predictive value of these indicators in the field.. In our laboratory study, DON was not well related to N mineralization in chemically killed grassland. This is, in contradiction with other studies which showed that DON is a promising indicator for mineralization.
The high N mineralization rates (0.5 to 3.0 g N m−2 week−1) in our experiment and results of the field study of Velthof et al. (2009), suggest that killing the sward is the major factor controlling N mineralization in destroyed grasslands. Soil cultivation after killing of the sward may not further enhance N mineralization. Further experiments, either in the laboratory or in the field, have to be carried out to get more insight in N mineralization in destroyed grassland.
References
Aarts HFM, Conijn JG, Corré WJ (2001) Nitrogen fluxes in the plant component of the ‘De Marke’; farming systems, objectives and results. Neth J Agric Sci 49:153–162
Accoe F, Boeckx P, Busschaert J, Hofman G, Van Cleemput O (2004) Gross N transformation rates and net N mineralisation rates related to the C and N contents of soil organic matter fractions in grassland soils of different age. Soil Biol Biochem 36:2075–2087
Adams WA, Jan MT (1999) Utilization of nitrogen accumulated by a clover containing ley following cultivation. Soil Use Manage 15:247–253
Antonopoulos VZ (1999) Comparison of different models to simulate soil temperature and moisture effects on nitrogen mineralization in the soil. J Plant Nutr Soil Sci 162:667–675
Appel T, Mengel K (1990) Importance of organic nitrogen fraction in sandy soils, obtained by electro-ultrafiltration or CaCl2 extraction, for nitrogen mineralization and nitrogen uptake of rape. Biol Fertil Soils 10:97–101
Appel T, Mengel K (1998) Prediction of mineralizable nitrogen in soils on the basis of an analysis of extractable organic N. J Plant Nutr Soil Sci 161:433–452
Arnott RA, Clement CR (1966) The use of herbicides in alternative husbandry as a substitute for ploughing. Weed Res 6:142–157
Ball BC, Watson CA, Crichton I (2007) Nitrous oxide emissions, cereal growth, N recovery and soil nitrogen status after ploughing organically managed grass/clover swards. Soil Use Manage 23(2):145–155
Besnard A, Laurent F, Hanocq D, Vertes F, Nicolardot B, Mary B (2007) Effect of timing of grassland destruction on nitrogen mineralization kinetics. Grassland Sci Eur 12:335–338
Bhogal A, Hatch DJ, Shepherd MA, Jarvis SC (1999) Comparison of methodologies for field measurement of net nitrogen mineralisation in arable soils. Plant Soil 207:15–28
Bhogal A, Murphy DV, Fortune S, Shepherd MA, Hatch DJ, Jarvis SC, Gaunt JL, Goulding KWT (2000) Distribution of nitrogen pools in the soil profile of undisturbed and reseeded grasslands. Biol Fertil Soils 30:356–362
Bhogal A, Shepherd MA, Hatch DJ, Brown L, Jarvis SC (2001) Evaluation of two N cycle models for the prediction of N mineralization from grassland soils in the UK. Soil Use Manage 17:163–172
Bommelé L (2007) Growing potatoes and grass-clover after turned down grassland. PhD thesis, University of Gent, Gent, p 176
Bregliani MM, Temminghoff EJM, van Riemsdijk WH, Haggi ES (2006) Nitrogen fractions in arable soils in relation to nitrogen mineralization and plant uptake. Commun Soil Sci Plant Anal 37:1571–1586
Curtin D, Wright CE, Beare MH, McCallum FM (2006) Hot water-extractable nitrogen as an indicator of soil nitrogen availability. Soil Sci Soc Am J l70:1512–1521
Davies MG, Smith KA, Vinten AJA (2001) The mineralisation and fate of nitrogen following ploughing of grass and grass-clover swards. Biol Fertil Soils 33:423–434
Eriksen J, Jensen LS (2001) Soil respiration, nitrogen mineralisation and uptake in barley following cultivation of grazed grasslands. Biol Fertil Soils 33:139–145
FAO-ISRIC (1990) Guidelines for soil description, 3rd edn. FAO, Rome
Gianello C, Bremner JM (1986) A simple chemical method of assessing potentially available organic nitrogen in soil. Commun Soil Sci Plant Anal 17:195–214
Gonçalves JLM, Carlyle JC (1994) Modelling the influence of moisture and temperature on net nitrogen mineralization in a forested sandy soil. Soil Biol Biochem 26:1557–1564
Groot JJR, Houba VJG (1995) A comparison of different indices for nitrogen mineralization. Biol Fert Soils 19:1–9
Hansen EM, Eriksen J, Vinther FP (2007) Catch crop strategy and nitrate leaching following grazed grass-clover. Soil Use Manage 23:348–358
Hassink J (1995) Prediction of the non-fertilizer N supply of mineral grassland soils. Plant Soil 176:71–79
Hatch DJ, Bhogal A, Lovell RD, Shepherd MA, Jarvis SC (2000) Comparison of methodologies for field measurement of net nitrogen mineralization in pasture soils under different soil conditions. Biol Fertil Soils 32:287–293
Hatch DJ, Hopkins A, Velthof GL (2004) Prediction of N offtake in resown grassland based on temperature and soil chemical and physical characteristics. Grassland Sci Eur 9:744–749
Houba VJG, van der Lee JJ, Novomzamsky I (1997) Soil analysis procedures; Other procedures (Soil and Plant Analysis, part 5B). Department of Soil Science and Plant Nutrition, Wageningen Agricultural University, Wageningen, p 217
Houba VJG, Temminghoff EJM, Gaikhorst GA, van Vark W (2000) Soil analysis procedures using 0.01 M calcium chloride as extraction reagent. Commun Soil Sci Plant Anal 31:1299–1396
Johnston AE, McEwen J, Lane PW, Hewitt MV, Poulton PR, Yeoman DP (1994) Effects of one to six year old ryegrass-clover leys on soil requirements of the arable sequence winter wheat, potatoes, winter wheat, winter beans (Vicia faba) grown on a sandy loam soil. J Agric Sci 122:73–89
Keeney DR (1982) Nitrogen-availability indices. In: Page AL, Miller RH, Keeney DR (eds) Methods of Soil analysis, Part 2. Chemical and microbiological properties. ASA-SSSA, Madison, pp 711–733
Lloyd A (1992) Nitrate leaching under arable land ploughed out from grass. Proceedings Fertiliser Society 330, p 32
Mengel K, Schneider B, Kosegarten H (1999) Nitrogen compounds extracted by electroultrafiltration (EUF) or CaCl2 solution and their relationships to nitrogen mineralization in soils. J Plant Nutr Soil Sci 162:139–148
Murphy DV, Macdonald AJ, Stockdale EA, Goulding KWT, Fortune S, Gaunt JL, Poulton PR, Wakefield JA, Webster CP, Wilmer WS (2000) Soluble organic nitrogen in agricultural soils. Biol Fertil Soils 30:374–387
Murphy DV, Stockdale EA, Poulton PR, Willsion TW, Goulding KWT (2007) Seasonal dynamics of carbon and nitrogen pools and fluxes under continuous arable and ley-arable rotations in a temperate environment. Eur J Soil Sci 58:1410–1424
Nevens F, Reheul D (2002) The nitrogen- and non-nitrogen-contribution effect of ploughed grass leys on the following arable forage crops: determination and optimum use. Eur J Agron 16:57–74
Schils RLM, Aarts HFM, Bussink DW, Conijn JG, Corré WJ, van Dam AM, Hoving IE, van der Meer HG, Velthof GL (2002) Grassland renovation in the Netherlands; agronomic, environmental and economic issues pp. In: Conijn JG, Velthof GL, Taube F (eds) Grassland resowing and grass-arable crop rotations; international workshop on agricultural and environmental issues, Report 47. Plant Research International, Wageningen, pp 9–24
Shepherd MA, Hatch DJ, Jarvis SC, Bhogal A (2001) Nitrate leaching from reseeded pasture. Soil Use Manage 17:97–105
Six J, Bossuyt H, Degryze S, Denef K (2004) A history of research on the link between (micro)aggregates, soil biota and soil organic matter dynamics. Soil Tillage Res 79:7–31
Smith KA, Li SX (1993) Estimation of potentially mineralisable nitrogen in soil by KCl extraction. I. Comparison with pot experiments. Plant Soil 157:167–174
Stanford G, Frere MH, Schwaninger DH (1973) Temperature coefficient of soil nitrogen mineralization. Soil Sci 115:321–323
Taube F, Conijn JG (2004) Grassland renovation in Northwest Europe: Current practices and main agronomic and environmental questions. In: Luscher A, Jeangros B, Kessler W, Huguenin O, Lobsiger M, Millar N, Suter D (eds) Land use systems in grassland dominated regions, vol 9. Grassland Science in Europe, pp 520–522
Temminghoff EJM (2000) Plant analysis procedures. Wageningen University, Environmental Sciences, Wageningen, p 197
Thornley JHM, Verberne ELJ (1989) A model of nitrogen flows in grassland. Plant Cell Environ 12:863–886
Velthof GL (2003) Relaties tussen mineralisatie, denitrificatie en indicatoren voor bodemkwaliteit in landbouwgronden, Alterra report 769, p 38. (In Dutch)
Velthof GL, Hoving IE, Dolfing J, Smit A, Kuikman PJ, Oenema O (2009) Method and timing of grassland renovation affects herbage yield, nitrate leaching, and nitrous oxide emission in intensively managed grasslands. Nutr Cycl Agroecosyst. doi:10.1007/s10705-009-9302-7
Vertès F, Hatch D, Velthof G, Taube F, Laurent F, Loiseau P, Recous S (2007) Short-term and cumulative effects of grassland cultivation on nitrogen and carbon cycling in ley-arable rotations, p. 227-246. In: de Vliegler A, Carlier L (eds) Grassland Science in Europe, 12
Whitehead DC, Bristow AW, Lockyer DR (1990) Organic matter and nitrogen in the unharvested fractions of grass swards in relation to the potential for nitrate leaching after ploughing. Plant Soil 123:39–49
Wienhold BJ (2007) Comparison of laboratory methods and an in situ method for estimating nitrogen mineralization in an irrigated silt-loam soil. Commun Soil Sci Plan Anal 38:1721–1732
Acknowledgements
This research was financed by the ministry of Agriculture, Nature en Food Quality (BO-programme BO-05). The authors want to thank Jaap Nelemans for his help on design and performing the laboratory experiment and Eduard Hummelink and Jan van Kleef for collecting samples all over the country. All farmers who allowed us to sample their fields are acknowledged. Johan van Riel assisted with statistical analyses. Two anonymous reviewers, Oene Oenema and Jan Willem van Groenigen are gratefully thanked for their very useful comments on an earlier version of the manuscript.
Open Access
This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
Author information
Authors and Affiliations
Corresponding author
Additional information
Responsible Editor: Elizabeth (Liz) A. Stockdale.
Rights and permissions
Open Access This is an open access article distributed under the terms of the Creative Commons Attribution Noncommercial License (https://creativecommons.org/licenses/by-nc/2.0), which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
About this article
Cite this article
Smit, A., Velthof, G.L. Comparison of indices for the prediction of nitrogen mineralization after destruction of managed grassland. Plant Soil 331, 139–150 (2010). https://doi.org/10.1007/s11104-009-0240-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11104-009-0240-6