Effects of dairy cow treading pressures and food resources on invertebrates in two contrasting and co-occurring soils.
Nitrogen (N) fertiliser inputs to boost growth of the traditional phosphorus (P) fertilised, legume-based pastures is now a feature of New Zealand pastoral agriculture. The lift in pasture productivity has often been accompanied by an increase in stocking rate and associated treading pressures, leading to soil compaction (Greenwood and McKenzie 2001). Soil compaction can affect the composition of soil faunal communities by altering the size distribution and connectivity of the pore space. This influences both the organisms that can inhabit the pores and their trophic interactions (King and Hutchinson 1976; Elliott et al. 1980; Bouwman and Arts 2000; Nielsen et al. 2008). On the other hand, increased food supply associated with increased soil fertility often stimulates the abundance of soil invertebrates (Yeates 1976; Cole et al. 2005; Curry et al. 2008), particularly bacterial-feeding, plant-feeding, and plant-associated nematodes (Yeates and Bongers 1999). The use of crops (e.g. maize silagc, brassicas) to supplement the feed of grass-fed livestock increases the deposition of urine and dung to the soil surface, and therefore the supply of carbon (C) and plant-available nutrients to the soil--plant system (Ruess and Seagle 1994). Interestingly, while N-fertilised, legume-based pastures are more productive with increases in the potential inputs of C (i.e. litter) into the soil, recent data by Schipper et al. (2010) suggest a trend for losses, rather than gains, of soil C in intensive lowland pastoral soils.
It is often difficult to assess the impact of intensification practices--defined here as increasing dairy cow numbers and feed inputs through increased N use and maize supplements on soil biota across soil types. This is because different soils require different management practices and often have different stocking rates and fertiliser inputs. In New Zealand, different soils have formed in close proximity in several landscapes (Hewitt 1993). A good example is in the Waikato, where rhyolitic alluvium was deposited in higher areas and formed well-structured Andosol soils, while finer rhyolitic alluvium deposited in low-lying areas of the alluvial plain has formed poorly structured Gleysol soils (Molloy 1998). In both soils, porosity declines with intensive grazing; however, the Gleysol, with its high silt content, is more susceptible to compaction (Singleton and Addison 1999). The Gleysol--Andosol mosaic in close proximity provides a unique opportunity to investigate the effects of the same long-term farm management practices on soil properties and processes and, specifically, on soil invertebrates, which are otherwise often confounded.
This study investigated the influence of pastoral intensification in two co-occurring, but very different, soil types (Andosol and Gleysol) on soil invertebrates. Our hypothesis was that there would be a shift in the soil invertebrate community as the treading pressure mounted and the quantity and quality of plant litter and dung changed, and this would include an increase in plant- and bacterial-feeding nematodes. Further, this shift would be more profound on poorly structured Gleysol soils, particularly for organisms such as Oribatida, which are sensitive to physical disturbance or changes in soil porosity.
Materials and methods
Study sites The study site was on the DairyNZ Scott Farm in the Waikato region of New Zealand (37[degrees]45'S, 175[degrees]21'E). The trial site is at an altitude of 30 m and has an average air temperature of 14[degrees]C and annual rainfall of 1200 mm. Rainfall was less than usual in the year leading up to the sampling (932 mm) (Fig. 1). The soils are classified as Andosol (New Zealand Soil Classification: Allophanic, Horotiu silt loam) and Gleysol (New Zealand Soil Classification: Gley, Te Kowhai silt loam) (Hewitt 1993). Both soils had predominantly been at ~20 mm available water (where available water capacity is the difference between the water content at -10 and -1500kPa at 0-0.10m soil depth) in the month leading up to the sampling, with the Gleysol remaining wetter for longer after rainfall events. Livestock treading events that lead to significant soil compaction are likely to occur more frequently on Gleysols, as they have a lower plastic limit (Fig. 1); however, these events also occur on Andosols (Singleton and Addison 1999).
The 'Resource Efficient Dairy' (RED) Trial began in 2000 and included three management treatment levels: 2.3, 3, and 3.8 cows/ha. Each treatment was operated as a self-contained farmlet (varying in size from 6 to 9 ha), consisting of dairy cow herds of 21 cows which were rotationally grazed. Treatments were not replicated. In each treatment the two soil types occur together and are not differentiated for either fertiliser application or stock management. Each treatment received the same application of maintenance fertiliser each year, including 50 kg P/ha.year as superphosphate (Table 1). Nitrogen as urea (170kg N/ha.year) was applied to the treatments with 3 and 3.8 cows/ha. The 3.8 cows/ha treatment also received maize supplement at a rate of 4600 kg DM/ha.year. For further details on the trial, see Jensen et al. (2005). Soil sampling was carried out in August 2007 (Southern Hemisphere winter).
Pasture production was calculated from stocking rate, assuming a standard cow is 450kg liveweight (www.lic.co.nz) and consumes 4500kg DM/year at 85% pasture utilisation. The values are within the ranges that would be expected on Waikato farms (Crush et al. 2006; Clark et al. 2007). The static treading pressure of a cow is 98-168kPa (Greenwood and McKenzie 2001), but this increases as a cow moves (Di et al. 2001). Dry matter input from litter was calculated following Parsons et al. (1983), using the relationship between grazing intensity and the partitioning of fixed C between shoot and root growth, respiration, and animal intake. These values are in line with those observed by Saggar et al. (1997) and Dodd and Mackay (2011). It was assumed that grazing occurred at a time optimal for pasture growth. Dry matter from dung was calculated as 35% of pasture intake (Vanderholm 1984; Takahashi et al. 2007).
Soil biological sampling In each of the three intensification treatments, soil samples were collected randomly from two paddocks, each paddock being dominated by either Andosol or Gleysol soil. Five cores for macrofauna (15.5 cm diameter, 0-15.5 cm depth) were collected and taken back to the laboratory for handsorting and identification; earthworms residing between 15.5 and 50 cm depth were collected in the field and taken back to the laboratory for identification. Four intact soil cores for mesofauna (5 cm diameter, 0-7.5 cm depth) and four composite soil samples for nematodes (each comprising five intact soil cores 2.5 cm diameter, 0-7.5 cm depth) were collected from each soil type in each treatment. Mesofauna were extracted in a modified Berlese-Tullgren extractor (for details see Schon et al. 2008). The mesofauna was classified into trophic groups according to Petersen and Luxton (1982) and Symstad et al. (2000). Nematodes were extracted using a modified tray method, as described by Yeates (1978). Nematodes were identified to nominal genera and allocated to feeding groups, following Yeates et al. (1993a, 1993b). The nematode coloniser-persister (CP) groups (range from 1 = short-lived colonisers to 5=long-lived persisters), channel ratio (NCR), maturity index (MI), plant parasitic index (PPI), and Ematurity index ([ZIGMA]MI) were calculated (Bongers 1990; Yeates 1994, 2003). The Shannon-Wiener diversity index (H'), Margalef's richness (SR), and Pielou's evenness (J') were calculated to describe the diversity of soil fauna (Yeates 1984a; Ludwig and Reynolds 1988).
Soil microbial biomass was measured using substrate-induced respiration methods. Three soil samples (20 cores pooled, each core 2.5cm diameter, 0-7.5cm deep) were collected from each soil type in each treatment. Samples were sieved to <2 mm, and the amount of C[O.sub.2] respired in 2 h was estimated by collecting 25 mL of headspace gas in a pre-evacuated (-80kPa for 2min) 12-mL Exetainer[R]. Gas samples were analysed in a Gilson 222XL autosampler (Gilson, Inc., Middleton, WI, USA) and Shimadzu-20190 gas chromatograph (Shimadzu Scientific Instruments, Columbia, MD, USA).
Soil and pasture sampling
Soil temperature (Checktemp, Hanna Instruments, UK) and moisture (TDR 300 Soil Moisture Probe, Spectrum Technologies, Inc., East Plainfield, IL, USA) at 0-10cm depth were recorded in the field at the time of sampling. The mesofauna cores were subsequently analysed for soil pH (1 : 2.5 soil : water), Olsen P (Olsen et al. 1954), total N, and total C (dry combustion using LECO-2000, LECO Equipment Corp., St. Joseph, MI, USA). Bulk density was determined by collecting three intact soil cores (10cm diameter, 0-7.5cm depth), drying (105[degrees]C), and weighing.
[FIGURE 1 OMITTED]
Pasture species were determined from pasture samples collected using a 'trim' method, in which herbage is cut 1 cm above the soil surface (Piggot 1989). Root biomass was determined using three soil samples (20 cores pooled, each core 2.5 cm diameter, 0-7.5 cm deep) from each soil type, on each treatment. Samples were crumbled and washed through a hydropneumatic root washer until soil was removed. Samples were towel-dried, and roots and tillers were separated, dried at 60[degrees]C, and weighed.
Pore size distribution for small water-filled pores <60 [micro]m diameter was determined using pressure plates (Danielson and Sutherland 1986), with tensions of -10, -50, and -1500kPa equating to water-filled pore sizes of 30, 6, and 0.2 [micro]m diameter, respectively. Larger pores (>50[micro]m) were charactefised using a fluorescent resin technique. Three cores 15 cm in diameter were collected in 2009 from each soil type for treatments with 2.3 and 3 cows/ha, but collection was not possible with 3.8 cows/ha due to the discontinuation of this treatment. The cores were impregnated with a fluorescent resin, and images of horizontal soil sections at depths 2.5 and 5 cm were analysed using Solicon[C] analysis software (The University of Sydney, Cotton Research and Development Corporation) (Vervoort and Cattle 2003). Images were described in terms of percentage porosity and pore area ([mm.sup.2], estimated using limbs of a 16sided polygon).
The farm system comparison had been in place for 7 years at the time of sampling, with the same paddocks receiving the same treatment (i.e. 2.3, 3.0, and 3.8 cows/ha) throughout that period. At the treatment level, paddocks are subsamples rather than replicates, and it had to be assumed that the differences between treatments can be attributed to the differences in longterm farm management. Large-scale experiments such as this can be difficult to replicate, hut with caution, statistics can still he used (Oksanen 2001). At the soil-type level, the study has true replicates. Due to low replication, a significance level of [alpha] = 0.1 was chosen.
To test the null hypothesis--that there was no change in the composition of the invertebrate community within each soil type or with pastoral intensification--macrofauna, mesofauna, and microfauna data were log (x + 1) transformed and analysed using PROC MIXED, which fits the data to a mixed linear model, in SAS v.9.1 (SAS Institute Inc., Cary, NC, USA), using the Sattcrthwaite formula to approximate the degrees of freedom. To determine the trends resulting from increased pastoral intensification, results from each soil type were analysed for a [greater than or equal to] 10% consistent increase or decrease from 2.3 cows/ha to 3.8 cows/ha, and then a regression analysis was run using PROC REG, using a linear model in SAS v.9.1. The Figures and Tables show untransformed arithmetic means. Least-squares means were used to show treatment differences in a given soil in the Tables.
[FIGURE 2 OMITTED]
The functional groups of macrofauna, mesofauna, and nematodes were analysed with respect to the site and soil environmental variables using canonical correspondence analysis (CCA) with PCord v.4 (MJM Software, Gleneden Beach, OR, USA). In CCA settings, the data were biplotscaled, the rows and columns were compromised, and the null hypothesis of no significant effect of soil and management intensity level on species assemblages was tested using a Monte Carlo Test. The assemblages of macrofauna, mesofauna, and nematodes were also analysed for the effects of soil using multi-response permutation procedures (MRPP) with PCord v.4; MRPP is a non-parametric method that evaluates how likely it is that the fauna assemblages are different due to chance. In the MRPP settings, Euclidean distance was used.
Soil and pasture properties
The Gleysol had higher soil moisture, temperature, bulk density, and Olsen P (Table 2) and lower soil total N than the Andosol. The sieved Gleysol had more pores of diameter 0.2 30 [micro]m than the Andosol (on average 37% v. 19% v/v, respectively). In sieved Andosol, there were more small pores (0.2-6[micro]m diameter) in the treatment with 2.3 cows/ha, where larger pores (6-30 [micro]m) were fewer. In both soils, the treatment 3.8 cows/ha had the highest percentage of pores 0.2-30[micro]m diameter. In the resin-embedded cores, the Andosol tended to have more pores <1 mm diameter, while the Gleysol soil had more pores >4 mm for both treatments assessed (Fig. 2).
Soil total C and N (0-7.5cm) declined with pastoral intensification in both the Gleysol and Andosol (Table 2), despite more calculated dry matter (and hence C) potentially entering the soil food-web (Table 1). On both soils, pasture composition was dominated by Lolium perenne (ryegrass), Trifolium repens (white clover), and Poa annua (annual poa) in all treatments.
The distinction between the Andosol and the Oleysol was highlighted in the CCA for macrofanna (P=0.004), even though this was not significant in the MRPP results (P=0.785), with the dense Gleysol negatively associated with anecic earthworms and herbivorous macrofauna (Fig. 3). Within the Andosol, there was no significant effect of treatment on total earthworm and other macrofauna abundance (Table 3, Fig. 4). The abundance of Aporrectodea longa showed a consistent increase with pastoral intensification, while the other anecic species, Lumbricus terrestris, declined. Epigeic earthworm abundance, as a proportion of total earthworm abundance, was highest at 3 cows/ha, where the proportion of endogeic abundance was lowest (Fig. 4). Within the Gleysol, there was a decline in abundance of both A. caliginosa and L. terrestris with pastoral intensification (Table 3, Fig. 4). Neither A. rosea nor A. longa were detected in the Gleysol. There were also fewer immature earthworms at higher stocking rates in the Gleysol (83% at 2.3 cows/ha v. 50% at 3.8 cows/ha). Other macrofauna, such as the clover-root weevil, also declined with intensification in the Gleysol. Aporrectodea caliginosa made up >50% of the earthworm abundance in all treatments.
The MRPP results (P= 0.527) showed that soil mesofauna was not significantly influenced by soil type as also observed in the CCA plots (Fig. 3). Within the Andosol, total mesofauna abundance was negatively associated with higher inputs and associated stocking rate (Table 4, Fig. 4). This reflected a decline in Collembola and the elimination of aphids (Hemiptera). Consequently, there was a decrease in the proportion of general detritivores and herbivores, and an increase in the proportion of predators (largely Mesostigmata). Common Mesostigmata included Parasitidae, Hypoaspis and Rhodacarellus silesiacus. Oribatid abundance was low, with no Oribatida detected at the highest stocking rate. In total, only four Oribatid species were recovered. With the exception of the larger, New Zealand endemic, omnivorous Galumna rugosa, they were short-lived, cosmopolitan species, either fungivorous or herbofungivorous. Within the Gleysol, there was no significant effect of treatment on total mesofauna abundance (Table 4, Fig. 4). However, total Acari, including Oribatida, declined with intensification. Adult Oribatida were found solely at 2.3 cows/ha, and were dominated by Liebstadia similis. Collembola increased with increased intensification in the Gleysol, in contrast to the decrease in abundance in the Andosol. Among the soil mesofauna, Symphyla were not found in the Gleysol and Astigmata were significantly less abundant in the Gleysol. In both soils, mesofauna diversity was greatest at 3 cows/ha, but at a given stocking rate it was always higher in the Andosol.
[FIGURE 3 OMITTED]
[FIGURE 4 OMITTED]
The CCA for nematodes (P=0.02) highlighted the distinction between the Andosol and the Gleysol, although this was not significant in the MRPP results (P=0.357), with bacterial-feeding nematodes associated with the Andosol (Fig. 3). Within the Andosol, total nematode abundance was not significantly influenced by treatment even though it seemed to increase from legume-based to N-fertilised pastures (Table 5, Fig. 4). In total, 33 nematode taxa were recorded. Pastures receiving N fertiliser showed an increase in the relatively responsive bacterial-feeding Rhabditidae (CP1) and Cephalobus (CP2). Among plant-feeding nematodes, there was a decline in Heterodera trifolii (clover-cyst nematode) under N-fertilised pastures but at least a 6-fold increase in Pratylenchus abundance from stocking rate 2.3 to 3.8 cows/ha in both soils. Monhystera and Aporcelaimus also increased with intensification, whereas Pungentus decreased. Predator and omnivore abundance, driven by Aporcelaimus, also increased with N-fertiliser use on the Andosol (Fig. 4). The maturity indices (MI, PPI, and EMI) were not significantly influenced by treatment (Table 5). Within the Gleysol, total nematode
abundance was not significantly influenced by treatment, although it increased with N-fertiliser use (Table 5, Fig. 4). Thirty-three nematode taxa were also recorded in the Gleysol. The proportion of plant-feeding and plant-associated nematodes increased under N-fertilised pastures in the Gleysol. This largely reflects a 9- and 5-fold increase in Hoplolaimidae and Pratylenchus, respectively, even though there was a decline in H. trifolii with N-fertiliser inputs and the associated decline in the legume content in the sward (Table 1). Pastures receiving N fertiliser showed an increase in the Rhabditidae (CP1), and in Pungentus, Aporcelaimus, and Dorylaimus, while the putative fungal-feeder Doryllium decreased with intensification. The NCR increased from 0.81 at 2.3 cows/ha to 0.93 at 3.8 cows/ ha. The abundance of predators and omnivores declined with increasing cow number and food supply in the Gleysol (Fig. 4). The lowest population of Aporcelaimus, at 3.8 cows/ha in the Gleysol, contrasts with this treatment having the highest Aporcelaimus abundance in the Andosol. The MI was highest at 2.3 cows/ha (Table 5). Aphelenchoides, Anaplectus, and Dorylaimus were found at the highest abundances in the Gleysol at 2.3 cows/ha but found at lowest abundance in the Andosol under the same treatment.
The small differences in the faunal communities (Tables 3 and 4) across the lowest dairy stocking rate between the two contrasting soils, and the low faunal community abundance compared with a New Zealand sheep-grazed pasture (Schon et al. 2008), indicates that even at the low stocking rate these soils are under sustained pressure.
Even at the low dairy stocking rates in this study, the treading pressure of cows, which is double that of sheep (Greenwood and McKenzie 2001), was sufficient to limit the abundance and diversity of the Oribatida community to <12 000 individuals/[m.sup.2] and four species. In a New Zealand sheep-grazed pasture, Oribatid abundances reached abundances >50 000 individuals/ [m.sup.2] with >20 species detected (Schon et al. 2008). Oribatid mites have previously been shown to be sensitive to treading (King and Hutchinson 1980; Cole et al. 2008; Schon et al. 2008), and in both the Andosol and Gleysol, soil porosity measured by resin impregnation was low (only 3% for pores >50[micro]m diameter). Despite the Gleysol soil being more susceptible to treading than the Andosol (Hewitt and Shepherd 1997; Singleton and Addison 1999), with a higher bulk density (Table 1, Fig. 1 e), both soils were subject to the same level of disturbance through stock treading. Interestingly, the Gleysol, which had fewer smaller pores (<1 mm diameter) than the Andosol at the lowest stocking rate, had similar abundance of mesofauna and nematodes (but differing community compositions, see below). This may reflect the overriding impact of ongoing livestock treading, although there were more of the larger size pores (>4 mm) in the Gleysol which may provide alternate habitats for soil invertebrates.
Earthworms, as structural engineers, were not necessarily associated with pore size distribution in this study. The larger pores (>4mm diameter) in the Gleysol compared with the Andosol were more likely to be due to soil wetting and drying processes (Greenwood and McKenzie 2001) than caused by earthworms, which can create burrows ~2.5 mm in diameter (for dominant A. caliginosa) (Springett 1983). The observation that there were fewer immature earthworms at higher stocking rates in the Gleysol (83% at 2.3 cows/ha v. 50% at 3.8 cows/ha) may reflect increased treading pressures, as immature earthworms are reportedly more sensitive than adults to treading (Cluzeau et al. 1992). This resulted in a similar earthworm biomass at all stocking rates in the Gleysol (as abundance declined with stocking rate) (Fig. 4). The Gleysol also appears to be a challenging soil environment for some lumbricids to function and survive, with neither A. longa nor A. rosea detected, despite populations of both species in the adjacent, co-occurring Andosol. In the Andosol, two anecic earthworm species showed opposite trends in abundance; A. longa increased with increased stocking rates, whereas L. terrestris decreased. This may reflect the poor competitiveness of L. terrestris under field conditions, as described by Butt (1998). Further, the more permanent vertical burrows of L. terrestris, compared with those of A. longa with burrowing activities similar to those of endogeic earthworms (Felten and Emmerling 2009), may be more susceptible to treading damage.
Soil nematodes, particularly the abundance and biomass of plant-feeding and plant-associated nematodes, responded to increased pasture growth and stocking rates (Fig. 4). The largest differences were observed between 2.3 cows/ha and the other two stocking rates, which both received N-fertiliser inputs. This included a large increase in Homplolaimidae, whose feeding has not been reported to affect herbage accumulation (Ycates 1984b), although leakage of microbe-available nutrients from roots may be significant (Yeates et al. 1999). Bacterial-feeding nematodes (i.e. Cephalobus in the Andosol) also increased in response to N-fertiliser use, presumably responding to the lift in the quantity and quality of plant residue inputs. In fact in the Gleysol, the relative dominance of the bacterial pathway over the fungal pathway in the soil food-web (reflected in the NCR) increased with N-fertiliser use. In contrast, the clover-cyst nematode (H. trifolii) declined, as application of N fertiliser is known to reduce legume content (Gillingham et al. 2008). The response of total nematode abundance to the influence of N-fertiliser inputs was less pronounced in the Gleysol, confirming that both productivity and soil type are important factors influencing nematodes (Yeates 1980, 1984a).
plant litter and animal dung on the soil surface can be washed down pores, or incorporated into the soil through the treading actions of grazing ruminants and feeding actions of soil invertebrates. Despite potentially more organic material available for incorporation into the soil profile with increasing N-fertiliser inputs and supplement use, lower abundances of litter- and dung-incorporating anecic earthworms, Collembola, and Oribatida were found (Fig. 4), and increased turnover by the bacterial pathway (NCR, especially in the Gleysol) may collectively have contributed to a measured decline in topsoil C contents. Until the plant residue and dung on the soil surface is incorporated and mixed with the mineral soil, organic matter is exposed to oxidation and vulnerable to being lost as carbon dioxide. Schipper et al. (2010) reported losses of soil C in lowland pastoral systems under intensive livestock farming. Few soil plant process models consider the role of soil invertebrates in the C cycle or have the capacity to explore the effects of change in abundance and diversity of the invertebrate community on the incorporation of plant litter and dung in sustaining the soil C in intensive pasture systems.
Two contrasting and co-occurring soils under the same pasture management allowed the assessment of response of soil invertebrates to pastoral intensification and soil type. Addition of N fertiliser increased pasture production and stimulated plant-feeding nematodes, although the clover-cyst nematode, Heterodera, declined as clover content declined. Treading by dairy cows resulted in low porosity in both soils, and consequently low Oribatida abundance. The difference in habitable pores between the two soils was not reflected in invertebrate abundance at the lowest stocking rate, suggesting that ongoing treading disturbance by livestock is an important factor in determining abundance. The low faunal abundance and biomass associated with these dairy pastures limits the capacity to incorporate litter into the soil profile, potentially contributing to the decline in soil C observed in this study and reported in recent literature.
We thank G. W. Yeates for his extensive and altruistic supervision. We thank MJ. Hedley and two anonymous reviewers for helpful suggestions on the manuscript. We wish to thank DairyNZ fur allowing us to sample the RED Trial on Scott Farm. Field and laboratory assistance from D. Waugh (DairyNZ), R. Gray (AgRcsearch), P. Budding (AgResearch), and S. Lambie (Landcare Research) was much appreciated. S. Cattle gave guidance on the method for porosity assessment. The project was funded by the FRST contract CO2XO405 and an AGMARDT Doctoral Scholarship.
Bongers T (1990) The maturity index an ecological measure of environmental disturbance based on nematode species composition. Oecologia 83, 14 19. doi:l 0.1007/BF00324627
Bouwman LA, Arts WBM (2000) Effects of soil compaction on the relationships between nematodes, grass production and soil physical properties. applied Soil Ecology 14, 213 222. doi: 10.1016/S0929-1393 (00)00055-X
Brewer R (1964) 'Fabric and mineral analysis of soils.' (Kreiger: New York) Butt KR (1998) Interactions between selected earthworm species: A preliminary, laboratory-based study. applied Soil Ecology 9, 75-79. doi:10.1016/S0929-1393(98)00057-2
Clark DA, Caradus JR, Monaghan RM, Sharp P, Thorrold BS (2007) Issues and options fur future dairy farming in New Zealand. New Zealand Journal of Agrieultural Research 50, 203-221. doi:10.1080/ 00288230709510291
Cluzeau D, Binet F, Vertes F, Simon JC, Rivierc JM, Trehen P (1992) Effects of intensive cattle trampling on soil plant-earthworms system in two grassland types. Soil Biology & Biochemistry 24, 1661-1665. doi:10.1016/0038-0717(92)90166-U
Cole L, Buckland SM, Bardgett RD (2005) Relating microarthropod community structure and diversity to soil fertility manipulations in temperate grassland. Soil Biology & Biochemistry 37, 1707-1717. doi: 10.l016/j.soilbio.2005.02.005
Cole L, Buckland SM, Bardgett RD (2008) Influence of disturbance and nitrogen addition on plant and soil animal diversity in grassland. Soil Biology & Biochemistry 40, 505 514. doi: 10.1016/j.soilbio.2007.09.018
Crush JR, Woodward SL, Ecrens JPJ, MacDonald KA (2006) Growth and milksolids production in pastures of older and more recent ryegrass and white clover cultivars under dairy grazing. New Zealand Journal of Agricultural Research 49, 119-135. doi:10.1080/00288233.2006. 9513702
Curry JP, Doherty P, Purvis G, Schmidt O (2008) Relationships between earthworm populations and management intensity in cattle-grazed pastures in Ireland. applied Soil Ecology 39, 58-64. doi:10.1016/ j.apsoil.2007.11.005
Danielson RE, Sutherland PL (1986) Porosity. In 'Methods of soil analysis: Physical and mineralogical methods. Vol. 1 '. lEd. A Klute) pp. 443 460. (American Society of Agronomy: Madison, WI)
Di HJ, Cameron KC, Milne J, Drewry JJ, Smith NP, Hendry T, Moore S, Reijncn B (2001) A mechanical hoof for simulating animal treading under controlled conditions. New Zealand Journal of Agricultural Research 44, 111-116. doi:10.1080/00288233.2001.9513465
Dodd MB, Mackay AD (2011) Effects of contrasting soil fertility on root mass, root growth, root decomposition and soil carbon under a New Zealand perennial ryegrass/white clover pasture. plant and Soil 349, 291-302. doi:10.1007/sl1104-011-0873-0
Elliott ET, Anderson RV, Coleman DC, Cole CV (1980) Habitable pore space and microbial trophic interactions. Oikos 35, 327-335. doi: 10.2307/3544648
Felten D, Emmerling C (2009) Earthworm burrowing behaviour in 2D terraria with single- and multi-species assemblages. Biology and Fertility of Soils 45, 789-797. doi:10.1007/s00374-009-0393-8
Gillingham AG, Morton JD, Gray MH (2008) Pasture responses to phosphorus and nitrogen fertilisers on east coast hill country: 2. Clover and grass production from easy slopes. New Zealand Journal of Agricultural Researeh 51, 85-97. doi:10.1080/00288230809510438 Greenwood KL, McKenzie BM (2001) Grazing effects on soil physical properties and the consequences for pastures: a review. Australian Journal of Experimental Agriculture 41, 1231-1250. doi:10.1071/ EA00102
Hewitt AE (1993) 'New Zealand Soil Classification.' Landcare Research Science Series No. 1. (Manaaki-Whenua Press: Lincoln, NZ)
Hewitt AE, Shepherd TG (1997) Structural vulnerability of New Zealand soils. Australian Journal of Soil Research 35, 461 474. doi: 10.1071 / $96074
Jensen RN, Clark DA, Macdonald KA (2005) Resource Efficient Dairying trial: measurement criteria for farm systems over a range of resource use. Proceedings of the New Zealand Grassland Association 67, 47-52.
King KL, Hutchinson KJ (1976) Effects of sheep stocking intensity on abundance and distribution of mesofauna in pastures. Journal of applied Ecology 13, 41-55. doi:10.2307/2401928
King KL, Hutchinson KJ (1980) Effects of super-phosphate and stocking intensity on grassland microarthropods. Journal of applied Ecology 17, 581-591. doi:10.2307/2402638
Ludwig JA, Reynolds JF (1988) 'Statistical ecology.' (John Wiley and Sons: New York)
Molloy L (1998) 'Soils in the New Zealand landscape: The living mantle." (Mallinson Rcndel Publishers Ltd: Wellington)
Nielsen UN, Osier GHR, van dcr Wal R, Campbell CD, Burslem D (2008) Soil pore volume and the abundance of soil mites in two contrasting habitats. Soil Biology & Biochemistry 40, 1538-1541. doi:10.1016/ j.soilbio.2007.12.029
NIWA (2009) Cliflo. National Climate Database. Retrieved March 2009 from: http://cliflo.niwa.co.nz.
Oksanen L (2001) Logic of experiments in ecology: is pseudoplication a pseudoissue? Oikos 94, 27 38. doi:10.1034/j.1600-0706.2001.1131 l.x
Olsen SR, Cole CV, Wanatabe FS, Dean LA (1954) Estimation of available phosphorus in soils by extraction with sodium hydrogen carbonate. USDA Circular No. 939.
Parsons AJ, Leafe EL, Collett B, Penning PD, Lewis J (1983) The physiology of grass production under grazing. 2. Photosynthesis, crop growth and animal intake of continuously-grazed swards. Journal of applied Ecology 20, 127 139. doi: 10.2307/2403381
Petersen H, Luxton M (19821 A comparative analysis of soil fauna populations and their role in decomposition processes. Oikos 39, 288-388. doi:10.2307/3544689
Piggot GJ (1989) A comparison of four methods for estimating herbage yield of temperate dairy pastures. New Zealand Journal o[" Agricultural Research 32, 121-123.
Ruess RW, Seagle SW (1994) Landscape patterns in soil microbial processes in the Serengeti National Park, Tanzania. Ecology 75, 892-904. doi: 10.2307/1939414
Saggar S, Hedley C, Mackay AD (1997) Partitioning and translocation of photosynthetically fixed C-14 in grazed hill pastures. Biology and Fertility of Soils 25, 152-158. doi:l 0.1007/s003740050296
Schipper LA, Parfitt RL, Ross C, Baisden WT, Claydon J J, Fraser S (2010) Gains and losses in C and N stocks of New Zealand pasture soils depend on land use. Agriculture, Ecosystems & Environment 139, 611-617. doi: 10.1016/j.agee.2010.10.005
Schon NL, Mackay AD, Minor MA, Yeates GW, Hedley MJ (2008) Soil fauna in grazed New Zealand hill country pastures at two management intensities. applied Soil Ecology 40, 218-228. doi:10.1016/ j.apsoil.2008.04.007
Singleton PL, Addison B (1999) Effects of cattle treading on physical properties of three soils used for dairy farming in the Waikato, North Island, New Zealand. Australian Journal of Soil Research 37, 891-902. doi:10.1071/SR98101
Sparling GP, Schipper LA, Russell JM (2001) Changes in soil properties after application of dairy factory effluent to New Zealand volcanic ash and pumice soils. Australian Journal of Soil Research 39, 505-518. doi: 10.1071/SR00043
Springett JA (1983) Effect of five species of earthworm on some soil properties. Journal of applied Ecology 20, 865-872. doi:10.2307/ 2403131
Symstad A J, Siemann E, Haarstad J (2000) An experimental test of the effect of plant functional group diversity on arthropod diversity. Oikos 89, 243-253. doi: 10.1034/j.1600-0706.2000.890204.x
Takahashi S, Nakagami K, Sakanoue S, Itano S, Kirita H (2007) Soil organic carbon storage in grazing pasture converted from forest on Andosol soil. Japanese Society of Grassland Science 53, 210-216. doi:10.1111/ j.1744-697X.2007.00095.x
Vanderholm DH (1984) Agricultural waste manual, NZAEI Project Report No. 32. New Zealand Agricultural Engineering Institute, Lincoln College, Canterbury, NZ.
Vervoort RW, Cattle SR (2003) Linking hydraulic conductivity and tortuosity parameters to pore space geometry and pore-size distribution. Journal of Hydrology 272, 36-49. doi:10.1016/S0022-1694(02)00253-6
Yeates GW (1976) Effect of fertilizer treatment and stocking rate on pasture nematode populations in a yellow-grey earth. New Zealand Journal of Agricultural Research 19, 405-408.
Yeates GW (1978) Populations of nematode genera in soils under pasture. 1. Seasonal dynamics in dryland and irrigated pastures on a southern yellow-grey earth. New Zealand Journal of Agricultural Research 21, 321-330.
Yeates GW (1980) Populations of nematode genera in soils under pasture. III. Vertical distribution at eleven sites. New Zealand Journal of Agricultural Research 23, 117-128.
Yeates GW (1984a) Variation in soil nematode diversity under pasture with soil and year. Soil Biology & Biochemistry 16, 95-102. doi:10.1016/ 0038-0717(84)90098-1
Yeates GW (1984b) Variation of pasture nematode populations over 36 months in a summer moist silt loam. Pedobiologia 27, 207-219.
Yeates GW (1994) Modification and qualification of the nematode maturity index. Pedobiologia 38, 97-101.
Yeates GW (2003) Nematodes as soil indicators: functional and biodiversity aspects. Biology and Fertility of Soils 37, 199 210.
Yeates GW, Bongers T (1999) Nematode diversity in agroecosystems. Agriculture, Ecosystems & Environment 74, 113 135. doi:10.1016/ S0167-8809(99)00033-X
Yeates GW, Bongers T, De Goede RGM, Freckman DW, Georgieva SS (1993a) Feeding-habits in soil nematode families and genera an outline for soil ecologists. Journal of Nematology 25, 315-331.
Yeates GW, Wardle DA, Watson RN (1993b) Relationships between nematodes, soil microbial biomass and weed-management strategies in maize and asparagus cropping systems. Soil Biology & Biochemistry 25, 869-876. doi:10.1016/0038-0717(93)90089-T
Yeates GW, Saggar S, Hedley CB, Mercer CF (1999) Increase in 14C-carbon translocation to the soil microbial biomass when five species of plant-parasitic nematodes infect roots of white clover. Nematology 1,295-300. doi:10.1163/156854199508298
N.L. Schon (A,C), A.D. Mackay (B), and M. A. Minor (A)
(A) Ecology, Institute of Natural Resources, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
(B) AgResearch Grasslands, Private Bag 11008, Palmerston North 4442, New Zealand.
(C) Corresponding author. AgResearch Lincoln, Private Bag 4749, Christchurch 8140, New Zealand. Email: email@example.com
Table 1. Treatment properties and management inputs in dairy grazed pasture under three management intensities, Waikato, New Zealand, 2007 See Methods for description of the pasture parameter calculations. DM, Dry matter Stocking rate (cows/ha): 2.3 3 3.8 Liveweight (kg/ha) 1150 1500 1900 Inputs (/ha.year) Phosphorus (superphosphate) (kg P) 50 50 50 Nitrogen (urea) (kg N) 0 170 170 Maize supplements (kg DM) 0 0 4600 Pasture parameters (1000kg DM/ha.year): Pasture production 12.2 15.9 14.7 Pasture intake 10.4 13.5 12.5 DM returned in litter 11.6 24.5 27.5 DM returned in dung 3.6 4.7 5.9 DM returned in roots 6.0 9.0 10.0 Total DM returned 21.2 38.2 43.5 Pasture composition (%) Grass 84 70 89 Legume 13 1 I Other (including weeds) 0 17 1 Dead matter 3 13 9 Root mass (g dry wt/rn) 209 224 179 Table 2. Soil properties in dairy--grazed pasture under three stocking rates on two soil types, Waikato, New Zealand, 2007 Bold indicates values statistically significant at [alpha]=0.1; means followed by different letters are significantly different for treatment effects in a given soil (least squares means). The T columns show consistent 10% change across stocking rates ([down arrow] or [up arrow]) Soil type: Andosol Stocking rate (St, cows/ha): 2.3 3 3.8 Soil moisture (%) (A) 45 43 45 Soil temperature ([degrees]C) (A) 7.4 6.9 7.4 Bulk density (Mg/[m.sup.3]) (B) 0.69 0.67 0.70 Porosity (% v/v of sieved soil) 0.2-6 [micro]m (C) 14b 9a 12a 6-30[micro]m (C) 2a 116 10b Porosity (intact cores 2.5 cm depth) Porosity (%) 2 3 -- Mean pore area ([mm.sup.2]) 3.0 7.1 -- Pores <175 [micro]m (%) (D) 23 19 -- Pores >350 [micro]m (%) (D) 53 56 -- Porosity (intact cores 5 cm depth) Porosity (%) I 1 -- Mean pore area ([micro][m.sup.2]) 6.5 4.3 Pores < 175 [micro]m (%) (D) 24 21 -- Pores >350 [micro]m (%) (D) 53 57 -- Microbial biomass (C/g soil) (B) 1098 1039 936 pH (B) 6.1 5.7 6.2 Olsen P (mg/L) (B) 34 31 53 Total N (%) (B) 0.77 0.70 0.47 Total C (%) (B) 6.2 5.1 4.9 C : N ration (B) 10.6 10.5 10.7 Soil type: T Gleysol Stocking rate (St, cows/ha): 2.3 3 Soil moisture (%) (A) 51 52 Soil temperature ([degrees]C) (A) 8.9 7.8 Bulk density (Mg/[m.sup.3]) (B) 0.75 0.79 Porosity (% v/v of sieved soil) 0.2-6 [micro]m (C) 13b 10a 6-30[micro]m (C) 22a 25c Porosity (intact cores 2.5 cm depth) Porosity (%) 2 3 Mean pore area ([mm.sup.2]) 18.3b 8.9a Pores <175 [micro]m (%) (D) 12 13 Pores >350 [micro]m (%) (D) 75 70 Porosity (intact cores 5 cm depth) Porosity (%) 2 1 Mean pore area ([micro][m.sup.2]) 13.9 6.1 Pores < 175 [micro]m (%) (D) 11 18 Pores >350 [micro]m (%) (D) 78 66 Microbial biomass (C/g soil) (B) [down arrow] 762 1185 pH (B) 6.1 5.9 Olsen P (mg/L) (B) 37 52 Total N (%) (B) [down arrow] 0.52 0.47 Total C (%) (B) [down arrow] 8.1 7.4 C : N ration (B) 11.9 10.8 Soil type: T P--value Stocking rate (St, cows/ha): 3.8 Soil Soil moisture (%) (A) 52 0.0006 Soil temperature ([degrees]C) (A) 8.4 0.034 Bulk density (Mg/[m.sup.3]) (B) 0.76 0.002 Porosity (% v/v of sieved soil) 0.2-6 [micro]m (C) 17c 0.183 6-30[micro]m (C) 23b 0.0001 Porosity (intact cores 2.5 cm depth) Porosity (%) -- 0.914 Mean pore area ([mm.sup.2]) 0.046 Pores <175 [micro]m (%) (D) -- 0.089 Pores >350 [micro]m (%) (D) -- 0.047 Porosity (intact cores 5 cm depth) Porosity (%) -- 0.586 Mean pore area ([micro][m.sup.2]) -- 0.059 Pores < 175 [micro]m (%) (D) -- 0.019 Pores >350 [micro]m (%) (D) -- 0.010 Microbial biomass (C/g soil) (B) 931 pH (B) 5.7 0.769 Olsen P (mg/L) (B) 67 [up arrow] 0.322 Total N (%) (B) 0.46 [down arrow] 0.154 Total C (%) (B) 5.0 [down arrow] 0.231 C : N ration (B) 10.8 0.214 Soil type: Stocking rate (St, cows/ha): SoilxSt Soil moisture (%) (A) -- Soil temperature ([degrees]C) (A) -- Bulk density (Mg/[m.sup.3]) (B) 0.638 Porosity (% v/v of sieved soil) 0.2-6 [micro]m (C) 0.015 6-30[micro]m (C) 0.001 Porosity (intact cores 2.5 cm depth) Porosity (%) 0.802 Mean pore area ([mm.sup.2]) 0.099 Pores <175 [micro]m (%) (D) 0.623 Pores >350 [micro]m (%) (D) 0.655 Porosity (intact cores 5 cm depth) Porosity (%) 0.365 Mean pore area ([micro][m.sup.2]) 0.212 Pores < 175 [micro]m (%) (D) 0.118 Pores >350 [micro]m (%) (D) 0.161 Microbial biomass (C/g soil) (B) pH (B) Olsen P (mg/L) (B) -- Total N (%) (B) -- Total C (%) (B) -- C : N ration (B) (A) 0-10 cm depth. (B) 0-7.5 cm depth. (C) Pores 0.2-6 [micro]m diameter retain mostly plant-unavailable water and exclude most microorganisms, with no predation on bacteria. Pores 6-30 [micro]m retain mostly plant-available water and accommodate most bacteria and their predators (Brewer 1964). (D) Soil pores which fit a 16-sided polygon of the specified diameter. Table 3. Earthworm and macrofauna (>2 mm diameter) abundance (0-15 cm soil) in dairy-grazed pasture under three stocking rates on two soil types, Waikato, New Zealand, 2007 Bold indicates values statistically significant at [alpha] = 0.1; means followed by different letters are significantly different for treatment effects in a given soil (least squares means). The T columns show consistent 10% change across stocking rates ([down arrow] or [up arrow]), [up arrow][up arrow] significant regression at [alpha]=0.1. H', Shannon-Wiener diversity index; SR, Margalefs richness; J', Pielou's evenness Soil type: Andosol T Stocking rate (St, cows/ha): 2.3 3 3.8 Earthworms (no ./[m.sup.2]) Lumbricus rubellus (A) 11 64 64 [up arrow] Aporrectodea caliginosa (B) 265 201 350 Aporrectodea rosea (B) 21 11 11 [down arrow] Aporrectodea longa (C) 0 42 64 [up arrow] Lumbricus terrestris (D) 127 64 32 [down arrow] Total earthworms 424 382 519 Earthworm biomass 307 187 295 (g wet Wt/[m.sup.2]) Anecic: total earthworm abundance 0.30 0.28 0.18 [down arrow] Anecic: total earthworm biomass 0.44 0.21 0.33 SR 2.08 1.66 1.81 J' 0.46 0.52 0.50 H' 0.74 0.84 0.81 Other macrofauna (no./[m.sup.2]) (E) Costelytra zealandica (F) larvae 32 21 21 (Scarabaeidae, Coleoptera) Click beetle larvae 21 0 0 (Elateridae, Coleoptera) Weevils (Circulionidae, 85 106 477 [up arrow] Coleoptera) [up arrow] Coleoptera (adult) 0 11 11 [up arrow] Diptera larvae 42 11 0 [down arrow] Gastropoda 11 0 0 Turbellaria 11 0 0 Total macrofauna 201 148 509 Macrofauna biomass 11.0 8.8 14.4 (g wet wt/[m.sup.2]) SR 2.16 3.22 1.51 J' 0.27 0.17 0.09 [down arrow] H' 0.53 0.34 0.18 [down arrow] Soil type: Gleysol Stocking rate (St, cows/ha): 2.3 3 3.8 Earthworms (no ./[m.sup.2]) Lumbricus rubellus (A) 95 106 53 Aporrectodea caliginosa (B) 445 254 185 Aporrectodea rosea (B) 0 0 0 Aporrectodea longa (C) 0 0 0 Lumbricus terrestris (D) 74 74 53 Total earthworms 615 435 291 Earthworm biomass 257 213 223 (g wet Wt/[m.sup.2]) Anecic: total earthworm abundance 0.12 0.17 0.18 Anecic: total earthworm biomass 0.11 0.17 0.30 SR 2.44 2.05 2.01 J' 0.36 0.48 0.32 H' 0.58 0.77 0.51 Other macrofauna (no./[m.sup.2]) (E) Costelytra zealandica (F) larvae 21 0 0 (Scarabaeidae, Coleoptera) Click beetle larvae 0 11 0 (Elateridae, Coleoptera) Weevils (Circulionidae, 201 127 13 Coleoptera) Coleoptera (adult) 11 0 0 Diptera larvae 0 11 0 Gastropoda 0 0 0 Turbellaria 0 0 0 Total macrofauna 233b 148b l3a Macrofauna biomass 7.5b 1.4a 0.7a (g wet wt/[m.sup.2]) SR 2.28 2.31 0 J' 0.16 0.11 0 H' 0.31 0.21 0 Soil type: T P-value Stocking rate (St, cows/ha): Soil Soil x St Earthworms (no ./[m.sup.2]) Lumbricus rubellus (A) 0.766 0.314 Aporrectodea caliginosa (B) [down arrow] 0.502 0.249 Aporrectodea rosea (B) 0.034 0.840 Aporrectodea longa (C) 0.016 0.149 Lumbricus terrestris (D) [down arrow] 0.398 0.066 Total earthworms [down arrow] 0.328 0.150 Earthworm biomass 0.532 0.798 (g wet Wt/[m.sup.2]) Anecic: total earthworm abundance [up arrow] 0.559 0.293 Anecic: total earthworm biomass [up arrow] 0.955 0.618 SR [down arrow] 0.180 0.731 J' 0.785 0.801 H' 0.180 0.730 Other macrofauna (no./[m.sup.2]) (E) Costelytra zealandica (F) larvae 0.085 0.511 (Scarabaeidae, Coleoptera) Click beetle larvae 0.912 0.232 (Elateridae, Coleoptera) Weevils (Circulionidae, [down arrow] 0.296 0.028 Coleoptera) [down arrow] Coleoptera (adult) 0.431 0.185 Diptera larvae 0.308 0.269 Gastropoda 0.331 0.384 Turbellaria 0.331 0.384 Total macrofauna [down arrow] 0.014 0.071 [down arrow] Macrofauna biomass [down arrow] 0.007 0.285 (g wet wt/[m.sup.2]) SR 0.211 0.113 J' [down arrow] 0.598 0.992 H' [down arrow] 0.113 0.994 (A) Epigeic (Hoffmeister 1843). (B) Endogeic (Savigny 1826). (C) Anecic (Ude 1885). (D) Anecic (Linnaeus 1758). (E) All macrofauna are considered herbivores with the exception of adult Coleoptera and Diptera larvae, which are considered general feeders, and Turbellaria, which is considered predatory. (F) (White 1846). Table 4. Mesofauna (<2 mm diameter) and Oribatid species abundance (1000 no. of individuals/MZ) (0-7.5 cm soil) in dairy-grazed pasture under three stocking rates on two soil types, Waikato, New Zealand, 2007 Feeding groups (FG): G, general detritivore; F, fungal feeding; H, herbivore; P, predatory. Bold indicates values statistically significant at [alpha]=0.1; means followed by different letters are significantly different for treatment effects in a given soil (least-squares means). The T columns show consistent 10% change across stocking rates ([down arrow] or [up arrow]), [up arrow][up arrow] significant regression at [alpha]=O.1. H', Shannon-Wiener diversity index; SR, Margalefs richness; f, Pielou's evenness Soil type: FG Andosol Stocking rate (St, cows/ha): 2.3 3 3.8 Tectocepheus sarekenSis (A) 0.3 0 0 Punctoribates punctum (B) 0 0.1 0 Galumna rugosa (C) 0 0.3 0 Liebstadia similis (C) 0 0.1 0 Oribatida (nymphs) 1.1 3.4 0 Oribatida (adult) 0.3 0.5 0 Total Oribatida G 1.4a 3.9b Oa Astigmata G 0.3a 1.1b 1.8b Mesostigmata P 4.1 4.4 4.8 Prostigmata P 1.7 0.9 0.3 Scutacaridae P 0.1 0.4 0.5 Total Acari 7.5 10.8 7.4 Entomobryomorpha G 5.2 3.3 1.3 Poduromorpha G 6.5c 0.4a 1.5b Sminthuridae G 0.4 0.4 0.1 Total Collembola 12.1 4.1 2.9 Coleoptera G 0.4 0.1 0.3 Diptera G 0.3 0.3 1.3 Symphyla G 0.1 0.1 0.3 Protura F 0.3 0 0 Hemiptera H 2.7 0.1 0 Thysanoptera H 0 2.0 0.3 Formicidae P 0.1 0 0 Arachnida P 0 0 0 Chilopoda P 0 0 0 Total mesofauna 23.4 17.6 12.1 SR 4.3 5.3 5.5 Y' 0.45 0.53 0.47 H' 1.29 1.50 1.33 Soil type: T Gleysol Stocking rate (St, cows/ha): 2.3 3 3.8 Tectocepheus sarekenSis (A) 0.3 0 0 Punctoribates punctum (B) 2.2 0 0 Galumna rugosa (C) 0 0 0 Liebstadia similis (C) 5.7b 0a 0a Oribatida (nymphs) 4.1 0.1 0.1 Oribatida (adult) 8.0b 0a 0a Total Oribatida 12.1b 0.1a 0.1a Astigmata [up arrow] 0 0.6 0.1 [up arrow] Mesostigmata [up arrow] 8.1 1.7 2.5 Prostigmata [down arrow] 0.1 0.3 0.4 Scutacaridae [up arrow] 0.5 0.5 0.3 Total Acari 20.9b 3.2a 3.4a Entomobryomorpha [down arrow] 1.4 1.8 4.5 Poduromorpha 0.1 0.9 0.5 Sminthuridae 0.3 0.3 0.6 Total Collembola [down arrow] 1.8 2.9 5.6 [down arrow] Coleoptera 0.3 0 0.3 Diptera [up arrow] 0.4 0.6 0.1 Symphyla 0 0 0 Protura 0 0 0.3 Hemiptera [down arrow] 1.8b 0a 0a Thysanoptera 0.4 0.8 0.6 Formicidae 0 0 0 Arachnida 0 0 0.1 Chilopoda 0 0.3 0 Total mesofauna [down arrow] 25.5 7.8 10.4 SR [up arrow] 4.3a 6.2b 5.5b Y' 0.41 0.49 0.44 H' 1.15 1.38 1.25 Soil type: P-value Stocking rate (St, cows/ha): T Soil SoilXSt Tectocepheus sarekenSis (A) 0.941 0.994 Punctoribates punctum (B) 0.375 0.065 Galumna rugosa (C) 0.100 0.075 Liebstadia similis (C) 0.854 0.004 Oribatida (nymphs) [down arrow] 0.963 0.513 Oribatida (adult) 0.928 0.006 Total Oribatida 0.860 0.004 Astigmata 0.009 0.425 Mesostigmata 0.235 0.909 Prostigmata [up arrow] 0.330 0.108 Scutacaridae [down arrow] 0.498 0.895 Total Acari 0.280 0.030 Entomobryomorpha [up arrow] 0.814 0.146 Poduromorpha 0.169 0.047 Sminthuridae [up arrow] 0.783 0.407 Total Collembola [up arrow] 0.899 0.178 [up arrow] Coleoptera 0.676 0.615 Diptera 0.713 0.749 Symphyla 0.100 1.000 Protura 0.586 0.081 Hemiptera 0.986 0.559 Thysanoptera 0.264 0.639 Formicidae 0.331 0.387 Arachnida 0.331 0.387 Chilopoda 0.331 0.387 Total mesofauna 0.369 0.506 SR 0.462 0.230 Y' 0.618 0.976 H' 0.159 0.991 (A) Tragardh (1910). (B) Koch (1839). (C) Hammer (1968). (D) Michael (1888). Table 5. Nematode abundance (1000 ind./[m.sup.2] in 0-7.5cm soil) in dairy-grazed pasture under three stocking rates (cows/ha) on two soil types, Waikato, New Zealand, 2007 Feeding groups (FG): P, plant feeding; F, fungal feeding; B, bacterial feeding; O, predatory and omnivorous following Yeates (1993). CP groups range from 1 to 5: 1, short-lived; 5, long-lived. Bold indicates values statistically significant at [alpha]=0.1; means followed by different letters are significantly different for treatment effects in a given soil (least-squares means). The T columns show consistent 10% change across stocking rates ([down arrow] or [up arrow]), [up arrow][up arrow] significant regression at [alpha]=0.1. H', Shannon Wiener diversity index; SR, Margalefs richness; J', Pielou's evenness; NCR, nematode channel ratio; MI, maturity index; PPI, plant parasitic index; [SIGMA]MI, Ematurity index. Seinura, Tobrilus, Dorvlaimellus detected in one treatment at <2000 ind./[m.sup.2] so are not included in table Soil type: FG CP Andosol Stocking rate (St): 2.3 3 3.8 Tylenchus P 2 30.8a 111.6b 101.8b Cephalenchus P 2 0 0 0 Heterodera juv. P 3 32.3 19.1 18.9 Meloidogvne juv. P 3 0 2.7 4.7 Tvlenchorhynchus P 3 3.1 5.4 7.1 Hoplolaimidae P 3 20.0 16.3 23.7 Pratvlenchus P 3 3.1a 13.6b 18.9b Paratvlenchus P 2 0 2.7 0 Trichodoridac P 4 3.1 5.4 0 Pungentus P 4 30.8 16.3 11.8 Aphelenchus F 2 46.2 51.7 52.1 Aphelenchoides F 2 0 8.2 2.4 Diphtherophora F 3 0 0 2.4 Dorvllium F 4 4.6 10.9 9.5 Diplogaster B 1 0 5.4 2.4 Rhabditidae B 1 78.5 103.5 104.2 Dauerlarvae B 1 6.2 2.7 11.8 Panagrolaimus B 1 53.9 117.1 68.7 Cephalobus B 2 89.3a 212.4b 213.1b Heterocephalobus B 2 15.4 46.3 18.9 Euteratocephalus B 3 0 0 0 Acrobeles B 2 6.2 8.2 4.7 Acrobeloides B 2 0 0 0 Stegellata B 2 0 5.4 2.4 Plectus B 2 0 0 2.4 Anaplectus B 2 0 5.4 9.5 Plectid B 2 0 5.4 0 Prismatolaimus B 3 1.5 8.2 0 Monhvstera B 2 7.7 8.2 11.8 Alaimidac B 4 0 0 2.4 Chromadoridae B 3 0 2.7 0 Dor vlaimus 0 4 0 10.9 9.5 Eudorvlaimus 0 4 6.2 5.4 7.1 Aporcelaimus 0 5 29.3 40.8 49.7 Clarkus 0 4 1.5 13.6 4.7 Prionchulus O 4 0 0 0 Total nematodes 471.2 865.8 776.6 SR 4.8 5.0 5.5 J' 0.64 0.64 0.63 H' 2.32 2.32 2.30 NCR 0.84 0.88 0.87 Maturity groups (%) CPI 29 26 24 CP2 42a 54b 54b CP3 13 8 10 CP4 10 7 6 CP5 7 5 6 MI 1.45 1.56 1.53 PPI 0.77 0.54 0.65 [SIGMA]MI 2.22 2.10 2.18 Soil type: T Gleysol Stocking rate (St): 2.3 3 3.8 Tylenchus 31.7 68.0 18.7 Cephalenchus Oa 5.1b Oa Heterodera juv. [down arrow] 24.5c Oa 5.1 b Meloidogvne juv. [up arrow] 0 6.8 1.7 Tvlenchorhynchus 2.9 0 3.4 Hoplolaimidae 15.9 91.7 144.1 Pratvlenchus 4.3 3.4 22.0 Paratvlenchus Oa 5.1b Oa Trichodoridac 0 0 0 Pungentus [down arrow] 21.6 3.4 10.2 Aphelenchus 26.0 5.1 18.7 Aphelenchoides 4.3 1.7 3.4 Diphtherophora 0 0 0 Dorvllium 21.6b 11.9b 1.7a Diplogaster 0 6.8 0 Rhabditidae [up arrow] 49.1 112.1 115.3 Dauerlarvae 0 35.7 13.7 Panagrolaimus 60.6 68.0 35.6 Cephalobus [up arrow] 56.3 42.5 40.7 Heterocephalobus 10.1 17.0 50.9 Euteratocephalus 0 0 17.0 Acrobeles 0 0 0 Acrobeloides 1.4 1.7 0 Stegellata 0 0 0 Plectus 0 47.6 1.7 Anaplectus [up arrow] 21.6 1.7 5.1 Plectid 0 0 0 Prismatolaimus 1.4 6.8 8.5 Monhvstera [up arrow] 18.8b 1.7a 15.3b Alaimidac 0 3.4 1.7 Chromadoridae 4.3 3.4 0 Dor vlaimus 26.0 6.8 3.4 Eudorvlaimus 15.9 1.7 8.5 Aporcelaimus 28.9 23.8 8.5 Clarkus 15.9 15.3 15.3 Prionchulus 2.9b Oa Oa Total nematodes 467.5 599.7 569.8 SR 5.1 5.1 5.7 J' 0.72 0.62 0.61 H' 2.62b 2.24a 2.22a NCR 0.81a 0.95c 0.93b Maturity groups (%) CPI [down arrow] 23 37 29 CP2 [up arrow] 36 33 27 CP3 12 19 35 CP4 [down arrow] 22b 7a 7a CP5 6 4 1 MI 1.88b 1.28a 1.18a PPI 0.62 0.77 1.08 [SIGMA]MI 2.51 2.05 2.25 Soil type: T P-value Stocking rate (St): Soil Soil x St Tylenchus 0.134 0.183 Cephalenchus 0.069 0.047 Heterodera juv. 0.261 0.319 Meloidogvne juv. 0.999 0.999 Tvlenchorhynchus 0.629 0.827 Hoplolaimidae [up arrow] 0.792 0.324 [up arrow] Pratvlenchus 0.546 0.165 Paratvlenchus 0.506 0.636 Trichodoridac 0.192 0.618 Pungentus 0.900 0.510 Aphelenchus 0.166 0.303 Aphelenchoides 0.384 0.074 Diphtherophora 0.3330 0.397 Dorvllium [down arrow] 0.628 0.359 [down arrow] Diplogaster 0.617 0.739 Rhabditidae [up arrow] 0.856 0.990 Dauerlarvae 0.457 0.097 Panagrolaimus 0.466 0.490 Cephalobus [down arrow] 0.006 0.138 Heterocephalobus [up arrow] [up arrow] 0.563 0.821 Euteratocephalus 0.337 0.397 Acrobeles 0.043 0.792 Acrobeloides 0.183 0.618 Stegellata 0.183 0.619 Plectus 0.228 0.240 Anaplectus 0.331 0.064 Plectid 0.337 0.397 Prismatolaimus [up arrow] 0.223 0.530 Monhvstera 0.587 0.480 Alaimidac 0.600 0.716 Chromadoridae [down arrow] 0.274 0.296 Dor vlaimus 0.317 0.057 Eudorvlaimus 0.531 0.479 Aporcelaimus 0.225 0.288 Clarkus 0.051 0.680 Prionchulus 0.069 0.047 Total nematodes 0.770 0.467 SR [up arrow] 0.912 0.436 J' [down arrow] 0.533 0.092 H' [up arrow] [up arrow] 0.553 0.097 NCR 0.182 0.192 Maturity groups (%) CPI 0.954 491 CP2 [down arrow] 0.058 0.279 CP3 [up arrow] [up arrow] 0.207 0.119 CP4 [down arrow] 451 0.085 [down arrow] CP5 [down arrow] 0.176 0.353 MI [down arrow] 0.393 0.011 PPI [up arrow] [up arrow] 0.257 0.244 [SIGMA]MI 0.467 0.515
|Printer friendly Cite/link Email Feedback|
|Author:||Schon, N.L.; Mackay, A.D.; Minor, M.A.|
|Date:||Nov 1, 2011|
|Previous Article:||Field-scale verification of nitrous oxide emission reduction with DCD in dairy-grazed pasture using measurements and modelling.|
|Next Article:||Archaeal ammonia oxidisers are abundant in acidic, coarse-textured Australian soils.|