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CROP RESPONSE Roots A characteristic response of root system to increased compaction level is a decreased root size, retarded root penetration and smaller rooting depth (Gliński and Lipiec, 1990; Whalley et al., 2000; Lipiec et al., 2003). This results in greater distances between the neighbouring roots and affects water and nutrient uptake. Table 1 shows that half distance between the neighbouring spring barley roots on horizontal planes till depth of 30 cm in loamy sand was less than 3.7 mm for loose soil and increased to 64 mm in the most compacted soil. However, absorption of water and nutrients takes place commonly in the soil adjacent to the root surface from 2 to 8 mm depending on soil and nutrient types. This implies that larger distances between the roots may increase leaching and ground water contamination. However, lower root size and uneven spatial distribution in compacted soil may favor groundwater contamination through leaching due to increased distances between the nearest roots. Table 1. Half distances (mm) between the neighbouring roots at the heading growth of spring barley grown on loamy sand (after Lipiec and Hatano, 2003). Depth, cm Tractor passes 0 1 3 8 0-10 1.3 1.4 1.1 0.9 10-20 2.5 3.0 4.5 9.1 20-30 3.7 4.9 31.8 64 30-40 16 21.2 - - 40-50 64 - - - 50-60 64 - - - Root growth conditions in compacted soil can be improved by macropores formed by soil fauna or aggregate structure if not destroyed by compaction. The macropores allow roots by pass the zones of high mechanical impedance (Gliński and Lipiec, 1990). Preferential growth of roots into macropores is more pronounced in deeper and stronger layers (Goss, 1991) where the macropores can be the only possible pathways for root growth. The preferential root growth into macro-pores results in greater critical limits of soil strength measured by large penetrometer cones (Ehlers et al., 1983) which are relatively insensitive to pores having diameter greater than the roots and to heterogeneity in the soil at the scale of root tip (Whalley et al., 2000). The relationship between the distribution of macropores and roots in loose and moderately compacted soil can be described numerically using fractal analysis (Hatano and Sakuma, 1990; Lipiec et al., 1998). Recent developments based on computer-assisted tomography (CAT) and magnetic resonance imaging (MRI) provide potential to non-destructive measurements of spatial distribution of bulk density and the dynamics of plant root systems and water uptake (Asseng et al., 2000). 128
Water uptake and stomatal diffusive resistance Experiments performed in growth chamber allowed controlling soil physical conditions and precise measurements of water uptake and eliminating the effects of different weather conditions. Under conditions of sufficient water supply, total water use decreased with increasing soil compaction level while root water uptake rate was highest in moderately compacted soil owing to higher unsaturated hydraulic conductivity and greater water movement towards the roots and better root-soil contact area. However, increased water uptake rate was insufficient to entirely compensate the reduction in total root length and resulted in reduced total water uptake. Water uptake depends on spatial distribution of soil compaction. Split root experiment showed that in treatment with root system of wheat seedlings split to loose and strongly compacted (vertically divided by plastic wall) reduced water uptake in compacted compartment was partly compensated for by greater water use in loose compartment (Fig. 3.). 50 L/L Cumulative water use (ml) 40 30 20 10 0 L(L/SC) SC(L/SC 1 5 9 13 17 21 25 Fig. 3. Cumulative water use from loose and strongly compacted soil compartments (after Lipiec et al. 2002). Days after planting In treatment with loose and moderately compacted soil compartments the compensatory effect was less pronounced. Root water use efficiency was higher from compartments with moderately compacted than loose and strongly compacted soil. This indicates plasticity of root water absorption in response to localized soil compaction. The alterations in the root water use efficiency are of great importance in modelling plant water use (Novak, 1995; Walczak. et al., 1997). Stomatal resistance responses to soil compaction relate to soil water status. In growth chamber with transient wetting the stomatal resistance and its variation over the growth period were markely higher in severely compacted soil than in low or medium compacted soil. Substantial increase of stomatal resistance in most compacted soil occurred when soil matric potential increased from approximately 400hPa (increasing soil moisture) (Lipiec et al., 1996). The highest stomatal diffusive resistance in most compacted soil has also been reported in dry period (Lipiec, Gliński, 1997). Some authors (Tardieu, 1994) stated that abscissic acis increase in plants grown in compacted soil is a result of root dehydration due to a limited water supply to the roots. Ali et al. (1999) reported that the increased leaf stomatal resistance occurred even before a measurable change in leaf water potential. 129
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Jan Gliński, Grzegorz Józefaciuk,
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CONTENTS PART A: GAS EXCHANGE Revie
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SOIL - PLANT - ATMOSPHERE AERATION
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In single observations, rates of N
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than in the night while CH 4 uptake
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Pumpanen et al. (2003b) measured wi
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5. Liikanen A 2002. Greenhouse gas
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EFFECT OF SOIL TILLAGE AND COMPACTI
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Cumulative CO 2 (kg C ha -1 ) 600 F
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Soil depth (mm) 0 20 40 60 80 Diffu
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METHANE Main suppliers to the atmos
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3. Emission of N 2 O is higher from
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30. Kusa, K., Sawamoto, T., Hatano,
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GAS EMISSION FROM WETLANDS Stępnie
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ater retention capacity in the chan
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zone, while in Nadrybie lake the le
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Eh 350 300 250 mV 200 150 100 50 0
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Table 1. Sources and sinks of atmos
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Fig. 1. Quasi - equilibrium methane
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Fig. 5. Concentration of nitrous ox
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drooxygenology, such subbranches as
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Fig. 3. Soil microbial respiration
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NITROUS OXIDE EMISSION FROM SOILS W
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N2O-N [mg kg -1 ] 100 80 60 40 20 0
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7. McKenney, D.J., C.F. Drury, and
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AERATION STATUS OF SOIL AND ENZYME
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Catalase is heme-containing enzyme
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8. Deng S., Dick R. Sulfur oxidatio
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The number of profiles representing
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tics (Stępniewski et al., in press
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MICROBIAL ECOLOGY OF SOIL POROUS ME
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The bulk of non-rhizosphere soil is
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RELATIONS The relations between soi
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23. Mamilov A.Sh., Byzov, B.A. Zvya
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silts. The content of C org in the
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Table 2. Continued Location Day of
Page 74 and 75: 5 o C Eh (mV 400 300 200 100 1A 1B
Page 76 and 77: STRUCTURE FORMATION AND ITS CONSEQU
Page 78 and 79: when water content differences are
Page 80 and 81: authors stated that O 2 gradients i
Page 82 and 83: strength of the already existing st
Page 84 and 85: source of transforming DNA for Acin
Page 86 and 87: THE BIOCHEMISTRY OF THE RHIZOSPHERE
Page 88 and 89: der field conditions r-strategists
Page 90 and 91: 22. Tarafdar JC and Jungk A 1987. P
Page 92 and 93: ics behavior have been published (K
Page 94 and 95: Activity of dehydrogenase (DHA) was
Page 96 and 97: The rather small concentration of A
Page 98 and 99: The effect of the pesticide dosage
Page 100 and 101: METHANOTROPHIC ACTIVITY OF COAL MIN
Page 102 and 103: GC TESTS Air-tight bottles (60 ml)
Page 104 and 105: dumping. For older rock samples, af
Page 106 and 107: SOIL - PLANT - ATMOSPHERE AERATION
Page 108 and 109: - properties of plant surface and c
Page 110 and 111: mination, should be considered.The
Page 112 and 113: Considering a possibility of detect
Page 114 and 115: SURFACE PROPERTIES OF SOILS AND THE
Page 116 and 117: clay content the latter processes p
Page 118 and 119: der alkaline treatment the silica o
Page 120 and 121: COMPACTION EFFECTS ON SOIL PHYSICAL
Page 122 and 123: suming and expensive regression-bas
Page 126 and 127: CONCLUSIONS Alterations in the aggr
Page 128 and 129: 27. Keller, T., Arvidsson, J., Dawi
Page 130 and 131: MONITORING OF POROUS MEDIA PROCESSE
Page 132 and 133: - temperature: semiconductor, therm
Page 134 and 135: This is the reason why the optimisa
Page 136 and 137: CONCEPTS AND MORPHOLOGY OF HYDROMOR
Page 138 and 139: conditions applied to the soil samp
Page 140 and 141: ESTIMATION OF THE HYDROPHYSICAL CHA
Page 142 and 143: Fig. 6. Scheme of EURO-ACCESS-II mo
Page 144 and 145: The experimental field is located a
Page 146: Nannipieri Paolo Ostrowska Aneta Os
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