scholarly journals Site Preparation Effects on 20 Year Survival and Growth of Douglas-Fir (Pseudotsuga menziesii) and on Selected Soil Properties

2003 ◽  
Vol 18 (1) ◽  
pp. 44-51 ◽  
Author(s):  
C.A. Harrington ◽  
K.B. Piatek ◽  
D.S. DeBell

Abstract Long-term effects of site preparation on tree performance and soil properties are not well known. Five site preparation treatments were evaluated to determine how they affected survival and growth of Douglas-fir 3, 10, and 20 yr after planting, and soil bulk density, C, N, P, and organic matter concentrations at 0 to 20 cm soil depth 21 yr after planting. The site preparation treatments were imposed following logging of three harvest units of old-growth forest on a volcanic soil in southwestern Washington; the units were logged to leave 17, 38, and 53 ton/ha of woody residue. The site preparation treatments were hand-pile-and-burn, machine-pile-and-burn, scarification, broadcast burn, and control. Mean survival ranged from 86% at age 3 to 70% at age 20, and average tree heights at 3, 10, and 20 yr were 0.6, 4.1, and 11.7 m. The scarification treatment had the best growth; at age 20, its average tree was 21% taller, 26% larger in diameter, and 82% greater in volume than the control. The hand-pile-and-burn treatment did not differ from the control in tree growth; the machine-pile-and-burn and broadcast burn treatments were intermediate in their growth response. Average soil bulk density was 0.74 g/cm3, organic matter concentration was 118 g/kg, and C, N, and P concentrations were 49, 1.6, and 0.7 g/kg with no significant treatment effects. Site preparation may have benefited growth of the trees on these units by decreasing competition from invading and regrowing vegetation, increasing nutrient availability, or increasing soil temperature. West. J. Appl. For. 18(1):44–51.

2012 ◽  
Vol 88 (03) ◽  
pp. 306-316 ◽  
Author(s):  
Richard Kabzems

Declines in forest productivity have been linked to losses of organic matter and soil porosity. To assess how removal of organic matter and soil compaction affect short-term ecosystem dynamics, pre-treatment and year 1, 5 and 10 post-treatment soil properties and post-treatment plant community responses were examined in a boreal trembling aspen (Populus tremuloidesMichx.)-dominated ecosystem in northeastern British Columbia. The experiment used a completely randomized design with three levels of organic matter removal (tree stems only; stems and slash; stems, slash and forest floor) and three levels of soil compaction (none, intermediate [2-cm impression], heavy [5-cm impression]). Removal of the forest floor initially stimulated aspen regeneration and significantly reduced height growth of aspen (198 cm compared to 472–480 cm) as well as white spruce (Picea glauca [Moench] Voss) height (82 cm compared to 154–156 cm). The compaction treatments had no effect on aspen regeneration density. At Year 10, heights of both aspen and white spruce were negatively correlated with upper mineral soil bulk density and were lowest on forest floor + whole tree removal treatments. Recovery of soil properties was occurring in the 0 cm to 2 cm layer of mineral soil. Bulk density values for the 0 cm to 10 cm depth remained above 86% of the maximum bulk density for the site, a soil condition where reduced tree growth can be expected.


1995 ◽  
Vol 35 (8) ◽  
pp. 1151 ◽  
Author(s):  
A Costantini ◽  
MR Nester ◽  
M Podberscek

In south-eastern Queensland, Australia, standard site preparation practices used for Pinus plantation establishment are mounding (bedding) on poorly drained soils and blade cultivation (subsurface, wing rip) on well-drained soils. This paper reports the impacts of both site preparation treatments on soil bulk density over time. Following site preparation, the extent of bulk density reduction and the nature of bulk density consolidation was affected by soil type, soil depth and the site preparation technique used. On high strength, hardsetting soils, bulk density reductions from both mounding and blade cultivation persisted throughout the 28-month period, and contrasted with non-hardsetting soils in the plantation estate, which consolidated more rapidly and had higher bulk densities relative to precultivation levels for the period 4-28 months following site preparation. The studies reported in this paper were the first in south-eastern Queensland to investigate the impact of site preparation for Pinus establishment on the nature and longevity of bulk density reductions. Previously, plantation managers assumed that positive site preparation impacts would be relatively short-lived, and therefore developed a prudential policy of planting Pinus seedlings immediately following site preparation. For the soils studied, delays of 2-4 months, and perhaps up to 6 months, between site preparation and planting would not compromise Pinus growth, but would assist management planning.


Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 351
Author(s):  
Aiguo Duan ◽  
Jie Lei ◽  
Xiaoyan Hu ◽  
Jianguo Zhang ◽  
Hailun Du ◽  
...  

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) is a fast-growing evergreen conifer with high-quality timber and is an important reforestation and commercial tree species in southern China. Planting density affects the productivity of Chinese fir plantations. To study the effect of five different planting densities and soil depth on soil nutrient contents of a mature C. lanceolata plantation, the soil nutrient contents (soil depths 0–100 cm) of 36-year-old mature Chinese fir plantations under five different planting densities denoted A (1667 trees·ha−1), B (3333 trees·ha−1), C (5000 trees·ha−1), D (6667 trees·ha−1), and E (10,000 trees·ha−1) were measured in Pingxiang county, Guangxi province, China. Samples were collected from the soil surface down to a one meter depth from each of 45 soil profiles, and soil samples were obtained at 10 different soil depths of 0–10, 10–20, 20–30, 30–40, 40–50, 50–60, 60–70, 70–80, 80–90, and 90–100 cm. Twelve soil physical and chemical indicators were analyzed. The results showed that: (1) as planting density increased, the organic matter, organic carbon, total N and P, available N, effective Fe, and bulk density decreased. Soil pH, total K, and effective K increased with increasing planting density. Planting density did not significantly influence the exchangeable Ca and Mg. (2) Soil organic matter; organic carbon; total N and P; effective N, P, and K; exchangeable Ca and Mg; effective Fe content; and bulk density decreased with increasing soil depth. This pattern was particularly evident in the top 30 cm of the soil. (3) Excessively high planting density is not beneficial to the long-term maintenance of soil fertility in Chinese fir plantations, and the planting density of Chinese fir plantations should be maintained below 3333 stems·ha−1 (density A or B) to maintain soil fertility while ensuring high yields.


Geosciences ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 117 ◽  
Author(s):  
Ahmed Abed Gatea Alshammary ◽  
Abbas Z. Kouzani ◽  
Akif Kaynak ◽  
Sui Yang Khoo ◽  
Michael Norton ◽  
...  

The estimation of soil wet bulk density (ρn) and dry bulk density (ρb) using the novel digital electromechanical system (DES) has provided information about important parameters for the assessment of soil quality and health with a direct application for agronomists. The evaluation of the DES performance is particularly appropriate for different tillage methods, mulching systems, and fertilizers used to increase soil fertility and productivity, but currently, there is a lack of information, particularly in the arid areas in underdeveloped countries. Therefore, the main aim of this study was the application of a novel digital electromechanical system (DES) to evaluate bulk density, wet (ρn) and dry (ρb), under different soil treatments according to the variations in thermal efficiencies (ηth), microwave penetration depths (MDP), and specific energy consumption (Qcon) in an experimental area close to Baghdad (Iraq). The experimental design consisted of 72 plots, each 4 m2. The agronomic practices included two different tillage systems (disc plough followed by a spring disk and mouldboard plough followed by a spring disk) and twelve treatments involving mulching plastic sheeting combined with fertilizers, to determine their effect on the measured soil ρn and ρb and the DES performance in different soils. The results indicated that soil ρn and ρb varied significantly with both the tillage systems and the mulching systems. As expected, the soil ρn and ρb, MDP, and Qcon increased with an increase in the soil depth. Moreover, the tillage, soil mulching, and soil depth value significantly affected ηth and Qcon. A strong relationship was identified between the soil tillage and MDP for different soil treatments, leading to the changes in soil ρb and the soil dielectric constant (ε’).


2012 ◽  
Vol 92 (4) ◽  
pp. 685-693 ◽  
Author(s):  
C. R. W. Evans ◽  
M. Krzic ◽  
K. Broersma ◽  
D. J. Thompson

Evans, C. R. W., Krzic, M., Broersma, K. and Thompson, D. J. 2012. Long-term grazing effects on grassland soil properties in southern British Columbia. Can. J. Soil Sci. 92: 685–693. Although grazing effects on soil properties have been evaluated on various temperate grasslands, no study has dealt with these effects in the southern interior of British Columbia. The objective of this study was to determine the effects of spring versus fall season grazing as well as grazing [at a moderate rate of 0.6 animal unit months (AUM) ha−1] versus non-grazing by beef cattle on selected soil properties. Effects were determined 20 and 30 yr after the establishment of the field experiment. Soil properties were determined for the 0- to 7.5-cm, 7.5- to 15-cm, and 15- to 30-cm depths. In comparison with fall grazing, spring grazing had greater soil bulk density, greater mechanical resistance within the top 15 cm of the soil profile, higher pH, and lower polysaccharides. This was true for both 20 and 30 yr of treatment. Grazing effects on aggregate stability were observed only after 30 yr with spring grazing leading to a more stable structure with a mean weight diameter (MWD) of 1.5 mm and 32% and 10% of aggregates in the 2- to 6-mm and 1- to 2-mm size fractions, respectively, compared with a MWD of 1.0 mm and 20% and 6% under fall grazing. Greater soil bulk density, mechanical resistance, and pH were observed under the grazed treatment relative to the control without grazing, but as we used a moderate stocking rate the impacts were not as great as in previous studies, which used heavy stocking rates. Our findings show that long-term grazing at a moderate stocking rate of 0.6 AUM ha−1did not have critical detrimental effects on soil properties as some land managers and ranchers have suggested.


Soil Research ◽  
2009 ◽  
Vol 47 (4) ◽  
pp. 362 ◽  
Author(s):  
Xirui Zhang ◽  
Hongwen Li ◽  
Jin He ◽  
Qingjie Wang ◽  
Mohammad H. Golabi

Conservation tillage is becoming increasingly attractive to farmers because it involves lower production costs than does conventional tillage. The long-term effects of sub-soiling tillage (ST), no tillage (NT), and conventional tillage (CT) on soil properties and crop yields were investigated over an 8-year period (2000–07). The study was conducted in a 2-crop-a-year region (Daxing) and a 1-crop-a-year region (Changping) of the Beijing area in China. At 0–0.30 m soil depth, water stability of macro-aggregates (>0.25 mm) was much greater for ST (22.1%) and NT (12.0%) than for CT in Daxing, and the improvements in Changping were 18.9% and 9.5%, respectively. ST and NT significantly (P < 0.05) improved aeration porosity by 14.5% and 10.6%, respectively, at Daxing and by 17.0% and 8.6% at Changping compared with CT treatment. Soil bulk density after 8 years was 0.8–1.5% lower in ST and NT treatments than in CT at both sites. Soil organic matter and available N and P followed the same order ST ≈ NT > CT at both sites. Consequently, crop yields in ST and NT plots were higher than in CT plots due to improved soil physical and chemical properties. Within the conservation tillage treatments, despite similar economic benefit, the effects on crop yields for ST were better than for NT. Mean (2000–07) crop yields for ST were 0.2% and 1.5% higher than for NT at Daxing and Changping, respectively. We therefore conclude that ST is the most suitable conservation tillage practice for annual 2-crop-a-year and 1-crop-a-year regions in the Beijing area.


2017 ◽  
Vol 39 (4) ◽  
pp. 363 ◽  
Author(s):  
Nallely A. Carbajal-Morón ◽  
Mario G. Manzano ◽  
Ricardo Mata-González

Shrubland ecosystems are less studied than grasslands regarding the role of domestic grazing on ecosystem degradation in the world, but particularly in Mexico. Of special concern is the paucity of research on soil hydrological responses to the impact of livestock. Here, we assessed the role that specific soil and surface characteristics play in soil hydrology as a response to goat grazing intensity in two different soil types, Regosol and Vertisol, in the Tamaulipan thornscrub of north-eastern Mexico. At each soil unit, a set of grazing regimes was identified, including heavy grazing (HG), moderate grazing (MG) and a no-grazing (NG) reference area, and selected soil properties and plant cover were evaluated. In Regosol sites, soil organic matter varied among all grazing regimes (4.6% higher on NG and 2.1% higher on MG with respect HG) and no dissimilarities on bulk density were recorded. For Vertisol sites, soil bulk density increased with grazing intensity (16% higher on MG and 37% higher on HG with respect to NG) whereas plant cover linearly decreased from 86% in NG to 29% in MG and 9% in HG sites. Soil organic matter content for Regosol, and plant cover and soil bulk density for Vertisol appeared as the best indicators of water infiltration and moisture retention for the grazing conditions assessed. Differences in those key driving variables may help explain surface hydrology responses to goat grazing in rangeland soils of Tamaulipan thornscrub ecosystems and possibly on similar rangelands around the world. Clear signs of vegetation degradation were also observed, manifested by a loss in species diversity and plant cover, especially under heavy grazing. This reflects unsustainable livestock management practices that should be avoided. This study contributes to improve our understanding of rangeland degradation processes and justifies devising more sustainable grazing management schemes.


1999 ◽  
Vol 79 (3) ◽  
pp. 501-504 ◽  
Author(s):  
B. J. Zebarth ◽  
G. H. Neilsen ◽  
E. Hogue ◽  
D. Neilsen

Sandy, infertile soils can benefit from the addition of organic waste amendments. Annual applications of organic wastes for as long as 4 yr increased soil organic matter content, decreased soil bulk density, and increased soil water retention of a coarse-textured soil. However, soil water-holding capacity was not necessarily increased, and there was a limited effect on soil cation exchange capacity. Key words: Cation exchange capacity, water retention, soil pH, soil organic matter, soil bulk density


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