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Neira Pablo Henríquez-Castillo Carlos Ortiz Juan Stolpe Neal Dube Francis 《Agroforestry Systems》2021,95(8):1465-1478
Agroforestry Systems - Soil biota is considered a crucial component of soil health. Currently, the soil microbiota and its genomic material (microbiome) have received increasing attention due to... 相似文献
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J Stolpe 《Archiv fuer experimentelle veterinaermedizin》1977,31(5):681-688
High indoor temperatures in modern stables of livestock farming units have to be offset to avoid loss in animal performance, and this is possible only through improved heat emission of the organism. Increase in air movement, for the time being, is the most effective method. A theoretical account is given of the amount of air movement required in temperatures above optimum and compared with literature data. 相似文献
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Investigations of the performance of growing pigs in the live weight range of 30 to 60 kg kept individually and in groups with ad libitum and rationed feeding were carried out in two air-conditioned rooms. The air temperature in the individual experiments was 20 degrees C, 10 degrees C and 5 degrees C, the relative atmospheric moisture in all experiments was between 70 and 80%. A diminished growth of 24 g per day per degrees C below 20 degrees could be ascertained for pigs kept individually. The diminishing of the growth can be compensated by an increase of the feed intake of 1.3 g per kg live weight, day and degrees C resp. the intake of metabolisable energy of 4 kcal per kg live weight, day and degrees C until the capacity of feed consumption is reached. 相似文献
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Land-use changes can modify soil carbon contents. Depending on the rate of soil organic matter (SOM) formation and decomposition, soil-vegetation systems can be a source or sink of CO2. The objective of this study was to determine the influence of land-use change on SOM distribution, and microbial biomass and respiration in an Andisol of the Chilean Patagonia. Treatments consisted of degraded natural prairie (DNP), thinned and pruned Pinus ponderosa plantations (PPP), and unmanaged second-growth Nothofagus pumilio forest (NPF). The soil was classified as medial, amorphic, mesic Typic Hapludands. Soil microbial respiration and microbial biomass were determined in the laboratory from soil samples taken at 0–5, 5–10, 10–20 and 20–40 cm depths obtained from three pits excavated in each treatment. Physical fractionation of SOM was performed in soil of the upper 40 cm of each treatment to obtain the three following aggregate-size classes: macroaggregates (>212 μm), mesoaggregates (212–53 μm) and microaggregates (<53 μm). Plant C content was 68% higher in PPP than in DNP and 635% higher in NPF than in PPP. Total soil and vegetation C content in both DNP and PPP were less than half of that in NPF. Total SOC at 0–10 cm depth decreased in the order DNP (7.82%) > NPF (6.16%) > PPP (4.41%), showing that land-use practices affected significantly (P < 0.01) SOC stocks. In all treatments, microbial biomass C and respiration were significantly higher (P < 0.05) in the upper 5 cm. Soil microbial respiration was also correlated positively with microbial biomass C and SOC. The different land uses affect the formation of organic matter, SOC and microbial biomass C, which in turn will affect soil microbial respiration. Conversion of DNP to PPP resulted in a 44% decrease of SOC stocks in 0–10 cm mineral soil. The largest amount of SOC was stabilized within the mesoaggregate fraction of the less disturbed system, NPF, followed by PPP. In the long term, formation of stable mesoaggregates in soils protected from erosion can behave as C sinks. 相似文献
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Francis Dube Naresh V. Thevathasan Neal B. Stolpe Erick Zagal Andrew M. Gordon Miguel Espinosa Katia Sáez 《Agroforestry Systems》2013,87(3):525-542
This study was undertaken to measure certain carbon (C) fluxes in a Pinus ponderosa-based silvopastoral systems (SPS) in Patagonia, Chile. Results are compared to those from adjacent 18-year-old managed pine plantations (PPP) and natural prairie (PST). Litter decomposition was determined using the litterbag method. Leached soil solution was collected with tension lysimeters at 80 cm depth, and soil respiration evaluated in situ with the soda lime technique. Wind direction influenced the litterfall distribution in SPS, with 94 % falling in the tree strips and within 3 m on the east side. In the first 6 months the initial needle decomposition was low and less than 5 % of the initial mass. The overall soil organic carbon (SOC) and N contents (0–40 cm depth) decreased significantly in the order SPS > PST > PPP, and within SPS were greater in the alleys, starting at 2.5 m from the tree strip, with the highest values always eastward of the strip, suggesting influence by the wind direction. Total soil respiration decreased in the order PST > SPS > PPP and leached C decreased in the order PPP > PST > SPS. In general, the mean annual soil moisture in the pasture alleys of SPS was twice that of PST. The air/soil temperatures decreased significantly in the second year only in PST and at 2 m and beyond from the tree strip in SPS. Soil moisture varied significantly among treatments, but showed the strong influence exerted by trees in the creation of a favorable microclimate within the pasture alleys of SPS. 相似文献
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Marco A. Sandoval Neal B. Stolpe Erick M. Zagal María Mardones 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):255-262
Abstract The effects of six crop-pasture rotations were evaluated on properties of soil aggregates in a volcanic soil (Humic Haploxerand) of south-central Chile. Rotations that included intensive cropping without pastures, and crops with short- or long-term pastures were maintained for 12 years after which soil samples were taken at 0–5 and 5–10 cm depths for analysis of the C, N and S contents in the different grades of water-stable aggregates. The mean weight diameter of the aggregates was also determined as an indicator of structural stability. The results showed that the rotations which included long-term pastures of alfalfa (Medicago sativa L.) or white clover (Trifolium repens L.) had higher contents of C, N and S in soil and there was a higher concentration of these elements in macro-aggregates (>0.5 mm) than in micro-aggregates (<0.5 mm). Additionally, the rotations with pastures also produced greater structural stability of the soil aggregates. Consequently, crop rotations that included pastures, particularly those of longer duration, improved the soil and were therefore a more sustainable use of the soil resource compared to the more intensive rotations. Additionally, there was evidence of hierarchical organization of the soil structure, which is a previously non-described feature of volcanic soils. 相似文献