Browsing by Subject "soil fertility"

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  • Kuusipalo, Jussi (Suomen metsätieteellinen seura, 1985)
    The vegetation and some physical and chemical soil properties were studied in 410 sample plots in a random sample of stands by two-way indicator species analysis, discriminant analysis and analysis of variance. Understorey vegetation was dependent on site fertility and on the tree stand (especially species composition). Although the forest vegetation was distributed in a rather continuous way along a soil fertility gradient, relatively unambiguous site classification was possible based on the appearance of indicator species and species groups.
  • Starr, Michael; Westman, Carl Johan (Suomen metsätieteellinen seura, 1978)
  • Mälkönen, Eino (Suomen metsätieteellinen seura, 1976)
  • Bekele, Abdissa; Kibret, Kibebew; Bedadi, Bobe; Yli-Halla, Markku Juhani; Balemi, Tesfaye (2018)
  • Westman, Carl Johan (Suomen metsätieteellinen seura, 1981)
  • Melese, Asmare; Gebrekidan, Heluf; Yli-Halla, Markku; Yitaferu, Birru (2015)
    Soil acidity and low availability of P limit crop production in the highlands of Ethiopia. The objective of this study was to determine the P status, distribution and forms of inorganic P and relate them to selected chemical properties of eight representative acidic surface soil samples from Farta District. Soil pH (H2O) varied between 4.74 and 5.50. The moderate to high CEC suggests that besides kaolinite, the soils also contain expandable 2 : 1 clay minerals. Though the total P content was high, the available Olsen P content was very low or low in all soils except one. In most soils, the abundance of inorganic P fractions was as follows: P bound by oxalate extractable iron (-P) reductant soluble Fe-P occluded Al-Fe-P P bound by oxalate extractable aluminum (-P) calcium bound P (Ca-P). Olsen P had a very strong positive correlation () with -P (), -P (), and oxalate extractable P (). Though Fe bound P reserves were quite abundant and the degree of P saturation of + (median 3.3%) was moderate, the extremely low P saturation of (median 0.5%) explains the P deficiency of the soils.
  • Pohjanmies, Tähti; Genikova, Nadezhda; Hotanen, Juha-Pekka; Ilvesniemi, Hannu; Kryshen, Aleksandr; Moshnikov, Sergey; Oksanen, Jari; Salemaa, Maija; Tikhonova, Elena; Tonteri, Tiina; Merilä, Päivi (2021)
    Questions Forest classifications are tools used in research, monitoring, and management. In Finland, the Cajanderian forest site type classification is based on the composition of understorey vegetation with the assumption that it reflects in a predictable way the site's productive value. In Russia, the Sukachevian forest classification is similarly based on understorey vegetation but also accounts for tree species, soil wetness, and paludification. Here we ask whether Cajander's and Sukachev's forest types are effectively the same in terms of species composition, site productivity, and biodiversity. Location Boreal forests on mineral soils in Finland and the Russian part of Fennoscandia. Methods We use vegetation and soil survey data to compare the Cajanderian and the Sukachevian systems in terms of the understorey community composition (that is supposed to define them), soil fertility and tree productivity (that they are expected to indicate), and biodiversity (that is of interest for conservation purposes). We create and employ class prediction models to divide Russian and Finnish sites into Cajander's and Sukachev's types, respectively, based on vegetation composition. We perform cross-comparisons between the two systems by non-metric multidimensional scaling ordination and statistical tests. Results Within both systems, the site types formed similar, meaningful gradients in terms of the studied variables. Certain site types from the two systems were largely overlapping in community composition and arranged similarly along the fertility gradient and may thus be considered comparable. Conclusions The Cajanderian and the Sukachevian systems were both developed in the European boreal zone but differ in terms of the exact rules by which site types are determined. Our results show that analogous types between the systems can be identified. These findings aid in endeavours of technology and information transfer between Finnish and Russian forests for the purposes of basic or applied ecological research and forest management.
  • Soinne, Helena; Keskinen, Riikka; Räty, Mari; Kanerva, Sanna; Turtola, Eila; Kaseva, Janne; Nuutinen, Visa; Simojoki, Asko; Salo, Tapio (2021)
    To achieve appropriate yield levels, inherent nitrogen (N) supply and biological N fixation are often complemented by fertilization. To avoid economic losses and negative environmental impacts due to over-application of N fertilizer, estimation of the inherent N supply is critical. We aimed to identify the roles of soil texture and organic matter in N mineralization and yield levels attained in cereal cultivation with or without N fertilization in boreal mineral soils. First, the net N mineralization and soil respiration were measured by laboratory incubation with soil samples varying in clay and organic carbon (C) contents. Secondly, to estimate the inherent soil N supply under field conditions, both unfertilized and fertilized cereal yields were measured in fields on clay soils (clay 30-78%) and coarse-textured soils (clay 0-28%). In clay soils (C 2.5-9.0%), both the net N mineralization and the cereal yields (without and with fertilization) decreased with increasing clay/C ratio. Moreover, in soils with high clay/C ratio, the agronomic N use efficiency (additional yield per kg of fertilizer N) varied considerably, indicating the presence of growth limitations other than N. In coarse-textured soils, the yield increase attained by fertilization increased with increasing organic C. Our results indicate that for clay soils in a cool and humid climate, the higher the clay content, the more organic C is needed to produce reasonable yields and to ensure efficient use of added nutrients without high N losses to the environment. For coarse soils having a rather high mean organic C of 2.3%, the organic C appeared to improve agronomic N use efficiency. For farmers, simple indicators such as the clay/C ratio or the use of non-N-fertilized control plots may be useful for site-specific adjustment of the rates of N fertilization. Highlights We aimed to identify simple indicators of inherent soil N supply applicable at the farm level. In clay soils, the net N mineralization was found to correlate negatively with the clay/C ratio. In coarse-textured soils, agronomic N use efficiency improved with increasing soil organic C. Clay soils with high clay/C ratio are at risk of low yield levels.
  • Rousi, Matti; Possen, Boy; Ruotsalainen, Seppo; Silfver, Tarja Hannele; Mikola, Juha Tapio (2018)
    The acclimation capacity of leading edge tree populations is crucially important in a warming climate. Theoretical considerations suggest that adaptation through genetic change is needed, but this may be a slow process. Both positive and catastrophic outcomes have been predicted, while empirical studies have lagged behind theory development. Here we present results of a 30-year study of 55,000 Scots pine (Pinus sylvestris) trees, planted in 15 common gardens in three consecutive years near and beyond the present Scots pine tree line. Our results show that, contrary to earlier predictions, even long-distance transfers to the North can be successful when soil fertility is high. This suggests that present northern populations have a very high acclimation capacity. We also found that while temperature largely controls Scots pine growth, soil nutrient availability plays an important role-in concert with interpopulation genetic variation-in Scots pine survival and fitness in tree line conditions. These results suggest that rapid range expansions and substantial growth enhancements of Scots pine are possible in fertile sites as seed production and soil nutrient mineralization are both known to increase under a warming climate. Finally, as the ontogenetic pattern of tree mortality was highly site specific and unpredictable, our results emphasize the need for long-term field trials when searching for the factors that control fitness of trees in the variable edaphic and climatic conditions of the far North.
  • Amoah, Samuel (Helsingin yliopisto, 2019)
    Tiivistelmä/Referat – Abstract Biochars, made from biomass heated in limited oxygen, have been suggested as a sustainable means of increasing crop productivity. Two of the most commonly reported benefits of biochars are improved soil water availability and nutrient status, due of which also yield increases have been reported. Most studies so far have focused on subtropical soils that are low in initial carbon content, and cereals have been the main crops studied. There is also lack of knowledge of the effects of biochar in longer term than five years on the yield formation of grain legumes like peas. A long-term field experiment was conducted in Helsinki, Finland to investigate the effects of softwood biochar on the soil properties and on the yield formation of peas. Three levels of biochar rates were used: 0 ton/ha, 5 ton/ha and 10 ton/ha in conjunction with 3 NPK fertilizer levels of 30, 65, and 100 percent of the recommended levels. The addition of biochar was tied to slightly elevated levels of soil moisture at the upper soil layers (0 – 18 cm). This increase was however not significant (p > 0.05). Changes in biochar porosity over the years may have led to decreased water holding capacity of the soil and hence low moisture content. The soil nutrient status was also not significantly affected by biochar additions, except for sulphur levels which recorded a marginal significance of p < 0.1. Changes in biochar properties over time could also be responsible for the lack of effects on soil nutrients. The soil used was relatively fertile (3.5 % C), hence the effects of biochar were insignificant. Fertilizer effects were also not significant, except for significant levels of such nutrient as P, Ca, P and S. The lack of fertilizer effects could be due to the relatively fertile nature of the Luvic Stagnosol soil. The lack of effects of biochar on soil properties resulted in non-significant results for yield components of peas. The relatively dry weather during the growing season could also be responsible for the vast lack of significance recorded.