Papers by Markku Yli-Halla
Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes, Feb 23, 2020
Fluazinam, a widely used pesticide in conventional potato cultivation, is effective against epide... more Fluazinam, a widely used pesticide in conventional potato cultivation, is effective against epidemics of the fungal disease late blight. To assess fluazinam persistence in soil, laboratory experiments were conducted with fluazinam added to soil as a pure chemical or contained in the commercial product Shirlan ®. In a follow-up experiment, the persistence was monitored under constant temperature and water content conditions during a maximum period of 1 year. In an annual climatic rotation experiment, fluazinam added to soil was exposed to the yearround temperature and water content conditions occurring in the boreal zone. A third experiment was undertaken to clarify the effect of soil organic matter (SOM) on the recovery of fluazinam. In the follow-up and annual climatic rotation experiments, more than half of the added fluazinam was recovered after 1 year of incubation. The estimated half-life of fluazinam ranged between 355 and 833 days. The degradation of fluazinam was enhanced by an abundance of SOM, a warm temperature, and wetness. Additionally, in over half of soil
Springer eBooks, 2016
Fertilization should be based on a proper diagnosis of the plant nutritional status. Without, the... more Fertilization should be based on a proper diagnosis of the plant nutritional status. Without, there is always the risk of under fertilization causing economic losses by not exploiting the yield potential of the site and its crop. On the opposite, over fertilization not only hampers fertilizer economy through inefficient nutrient rates, but also causes serious environmental impacts on neighboring ecosystems. There are four basic diagnostic methods each of which has its advantages and disadvantages: ceteris paribus fertilizer trials are complicated and time consuming delivering results far too late for fertilization planning. Visual assessment is fast but requires experts eyes and works only for a few nutrients and only when severe nutrient deficiency occurs. Plant analysis is accurate, however, bound to well defined growth stages, but shows only the actual stage of supply with little information about available reserves in the soil or growth media and is also too late with its results for practical fertilization. Last but not least: analyzing the soil can be independent of crop development, well in advance to contribute for the fertilizer design for the actual crop and offers insight into the reserves in the substrate. However, its value for fertilization planning is strongly depending on the quality of the calibration of the results. Of all essential plant nutrients phosphorus is the one for which the most and intensive research work on assessing soils has been conducted in the past. This chapter introduces the basic conceptions of soil analysis for plant available P, provides an overview on available methods and discusses their advantages and disadvantages.
Science of The Total Environment, Feb 1, 2022
The off-site effects of agricultural organic soils include the leaching of N, P, and organic carb... more The off-site effects of agricultural organic soils include the leaching of N, P, and organic carbon (OC) to watercourses and CO2, CH4, and N2O emissions into the atmosphere. The aim of this study was to quantify how the thickness of organic layers affects these loads. A 19.56-ha experimental field drained by subsurface pipes was established in Ruukki, northwestern Finland. Three plots had a 60-80 cm-thick sedge peat layer and three others had a thickness of 20 cm or less. The drainage pipes lie in mineral soil that, in this field, contains sulfidic material. This study documents the experimental settings and reports on the leaching of substances in the first two years, as well as CO2, CH4 and N2O emissions during eight weeks in one summer. Total N (TN) and OC loads were higher from the thicker peat plots. The mean TN loads during a hydrological year were 15.4 and 9.2 kg ha-1 from the thicker and thinner peat plots, respectively, with organic N representing 36% of TN load. Total P (TP) load averaged 0.27 kg ha-1 yr-1. Dissolved P load represented 63 and 36% of TP in the thicker peat area and only 23 and 13% in the thinner peat area, and was thus increased upon peat thickness. These N and P loads through the subsurface drainage system represented roughly 83% of TN and 64% of TP loads from this field. There were no clear differences in greenhouse gas emissions among the plots during the eight-week monitoring period. Slowly oxidizing sulfide in the subsoil resulted in annual leaching of 147 kg S ha-1, almost ten times that of non-sulfidic soils. Our first results emphasize the effect of the peat thickness on the leaching of substances and warn about considering all organic soils as a single group in environmental assessments.
Verhandlungen, Dec 1, 1991
Water repellency (WR) delays soil wetting process, increases preferential flow and may give rise ... more Water repellency (WR) delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95) at the time of sampling. WR increased as follows: sand (R = 1.8-5.0) < clay (R = 2.4-10.3) < organic (R = 7.9-undefined). At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr.), where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.
1. If a profile had pH<3.5 in a layer at least 15 cm thick (irrespective of the redox state of su... more 1. If a profile had pH<3.5 in a layer at least 15 cm thick (irrespective of the redox state of subsoil), it is an acid sulphate soil.
Zeitschrift für Pflanzenernährung und Bodenkunde, Aug 1, 1996
The objective of this study was to investigate possible ways of mobilizing residual fertilizer P ... more The objective of this study was to investigate possible ways of mobilizing residual fertilizer P as a result of local pH elevation caused by urea hydrolysis. The response of water‐soluble P (Pw) and dissolved organic C (DOC) to urea hydrolysis was monitored in three cultivated soils and at two P levels for up to 127–135 d and compared with corresponding changes in soils limed with Ca(OH)2. Hydrolysis of urea was complete in 8–15d during which soil pH increased by 1–1.5 units at the maximum. Subsequently, the pH decreased to or below the original level owing to nitrification. Mobilization of soil P was enhanced substantially in parallel with the increase in pH, the peak Pw occurring simultaneously with the highest pH value. In all urea‐treated soils, Pw remained at an elevated level for at least 60d. As compared to urea, elevation of soil pH with Ca(OH)2 had only a minor and inconsistent influence on Pw. In mobilization of soil P, the urea‐induced increase in pH and a simultaneous production of NH4+ ions proved to be superior to liming with Ca(OH)2. It was hypothesized that when an acid soil is amended with urea, phosphate is first displaced by OH− ions, resulting in elevated solution P concentrations. A simultaneous dissolution of organic matter contributes to the persistence of high P concentration by competition for sorption sites on Fe and Al oxides, and thus retards the resorption of P.
EGU General Assembly Conference Abstracts, Apr 1, 2018
Sisältö: Kuuluu sessioon Interaction of soil, water and the atmosphere.vokmpymk
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Papers by Markku Yli-Halla