Compensatory Fertilization Research Articles

Mechanical weeding enhances ecosystem multifunctionality and profit in industrial oil palm

Oil palm is the most productive oil crop, but its high productivity is associated with conventional management (that is, high fertilization rates and herbicide application), causing deleterious environmental impacts. Using a 22 factorial experiment, we assessed the effects of conventional vs reduced (equal to nutrients removed by fruit harvest) fertilization rates and herbicide vs mechanical weeding on ecosystem functions, biodiversity and profitability. Analysing across multiple ecosystem functions, mechanical weeding exhibited higher multifunctionality than herbicide treatment, although this effect was concealed when evaluating only for individual functions. Biodiversity was also enhanced, driven by 33% more plant species under mechanical weeding. Compared with conventional management, reduced fertilization and mechanical weeding increased profit by 12% and relative gross margin by 11% due to reductions in material costs, while attaining similar yields. Mechanical weeding with reduced, compensatory fertilization in mature oil palm plantations is a tenable management option for enhancing ecosystem multifunctionality and biodiversity and increasing profit, providing win–win situations.

Cup-plant potential for biogas production compared to reference maize in relation to the balance needs of nutrients and some microelements for their cultivation

The study was focused on the assessment of cup-plant (Silphium perfoliatum L.) as a potential feedstock for biogas production in comparison to reference maize related to the balance needs of nutrients and some microelements for their cultivation, especially with use of digestate for fertilization. Field experiments were carried out in areas of the Czech Republic with less favorable conditions for the cultivation of maize. Obtained results confirmed that cup-plant can be considered a promising novel crop for biogas production due to high yields of biomass (12–18 t/ha DM) and methane (3600–4250 Nm3/ha) competing with reference maize grown under the same soil and climatic conditions. The biochemical analyses characterizing the feed value of phytomass were conclusively better with maize than cup-plant. This corresponds with specific methane yields, which is about 5–10% higher in maize (269–319 Nm3/t VS) than in cup-plant (254–298 Nm3/t VS). On the basis of chemical analyses of tested crops, the uptake of basic nutrients (N, P, K, Ca, Mg and S) and selected trace elements (microelements B, Fe, Mn, Co, Cu, Mo, Ni and Zn) was determined. Then, using the element contents and average yields, it was possible to calculate the annual removal of each element from the field with cup-plant and reference maize as the basis value for the evaluation of compensatory fertilization needs. With respect to the cultivation of tested crops for biogas production, the possibilities of their compensatory fertilization were evaluated using digestate from biogas plants. The uptake of different nutrients and microelements on tested crops was verified. The experiment showed that cup-plant has higher requirements on all tested nutrients, except N, and microelements, except Cu and Zn. In the case of nutrients, the highest uptake differences between cup-plant and maize were at B (about 11× higher), followed by Mg (3.5×) and K (1.8×). In the case of microelements, the highest uptake differences were B at (about 9× higher), followed by Co (5×), Fe, and Mn (2×). Therefore, increasing yields of cup-plant after using these nutrients and microelements for compensative fertilizing can be expected. For the mixture of maize and cup-plant (1:1 of VS weight), the higher specific methane yield was obtained (292 Nm3/t VS). It was more than expected of the average value (286 Nm3/t VS). It cannot be explained by the improvement in the feed value of cup-plant and maize mixture, but a possible explanation could be the positive synergistic effect of cup-plant due to the better supply with biologically active essential nutrients and microelements. In any case, this phenomenon deserves more detailed research in the future.

Nutrient and carbon budgets in forest soils as decision support in sustainable forest management

Knowledge about the nutrient and carbon budgets in forest soils is essential to maintain sustainable production, but also in several environmental issues, such as acidification, eutrophication and climate change. The budgets are strongly influenced by atmospheric deposition as well as forestry. This study demonstrates how budget calculations for nitrogen (N), carbon (C) and base cations (BC) can be used as a basis for policy decisions on a regional level in Sweden. The study was based on existing nutrient and C budget calculations on a regional scale in Sweden. The nutrient budgets have been calculated for each square in a national 5 km × 5 km net by means of mass balances including deposition, harvest losses, leaching, weathering (BC) and fixation (N). Scenarios with different deposition and forestry intensity have been run and illustrated on maps. A simplified C budget has been estimated by multiplying the N accumulation with the C/N ratio in the organic layer, based on the assumption that the C/N ratio in the accumulating organic matter is equal to the ratio in the soil organic matter pool. The budget approaches differ from earlier budget studies since they involve regional high resolution data, combine deposition and forestry scenarios and integrate different environmental aspects. The results indicate that whole-tree harvesting will cause net losses of N and base cations in large parts of Sweden, which means that forestry will not be sustainable unless nutrients are added through compensatory fertilization. To prevent net losses following whole-tree harvesting, compensatory fertilization of base cations would be required in almost the whole country, whereas N fertilization would be needed mainly in the northern half of Sweden. The results further suggest that today's recommendations for N fertilization should be revised in southern Sweden by applying the southwest–northeast gradient of the N budget calculations. The C and N accumulation calculations show that C sequestration in Swedish forest soils is not an effective or sustainable way to decrease the net carbon dioxide emissions. A better way is to apply whole-tree harvesting and use the branches, tops and needles as biofuel replacing fossil fuels. This could reduce the present carbon dioxide emissions from fossil fuels substantially. The study shows that high resolution budget calculations that illuminate different aspects of sustainability in forest ecosystems are important tools for identifying problem areas, investigating different alternatives through scenario analyses and developing new policies. Cooperation with stakeholders increases the probability that the research will be useful.

Soil biochemical activity and growth response of rice Oryza sativa in flyash amended soil

Since the German reunification in 1990, lignite production in the Lusatian mining district has significantly decreased as a result of substantial economic and structural changes. This development coincides with efforts by the government of the state of Brandenburg to enhance the production of biomass on set-aside arable and mining land for energy transformation purposes. In this context the goal is that a share of 3% of the primary energy consumption should come from biomass. As part of the on-going recultivation activities in the post-mining landscapes, short-rotation tree plantations as a special form of energy forests have recently come into focus. Thus, in 1995 a 2.5 ha short-rotation plantation was established on clayed-sandy, nutrient-poor substrates in the Lusatian mining area Welzow-Süd in order to study the ecological potential of fast-growing tree species under the prevailing site conditions. Even under unfavourable soil conditions with a low N and P supply, above-ground biomass production ranged from 2.5 to 11.7 tons dry matter per hectare. Three-year-old plants of fast growing tree species like poplar, willow, and aspen were marked by low mean N (5.3 mg g−1), Cl (113 μg g−1), Cd (0.8 μg−1) and Pb (0.5 μg g−1) contents. Therefore, this material is a most favourable biofuel. For the biomass accumulated within this 3-year period a calorific value of 30 000 MJ ha−1 a−1 has been calculated. The ash content of 2.4% allows this material to be used for amelioration purposes. This recycling approach guarantees balanced phosphorus, calcium, and magnesium supply. To maintain adequate site productivity only for nitrogen and potassium, a compensatory fertilization is required.

Recycling of solid wastes from coking

Since the German reunification in 1990, lignite production in the Lusatian mining district has significantly decreased as a result of substantial economic and structural changes. This development coincides with efforts by the government of the state of Brandenburg to enhance the production of biomass on set-aside arable and mining land for energy transformation purposes. In this context the goal is that a share of 3% of the primary energy consumption should come from biomass. As part of the on-going recultivation activities in the post-mining landscapes, short-rotation tree plantations as a special form of energy forests have recently come into focus. Thus, in 1995 a 2.5 ha short-rotation plantation was established on clayed-sandy, nutrient-poor substrates in the Lusatian mining area Welzow-Süd in order to study the ecological potential of fast-growing tree species under the prevailing site conditions. Even under unfavourable soil conditions with a low N and P supply, above-ground biomass production ranged from 2.5 to 11.7 tons dry matter per hectare. Three-year-old plants of fast growing tree species like poplar, willow, and aspen were marked by low mean N (5.3 mg g−1), Cl (113 μg g−1), Cd (0.8 μg−1) and Pb (0.5 μg g−1) contents. Therefore, this material is a most favourable biofuel. For the biomass accumulated within this 3-year period a calorific value of 30 000 MJ ha−1 a−1 has been calculated. The ash content of 2.4% allows this material to be used for amelioration purposes. This recycling approach guarantees balanced phosphorus, calcium, and magnesium supply. To maintain adequate site productivity only for nitrogen and potassium, a compensatory fertilization is required.

Effects of compensatory fertilization on pollution-induced stress in scots pine

We tested the hypothesis that compensatory fertilization of Scots pine (Pinus sylvestris L.) stands polluted by theHarjavalta copper-nickel smelter in SW Finland alleviates thestress imposed by metal-contaminated soils. The treatments inthe experiment consisted of control, liming, slow-release mineral mixture and stand-specific fertilization, which comprised at least methylene urea and ammonium nitrate. Stresswas assessed by needle fluctuating asymmetry (FA) which increases with an increase in developmental instability. Sevenyears after the treatments, we found pronounced variation inboth FA and needle length among study sites (0.5, 2, 4 and 8 km from the smelter) and among treatments. FA increased and needlelength decreased with proximity to the pollution source. Variation in FA was independent of tree size (used as index ofgrowth rate in even-age stand); the effects of the treatmentson needle length, on the other hand, were expressed only inmedium-sized and large trees. Liming best alleviated pollutionstress, while the application of a slow-release mineral mixtureincreased FA by 30%. In pollution-stressed stands FA correlatedpositively with constitutive resin flow but was independent of volume growth. Our findings suggest that physiological stress (indicated by increase in developmental instability) and tree growth or stand productivity are not directly linked to one another, and that some increase in productivity can be achievedwithout the alleviation of pollution-induced stress.

Production of biomass for energy in post-mining landscapes and nutrient dynamics

Since the German reunification in 1990 lignite production in the Lusatian mining region has significantly been decreased as a result of substantial economic and structural changes. This development coincides with efforts of the government of the state of Brandenburg to enhance the production of biomass for energy use on arable set-aside and post-mining land. In this context, the goal is to obtain a share of 3% of the primary energy consumption from biomass. As a part of the ongoing recultivation activities in the post-mining landscapes, short-rotation tree plantations as a special form of energy forests have recently come into focus. Thus, in 1995 a 2.5 ha short-rotation plantation was established on clayey–sandy, nutrient-poor substrates in the Lusatian mining area Welzow–Süd in order to study the yield potential of fast-growing tree species under the prevailing site conditions. Even under unfavourable soil conditions with a low N and P supply, above-ground biomass production after 4 years ranged from 5.3 to 19.6 tons dry matter (DM) per hectare. 4-year-old plants of fast-growing tree species like clones of poplar and willow and aspen progenies were marked by low mean N — ( 4.9 mg g −1 DM), Cl — ( 113 μg g −1 DM), Cd — ( 0.8 μg g −1 DM) and Pb — ( 0.5 μg g −1 DM) concentrations and a high ash softening temperature point of about 1680°C. For the biomass accumulated within this 4 year period, a calorific value of 42.000 MJ ha −1 a −1 has been calculated. The ash content of 2.4% allows this material to be used for amelioration purposes. This recycling approach guarantees balanced phosphorus, potassium, calcium and magnesium supply. To maintain adequate site productivity only for nitrogen a compensatory fertilization is required.

Production of bioenergy in post-mining landscapes in Lusatia: Perspectives and challenges for alternative landuse systems

Since the German reunification in 1990, lignite production in the Lusatian mining district has significantly decreased as a result of substantial economic and structural changes. This development coincides with efforts by the government of the state of Brandenburg to enhance the production of biomass on set-aside arable and mining land for energy transformation purposes. In this context the goal is that a share of 3% of the primary energy consumption should come from biomass. As part of the on-going recultivation activities in the post-mining landscapes, short-rotation tree plantations as a special form of energy forests have recently come into focus. Thus, in 1995 a 2.5 ha short-rotation plantation was established on clayed-sandy, nutrient-poor substrates in the Lusatian mining area Welzow-Süd in order to study the ecological potential of fast-growing tree species under the prevailing site conditions. Even under unfavourable soil conditions with a low N and P supply, above-ground biomass production ranged from 2.5 to 11.7 tons dry matter per hectare. Three-year-old plants of fast growing tree species like poplar, willow, and aspen were marked by low mean N (5.3 mg g −1), Cl (113 μg g −1), Cd (0.8 μg −1) and Pb (0.5 μg g −1) contents. Therefore, this material is a most favourable biofuel. For the biomass accumulated within this 3-year period a calorific value of 30 000 MJ ha −1 a −1 has been calculated. The ash content of 2.4% allows this material to be used for amelioration purposes. This recycling approach guarantees balanced phosphorus, calcium, and magnesium supply. To maintain adequate site productivity only for nitrogen and potassium, a compensatory fertilization is required.

Impact of whole-tree harvesting and compensatory fertilization on growth of coniferous thinning stands

A series of 16 field experiments was established to quantify the growth response of first-thinning stands of Pinus sylvestris and Picea abies to whole-tree harvesting (WTH), and to estimate the need for nutrient compensation. The experiments were undertaken in Finland, Norway and Sweden and represent a wide range of climatic and soil conditions. The biomass and nutrient amounts removed were estimated on the basis of felled sample trees. On average, WTH reduced tree volume growth in both pine and spruce stands (5% and 6%, respectively) during the first 10-year period. The growth reduction was counteracted by fertilization (NPK) and the results indicate that the reduction was an effect of reduced N supply. The inclusion of various site descriptive variables in the linear models did not explain variation in growth response to WTH. Since the growth reductions due to WTH after 10 years were still present, the observation period needs to be extended.

Response of Compensatory-Fertilized Pinus sylvestris to Infection by Heterobasidion annosum

The effects of compensatory fertilization on the infection and growth rate of Heterobasidion annosum were studied in a 40-yr-old, naturally regenerated Scots pine (Pinus sylvestris L.) stand in south-eastern Finland. The treatments were: (1) unfertilized control, (2) a compound fertilizer containing P, K, Ca, Mg, S, Cu, Zn and B, (3) as treatment 2 but with nitrogen, (4) as treatment 3 but with limestone, (5) a mixture of nitrogen and limestone composed on the basis of needle analysis, and (6) wood ash. Pine roots were inoculated on two occasions four and five growing seasons after fertilization using four different strains of the P type of H. annosum. Two years after inoculation, the fungus was alive in 28.9% of the 135 inoculated roots. Fungus survival was highest in the control trees (50%) and poorest in the treatments 2 and 3 (10.5% and 16.7%, respectively). These two treatments differed significantly from the control. Total mycelial extension during the 2-yr study period was 16.4, 2.1, 4.5, 18.1, 15.2 and 5.3 cm in treatments 1, 2, 3, 4, 5 and 6, respectively. Only treatment 2 differed significantly from the control (p<0.05, df=23). The result suggests that the application of slow-release compound fertilizers without supplementary limestone may increase the resistance of Scots pine to infection by H. annosum. The nitrogen-free compound fertilizer may also retard the spread of annosum root rot in infected pine stands.

Effects of biomass removal in thinnings and compensatory fertilization on exchangeable base cation pools in acid forest soils

The effects of whole-tree harvesting and fertilization at first thinning on the exchangeable pools of base cations in the soil were examined on four sites five years after thinning. One site with Norway spruce ( Picea abies (L.) Karst.) is located in southwestern Sweden and three other sites with Scots pine ( Pinus sylvestris L.) are located in southeastern, south-central and northern Sweden. On all sites, the stands were thinned, and the following treatments were applied in a randomized block design ( n = 3): (i) stem-only harvest, logging residues left on site; (ii) whole-tree harvesting; (iii) whole-tree harvesting combined with compensatory fertilization (N–P–K were applied one year after thinning in the form of inorganic fertilizers, and the amounts were equal to the nutrient content of the harvested logging residues); (iv) stem-only harvesting in combination with N (pine sites) or NP (spruce site) fertilization (ammonium nitrate, 150 kg N ha −1, superphosphate, 30 kg P ha −1) and (v) whole-tree harvesting and nitrogen fertilization as in treatment (iv). There were no general treatment effects revealed from analysis across all sites. Effects of harvesting intensity were detected on two sites, indicating reduced pools of exchangeable K, Mg and Ca after whole-tree harvesting. The reductions were less pronounced than the effects observed in other studies from experiments with whole-tree harvesting at clear-felling of mature forests. Effects of application of nitrogen alone were more frequently observed than effects of harvesting of logging residues. In most cases, base cation pools were lower after N treatment than after other treatments, and this effect was probably due to exchange and translocation phenomena. However, Ca pools had increased after NP treatment on the spruce site due to high content of Ca in P fertilizer. No effect of compensatory fertilization with N–P–K was detected. A comparison between exchangeable nutrient pools before thinning and five years after indicated that K was generally lost from the soil profile.

Compensatory fertilization of Scots pine stands polluted by heavy metals

The results from four compensatory fertilization experiments located at different distances (0.5, 2, 4 and 8 km) along a heavy metal deposition gradient extending from the Harjavalta Cu-Ni smelter in SW Finland are presented. The experiments were established in middle-age Scots pine stands growing on dryish sites of sorted glaciofluvial sediments. The soil type in all the experiments is ferric podsol. The treatments in the experiments consisted of liming, a powdered slow-release mineral mixture and stand-specific fertilization which comprised at least methylene urea and ammonium nitrate.

Nutritional status of a Norway spruce stand in SW Sweden in response to compensatory fertilization

The response of a Norway spruce (Picea abies L. Karst.) forest, located in SW Sweden, to various combinations of nitrogen, phosphorus, potassium and dolomite was investigated two and five years after fertilization in a semi-factorial experiment. The aim has been to apply a diagnostic field test as a base for development of suitable composition of compensatory or vitality fertilizers within an area showing nutritional imbalances. Different ways of describing foliar analysis were tested: current needle (C) critical concentrations, Deviation from Optimum Percentage (DOP), and nutrient/N percentage ratios. The graphical Relative Concentration and Content change (RCC) technique was also used. Nutritional status of the control plots showed deficiency in N, P and K. According to the analyses, N alone or N together with P are the growth-limiting elements. Fertilization with N alone induced limitation of K or P. Based on our results, NPK is a suitable compensatory fertilizer at the site. The only significant difference between dolomite and non-dolomite treatments was in Ca and Mg concentrations. The effect of dolomite on Ca and Mg became more evident during the fifth season following fertilization.

Growth response of coniferous stands to whole‐tree harvesting in early thinnings

A series of 15 field experiments was established to quantify the growth response of first‐thinning stands of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst) to whole‐tree harvesting and to estimate the need for nutrient compensation. The experiments were undertaken in Finland, Norway and Sweden and represent a wide range of site conditions. The site index (H 100) of Scots pine stands varied from 19 to 29 m, and that of Norway spruce stands from 28 to 36 m. Total amounts of biomass and nutrients removed were calculated based on data obtained from felled sample trees. During the first 5‐yr period the growth response to the removal of logging residues varied considerably in both pine and spruce stands. Regression analyses did not reveal any functions that explained the variation in results satisfactorily. In cases where whole‐tree harvesting influenced tree growth negatively, this effect was counteracted by compensatory fertilization. It was concluded that to determine the respons...