Paludiculture Crops And Nitrogen Kick-Start Ecosystem Service Provisioning In Rewetted Peat Soils

PurposePaludiculture (crop cultivation in wet peatlands) can prevent carbon and nutrient losses while enabling biomass production. As vegetation in rewetted peatlands is often nitrogen (N) limited, input of N rich water may promote biomass production and nutrient removal. However, it is unclear how N loading and soil characteristics affect biomass yield, nutrient dynamics, and ecosystem service provisioning in paludicultures. MethodsWe studied the influence of N loading (0, 50, 150, and 450 kg N ha-1 yr-1) on biomass production and nutrient sequestration of Typha latifolia (broadleaf cattail) and Phragmites australis (common reed) on a limed agricultural peat soil after rewetting. To assess the interaction with soil characteristics T. latifolia was also grown on a non-limed former agricultural soil.ResultsN loading stimulated biomass production and nutrient uptake of both T. latifolia and P. australis, with T. latifolia showing the most pronounced response. Biomass yield of T. latifolia was higher in the limed soil than in the non-limed soil due to a higher pH, despite lower nutrient availability. N was largely taken up by the vegetation, whereas bare soils showed N accumulation in pore and surface water, and 80% loss through denitrification. Phosphorus in the soil was efficiently taken up by T. latifolia, especially at high N loads.ConclusionN loading in paludicultures with T. latifolia and P. australis boosts biomass production while kick-starting peatland ecosystem services including nutrient removal. Nutrient availability and pH appear to be decisive soil characteristics when it comes to crop selection.

Interactions between liming and availability of C and P regulate nitrogen transformations and denitrifying potential in an acidic arable soil

<p>Liming to increase pH of acidic soils is a common agricultural practice to optimize crop yields, which also modulates greenhouse gas emissions from soils. In particular, soil pH has been identified as a primary regulator of denitrification pathways with enhanced ratio of nitrous oxide (N<sub>2</sub>O) to dinitrogen (N<sub>2</sub>) emissions (i.e., enhanced N<sub>2</sub>O/N<sub>2</sub> ratio) at lower soil pH. Therefore liming could represent a potential management option to mitigate soil N<sub>2</sub>O emissions. However, changes in soil pH have pervasive effects on general microbial activity and on soil properties, including transformations of carbon (C) and bioavailability of phosphorus (P), with a feedback on microbial processes. Thus, the eventual net effects of liming on microbially derived N<sub>2</sub>O emissions may be complex. The aim of this study was to discern the interaction between liming (soil pH), and availability of C and P in regulating N<sub>2</sub>O emissions from acidic fertilized agroecosystems. Using coarse sandy soils from a long-term liming field experiment, N<sub>2</sub>O/N<sub>2</sub> ratios from denitrifying enzyme activity was shown to be strongly affected by liming, i.e., with gradually decreasing ratios at increasing soil pH. Although liming acidic soil (pH, 3.6) to almost neutral (pH, 6.4) favored the reduction of N<sub>2</sub>O to N<sub>2</sub>, it also enhanced the overall denitrification rate, which eventually resulted in the highest N<sub>2</sub>O emission from moderately limed treatments (pH, 4.7). Interactions between P availability and denitrification (and N<sub>2</sub>O emission) occurred, where P addition generally increased cumulative N<sub>2</sub>O emissions with strongest effect at the moderately limed soil. Mechanistic hypotheses for this effect are discussed. Overall, our results suggest that a critical liming rate should be pursued which may lead to substantial mitigation of N<sub>2</sub>O emissions from acidic arable soil.</p>

Effect of liming and fertilizer application on the changes in available K status of an acid soil

Irrespective of treatments, available K decreased in limed over that of un-limed soil. In general, available K progressively increased in both un-limed and half limed soils up to 60 day period of incubation but thereafter showed a decreasing trend on 90th day of the experiment. However, full limed soil showed a different trend of results. Available K increased up to 30th day, thereafter decreased on 60th day then again increased on 90th day of the experiment. The results thus revealed that available K is not retained in the soil for longer period rather it is converted to other forms at the later stage of the experiment.

Comparison of the effect of various long-term fertilization systems on the content and fractional composition of humic compounds in Lessive soil

A field experiment was established in 1972 on Luvisol. Three types of fertilizers – cattle manure (CM), cattle slurry (CS) and mineral fertilizers were used. CS was applied in the following doses: I – balanced with CM in terms of the amount of introduced total nitrogen and II – balanced with CM in terms of the amount of introduced total organic carbon (C_tot). 39 years after the experiment was established, half of each experimental plot was limed and since then the experiment was carried in two series – non-limed and limed soils. The paper presents the results of soil analyses 41 years after the experiment was started. It was found that each fertilization system increased the C_tot content in soil in relation to the unfertilized control plot. The increase of C_tot fluctuated between 0.35–6.22 g/kg of dry matter. In both series, the highest C_tot content was observed in the soil fertilized with CM and CM + PK. Limed compared to non-limed soil contained nearly 25% more carbon of humic acids than fulvic acids and nearly 20% lower content of low molecular humic bonds. Liming considerably widened the humic acids carbon:fulvic acids carbon (C_HA:C_FA) ratio of the fertilized soils, up to 1.32–1.87, while the corresponding objects of the non-limed series showed the C_HA:C_FA ratio between 0.75–0.97.

The effect of over 50 years of liming on soil aluminium forms in a Retisol

The aim of the current study was to evaluate the effect of long-term (56 years) liming on changes in soil pH and aluminium (Al) forms in the soil profile compared with an unlimed soil in a sandy moraine loam of a Dystric Glossic Retisol. Long-term liming had a significant influence on soil acidity of the whole profile, causing increased pH values in the following horizons to 120 cm depth: the ploughing horizon (Ahp), where humus accumulates; the eluvial horizon (E), from which clay particles are leached; a horizon having retic properties and predominantly coarser-textured albic material (E/B); and a horizon with retic properties and predominantly finer-textured argic material (B/E). In the solid phase, non-crystalline Al in limed soil decreased in the Ahp horizon; meanwhile a decrease in total organically bound Al (Alp) and organo–Al complexes of low to medium stability was detected in the deeper El and ElBt horizons. High-stability Al complexes with organic matter were the predominant form of Alp in the unlimed and limed whole soil profile. The concentration of total water-soluble Al ranged from 0.61 to 0.80 mg/l in the limed soil profile but 0.62–1.15 mg/l in the unlimed soil. The highest concentration of exchangeable Al was determined in the upper horizons of the unlimed soil profile and the concentration decreased significantly in the same horizons of the limed soil profile. Long-term liming promoted changes in Al compounds throughout the soil profile.

Role of arbuscular mycorrhizal symbiosis in phosphorus-uptake efficiency and aluminium tolerance in barley growing in acid soils

Arbuscular mycorrhizal fungi (AMF) play an important role in protecting plant growth against such stresses as phytotoxic aluminium (Al) in soil. To understand some of the AMF interactions that relate to amelioration of Al phytotoxicity and phosphorus (P)-uptake efficiency in barley (Hordeum vulgare L.), this study examined the effect of soil Al levels and mycorrhizal symbiosis on plant response, including root colonisation, AMF propagules and glomalin production. A greenhouse experiment was conducted using two native barley cultivars, Sebastián and Aurora, grown in an acidic soil at two Al-saturation levels (80% Al-sat, unlimed soil; 7% Al-sat, limed soil) with and without AMF propagules. Root dry weight, total and colonised root lengths, and root P and Al contents were determined at 60 and 150 days after sowing. AMF spore density, total hyphal length, glomalin-related soil protein (GRSP) and Al bound to GRSP (Al-GRSP) were analysed at final harvest. AM root colonisation was not inhibited in limed soil, mycorrhizal propagule numbers increased at high Al levels, and Al-GRSP ranged from 5.6% to 8.3% of the total GRSP weight. These values also increased in unlimed soil, particularly those associated with cv. Aurora. Root Al concentration correlated inversely with AMF spores (r = –0.85, P < 0.001) and Al-GRSP (r = –0.72, P < 0.01), but only in plants growing in limed soil. Conversely, the AMF treatments in which Al was present showed a greater relationship between total root length and both root Al (r = –0.72, P < 0.01) and root P (r = 0.66, P < 0.01) concentrations. Sebastián showed a greater response to lime, whereas Aurora responded better to mycorrhizal presence. The relative growth rate of roots, P uptake efficiency and mycorrhizal parameters such as root colonisation, spores, hyphae and GRSP showed Aurora to be more Al-tolerant than Sebastián. In conclusion, the greater rate of increase of AM propagules, GRSP and Al-GRSP associated with cv. Aurora supports the hypothesis that AMF play an important role in the Al-tolerance capacity and P-uptake efficiency of H. vulgare growing in soils with high Al levels.

Lime and organic manure effect on acid]clay soil, Okra growth and yield parameters

Two potted experiments were conducted at the screen]house of the Department of Crop, Soil and Pest Management of the Federal University of Technology, Akure to investigate the effects of lime and different levels of organicmanure amendment on acid]clay soil, Okra growth and yield parameters.The first experiment consisted of six treatments and a control; choppedTithonia diversifolia leaves were applied on limed soil (100g lime kg]1 Soil) at0g, 6.75g, 13.5g, 20.25g, 27.0g and 33.75g kg]1 Soil. The second experimentalso consisted of six treatments and a control; poultry manure was appliedon limed soil (100g lime kg]1 Soil) at 0g, 6.75g, 13.5g, 20.25g, 27.0g and33.75g kg]1 Soil. They were arranged in Complete Randomized Design. Soilsamples were collected at the 2nd, 4th, and 6th, week after planting and subjected to chemical analysis. Okra growth and yield data were collected and statistical analyses carried out using the SPSS Package and means compared with Duncan Multiple Range Test (DMRT) at 5% level of probability. The result of the study showed that soil pH, OC, OM, N, P, K, Ca, Na, Mg and CEC increased with lime application and with increases in rate of Tithonia leaves or poultry manure application. There were no significant differences in most of the soil parameters considered in Tithonia and poultry manure applied at 27.0g and 33.75 g kg ]1 soil. Growth parameters showed no significant differences for the two experiments except with regards to number of leaves in Tithonia application. Application of 33.75g Tithonia kg]1 gave the highest Okra pod weight for Tithonia treated soil while the application of 27g poultry manure kg]1 gave highest Okra weight for poultry manure treated soil.