Background
Climate change is increasingly impacting agriculture all over the world, with extended periods of drought, flooding, hail, winds and temperature extremes. To negate the effects of climate ...change, researchers are trying to find new agricultural production techniques, to save resources without losing yield quality and quantity. A study on
Capsicum annuum L
. 'Chili-AS Rot' and
Capsicum chinense
Jacq. 'Naga Morich' chilies, grown under field capacity, deficit irrigation (50% field capacity) and full and half dose of mineral fertilizer in peat soil substrate was conducted. Both cultivars were marked with the stable isotope
15
N, to follow nitrogen translocation in chili plants under stress conditions.
Results
The yield and plant biomass, capsaicin synthase (CS), phenylalanine ammonia lyase (PAL), and peroxidase (POX), as well as total and individual capsaicinoids were studied. In 'Chili-AS Rot' the deficit irrigation with the full-fertilization (Diff) dose showed the highest yield and fruit number, compared to other treatments. In the 'Naga Morich' cultivar the deficit irrigation and half-fertilization (Dihf), showed the highest yield, fruit number and dry weight of chilies, compared to other treatments. In the cultivar 'Chili-AS Rot', deficit irrigation was found to reduce the utilization of N fertilizer when the plant (leaves, stems, and roots) and fruit were considered. The utilization of nitrogen fertilizer was 60 to 70% under deficit fertilization, regardless of the irrigation treatment. The half dose fertilized plants of 'Chili-AS Rot' had higher CS activity and PAL activity (from 50 to 80%) than fully fertilized plants, with deficit irrigation having about 10% higher enzymatic activity than field-capacity irrigated plants. In 'Naga Morich', irrigation treatment affected lower enzymatic activity than field-capacity irrigated plants.
Conclusions
The results indicate that deficit irrigation and fertilization can be used to maintain enzymatic activity and thus capsaicinoid content, which could reduce the economic cost of irrigation water and fertilizer. It was confirmed that the yield was better under deficit irrigation and fertilization for the more pungent 'Naga Morich'. The result of the study shows that when water and fertilizer use is reduced by up to 50%, chili yield losses are minimal or non-existent.
Graphical Abstract
Research into the unsaturated zone and groundwater recharge can greatly improve understanding of hydrological processes and assist in sustainable groundwater management. Groundwater recharge of the ...Ljubljana Field aquifer, a coarse-gravel porous aquifer in Slovenia, was estimated with reference to soil characteristics, outflow data from a weighing lysimeter, and water-table fluctuation. The specific yield of the upper unsaturated zone determined from soil characteristics was 0.141 for the top soil layer (0–0.35 m), between 0.042 and 0.066 for the layer below the top soil (0.35–1.3 m), and between 0.239 and 0.219 for the underlying upper coarse layer. During long dry periods, especially in combination with times of high plant-water requirements, only substantial precipitation events directly contribute to considerable groundwater recharge, as ‘substantial precipitation’ is defined as those rainfall events that fill storage and exceed retention capacity of the upper soil layer. Lysimeter measurements show that 50% of the precipitation is lost by evapotranspiration and the other 50% contributes to groundwater recharge. Most infiltrated water was stored for a short time in the unsaturated zone and did not result in a significant discharge from the lysimeter. Average specific yield, calculated using the water-table fluctuation method, was 0.144. The nature of the gravely unsaturated zone is that once the retention buffer of the soil is exceeded, the water front travels through relatively quickly, which can be seen as an advantage for recharge or a disadvantage for prevention of groundwater pollution.
KLJUČNE BESEDE urejanje prostora, začasna uporaba, namenska raba, kmetijska zemljišča, odškodnine, boniteta ABSTRACT Easement of agricultural land for a fixed period for various construction and ...other non-agricultural purposes can influence soil quality, temporary decreases fertility or even permanently changes the value of the propriety. In severe cases, proprietors halt agricultural land use, which leads to overgrowing, the spread of invasive plant species and general cultural land degradation. The article reviews legislation covering compensation for easement of agricultural land for a fixed period and the influence of various fixed period easement cases on soil quality and offers methods of rehabilitation as basis for determination of compensation for fixed period easement. KEY WORDS landscape planning, fixed period easement, planned land use, agricultural land, compensation, land rating value 1UVOD Uporabnost kmetijskih zemljišč je zelo široka ter vpeta v tako rekoč vse sektorje prostorske rabe (Willemen et al., 2008; Montanarella, 2015), saj so v tleh pod vrhnjim, rodovitnim slojem lahko mineralne surovine, ki so zanimive za gospodarske panoge (Malucelli et al., 2014; Montanarella, 2015; Montanarella in Panagos, 2015), prostor se uporablja za turistične in rekreativne dejavnosti (Mastronardi et al., 2017).
A detailed knowledge of soil water repellency (SWR) and water infiltration capacity of soils under different land uses is of fundamental importance in Mediterranean areas, since these areas are prone ...to soil degradation risks (e.g., erosion, runoff of polluting compounds) as a response to different hydrological processes. The present study evaluates the effects of land uses on SWR and soil hydraulic conductivity (SHC) by direct measurements at the plot scale in three areas representing (1) intensive agricultural use, (2) abandoned farmland, and (3) a forest ecosystem in Southern Spain under Mediterranean climatic conditions. The physico-chemical properties and water content of the experimental soils were also measured. Significant SWR and SHC differences were found among the analyzed land uses. Forest soils showed high SWR and low SHC, while the reverse effects (that is, low SWR and high SHC) were detected in soils subjected to intensive agriculture. Organic matter and bulk density were important soil properties influencing SWR and SHC. The study, demonstrating how land uses can have important effects on the hydrological characteristics of soils, give land managers insights into the choice of the most suitable land use planning strategies in view of facing the high runoff and erosion rates typical of the Mediterranean areas.
•Deficit irrigation negatively affected yield quantity for both chili species.•Concentrations of sugars were lower at both plant species under deficit irrigation.•C. annuum 'Chili-AS Rot' fruits had ...higher organic acids content at field capacity.•Capsaicin concentration in C. annuum 'Chili-AS Rot' was higher under water deficit.
The effects of water stress on plant growth, yield, primary metabolites (sugars, organic acids, ascorbic acid) and secondary metabolites (total phenolic content, capsaicin and dihydrocapsaicin) accumulation, were evaluated for greenhouse production. A pot experiment was conducted on two species of chilies Capsicum annuum L. var 'Chili-AS Rot' and Capsicum chinense Jacq. var 'Naga Morich'. Plants were irrigated at two different treatments, optimal irrigation or field capacity and deficit irrigation or 50 % field capacity, which can be treated as drought stress. The effects of drought stress on quantity and quality of the yield, (primary and secondary metabolites) were studied. Deficit irrigation affected yield quantity, as both chili species had lower yield at deficit irrigation. Species C. chinense 'Naga Morich' under deficit irrigation abscised the flowers, thus no fruits were harvested at the third picking. Concentrations of sugars were lower at both plant species under deficit irrigation. Concentrations of organic acids in fruits of C. annuum 'Chili-AS Rot', such as citric acid, oxalic acid, fumaric acid, quinic acid were higher at optimal irrigation. Malic acid concentrations were similar at both irrigation treatments. In the fruits of C. chinense Jacq. 'Naga Morich' the concertation of citric acid and ascorbic acid was higher with optimal irrigation. Concentrations of other organic acids were higher at deficit irrigation. C. annuum 'Chili-AS Rot' had higher concentration of ascorbic acid and total phenolic content at optimal irrigation and higher capsaicin and dihydrocapsaicin concentrations in stressed plants. C. chinense 'Naga Morich' had higher concentrations of capsaicin, dihydrocapsaicin and total phenolic content at optimal irrigation regime.
The aim of the present study was to establish a reference site and its soil characteristics for use of fallout radionuclides in erosion studies in Slovenia. Prior to this study, no reference site and ...baseline data existed for Slovenia for this purpose. In the agricultural area of Goričko in East Slovenia, an undisturbed forest situated in Šalamenci (46°44’N, 16°7’E), was selected to establish the inventory value of fallout
137Cs and to establish a baseline level of multi-elemental fingerprint (major, minor, trace elements including heavy metals) and naturally occurring radionuclides in soils. A total of 20 soil profiles were collected at four 10 cm depth increments for evaluation of baseline level of
137Cs inventory. An exponential distribution for
137Cs was found and the baseline level inventory was established at 7300 ± 2500 Bq m
−2 with a coefficient of variation of 34%. Of this mean present-day inventory, approximately 45% is due to the Chernobyl contribution.
The physical degradation of soils through erosion is linked with biochemical degradation. This study introduces an approach to establishment of the naturally occurring radionuclide and elemental fingerprints baseline levels at a reference site which can provide comparative data to those from neighbouring agricultural fields for assessment of soil redistribution magnitude using fallout radionuclides. In addition, this information will be used to determine the impact of soil erosion processes and agricultural practices on soil quality and redistribution within agricultural landscapes in Slovenia.
Soil washing has been established as suitable remediation technology, with most research focused on metal removing efficiency and toxic effect on plants, less on the influence on soil physical ...characteristics, which was the focus of this study. In soil column experiment highly contaminated soil and soil washed with EDTA, mixed with additives (gypsum, hydrogel, manure, peat) were tested. White clover was used as a soil cover. Yield, metal concentration in soil and plant, aggregate fractionation and stability, saturated hydraulic conductivity and soil water retention of the soil were measured. Soil washing decreased metal concentration in soil and plants, but yield of white clover on remediated soil was significantly lower compared to the original soil. Significant differences in water retention characteristics, aggregate fractionation and stability between original and remediated soil have been determined. Gypsum, hydrogel and peat increased plant available water, manure and peat increased yield on remediated soil.
•Clover yield on washed soil was significantly lower than on original soil.•Organic additives increased yield on remediated soils.•Soil washing changed soil water retention and soil structure.•Hydrogen, gypsum and peat increased plant available water of remediated soil.
The study critically examines yield, plant metal uptake and possible changes in soil physical characteristics as a consequence of soil washing procedure for metal pollution remediation.
Greenhouse production of chilies requires constant irrigation and fertilization. Due to climate change, water availability is decreasing, and thus new techniques are being developed, one of which is ...deficit irrigation, also applied in controlled conditions, such as greenhouse production This allows us to improve yield quality with minimal or no reduction in yield with optimal water use. Nitrogen is an important macronutrient whose uptake can be hindered under deficit irrigation because deficit is a form of drought stress. In the pot experiment, two chili cultivars were tested to see how they responded to water deficit irrigation treatments compared to the field capacity treatment with peat substrate. Nitrogen fertilization, with the addition of the isotope 15N, was applied to all treatments. Seeds and leaves contained the most total nitrogen in both cultivars, followed by placenta. N utilization from fertilization was 3.32% at field capacity and 2.33% under deficit irrigation in 'Chili-AS Rot'. 'Naga Morich' utilized 4.58% of N from fertilizer under field capacity and 6.72% under deficit irrigation. Capsaicinoid content was strongly correlated with nitrogen content in both cultivars irrespective of irrigation regime. This study fills an important gap in our understanding of N assimilation, fertilization, and irrigation in chili plants. It shows that there is no universal rule for N absorption under different irrigation conditions in chili plants and that the right choice of cultivar and species is crucial for optimal and high-quality chili fruit production.
•'Naga Morich' has better N fertilizer utilization under deficit irrigation.•N, available water and capsaicinoids are strongly correlated in both species.•'Chili-AS Rot' contained from 12% to 18% higher capsaicinoid contents at field capacity.•'Naga Morich' placenta contained more capsaicinoid under deficit irrigation.•Stems, leafs and seed contained the highest contents’ of stable isotope 15N.
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