Evidence library

Research evidence behind crop production, irrigation and freshness

We connect Kumer-specific facts with independent research on weed prevention, parsley, lamb’s lettuce, young potatoes, pickling cucumbers, irrigation and the cold chain. Every research note keeps the external evidence separate from Kumer-specific claims.

Independent research is linked for context. It is not research performed on Kumer 1687 and does not certify our own practices.

Evidence review updated: 9 September 2026.

All 24 research landing pages in this library have now been checked against the full scientific papers supplied to the project. Methods, tables or figures, results and conclusions were reviewed before the website summaries were updated.

False seedbed: prevention before the crop emerges Cold reception, packing and the postharvest chain Leaf parsley Lamb's lettuce / Valerianella Young potatoes Pickling cucumbers Irrigation, crop stability and canopy temperature

False seedbed: prevention before the crop emerges

Kumer uses false-seedbed preparation broadly across crops. The method is preventive: encourage a first flush of weeds before the crop is established, remove it with very shallow control, and avoid bringing a new layer of buried weed seed back to the surface.

Weed Research · 2019

Reduction in field emergence and seedbank density after contrasting false seedbed strategies in organic vegetable fields

In three organic-vegetable field experiments the authors compared false-seedbed destruction by flaming, hoeing and harrowing, including different numbers of passes and very shallow working depths. About one month after seedbed creation, flaming reduced G. quadriradiata emergence by as much as about 99% and total weed emergence by up to about 73%; shallow hoeing at 1 cm reached roughly 74% and 67%, respectively.

Full paper reviewed

Weed Research · 2007

Effect of stale seedbed preparations and subsequent weed control in lettuce (cv. Iceboll) on weed densities

Across three years in Dutch lettuce, stale-seedbed preparation followed by pre-plant weed control reduced weed density during crop growth by about 43–83%, depending on year and site. Finger weeding, torsion weeding and hoeing applied without a stale seedbed reduced densities by roughly 88–99% compared with the untreated control.

Full paper reviewed

Scientia Horticulturae · 2021

Stale seedbed preparation for sustainable weed seed bank management in organic cropping systems

The Tuscany experiment repeated three stale-seedbed tillage types five times, roughly 5–6 weeks apart, and measured the weed seedbank by depth. The 10–30 cm seedbank changed little, while depletion was concentrated in the biologically active 0–10 cm layer.

Full paper reviewed

European Journal of Agronomy · 2022

An Integrated Weed Management framework: A pan-European perspective

This is a framework paper rather than a single-crop trial. It organises integrated weed management into five pillars: diversified cropping systems; cultivar choice and crop establishment; field and soil management; direct control; and continuous monitoring/evaluation.

Full paper reviewed

GOV.SI – integrated vegetable production: non-chemical weed control including slepa setev KGZS – mechanical weed management and slepa setev IVR – slepa setev in vegetable production EU CAP Network – false seedbed technique

Cold reception, packing and the postharvest chain

Independent postharvest research consistently treats time, temperature, airflow and packaging as connected variables. Kumer links this evidence to its own documented harvest, packing, cold-storage and dispatch steps without claiming that each paper describes its exact equipment.

Trends in Food Science & Technology · 2020

Postharvest precooling of fruit and vegetables: A review

The review compares room cooling, forced-air cooling, hydrocooling, vacuum cooling and related precooling approaches. Its key engineering message is that faster heat removal is useful only while product quality, moisture loss, chilling risk, sanitation and energy demand remain acceptable.

Full paper reviewed

Food Quality and Safety · 2020

Impact of ventilation design on the precooling effectiveness of horticultural produce — a review

This review focuses on the airflow path through produce packages during forced-air precooling. Vent area, vent position, alignment between neighbouring boxes, internal trays/liners, product arrangement and airflow rate jointly determine pressure drop, cooling rate and—critically—temperature uniformity.

Full paper reviewed

Food Control · 2007

Chemical and sensory characteristics and microbiological safety of fresh finely chopped parsley packed in modified atmosphere

The study used finely chopped, washed and disinfected parsley packed in 40 g portions and stored at 5 ± 1 °C and 90% RH.

Full paper reviewed

Leaf parsley

Weed competition, mechanical control, water availability, nutrient management and postharvest storage are recurring research themes around commercial parsley production.

Leaf parsley – Kumer 1687 →

Journal of Applied Research on Medicinal and Aromatic Plants · 2025

Mechanical intra-row weed control at early growth stages in medicinal and aromatic plants using parsley and lemon balm

Across eight field trials and all tested crops/devices, mean intra-row weed-control efficacy was 66% with very high variability (0–100% among applications). Tine harrows averaged about 68% control and finger weeders about 64%; rotative weeders produced the greatest average crop soil-cover/damage signal, while finger and torsion tools showed much lower crop covering.

Full paper reviewed

Crop Protection · 2012

The critical period for weed competition in parsley in Mediterranean areas

In two years of field work on Italian Giant parsley, season-long weed competition reduced parsley dry weight by about 93–95%. When plots remained weed-infested for the first 40 days after crop emergence, dry weight was about 87–91% lower; keeping plots weed-free for a similar period produced roughly 8–10 times more dry matter.

Full paper reviewed

Scientia Horticulturae · 2008

The effect of water deficit stress on the growth, yield and composition of essential oils of parsley

Two-year experiments on plain-, curly- and turnip-rooted parsley compared a near-field-capacity control with two water-deficit levels (about 30–45% and 45–60% on the study tensiometer scale). Even the milder deficit reduced fresh foliage biomass and usually leaf number; the stronger deficit caused further losses in several cultivars.

Full paper reviewed

Scientia Horticulturae · 2016

Irrigation dose and plant density affect the essential oil content and sensory quality of parsley (Petroselinum sativum)

In a commercial Spanish parsley field, the highest fresh yield occurred at the highest irrigation dose tested (1788 m³/ha), while the highest concentrations of many key volatile compounds and the strongest parsley-like/citrus/green-grass sensory notes occurred at the lower 861 m³/ha treatment.

Full paper reviewed

Scientia Horticulturae · 2008

The effect of nitrogen fertilization on plant growth and the nitrate content of leaves and roots of parsley

Across three parsley types, three years and two sowing dates, nitrogen supplied as ammonium nitrate increased foliage and root growth mainly up to about 150 mg N/kg substrate. Raising N to 300–450 mg/kg often produced little or no additional yield but increased nitrate accumulation in leaves and roots. The authors therefore identified 150 mg N/kg as the best compromise under their Mediterranean pot/outdoor conditions.

Full paper reviewed

European Food Research and Technology · 2026

The effect of LED-supported cold storage on some quality characteristics of parsley

Parsley was stored for 25 days in a cold chamber divided into green, blue, yellow, red, white LED and dark-control compartments. Under the authors’ conditions (about 0 ± 0.5 °C and 50 ± 5% RH), blue light produced the largest reported increases from baseline in ascorbic acid (13.2%), chlorophyll a (6.32%) and chlorophyll b (6.31%); green light gave the largest reported increase in antioxidant capacity (34.97%).

Full paper reviewed

Lamb's lettuce / Valerianella

Season, growing environment, cold-chain temperature and storage history influence the agronomic and postharvest quality questions around lamb’s lettuce.

Lamb's lettuce / Valerianella – Kumer 1687 →

Food Science & Nutrition · 2023

Yield and nutritional quality of soil-cultivated crisphead lettuce and corn salad harvested at different growing periods

At Jablje, Slovenia, four crisphead-lettuce and five corn-salad varieties were grown in replicated soil trials in 2017. Corn salad was compared in spring greenhouse, spring open field and autumn open field: mean marketable yields were about 3.19, 5.15 and 4.10 t/ha, respectively, with growing period significantly affecting yield.

Full paper reviewed

Frontiers in Nutrition · 2021

Changes in Metabolite Patterns During Refrigerated Storage of Lamb's lettuce

The Slovenian study compared home-grown lamb’s lettuce, a locally produced supermarket sample and two other supermarket sources during seven days at 4 °C. Home-grown material generally started with the highest sugars, organic acids, vitamin C and many phenolic/pigment values; the locally produced commercial sample also ranked highly for several components.

Full paper reviewed

Talanta · 2014

Monitoring of fresh-cut Valerianella locusta shelf life by electronic nose and VIS–NIR spectroscopy

Fresh-cut lamb’s lettuce was stored at 4, 10 and 20 °C and followed with reference quality measurements plus an electronic nose and Vis/NIR spectroscopy. Using selected e-nose variables, the average correct classification among “fresh”, “acceptable”, “spoiled” and “very spoiled” classes was reported as 95.5%, with 8.7% cross-validation error.

Full paper reviewed

Scientia Horticulturae · 2016

Nitrate content in Valerianella locusta plants is affected by supplemental LED lighting

Across two autumn and two winter greenhouse cycles, six supplemental-light treatments were compared in lamb’s lettuce harvested after 30 and 60 days and at noon versus evening. The 90% red + 10% blue LED treatment significantly reduced nitrate compared with HPS in the overall study; the largest reported difference was about 1600 mg NO₃⁻/kg fresh weight after 60 days in winter during evening illumination.

Full paper reviewed

Postharvest Biology and Technology · 2016

Estimation of the prior storage period of lamb’s lettuce based on visible/near infrared reflectance spectroscopy

The researchers collected Vis/NIR reflectance spectra from nine lamb’s-lettuce cultivars over multiple seasons and deliberately included variable origins and storage treatments to make the calibration more robust. A full-spectrum partial-least-squares model had a cross-validation error of about 6.0 days; after wavelength selection, only about 10% of the original wavelengths were retained and the error fell to about 3.6 days.

Full paper reviewed

Young potatoes

Young potatoes – Kumer 1687 →

Agricultural Water Management · 2012

Tuber yield and irrigation water productivity in early potatoes as affected by irrigation regime

A two-year Sicilian early-potato experiment compared four irrigation windows. Supplying 100% of calculated maximum evapotranspiration from tuber initiation to about 50% of tuber growth produced yields statistically comparable with irrigation through the whole tuber-growth period, while using roughly half as much irrigation water.

Full paper reviewed

Plant, Soil and Environment · 2015

Growth requirements of different potato cultivars

The University of Ljubljana field trial mapped individual tuber positions in ridges with a 3D coordinate device for four cultivars over two seasons. The first “minimum ellipse” approach included too much empty ridge space, so the 2013 method incorporated tuber mass and a compact cluster geometry; this better separated cultivar space requirements.

Full paper reviewed

Pickling cucumbers

Pickling cucumbers – Kumer 1687 →

Scientia Horticulturae · 2005

Growth and yield of pickling cucumber in different soil moisture circumstances

Pickling cucumber under a rain-excluding tunnel was irrigated when 20 cm soil-water potential reached −150, −300 or −600 hPa. The −150 hPa treatment used about 1.7–2.3 times as much irrigation water as the driest threshold, while −300 hPa used about 1.5–1.7 times as much.

Full paper reviewed

Packaging Technology and Science · 2021

Quality retention and shelf-life prolongation of cucumbers under different cool storage systems with passive modified atmosphere bulk packaging

Fresh seedless cucumbers were compared in open crates or 37.5 µm LDPE bags under ambient conditions, mechanical cool storage at about 10 °C/90% RH, and evaporative storage averaging about 19 ± 3 °C/82 ± 9% RH. LDPE packaging consistently reduced weight loss and better retained firmness.

Full paper reviewed

Irrigation, crop stability and canopy temperature

Irrigation is first an agronomic water-supply tool. Research also shows the physical link between adequate plant water status, transpiration and canopy temperature. We keep that scientific context separate from Kumer-specific claims about its irrigation equipment.

Hydrology and Earth System Sciences · 2021

Canopy temperature and heat stress are increased by compound high air temperature and water stress and reduced by irrigation — a modeling analysis

The mechanistic model couples canopy energy balance with soil–plant water transport and was parameterised for wheat. Under well-watered conditions, canopy temperature broadly followed air temperature; once soil water potential became more negative than about −0.14 MPa in the model, further drying caused canopy temperature to rise rapidly.

Full paper reviewed

Water · 2022

Estimating the Evaporative Cooling Effect of Irrigation within and above Soybean Canopy

Using soybean as the case crop, the authors estimated the evaporative-cooling contribution of irrigation at ten-minute resolution between irrigation events. Average cooling attributed to evapotranspiration was about 4.4 K within the canopy and 2.9 K above it during the middle and late season. Model agreement was stronger above the canopy (R² 0.98, mean absolute error 0.3 K) than within it (R² 0.87, MAE 0.9 K).

Full paper reviewed

We paraphrase rather than copy abstracts.
We link to the DOI or original institutional source.
We do not present independent research as a Kumer trial.
We do not turn agronomic results into unsupported health claims.
We keep Kumer-specific certification claims separate from general literature.

Research evidence behind crop production, irrigation and freshness

False seedbed: prevention before the crop emerges

Reduction in field emergence and seedbank density after contrasting false seedbed strategies in organic vegetable fields

Effect of stale seedbed preparations and subsequent weed control in lettuce (cv. Iceboll) on weed densities

Stale seedbed preparation for sustainable weed seed bank management in organic cropping systems

An Integrated Weed Management framework: A pan-European perspective

Cold reception, packing and the postharvest chain

Postharvest precooling of fruit and vegetables: A review

Impact of ventilation design on the precooling effectiveness of horticultural produce — a review

Chemical and sensory characteristics and microbiological safety of fresh finely chopped parsley packed in modified atmosphere

Leaf parsley

Mechanical intra-row weed control at early growth stages in medicinal and aromatic plants using parsley and lemon balm

The critical period for weed competition in parsley in Mediterranean areas

The effect of water deficit stress on the growth, yield and composition of essential oils of parsley

Irrigation dose and plant density affect the essential oil content and sensory quality of parsley (Petroselinum sativum)

The effect of nitrogen fertilization on plant growth and the nitrate content of leaves and roots of parsley

The effect of LED-supported cold storage on some quality characteristics of parsley

Lamb's lettuce / Valerianella

Yield and nutritional quality of soil-cultivated crisphead lettuce and corn salad harvested at different growing periods

Changes in Metabolite Patterns During Refrigerated Storage of Lamb's lettuce

Monitoring of fresh-cut Valerianella locusta shelf life by electronic nose and VIS–NIR spectroscopy

Nitrate content in Valerianella locusta plants is affected by supplemental LED lighting

Estimation of the prior storage period of lamb’s lettuce based on visible/near infrared reflectance spectroscopy

Young potatoes

Tuber yield and irrigation water productivity in early potatoes as affected by irrigation regime

Growth requirements of different potato cultivars

Pickling cucumbers

Growth and yield of pickling cucumber in different soil moisture circumstances

Quality retention and shelf-life prolongation of cucumbers under different cool storage systems with passive modified atmosphere bulk packaging

Irrigation, crop stability and canopy temperature

Canopy temperature and heat stress are increased by compound high air temperature and water stress and reduced by irrigation — a modeling analysis

Estimating the Evaporative Cooling Effect of Irrigation within and above Soybean Canopy

How we use research responsibly