Hemp (Cannabis sativa L.) is a productive multi-purpose crop that can be cultivated in different climatic conditions including northern latitudes. However, no comprehensive study on the hemp yield potential has been conducted, particularly in high latitude regions. This study investigates hemp development and the suitability of the AgroC model to simulate hemp growth in cool climate. Field experiments were conducted at the Lithuanian Research Centre for Agriculture and Forestry on Endogleyic Endostagnic Endocalcaric Luvisol. The AgroC model was calibrated using data sets from 2019, whereby validation was performed with 2020-2021 data sets. The model provided adequate results when simulating hemp and its individual parts biomass, leaf area index, soil water content, and development stages. The validated model was further used to provide hemp yields and water as well as temperature limited yield gaps for the historical 1990-2021 period. Simulated average hemp biomass potential reached up to 20.1 t ha- 1. Average biomass yield losses due to water stress are 8.7 t ha- 1 (gap 43.3 %), while reduction due to low temperatures may reach 6.4 %, but mean reduction was only 0.4 t ha- 1 (gap 2.0 %). Simulated results showed water stress as the main factor defining hemp yield losses, while low temperatures are of secondary importance.

AbstractThe 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.