Forage production and leaf proportion of lucerne in subtropical environments: cultivar, cutting frequency and canopy effects

In subtropical and humid environments the ‘winter-active’ cultivars of lucerne usually produce more forage with lower leaf proportion (i.e. leaf to stem ratio) than the ‘winter-dormant’ ones. Present research analyze (i) if differences in forage production changes with cutting frequency, and (ii) if differences in leaf proportion are intrinsic (i.e. ‘cultivar differences’) or are due to variations in plant morphology (i.e. ‘aerial biomass and canopy height’). In two subtropical locations a factorial experiment including three alfalfa cultivars (FD4= ‘winter-dormant’, FD6=‘semi-dormant’, FD9=‘winter-active’) and three cutting frequencies (‘high’, ‘intermediate’ and ‘low’) was established. As the cutting frequency decrease (i.e. from ‘high’ to ‘low’) the more winter-active cultivars were more productive than the more winter-dormant ones (FD9>FD6>FD4) due mainly to a higher stem production. However, differences between cultivars disappear (FD9=FD6=FD4) as the cutting frequency increases (i.e. from ‘low’ to ‘high’ cutting frequency). Compared at similar canopy height, differences between cultivars in leaf proportion were practically irrelevant. We confirm that (i) in subtropical and humid environments, the differences in forage production between cultivars contrasting in their winter activity depend of the cutting frequency, and that (ii) the leaf proportion depends mainly of plant morphology, especially canopy height’, being irrelevant the cultivar and the environment. Highlights This paper shows that (i) differences in forage production between cultivars of lucerne depend on the cutting frequency, and that (ii) leaf proportion is governed by plant morphology, especially canopy height. Forage production was similar between cultivars at high cutting frequency but at low cutting frequency winter-active and semi-dormant cultivars (FD6 and FD9) produce more forage than winter dormant (FD4) ones. Lucerne cultivars showing the same leaf proportion when they were compared at similar canopy height suggesting that leaf proportion is not an intrinsic trait Changes in leaf proportion were better explained by changes in canopy height than by changes in thermal time.

Revitalized Karuk and Yurok cultural burning to enhance California hazelnut for basketweaving in northwestern California, USA

Background Karuk and Yurok tribes in northwestern California, USA, are revitalizing the practice of cultural burning, which is the use of prescribed burns to enhance culturally important species. These cultural burns are critical to the livelihoods of indigenous peoples, and were widespread prior to the establishment of fire exclusion policies. One of the major objectives of cultural burning is to enhance California hazelnut (Corylus cornuta Marsh var. californica) basketry stem production for Karuk and Yurok basketweavers. To evaluate cultural burning as a form of human ecosystem engineering, we monitored hazelnut basketry stem production, qualities, and shrub density in 48 plots (400 m2) within two prescribed and 19 cultural burn sites. Socio-ecological variables that were analyzed included burn frequency, burn season, overstory tree (≥10 cm diameter at breast height) basal area, ungulate browse, and aspect. We also observed basketry stem gathering to compare travel distances, gathering rates, and basketweaver preferences across sites with different fire histories and land tenure. Results Hazelnut shrubs, one growing season post burn, produced a 13-fold increase in basketry stems compared with shrubs growing at least three seasons post burn (P < 0.0001). Basketry stem production and stem length displayed negative relationships with overstory tree basal area (P < 0.01) and ungulate browse (P < 0.0001). Plots burned at high frequency (at least three burn events from 1989 to 2019) had 1.86-fold greater hazelnut shrubs than plots experiencing less than three burn events (P < 0.0001), and were all located on the Yurok Reservation where land tenure of indigenous people is comparatively stronger. Basketweavers travelled 3.8-fold greater distance to reach gathering sites burned by wildfires compared with those that were culturally burned (P < 0.01). At cultural burn sites, wildfire sites, and fire-excluded sites, mean gathering rates were 4.9, 1.6, and 0.5 stems per minute per individual, respectively. Conclusions Karuk and Yurok cultural fire regimes with high burn frequencies (e.g., three to five years) promote high densities of hazelnut shrubs and increase hazelnut basketry stem production. This improves gathering efficiency and lowers travel costs to support the revitalization of a vital cultural practice. Our findings provide evidence of positive human ecosystem engineering, and show that increasing tribal sovereignty over fire management improves socio-economic well-being while at the same time supports measures of ecosystem structure and function.

Influence of edaphoclimatic conditions on stem production and stem morphological characteristics of 10 European hemp (Cannabis sativa L.) varieties

<p> </p><p>Six dioecious (Antal, KC Dóra, Kompolti hibrid TC, Monoica, Tiborszallasi and Tisza) and four monoecious (Fedora 17, Futura 75, Santhica 27 and USO 31) European hemp varieties were sown at a density of 300 viable seeds per m² and a row spacing of 12.5 cm in a three-year field trial (2017-2019) to evaluate the yield of the stems (fresh and dry) and some other biometric characteristics of the stems. No pesticides were used during plant growth to suppress weeds, diseases and pests. The highest yield of fresh and dry stems was achieved by the variety Antal with 12.3 t ha^-1 and 5.3 t ha^-1, respectively, followed by the varieties Futura 75 and Tiborszallasi. The lowest yields of fresh and dry stems were recorded for the monecious variety USO 31 (6.0 and 2.6 t ha^-1). In general, dioecious varieties had higher and thicker stems than monoecious varieties. The year of production had a highly significant impact on all variables, in particular on the proportion of weed biomass, which was the highest in 2019 (77.2 %), when weather conditions were most unfavourable for hemp cultivation. The correlation analysis between fresh/dry stem yields and weed biomass was highly negative (-0.85 and -0.83) and strongly statistically significant (<em>p </em>&lt; 0.001), indicating the issue related to weed management.</p><p><span style="font-family: Times New Roman;"><br /></span></p>

Stem production of Scots pine and black locust stands in Ukraine’s Northern Steppe

The research paper presents the results of the assessment of the annual stem production of Scots pine (Pinus sylvestris L.) and black locust (Robinia pseudoacacia L.) stands within the Northern Steppe of Ukraine. The research team has developed two- and three-factor regression models for assessing the live biomass stocks for the fractions of the wood and bark of the stems of the Scots pine and black locust stands. The paper also presents the dependences of the live biomass of the components of the stems of the stands on their selected biometric parameters. The direct positive correlation between the fractions of the wood, bark, and stem in total with the factors of age, mean diameter, mean height and stand density for both the studied species has been identified. The results include the distribution of the total stem production of the Scots pine and black locust stands by the state forestry enterprises of the Dnipro region. The mean annual stem production of Scots pine is characterised by lower values (stem wood –2.91 t·ha^–1·yr^–1, stem bark –0.38 t·ha^–1·yr^–1) compared with the investigated species – black locust with the stem wood 4.94 t·ha^–1·yr^–1 and stem bark 1.70 t·ha^–1·yr^–1.

Optimizing Planting Time for Some Selected Commercial Gladiolus Cultivars under Agro-Climatic Conditions of Faisalabad, Pakistan

A field experiment was conducted at Commercial Floriculture Research Area, Institute of Horticultural Sciences, University of Agriculture, Faisalabad, during 2017-18 to evaluate different planting times for quality production of selected gladiolus cultivars. Sixcommercial gladiolus cultivars, viz., Advance, Amsterdam, Essential, Grand Prix, Rose Supreme and White Prosperity were compared by planting at five different planting times from September to November at 15 days interval. Data regarding vegetative growth, flowering and quality parameters were collected. Early sprouting, best vegetative growth and higher quality gladiolus stems were produced when planted in September for all tested cultivars, while among cultivars, ‘Rose Supreme’ proved best for all planting times in the agro-climatic conditions of Faisalabad. Early planting of gladiolus crop in the season with favourably high temperature and longer photoperiod produced strong growth response as compared to late plantings when temperature dropped below 20 °C with photoperiods became shorter. The minimum time to 50% sprouting (7.0 days) along with the highest sprouting percentage (95%), number of leaves per plant (9.6), leaf area (67.6 cm2), plant height (96.4 cm), spike length (73.0 cm), the longest vase life (11.9 d), the best spike quality (8.3) and the greatest number of cormels per clump (30.5) were recorded for September plantation, which gradually decreased with delayed planting. In summary, the best time of planting gladiolus under agro-climatic conditions of Faisalabad, Punjab (Pakistan) is September, which may be adopted by growers for quality stem production.

Effects of Boron Omission and Foliar Fertilization on Nutrition Efficiency and Production of Cowpea

This study aimed to evaluate the effects of boron (B) omission on cowpea nutrition and to compare the impact of foliar B fertilization with and without sorbitol on cowpea growth, nutritional status, and B uptake. Two trials using a completely randomized experimental design were conducted. During the first experiment, nutrient solution was provided without B (−B) and with B (+B) in 10 replicates. During the second experiment, a 5 × 2 factorial treatment scheme was used. Five B concentrations (0, 1.25, 2.5, 3.75, and 5.0 g·L−1) were administered foliarly in the form of boric acid with or without sorbitol (500 mmol·L−1) in four replicates. B omission symptoms, root growth, plant organ dry mass and B content, and grain yield were evaluated. B omission induced greater losses in reproductive organ and root growth than in leaf and stem production. It also caused deformation of the middle lamella and accumulation of starch in the chloroplasts. Foliar applications of 2.6 to 2.9 g·L−1 B improved cowpea production. The addition of sorbitol did not enhance plant growth. However, it increased B absorption in the vegetative parts of the plant but did not enhance seed production.

Temporal stability of Heliconia spp. flower stem production

The instability of heliconia flower stem production may be related to climatic variation. Therefore, that information is very important for planning the species production throughout Brazil, mainly in northeast region. The objective of this work was analyzed the previous effects of photoperiod, air temperature and precipitation in the flower stem production of Heliconia psittacorum cv. Red Opal, H. psittacorum x H. spathocircinata cv. Golden Torch, H. stricta cv. Fire Bird and H. rauliniana, and the monthly temporal stability. The flower stems with two to three open bracts were harvested twice a week between May, 2004 and March, 2012 from a field in Camaragibe – PE, Rain Forest Zone of Pernambuco, Brazil. Pearson’s linear correlation demonstrate flower stem production occur in response to the environment stimulus. H. rauliniana inflorescence initiation response mainly to the shortest photoperiod and cv. Fire Bird to highest photoperiod. Production of the cv. Golden Torch was more stable in April, with reduction in September (39.46%) and an increase in December (87.02%), compared with the annual average. The cv. Red Opal produced more in September (31.43%), with a reduction in February (44.8%) and stable in July. H. rauliniana production was stable in September and increase in November (274.8%). The cv. Fire Bird production was stable in April, with the lowest production in November and the highest in March (65%). With this information is possible to predict the cultivar production in the Rain Forest Zone of Pernambuco State, Brazil