Plant Stands Research Articles

Crop Establishment Methods Affect Plant Stand and Yield of Lentil under Rice-lentil Cropping at Khumaltar Condition

Lentil variety Maheswor Bharati was evaluated in three establishment methods: relay, conventional tillage after rice harvest (post-rice CT), seeding by seed drill where seeds covered by minimum soil disturbance in single pass, and two rice residue heights: residue removed i.e., straw cut at 5 cm height and 30 cm residue retained at Agronomy Farm, Khumaltar from 2016/17 to 2018/19. Experiments were conducted in Randomized Complete Block design with four replications. Seeds broadcasted on standing rice during 2-16 November for relay crop; and 21-29 November for post-rice CT. Seed rates were 40 kg ha-1 for machine and manual line sowing and 50 kg ha-1 for broadcasting. Rice was harvested at 14-18 days after lentil relay. Fertilizers were applied based on soil fertility of experimental field. Significant variation was observed in plant stand, crop duration, growth and yield parameters among establishment methods; and year to year variation was also significant except for plant stand. Plant stand was greater (58-62 m-2) in machine sowing with or without residue retention and manual line sowing in post-rice CT, while low (32-40 m-2) in broadcasting methods either as relay or post-rice CT. Crop grew tall in relay with residue retained and machine sowing (41 cm) as compared to broadcasting in post-rice CT (33 cm). Grain yield was 46-115% and 24-83% higher in seeding by machine as compared to relay sown without residue (492 kg ha-1) and broadcasting in post-rice CT (578 kg ha-1), respectively.

Trends in genetic diversity of silver birch: Insights from varied planting scenarios

This study explores the impact of planting strategies on genetic diversity in silver birch (Betula pendula Roth) stands using simulation models. We examine the influence of different proportions of planted stands and the number of open-pollinated families on genetic diversity, focusing on the Shannon-Weiner Diversity Index and expected heterozygosity. Results indicate optimal genetic diversity increases with 50–55% planted stands. Additionally, using more families in planting enhances diversity, peaking when 30 families were used compared to five. Simulations suggest that combining natural regeneration with planting seed lots from at least 20 families enhances genetic diversity at the landscape level, supporting sustainable forest management. However, using only the top-performing five families does not harm genetic diversity if planted stands remain below 55%. Acknowledging the limitation, this study considers only a single generation, which may affect long-term applicability of the results over multiple generations. Keywords: expected heterozygosity; Shannon-Weiner Diversity Index

Establishing monarch butterfly overwintering sites for future climates: Abies religiosa upper altitudinal limit expansion by assisted migration

Climate change projections suggest a precarious future for the Monarch butterfly (Danaus plexippus) as the suitable climatic habitat of its exclusive overwintering host Abies religiosa (oyamel, Sacred fir, a conifer endemic to Mexico) inside the Monarch Butterfly Biosphere Reserve (MBBR) is expected to disappear by 2090. Since the upper elevation limit of A. religiosa is approximately 3,500 m and the summits of mountains within the MBBR are ca. 3,550 m, we tested the feasibility of establishing A. religiosa at four locations outside its current geographic range in the MBBR, on a geographically close volcano, Nevado de Toluca at 4000 (timberline, an extreme site), 3,800, and 3,600 m (to test species range expansion upward in elevation), and at 3400 m (a reference site, slightly lower than the upper elevation limit of A. religiosa). Using existing shrubs as nurse plants to protect the seedlings from extreme temperatures, at each site we planted five to eight populations, originating between 3,100 and 3,500 m within the MBBR. After three growing seasons in the field (6 years after sowing), we found that: (a) survival and height increment declined steeply with test site elevation; (b) even at the highest sites (3,800 and 4,000 m), survival was acceptable, at 68 and 44%, respectively, although the growth was very poor at 4000 m; (c) populations responded similarly to transfer; (d) transfer effects were best accounted for by annual dryness index; (e) to compensate for the expected 2.3°C increase in mean annual temperature or 0.009 √°Cmm−1 increase of annual dryness index from the reference period (1961–1990) to the decade centered in 2060, it would be necessary to shift populations approximately 500 m to higher elevations; and (f) upward transfers to compensate for the 2.3°C increase in mean annual temperature are expected to result in height increment and survival that are approximately 47 and 21% lower, respectively, than values expected at zero transfer distance. We conclude that the establishment of A. religiosa at 3600 and 3,800 m is feasible and that planted stands could eventually serve as overwintering sites for the Monarch butterfly under projected future climates.

Assessing the of carbon and nitrogen storage potential in Khaya spp. stands in Southeastern Brazil

The objective of this study was to assess the dynamics of carbon and nitrogen in soil, forest floor, and aboveground biomass in 9.5 years-old planted stands of three Khaya spp. (K. grandifoliola, K. ivorensis, and K. senegalensis). The study was conducted at the Reserva Natural Vale (RNV), Brazil. The stands were planted at 5 × 5 m spacing, distributed over rectangular plots of 1250 m2. Soil bulk density at the evaluated depths, as well nitrogen contents, were similar among the species. However, K. ivorensis exhibited higher carbon concentration in the soil. In general, there were no differences in carbon and nitrogen content in soil between the three species; however, the values obtained are comparable to those of the reference area–Native Forest. The carbon stocks in the aboveground biomass for K. grandifoliola, K. ivorensis, and K. senegalensis averaged 37.97, 33.66 and 33.86 Mg ha−1, respectively (p ≤ 0.05). These values collectively represent about 28% of the total carbon stocks across the observed compartments. Notably, the nitrogen content within the aboveground biomass did not differ among these species. Therefore, African mahogany possesses a robust potential to store both carbon and nitrogen.

Nitrogen availability and its related enzyme activities affect microbial residue nitrogen accumulation during Chinese fir plantation development

Microbial growth, metabolism, and reproductive activities have a significant role in the generation, transformation, and storage of soil nitrogen (N). However, the time-integrated effect of microorganisms on long-term N sequestration in plantation forests remains poorly understood. We investigated the microbial residue N (MRN) and its contribution to soil total N (TN) among the young (8-year), middle (16-year), near-mature (24-year), mature (34-year), and over-mature (106-year) stands of Chinese fir plantation (CFP) in subtropical China. The soil TN content showed a general pattern of increasing with stand age, ranging from 2.61 to 3.42 g kg−1, and was higher in the over-mature and mature stands than in the other three stands (p < 0.001). In addition, soil carbon (C), N, phosphorus (P), and hydrolase stoichiometric ratios indicated that P limitation was widespread during all stages of CFP development. The average ratio of soil fungal residue N (FRN) to bacterial residue N (BRN) was 3.64:1. The MRN content and its contribution to soil TN exhibited a falling and then rising pattern from young to over-mature stands, ranging from 1.24 to 1.70 g kg−1 and 38.8 % to 57.5 %, respectively. Soil N fraction contents and hydrolase activities were higher in the 0–5 cm soil layer than in the 5–30 cm soil layer (p < 0.05). Regression analysis showed that soil MRN content increased with soil N fraction contents, C-N-P stoichiometric ratios, and hydrolase activities (p < 0.001). Redundancy analysis and partial least squares path modeling revealed that soil available N (AN) and N hydrolase were the main factors affecting MRN accumulation. These parameters may partially indicate the dynamics of MRN accumulation. Our study discovered that the long-term development of CFP promotes soil N sequestration, with microbial residues playing a significant role in contributing to N pools.

Elms (Ulmus L.) in the Branch “Myrhorod Forestry” of the State Specialized Forest Enterprise “Forests of Ukraine”

Introduction Elms are spread in forests, landscaping settlements, and protective forest belts. After several waves of elm mortality from Dutch elm disease (DED) in the 20th century, individual populations recovered or formed resistant hybrids. However, epiphytoties of bacterial and fungal diseases sometimes develop, particularly due to pathogen vectoring by bark beetles. In Ukraine, the spread of elms and their damage by different causes are relatively poorly investigated. This research aimed to discover the features of Ulmus sp. distribution by stand origin, age, and forest site condition in the forest fund of the Branch “Myrhorod Forestry”. Materials and Methods The data as of 2010 and 2017 on the forest fund of enterprises belonging to the Branch “Myrhorod Forestry” of the State Specialized Forest Enterprise “Forests of Ukraine” were selected from the database of Ukrainian State Forest Management Planning Association “Ukrderzhlisproekt” using SQL-query and converted to the *.xls files. Area distribution by types of forest site conditions was assessed following the Ukrainian school of forest typology. Such distributions for the entire area covered with forest vegetation, for subcompartments with elms in the stand composition, and with elms as the dominant species were compared for various elm species and stand origins, using c2-test. The percentages of stand areas of different origins and elm species in 2010 and 2017 were compared using z-test in the two proportions comparisons. The data for subcompartments with various elms as the dominant species and as a part of stands composition have been analyzed by 10-year age classes for different origins (natural and planted). The proportion of the stand area of each 10-year age class was assessed for each set of subcompartments. Then the proportion of the stands’ area, which survives up to a certain age, was evaluated. Results and Conclusions In the Branch “Myrhorod forestry”, an area of natural stands with Ulmus sp. as the dominant species for 2010–2017, and the proportion of U. minor has significantly increased. The most dramatic decrease in the survival rate of all elm species of natural stands occurred in the VI age class and planted stands in the V age class. Respective natural and planted stands were formed in the 1960s and 1970s when the peak of DED occurred in many regions. In the Branch “Myrhorod Forestry”, U. minor prefers moist fertile forest site conditions. U. laevis grows mainly in moist forest site conditions, U. pumila occurs in dry to wet habitats, U. glabra is present only in natural stands and absent in plantations. As part of stand composition, the same elm species grow in a wider range of forest site conditions than elms as the dominant species. 2 Figs., 8 Tables, 31 Refs.

Enhancing precision in quantification and spatial distribution of logging residues in plantation stands

Enhancing precision in quantification and spatial distribution of logging residues in plantation stands

Effect of planting material and pre-planting storage method on rhizome sprouting, crop stand, and seed rhizome yield of Turmeric (Curcuma longa L.) at Teppi, Southwestern Ethiopia

A two-year study experiment was conducted from January 2021 to December 2022 at the Teppi Agricultural Research Center (TARC) with the aim of identifying suitable planting material and an appropriate pre-planting storage method that can enhance turmeric seed quality and yield under rain-fed conditions. The experiment consisted of three planting materials (mother rhizomes, finger rhizomes, and mixed rhizomes) and five pre-planting storage methods (cemented floor, under tree shade, raised mesh-wired bed, pit with grass cover, and pit with soil cover). These factors were factorially arranged using a randomized complete block design with three replications. The results from the analysis of variance revealed that the seed quality, growth, and seed rhizome yield of turmeric were significantly (p&lt;0.05) influenced by the main effect of both planting material and storage method. However, their interaction effect did not significantly affect these attributes (p&gt;0.05). The highest clean and sprouted seed rhizomes, as well as total sprouts, were recorded in mother seed rhizomes and seed rhizomes stored under tree shade. Conversely, storing mother seed rhizomes on cemented floors resulted in the highest seed weight losses. Finger seed rhizomes stored in soil-covered pits produced the highest percentages of non-sprouted and decayed seed rhizomes. Regarding growth attributes, mother seed rhizomes led to the highest plant stands, plant height, stem girth, leaf growth, and tiller number. Storing seed rhizomes under tree shade performed the best across these growth attributes. Turmeric plants grown from mother seed rhizomes yielded a higher number of mother and finger rhizomes per plant and the highest fresh rhizome yield. Likewise, storing seed rhizomes under tree shade resulted in the highest fresh rhizome yield. In general, utilizing mother seed rhizomes and storing them under tree shade improved turmeric seed quality, growth, and seed rhizome yield. Therefore, farmers in the area are recommended to adopt these practices, but further research is needed to assess their economic feasibility.

Row unit down force and coulter effects vary by environmental conditions in organic no‐till soybeans

AbstractConcerns over tillage intensity and soil erosion in organic cropping systems have prompted the development of reduced tillage organic systems that use cover crops rather than soil disturbance as the primary weed control tool. However, planting into high residue cover crop mulches may inhibit crop establishment due to poor seed placement. Adaptation of agricultural equipment to high residue planting conditions could reduce variability in crop stands, thereby improving grain yield. Field trials at the University of Wisconsin Arlington Agricultural Research Station, Marshfield Agricultural Research Station, and three on‐farm locations representing seven site‐years of data from 2019 to 2020 comprised a 2 × 2 × 2 × 2 factorial experiment comparing (1) a low (457,135 seeds ha−1) versus high (555,986 seeds ha−1) soybean [Glycine max (L.) Merr.] seeding rate, (2) a 13 fluted‐wavy coulter versus no coulter attachment, (3) low (667 N) versus high (1334 N) row unit down force, and (4) spiked versus rubber closing wheels on soybean stand establishment and grain yield in an organic cover crop–based reduced tillage system. Combined across site‐years, high row unit down force and coulters increased soybean stand establishment by 2.3% and 2.4%, respectively; however, the magnitude and direction of effects varied within each site‐year. Winter rye (Secale cereale L.) biomass accumulation negatively correlated to soybean stand establishment and demonstrated trends toward increasing soybean yield. Significant correlations between soybean stand establishment and yield were noted under high rye biomass conditions, indicating potential improvements to soybean yields by increasing plant stands.

Effect of planting material and pre-planting storage method on rhizome sprouting, crop stand, and seed rhizome yield of turmeric (Curcuma longa L.) at Teppi, Southwestern Ethiopia

A two-year study experiment was conducted from January 2021 to December 2022 at the Teppi Agricultural Research Center (TARC) with the aim of identifying suitable planting material and an appropriate pre-planting storage method that can enhance turmeric seed quality and yield under rain-fed conditions. The experiment consisted of three planting materials (mother rhizomes, finger rhizomes, and mixed rhizomes) and five pre-planting storage methods (cemented floor, under tree shade, raised mesh-wired bed, pit with grass cover, and pit with soil cover). These factors were factorially arranged using a randomized complete block design with three replications. The results from the analysis of variance revealed that the seed quality, growth, and seed rhizome yield of turmeric were significantly (p&lt;0.05) influenced by the main effect of both planting material and storage method. However, their interaction did not significantly affect these attributes (p&gt;0.05). The highest clean and sprouted seed rhizomes, as well as total sprouts, were recorded in mother seed rhizomes and seed rhizomes stored under tree shade. Conversely, storing mother seed rhizomes on cemented floors resulted in the highest seed weight losses. Finger seed rhizomes stored in soil-covered pits produced the highest percentages of non-sprouted and decayed seed rhizomes. Regarding growth attributes, mother seed rhizomes led to the highest plant stands, plant height, stem girth, leaf growth, and tiller number. Storing seed rhizomes under tree shade performed the best across these growth attributes. Turmeric plants grown from mother seed rhizomes yielded a higher number of mother and finger rhizomes per plant and the highest fresh rhizome yield. Likewise, storing seed rhizomes under tree shade resulted in the highest fresh rhizome yield. In general, utilizing mother seed rhizomes and storing them under tree shade improved turmeric seed quality, growth, and seed rhizome yield. Therefore, farmers in the area are recommended to adopt these practices, but further research is needed to assess their economic feasibility.

Importance of forest stand structures for gross rainfall partitioning on China’s Loess Plateau

Large-scale ecological restoration in the arid and semi-arid Loess Plateau region of northern China is challenged by the intensifying water stress due to the changes in precipitation regimes. Although the importance of Gross Precipitation Partitioning (GRP) has been well recognized in forest hydrology, especially in dry areas, the processes are not understood because site- or region-specific factors complicate the accurate quantifications. This study integrates meta-analysis and field observation to compare patterns of GRP in forest stands that had different origins (plantations vs. native forests) and tree species (deciduous vs. evergreen) compositions. We aimed at quantifying the dominant biotic and abiotic factors controlling each of the GRP components to form empirical relationships between the GRP components and the influencing factors via the Boosted Regression Trees (BRT) model. We found a convergence in the GRP components among the examined stands that have diverse tree species and origins. Our results indicated that, unlike stem flow (SF) and canopy interception (Ic), the throughfall (TF) did not differ between natural and plantation stands. Meanwhile, from the perspective of species composition, the broadleaf forest stands had significantly higher SF rates than the coniferous stands. We found that stand structures exerted limited influence on TF, but significantly affected SF and Ic. We hypothesized that the residence time of the GRP components was important in explaining the matrix of influencing factors. The cumulative influences of stand structure factors played a more important role than species in most conditions. Based on the most influential factors (cumulative explanatory power > 70 %) selected from the BRT model, we successfully built a general formula to represent the GRP processes across the diverse forest stands in the Loess Plateau. Our study provides insights into the underlying mechanism of GRP for developing more realistic forest hydrological models. An improved understanding of GRP and better models are important for guiding large scale reforestation efforts that account for hydrological processes across stand species and origins.

Elliott State Research Forest Timber Cruise, Oregon, 2015–2016

The Elliott State Research Forest comprises 33,700 ha of temperate, Douglas-fir rainforest along North America’s Pacific Coast (Oregon, United States). In 2015, naturally regenerated stands at least 92 years old covered 49% of the research area and sawtimber plantations younger than 68 years another 50%. During the winter of 2015–2016, a forest wide inventory sampled both naturally regenerated and plantation stands, recording 97,424 trees on 17,866 plots in 738 stands. The resulting dataset is atypical for the area as plot locations were not restricted to upland, commercially harvestable timber. Multiage stands and riparian areas were therefore documented along with plantations 2–61 years old and trees retained through clearcut harvests. This dataset constitutes the only open access, stand-based forest inventory currently available for a large area within the Oregon Coast Range. The dataset enables development of suites of models as well as many comparisons across stand ages and types, both at stand level and at the level of individual trees.

Evaluation of morpho-physiological characters of gamma rays-irradiated soybean mutant lines under shade stress environment

Soybean, being one of the primary food sources for the Indonesian population, currently faces insufficient production from domestic harvests. Intercropping cultivation technique offers a potential solution to increase soybean production by expanding planting area, such as the area under plantation stands. However, low productivity persists due to shade stress. This study aims to evaluate the morpho-physiological characters of soybean genotypes under shading stress. The genetic materials used were 13 genotypes consisting of 10 promising mutant lines, resulted from mutant induction and selection from soybean variety Mutiara 1, and 3 check varieties, namely Dena 1, Dena 2, and Mutiara 1. This study employed a split plot arrangement, with shading treatment as the whole plot and soybean genotypes as subplots. ANOVA tests and stress tolerance index analyses revealed a significant increase in plant height and stomatal conductivity among soybean genotypes under shading environments. Conversely, shading treatments exhibited a significant impact on reducing plant branching and leaf chlorophyll content.

ЗМІНА ПРОДУКТИВНОСТІ СОЇ ЗАЛЕЖНО ВІД ВПЛИВУ СИСТЕМИ ОСНОВНОГО ОБРОБІТКУ ҐРУНТУ ТА СТИМУЛЮЮЧИХ РЕЧОВИН

The purpose of the research work is to determine the influence of the tillage system and stimulating substances on the amount and structure of the biological yield of soybeans, to justify the feasibility of using the studied stimulating substances in the technology of growing soybeans for the use of different systems of the main tillage in the conditions of the forest-steppe of Ukraine to overcome the negative impact of climatic factors. Materials and methods. Field experiments were carried out in the five-field research crop rotation of Leonid Pogorilyy UkrNDIPVT (Kyiv agro-soil district of Right Bank Forest Steppe). Factors of the experiment: factor A – stimulating biological drugs (A1 – use of drugs; A2 – control (without the use of drugs); factor B – soil cultivation system (B1 – traditional, B2 – conservation, B3 – mulching, B4 – mini-till). Soy was grown according to the technology traditional for the region, with the exception of the elements included in the experiment scheme. The effectiveness of the researched elements of cultivation technology was established by determining the biological yield of soybeans and their structure. Results. Correlation analysis indicates that the elements of cultivation technology that we studied significantly affect the density of plant stands of agrophytocenoses: the depth of soil cultivation and the density of plant stands, as well as the use of biological preparations and the density of plant stands are connected by average direct correlations expressed by coefficients r = 0.4901 and r = 0.5380, respectively. After conducting a correlation analysis, we established that an increase in the depth of tillage, within the framework of our experiments, contributes to the growth of abortiveness of seeds (r = 0.7215), and the use of biological preparations in the technology of growing soybeans - to a decrease in the rate of abortiveness of seeds (r = –0.6501 ). The level of biological yield significantly depends on the factors included by us in the scheme of experiments. Increasing the depth of tillage had a positive effect on the growth of soybean biological yield, as indicated by the correlation coefficient r = 0.5876. The value of the biological yield of soybeans, within the limits of the schemes of our experiments, was also affected by the use of biological preparations – the presence of a direct average correlation between them was established, which is expressed by the coefficient r = 0.5880. Conclusions. Increasing the depth of tillage had a positive effect on the growth of soybean biological yield, as indicated by the correlation coefficient r = 0.5876. The value of the biological yield of soybeans, within the limits of the schemes of our experiments, was influenced by the use of biological preparations - the presence of a direct average correlation between them was established, which is expressed by the coefficient r = 0.5880. The use of biological preparations in the technology of growing soybeans contributed to the reduction of the abortiveness of its seeds (r = –0.6501) and the improvement of biometric indicators of plants. Keywords: soybean, growing technologies, stimulants, tillage, yield, abortiveness of seeds.

Genetic underpinning of historical afforestation with allochthonous Pinus cembra in the northwestern Swiss Alps

AbstractThroughout the last centuries, the structure and genetic composition of forests have been strongly affected by forest management. Over 30% of European forests are artificially regenerated, very often using translocated forest reproductive material, among these species the Swiss stone pine (Pinus cembra L.). In the late nineteenth and early twentieth centuries, the species was largely used for artificial afforestation in the northern Alps. However, only a few planted trees have survived. Therefore, we aimed to evaluate if the historical afforestation of P. cembra in the northwestern Swiss Alps relied on allochthonous material. We sampled 12 sites, genotyping 11 nuclear microsatellites, to infer the spatial genetic structure of regional populations, to test for genetic differences between natural and planted stands, and to infer potential source regions of planted stands using reference samples covering the entire Alps. Population genetic structure analysis allowed us to distinguish planted from natural stands and to determine that forest reproductive material used for plantations was not of regional origin. We found similar levels of genetic diversity between natural and planted stands. Assignment tests revealed that reproductive material for planting was translocated to the study area from two source regions, i.e., near the border of Switzerland and Austria, and further to the East, between Austria and Italy. Our study shows how genetic tools may inform about historical transfer of forest reproductive material, which still may affect the population genetic make-up of regional occurrences, e.g., because of reduced natural regeneration.

Genetic Variability and Character Association in Linseed (Linum usitatissimum L ) Genotypes for Yield

The study evaluated 10 accessions of linseed annonating and recording nine quantitative characters were recorded and annotated, viz., days to flowering (DTF), plant height in (cm) (H), primary branches (PB), secondary branches (SB), capsules per plant (CP), seeds per capsule (SC), plant stand (PS) and seed weight in (gms) (SW) and seed yield in (Kg/hectare) (YH). The evaluation of coefficient of variation phenotypic (PCV) and genotypic (GCV) indicated higher environmental impact revealed degree of differences in both the estimates in case of days to flowering (DTF), height (H), seeds per capsule (SC), primary branches per plant (PB), plant stand (PS), seed weight (SW) and seed yield hectare (SYH) (Kg per hectare). The PCV and GCV were highest for secondary branches with value of (33.16 ,32.39) whereas minimal value for days to flowering (DTF) (0.64,1) and seed weight(gm) (4.27,3.24). The role of additive gene action was suggested by high heritability linked with high genetic advance for capsules per plant (CP) (99.49,30.25) and secondary branches per plant (95.40,65.17). The relationship of seed yield with other components viz., high secondary branches and higher capsules per plant and moderate values for seed weight in grams (gm) and height (cm) is basis of selection criteria based on the formulation of breeding programs. The estimates of heritability were highest for capsules (99.27%) and secondary branches (97.41%) and minimum for seeds per capsule (SC) (38.37%). Likewise, highest genetic advance mean percentage was for secondary branches and lowest for days to flowering (DTF). The highest heritability for the traits like capsules per plant (CP) and secondary branches give a positive response to the selection. Traits with high (heritability) h2 as well as genetic advance (GA) are under the control of additive genes hence, these can be improved by selection based on phenotypic performance. Invariably higher PCV as compared to GCV indicated the role of environment in the manifestation of the traits. The positive and substantial genotypic and phenotypic correlation were for days to flowering (DTF) via height (H), capsules per plant (CP) via plant stand, primary branches genotypically and negatively are important with seed weight and positively yield per hectare (YH)(Kg/hectare). Height (cm), capsules per plant (CP), secondary branches and plant stand showed major positive direct effect. The information about yield improvement is associated with yield components which is essential for the formulation of breeding programs.

Detecting drought stress occurrence using synergies between Sun induced fluorescence and vegetation surface temperature spatial records

Drought stress occurrence and recovery from drought can be detected using a single spatial set of simultaneous observations of SIF and canopy temperature records. Temporal and spatial responses to drought and heat stresses by plant stands of a drought-adapted diverse grassland ecosystem were studied using sun induced fluorescence (SIF,O2A and O2B bands) and further ecophysiological (canopy temperature (Tsurf), spatially modeled evapotranspiration, vegetation reflectance spectra) variables collected along spatial sampling grids while also utilizing eddy covariance measured carbon dioxide (net ecosystem exchange: NEE, gross primary production: GPP) and water flux (evapotranspiration: ET) data. The grids were of 0.5 and 5 ha spatial extents and contained 78 sampling points. Data were collected in four spatial sampling campaigns, two under drought (early summer) and another two during and after recovery (midsummer) at both spatial resolutions.Small values of spatial SIF_A averages (around 0.5 mW m−2 nm−1 sr−1) under strong early summer drought increased (to around 2 mW m−2 nm−1 sr−1) due recovery upon rain arrivals, showing high (R2: 0.8–0.88) positive temporal correlations to eddy covariance measured carbon (GPP, NEE) and water (ET) fluxes. Spatial averages of LAI, vegetation indices (NDVI, NIRv) and modeled ET followed similar temporal patterns.While SIF was depressed by drought, it showed higher values in high canopy temperature vegetation patches than in vegetation patches with lower Tsurf. The spatial pattern of higher SIF in higher Tsurf patches was persistent (2 weeks) under drought. The positive SIF_A-Tsurf spatial correlation turned into negative/not significant after recovery of the grassland from the drought, while hot summer weather persisted. It is proposed that, by using a single set of simultaneously measured spatial SIF and Tsurf data it is possible to infer whether the studied vegetation is under drought (and heat) stress while it could not be decided on the base of SIF data alone. Evaluation of the slope of the above relationship seems therefore beneficial before e.g. starting the (stress) classification procedure based on SIF.

Competitive asymmetry in a forest composed of a shade-tolerant species depends on gap formation

Competitive asymmetry is one of the most important determinants of size structure in plant communities. Light competition was believed to be size-asymmetric, as taller individuals preempt light. In fact, many studies indicated that light competition is size-asymmetric in monospecific stands of herbaceous plants. However, competition is size-symmetric in multispecific stands because shorter, shade-adapted species compensate for the low light availability through higher leaf area per aboveground mass (leaf area ratio; LAR) or higher light use efficiency for growth (LUE). Then, a question arises on whether light competition is asymmetric or symmetric if the stand is occupied by a shade-tolerant species. Moreover, it is also interesting how gap dynamics affect competitive asymmetry, given the fact that gap formation can improve light availability in lower layers of the canopy. We investigated the plant size, growth rate, and three-dimensional distribution of foliage and light availability in a natural forest dominated by a shade-tolerant tree, Fagus crenata. We found that competitive asymmetry varied dynamically across the forest. In closed canopies, the relative growth rate (RGR) was higher in taller trees, indicating size-asymmetric growth. Shorter trees partly compensated for their light interception by having higher LAR but did not achieve comparative RGR to taller trees. Conversely, in gaps, the RGR of shorter trees was equivalent to those of taller trees because of the improved light availability for smaller trees, indicating size-symmetric growth. These results suggest that changes in competitive asymmetry driven by gap dynamics can influence the spatiotemporal diversity of size structures in forests.

Produktivitas Serasah Daun Kopi Robusta (Coffea canephora Pierre) di Kebun Percobaan Politeknik Negeri Jember

Indonesia’s coffee production in 2021 will reach 774,6 thousand tons. The volume increased by 2,75% compared to the previous year of 753,9 thousand tons. Coffee production is directly proportional to litter production. Litter includes organic matter produced by plants and will return to the coffee soil. Litter plays an important role in the coffee plantation ecosystem because it is related to suppression of soil erosion and nutrient cycling. The existence of abundant litter if managed optimally is able to improve the physical properties of the soil and the litter can be used as compost by decomposition. The aim of the study was to examine the productivity of coffee plant litter. Litter productivity on coffee plants was measured using the litter trap method. The fallen litter was collected using litter traps measuring 1m x 1m as many as 24 pieces which were placed at the study site under stands of coffee plants with a trap height of 50 cm from the ground. The environmental parameters used are temperature, humidity, and wind speed. The results showed that the highest litter productivity occurred in the 3rd week of 18.07 g/m2/week in October 2022-January 2023, which coincided with the rainy season.

Impact of Variety and At-Planting Insecticides on Thrips (Thysanoptera: Thripidae) Management in Peanut

Tobacco thrips are one of the most prevalent early season insect pests in peanut production systems. Experiments were conducted in 2018 and 2019 in Stoneville Mississippi to evaluate integrated pest management approaches to mitigate negative effects of thrips. Experimental treatments included a normal and late planting date, varieties Georgia-06G and QR-14, and in-furrow insecticide treatments consisting of a non-treated control, phorate, and imidacloprid. Measurements included early and final plant stands, immature and adults thrips counts, and pod yield. In-furrow insecticide had a strong effect on number of thrips per plant with treatment thrips ranking of: phorate &lt; imidacloprid &lt; non-treated control. However, in-furrow insecticide had no interaction with variety or plating date. Although phorate provided greater thrips control than imidacloprid, pod yield for the two treatments was similar, and both in-furrow treatments had greater yield than the non-treated control. The variety QR-14 had greater pod yield than Georgia-06G when planted late. Overall, these results confirm that in-furrow insecticide applications of either imidacloprid or phorate are adequate in protecting against yield loss from thrips within a midsouthern peanut production environment.