Nutrient Release through Litterfall in Short Rotation Poplar Crops in Mediterranean Marginal Land

A detailed knowledge of how poplar leaf litter decomposes under Mediterranean marginal conditions can help to minimize fertilization inputs and determine the profitability and sustainability of energy crops established in these particularly sensitive areas for bioenergy. Leaf litter decomposition was monitored for 32 months using the litterbag technique in a poplar crop under short rotation conditions in a marginal Mediterranean area. In addition, nutrient dynamics, together with the production and composition of the woody and foliar biomass produced, were studied for a period of four years. Leaf litter decomposition was relatively slow, particularly during the winter months, and accelerated in early spring, coinciding with the rainy season. At the end of the decomposition study 50% of the initial litterfall was decomposed, releasing roughly 60% of the N, 40% of the K, and 70% of the P initially present in fresh leaves. Annual yields of 6.0 dry Mg ha−1 were obtained. The aerial biomass produced the first year of the second rotation cycle extracted 83, 8.7, and 29 kg ha−1 of N, P, and K, respectively, whereas the amount of nutrients that were estimated to be naturally supplied to the system through leaf litter decomposition were 180 kg ha−1 of N, 19 kg ha−1 of P, and 30 kg ha−1 of K. Therefore, four years after establishing the energy crop, leaf litter was able to release higher amounts of primary macronutrients into the environment than the nutrient uptake by the produced aboveground biomass (woody and foliar biomass).

Essential oil and linalool contents in basil (Ocimum basilicum) irrigated with reclaimed water

Essential oils (EO) are volatile compounds with complex chemical compositions that are derived from the secondary metabolism of aromatic herbs. There are several applications of EO in the industrial and medical sectors. Basil (Ocimum sp.) is one of the most important EO-producing aromatic herbs. In this study, EO content (EOC) and linalool content (LC) in basil irrigated with reclaimed water were investigated. Plant development parameters, nutrient absorption and crude protein (CP) content were also evaluated. The experiment was conducted in a greenhouse, with five different treatments and five repetitions each. Compared with treatments only using water, the results of those with reclaimed water irrigation showed higher nutrient absorption, CP contents (in their foliar tissue), length of plant branches, foliar biomass weights, and EOC and LC. EOC reached up to 0.58% of the dry biomass and LC was up to 5.84% of EO mass. In practice, it is estimated that around 5.8 kg of EO and 0.34 kg of linalool can be obtained from one ton of dry basil biomass.

The Effect of Foliar and Soil Application of Flufenacet and Prosulfocarb on Italian Ryegrass (Lolium multiflorum L.) Control

Italian ryegrass (Lolium multiflorum Lam.) can be a troublesome weed that may causes high yield losses to several crops. Ryegrass resistance to the typically used acetolactate synthase (ALS) and acetyl-CoA carboxylase (ACCase) inhibiting herbicides complicates the control. As an alternative, we evaluated and compared the effects of two soil-acting herbicides, flufenacet and prosulfocarb, on susceptible L. multiflorum. The herbicides were applied in two doses in three different methods of applications: (1) soil and foliar application (2) foliar application, and (3) soil application only. Two greenhouse experiments separated in time showed that both herbicides reduced root and foliar biomass significantly as compared to the nontreated plants. In experiment 1, both herbicides resulted in lower efficacy when they only were applied to the leaves compared to the nontreated plants. Especially the foliar effect of flufenacet was small. The highest dose of prosulfocarb (4200 g ai ha−1) reduced the fresh foliar weight by 61% in experiment 1 and by 95% in experiment 2. The lowest dose of prosulfocarb (2100 g ai ha−1) reduced the weights by 73% (experiment 1) and 98% (experiment 2), respectively. For both herbicides the soil and foliar application applied postemergence were effective in reducing growth of L. multiflorum significantly in both experiments. Foliar application showed inconsistent results, showing that soil absorption plays an important role on herbicide efficacy even when the herbicides are applied postemergence. Postemergence application of prosulfocarb and flufenacet were effective to reduce L. multiflorum growth having apparently good root and leaf absorption.

Browse potential of bristly locust, smooth sumac, and sericea lespedeza for small ruminants

Temperate grass and legume yield and quality are markedly reduced during hot, dry summer months in the southern USA; therefore, browse species could add feed options for small ruminants during this season. Our objective was to compare total biomass yield and forage nutritive value of two browse species, leguminous bristly locust (Robinia hispida) and smooth sumac (Rhus glabra), as well as a leguminous shrub known as sericea lespedeza (Lespedeza cuneate), during summer months (June, July, August and September). Plants were sampled monthly during growing-seasons in 2012 and 2013 to determine biomass yield (foliar, shoot, and total above ground) and foliar nutritive value [crude protein (CP), acid detergent fiber (ADF), acid detergent lignin (ADL), and condensed tannins (CT)]. There was a species × harvest time interaction for foliar biomass yield (P = 0.0125). This interaction was likely due to low yield in June for bristly locust compared with sericea lespedeza and smooth sumac, but in all other months (July, August, and September) yields were similar for each species. Bristly locust had the highest CP (16.9%), followed by sericea lespedeza (14.8%), and smooth sumac (12.3%). Acid detergent fiber and ADL were similar between bristly locust (ADF 38.5%; ADL 24.1%) and sericea lespedeza (ADF 38.4%; ADL 23.1%), but was lower for smooth sumac (ADF 22.1%, ADL 6.3%; P < 0.05). Condensed tannins, an anti-nutritive yet anti-parasitic phenolic compounds, were highest in smooth sumac, intermediate in bristly locust, and lowest in sericea lespedeza. Plant foliar percentage (ratio of foliar to shoot mass), was highest in smooth sumac (55.1%), followed by sericea lespedeza (47.7%), and bristly locust (42.6%). Overall, smooth sumac had the highest foliar biomass and lowest ADF and ADL; however, this species had the lowest CP and highest CT. Consequently, average foliar biomass yield of all three browse species in our study far exceeded forage yield from dominant forage species [tall fescue (Schedonorus arundinaceus) and bermudagrass (Cyanodon dactylon)] in this region and may provide high-yielding, low input, anti-parasitic fodder for small ruminants during this period in the Southeastern U.S.

Seasonal Effect on Growth Performance and Leaf Biomass Production of Two Moringa oleifera Lam. Varieties Grown under Sahelian Condition in Burkina Faso

Aims: An experiment was conducted to compare the growth performance of two varieties of Moringa oleifera (wild variety and PKM-1) under different seasonal period at two locations in northern Burkina Faso, and the potential for improving household nutrition. Study Design, Place and Duration of Study: Two separate trials corresponding to sowing period (cold and warm) were laid out at each site (Bani and Tougou) in a completely randomized block design with three replicates between December 2017 and September 2018. Methodology: Each block was subdivided into two plots of 8 m² (separated from each other by 3 m break) intended to receive each variety of Moringa at each sowing period. The seeds were sown with 2 seeds by pit at 2 cm depth with spacing of 0.5 m x 0.5 m in each plot ploughed up to 30 cm. Watering was done daily during the dry season and consisted of applying 24 liters of water in each plot at two times. Vegetative growth measurements (plant height, number of leaves) were done weekly while leaf biomass production was assessed monthly from the 40th day after sowing. Results: The results showed that seedlings growth parameters and foliar biomass differed significantly (p < 0.001) among the two Moringa oleifera varieties and were influenced by the sowing period and sites. Although the two varieties grew well, Moringa oleifera var PKM-1 grew faster and produced much leaves compared to the wild or local variety. Then, greater growth attributes (height and number of leaves) and foliar biomass were noted for PKM-1. Conclusion: The warm period (March / April) appear to be the most recommendable period for the growth and biomass accumulation of the two varieties of Moringa oleifera.

The biosynthesis of pharmacologically active compounds in Calophyllum brasiliense seedlings is influenced by calcium and potassium under hydroponic conditions

<p><strong>Background:</strong> The influence of soil nutrients on biosynthesis of secondary metabolites from tropical trees has been poorly investigated.</p><p><strong>Questions: </strong>Does<strong> </strong>the deprival of Ca²⁺ and K⁺ influence the production of pharmacologically active compounds in the seedling of <em>Calophyllum brasiliense</em>?</p><p><strong>Species study</strong>: <em>Calophyllum brasiliense</em> Cambess.</p><p><strong>Study site: </strong>Los Tuxtlas, Veracruz, Mexico; November 2005 to November 2009.</p><p><strong>Methods: </strong>The seedlings were obtained from seeds and subjected to different hydroponic treatments: 1) modified Hoagland solution (MHS), 2) MHS-Ca²⁺, and 3) MHS-K⁺. Growth, height, foliar biomass, and HPLC analysis were performed after 7 months.</p><p><strong>Results: </strong>Under hydroponic conditions Ca²⁺ and K⁺ deficiency induced the mortality of 53 % and 28 % of the seedlings, respectively. The foliar biomass, and plant height of the survivors were also drastically reduced. MHS-K⁺ treatment induced a 15, 4.2 and 4.3-fold decrease for calanolides B, C, and apetalic acid in the leaves, respectively. MHS-Ca²⁺ treatment induced a decrease of 4.3, and 2.4-fold for calanolide B, and C, respectively.</p><p><strong>Conclusion: </strong>Ca²⁺ is essential for survival of <em>C. brasiliense</em> seedlings under hydroponic conditions, Ca²⁺ and K⁺ are critical for growth, foliar production, and biosynthesis of apetalic acid, and calanolide B.</p>

Vertical distribution of foliar biomass in western larch (Larix occidentalis)

Western larch (Larix occidentalis Nutt.) is an endemic pioneer species in northwestern North America and unique as a deciduous conifer and the most shade-intolerant, fastest growing, and most fire-resistant species in the northwestern United States. To better understand its production ecology, we used a multilevel modeling approach to analyze the intrinsic dynamics of western larch vertical foliage distribution and compared it with other species. We found that western larch allocates foliage into a more diffuse distribution as the crown lengthens, whereas shade-tolerant evergreens concentrate foliage into a more monolayered distribution higher within the crown as it lengthens. Crown foliar biomass scaled linearly with diameter at breast height, indicating that western larch does not fill volume in the crown with foliage at an increasing rate like other conifers. Our model supports the hypothesis that foliar shade intolerance and water stress jointly influence foliage allocation in this deciduous conifer. These results also highlight intrinsic foliage distribution as a factor potentially contributing to the inability of western larch to survive light-limiting conditions and its preference for mesic sites. The models developed here provide a basic framework that may be built upon to study the morphological response of western larch to modified stand conditions such as disturbance and silvicultural treatment.

Foliar biomass production and litterfall pattern of five timber species in forest plantations of semi-arid lands of the northeastern Mexico

<p>Fodder shrubs and trees have both economic as well as ecological values in most extensive systems of arid and semiarid regions.</p><p> As hypothesis, there is a relationship between the litterfall pattern and the foliar biomass production in forest plantations of semiarid areas, depending on the different seasons and species.</p><p> The studied species were: <em>Acacia berlandieri </em>(Benth.), <em>Acacia wrightii </em>(Benth.), <em>Ebenopsis ebano </em>(Berl.)<em> </em>Barneby,<em> Havardia pallens </em>(Benth.) Britton &amp; Rose and <em>Helietta parvifolia </em>(Gray) Benth.</p><p> The foliar biomass was evaluated seasonally, from the dry weight of a representative branch of each species. The litterfall was collected every 15 days through litter traps installed under tree canopies, in experimental plantations of 30 years old, in the semi-arid zone of northeastern Mexico.</p><p> There were highly significant differences (p&lt;0.01) both among<strong> </strong>species as seasons in the foliar biomass values, whereas there were no significant differences (P&gt;0.05) among species in litterfall, but highly significant differences (P&lt;0.01) among seasons. The foliar biomass reached the maximum production in summer (9029 kg ha^-1) with <em>E. ebano</em>, while the lowest value (103 kg ha^-1) was recorded with <em>A. wrightii</em> in winter. The litterfall greatest accumulation occurred in winter (296 kg ha^-1) with <em>A. wrightii</em>. A significant linear correlation (R²=63%) was determined between accumulation of litterfall and foliar biomass production.</p> As conclusion, the litterfall pattern is related to the foliar biomass production, depending on the seasons and species. That constitutes a practical tool for the management of the forest ecosystems in semiarid areas.

A management experiment reveals the difficulty of altering seedling growth and palatable plant biomass by culling invasive deer

Context There is concern that deer are shifting forests towards undesirable trajectories, and culling of deer is often advocated to mitigate these impacts. However, culling deer is expensive and sometimes controversial. To reliably ascertain whether such action is beneficial, management-scale experiments are needed. We conducted a management experiment to evaluate the benefits of culling deer in four New Zealand forests. Aims Our experiment tested the predictions that culling deer should increase (1) canopy tree seedling height relative growth rate (SHRGR), and (2) the foliar biomass of understorey species palatable to deer (FBP). Methods Each forest was divided into two 3600-ha areas, with deer culling randomly assigned to one area. Deer abundances were indexed using faecal pellet counts, and forest variables were measured at the start and end of the 8-year experiment. Deer were already at low abundance in one forest and were not culled there. We used structural equation modelling (SEM) with Bayesian variable selection to update our a priori graphical forest–deer model with data from all four forests. Key results Deer abundances were significantly reduced in one forest but increased or did not change in the other two forests in which deer culling occurred. Culling deer did not increase seedling height relative growth rate (SHRGR) or the foliar biomass of understorey species palatable to deer (FBP) in the three areas subject to deer culling compared with the three areas not subject to deer culling. SEM revealed no significant relationships between local-scale deer abundance and either SHRGR or FBP. Rather, tree basal area and the foliar biomass of unpalatable understorey species were important predictors of FBP and SHRGR, respectively, in some forests. Conclusions Our study revealed that culling deer, as currently practiced by New Zealand land managers, did not generate the desired responses in New Zealand forests, possibly due to deer not being culled to sufficiently low densities and/or because forest dynamics and abiotic drivers determined plant growth more than deer. Implications Managers should consider actions other than ineffective deer culling (e.g. creating canopy gaps) to alter the dynamics of New Zealand forests. Alternatively, managers will need to substantially increase culling effort above what is currently practised for this activity to substantially reduce deer populations and thus potentially alter forest dynamics.