Intermediate Harvest Research Articles

Can fertilization of potato (Solanum tuberosum L.) with potassium sulfate cause oxidative stress in the plants?

AbstractBackgroundPotatoes are regarded very prone to chloride toxicity, and the application of sulfate‐based potassium fertilizers is therefore recommended. However, in several studies, no significant differences between KCl and K2SO4 on tuber yield and starch concentration were found. In addition, plant shoots occasionally showed more pronounced stress symptoms after sulfate compared to chloride treatment.AimsThis study aimed to identify reasons for enhanced stress occurrence of potato plants after K2SO4 instead of KCl fertilization.MethodsWe conducted a pot experiment with the potato cultivar Marabel, which showed to be chloride‐resistant in our previous study, and applied 1 g K or 2 g K either as K2SO4 or KCl. Plant shoots were analyzed for nutrients, sugars, and antioxidative capacity shortly before start of flowering (intermediate harvest), and tubers were harvested at physiological maturity and their starch concentration and yield were determined.ResultsWith sulfate‐based K fertilization, the start of flowering and ripening as well as the achievement of physiological maturity occurred earlier than with KCl supply. However, the accelerated development of K2SO4‐treated plants did not affect shoot fresh and dry mass shortly before flowering and at maturity, showing similar values as in the KCl treatment. With 2 g K as K2SO4, the potato plants produced much larger and less than half the number of tubers compared to 2 g K as KCl, resulting in a significantly reduced tuber fresh mass. Tuber starch concentration as well as starch yield per plant were not significantly affected by the kind of K fertilization. In plant shoots shortly before flowering, calcium and magnesium concentrations were significantly decreased, combined with a significant increase in antioxidative capacity after application of 2 g K as K2SO4 compared to KCl. Sugar concentrations and contents in potato shoots at flowering were mostly unaffected by the kind of K fertilizer.ConclusionsStronger toxicity symptoms and growth inhibition after sulfate compared to chloride application, combined with a significant increase in antioxidative capacity, provide evidence for sulfate‐induced oxidative stress. A higher production of organic anions such as succinate may be involved in the stress reaction. This needs to be investigated in more detail in further studies.

English

Harvest time has an important influence on the storability of fruits. And the blueberry fruits bloom and mature in batches. Present study was conducted to investigate the effect of harvest dates on the postharvest quality of Northland blueberries during 49 days of storage at 4?1 ?C. We examined fruit weight loss decay rate firmness soluble solid content (SSC) titratable acidity (TA) vitamin C (VC) total phenol flavonoid anthocyanin and malondialdehyde (MDA) content polyphenol oxidase (PPO) and peroxidase (POD) activities in five blueberry batches with different (early middle and late) harvest times. Results indicated that after harvest blueberries underwent deterioration of their qualities owing to fast ripening and senescence. Among the five examined batches those harvested 60 and 65 days after flowering (middle harvest) were less affected by the storage period. Fruits from these batches maintained longer postharvest quality and showed extended storage life through the deceleration of weight loss decay incidence PPO activity softness TA SSC VC and increase in the total POD activity phenol flavonoid anthocyanin and MDA content. Based on our data the early and late harvested fruits are better suited for fresh fruit sales while fruits with intermediate harvest dates are optimal for long-term storage. Our study provides a reference framework for the postharvest storage of certain blueberry cultivars by taking into account their harvest dates.

Producción de restos vegetales y descomposición de hojarasca foliar bajo distintas intensidades de corta en fajas en matorrales

Biomass extraction in native forests can induce changes in the functioning of these ecosystems; these changes are poorly studied, and this represents a knowledge gap. In this work, we evaluated the response of plant litter production and decomposition to increasing intensities of strip cutting in native scrublands. We set an experiment replicated in three sites: hillside with southern exposure (FS), hillside with northern exposure (FN) and valley bottom (R), with four intensities of strip cutting (0, 30, 50, and 70% of the area). To evaluate decomposition, we used bags filled with ñire leaves (Nothofagus antarctica), and for the production of litter, plastic mesh collectors. In addition, vegetation height and cover were measured. In the three sites, we observed the same temporal pattern of decomposition, with a marked decrease in organic matter during the coldest period of the year. The effects of cutting intensity were strongly influenced by the site: at FS, litter production increased, but there was no effect on decomposition; in contrast, at FN and R, production decreased and a curvilinear pattern was observed, with highest decomposition at intermediate harvest intensity. Aerial cover was positively correlated with production, and this, in turn, negatively correlated with decomposition. Our results suggest that in scrublands with high vegetation cover, strip cutting could promote litter production without affecting decomposition. In contrast, less productive sites with lower vegetation cover would be more sensitive to forestry interventions.

Effects of animal manures on growth and yield of maize (Zea mays L.)

A spatial survey to investigate the effects of the use of poultry, sheep, and horse manure on intermediate harvests and maize growth restrictions was conducted on the research farm of Woillu Woreda, Ethiopia during the 2017 planting season. Treatment was performed with Randomized Complete Block Design (RCBD) with three responses. The measured variables were plant length, number of leaves, location indicator (LAI), stem girth, and grain yield obtained. The data collected is subject to variance analysis (ANOVA). Methods were categorized using LSD at a 5% significance level. The results obtained showed that the growth and yield of Maize were significantly lower in treatment control, indicating that the manure used in the study, especially the chicken manure, had a positive effect on the performance and yield of Maize. The results also revealed that poultry-cleaned sites offer the highest number of leaves per plant, the thick stem, the highest LAI, and the grain yield of 5.7 t/ha. In comparison, a small grain yield of 4.2 t/ha was obtained with the application of horse manure. Sheep manure produced 3.9 t/ha of maize and a small yield of 2.8t/ha of maize was recorded in the control management. Based on the results of the study it can be found that chicken manure seems to promote the growth of maize yield. Therefore, it should be recommended for maize growers in the study area.

Introducing a New Approach in Stand Tending Planning and Thinning Block Designation by Using Mixed Integer Goal Programming

Long-term management plans have been developed for nearly all of the forests in Turkey. These plans are applied at a sub-district management unit level and may contain guidance for both intermediate yield and final yield harvests. To implement an intermediate yield plan, which involves the scheduling of forest thinnings (stand tending), consideration in Turkey is given to the advantages of working in the same terrain and the same general area each year. Therefore, compartments are often clumped together to create thinning blocks, taking into consideration the thinning priority of the stands, road conditions, site index, age, and proximity of the compartments. Further, when preparing annual budgets and planning to meet the market’s needs, forest enterprises require an even flow of intermediate wood volume each year. In this paper, we introduce a new approach in stand tending planning designed to schedule an equal amount of intermediate wood volume each year and to create thinning blocks by minimizing the distance to pre-defined ramps (landings). We developed both linear and nonlinear goal programming models to minimize both the deviations from a harvest volume (annual intermediate yield allowable cut) target and the deviations from a target value determined for the distances (total and average) of the centroid of each compartment to the hypothetical forest ramps. By using the extended version of Lingo 16, we solved the problem with different weights for the deviations in volume and distance that ranged from 0.0 to 1.0, in 10% intervals, which created 11 scenarios. We carefully analyzed the results of each scenario by taking into consideration the wood volume and distance of compartments to the ramps. The best scenario using the linear model produced a deviation in volume scheduled for the entire decade of 6 m3, while the deviation in total distance between harvest areas and ramps was 59.7 km. Scenario 5, with weights of 0.6 for volume and 0.4 for distance, produced these results, where compartments were closest to one another. The best scenario using the nonlinear model also produced a deviation in volume of 0 m3 and the total average deviation in distance between harvest areas and ramps was 8.7 km. Scenario 3, with weights of 0.8 for volume and 0.2 for distance, produced these results. The approach and models described through this study may be appropriate for further integration into forest management planning processes developed for the planning of Mediterranean forests.

EFFECT OF HARVESTING TIME ON GRAIN YIELD AND QUALITY CHARACTERISTICS OF SOME RICE CULTIVARS AT DIFFERENT STORAGE PERIODS

The field experiments were conducted at The Experimental Farm of Sakha Agricultural Research Station, Kafr El-Sheikh, Egypt during 2018 and 2019 seasons to investigate the effect of harvest time on grain yield and its attributes as well as grain quality characteristics of some rice cultivars at different storage periods. The experiments were laid out in a split-plot design, with three replications. The main plots were devoted to harvest time i.e. harvest after 7, 14, and 21-day after irrigation cut-off (DAIC). However, the sub-plots were assigned to rice cultivars (Sakha106, Sakha107 and Sakha 108). The grain quality characteristics were studied at 6, 9 and 12-month after harvesting. Delaying the harvest date to 21-DAIC lead to a significant decrease in number of filled and unfilled grains/panicle, panicle weight and grain yield compared with 7- and 14-DAIC. The inverse was true in 1000-grain weight. Sakha 108 was superior to Sakha 106 and Sakha 107 in grain yield and its attributes. The highest grain yield was obtained from Sakha 108 at harvest time of 14-DAIC. Moisture content, hulling, milling and head rice percentages were gradually decreased by increasing storage period from 6 to 9 and 12-month. The inverse was found in amylose, elongation percentages and gelatinization temperature (GT). The intermediate harvest time 14-DIAC registered the highest values of all grain quality characteristics. Sakha 108 registered the lowest moisture content and the highest values of other grain quality. Generally, Sakha 108 harvested at 14-DAIC achieved the highest grain yield and quality at the 9-month storage period.

Drought stress in sunflower causes inhibition of seed filling due to reduced cell‐extension growth

AbstractCultivation of sunflower (Helianthus annuus L.) as one of the most important oil crops is of great importance, especially with focus on drought tolerance under the current climate change. Less precipitation and increasing temperatures lead to more regions with drought problems. In a container experiment, with two different sunflower cultivars, drought stress of 40% water‐holding capacity was applied at the seed‐filling phase and compared to a control group with regular irrigation to 70% water‐holding capacity. Four intermediate harvests during the seed‐filling phase and a final harvest at maturity were conducted. During the seed‐filling phase, sugar and α‐amino‐acid concentrations of seeds were not reduced by drought stress. Thus, assimilate availability was sufficient, pointing to no source limitation of seed development. The DNA content of the seeds was also not affected and pointed to no limitation of cell division. However, 40 days after flowering a reduction of cell extension was found. Consequently, a sink limitation occurred under drought stress. At final harvest, seed yield was significantly reduced under drought stress due to a lower single seed weight, whereas seed number per plant was unaffected. Oil concentration was not reduced by drought stress. Thus, oil synthesis did not limit oil yield. Consequently, a reduced oil yield under drought stress during the seed‐filling phase was caused by a lower seed weight, which resulted from a decreased cell extension.

Effect of stocker management program on beef cattle skeletal muscle growth characteristics, satellite cell activity, and paracrine signaling impact on preadipocyte differentiation.

The objective of this study was to determine the effect of different stocker management programs on skeletal muscle development and growth characteristics, satellite cell (SC) activity in growing-finishing beef cattle as well as the effects of SC-conditioned media on preadipocyte gene expression and differentiation. Fall-weaned Angus steers (n = 76; 258 ± 28 kg) were randomly assigned to 1 of 4 stocker production systems: 1) grazing dormant native range (NR) supplemented with a 40% CP cottonseed meal-based supplement (1.02 kg · steer−1 · d−1) followed by long-season summer grazing (CON, 0.46 kg/d); 2) grazing dormant NR supplemented with a ground corn and soybean meal-based supplement fed at 1% of BW followed by short-season summer grazing (CORN, 0.61 kg/d); 3) grazing winter wheat pasture (WP) at high stocking density (3.21 steers/ha) to achieve a moderate rate of gain (LGWP, 0.83 kg/d); and 4) grazing winter WP at low stocking density (0.99 steers/ha) to achieve a high rate of gain (HGWP, 1.29 kg/d). At the end of the stocker (intermediate harvest, IH) and finishing (final harvest, FH) phases, 4 steers / treatment were harvested and longissimus muscles (LM) sampled for cryohistological immunofluorescence analysis and SC culture assays. At IH, WP steers had greater LM fiber cross-sectional area than NR steers; however, at FH, the opposite was observed (p < 0.0001). At IH, CORN steers had the lowest Myf-5+:Pax7+ SC density (p = 0.020), while LGWP steers had the most Pax7+ SC (p = 0.043). At FH, CON steers had the highest LM capillary density (p = 0.003) and their cultured SC differentiated more readily than all other treatments (p = 0.017). At FH, Pax7 mRNA was more abundant in 14 d-old SC cultures from HGWP cattle (p = 0.03). Preadipocytes exposed to culture media from proliferating SC cultures from WP cattle isolated at FH had more PPARγ (p = 0.037) and less FABP4 (p = 0.030) mRNA expression compared with NR cattle. These data suggest that different stocker management strategies can impact skeletal muscle growth, SC function, and potentially impact marbling development in growing-finishing beef cattle.

Chemical and Sensorial Characteristics of Olive Oil Produced from the Lebanese Olive Variety ‘Baladi’

The olive oil quality, nutritional and sensorial characteristics are associated with the chemical composition, which is the result of a complex interaction between several environmental, agronomical and technological factors. The aim of the present study is to investigate the impact of the geographical origin, harvesting time and processing system on the chemical composition and sensorial characteristics of olive oils produced from the Lebanese olive ‘Baladi’. Samples (n = 108) were collected from North and South Lebanon, at three different harvesting times and from four processing systems. Results showed a strong effect of origin, processing system and harvest time on oil quality, fatty acid composition, total phenols and OSI. The early harvest showed higher total phenols content (220.02 mg GAE/Kg) and higher OSI (9.19 h). Moreover, samples obtained from sinolea and 3-phases recorded the lowest free acidity (0.36% and 0.64%), and the highest OSI (9.87 and 9.84 h). Consumers were not unanimous regarding the studied factors, although samples recording high ranks were mostly from South using sinolea, 3-phases and press systems at early and intermediate harvest. The overall findings suggest that the selection of the harvesting time and of the processing system could have significant influence on the characteristics of the olive oil.

Community forest management: Comparison of simulated production and financial returns from agarwood, tengkawang and rubber trees in West Kutai, Indonesia

Lahjie AM, Isminarti, Simarangkir BDAS, Kristiningrum, R, Ruslim Y. 2018. Community forest management: Comparison of simulated production and financial returns from agarwood, tengkawang and rubber trees in West Kutai, Indonesia. Biodiversitas 19: 126-133. Research was conducted in planted forests of agarwood (Aquilaria spp.) and tengkawang (Shorea macrophylla) and in plantations of natural rubber (Hevea brasiliensis) in West Kutai District, East Kalimantan Province, Indonesia. The research aimed (i) to find out the productivity of agarwood and tengkawang trees in mixed plantings (ii) to measure their rate of development in order to estimate the maximum Mean Annual Increment (MAI) for agarwood and tengkawang and (iii) to carry out a comparison with natural rubber production of the investment feasibility of planted forests of these trees using a financial analysis of Pay Back Period, Net Present Value (NPV), Net Benefit/ Cost (B/C) Ratio and Internal rate of Return (IRR). The research was based on measurements carried out in plots, 0.25 ha in extent, selected by systematic random sampling from three model plantations. Plantation Model I was a combination of agarwood and tengkawang in one piece of land in which the agarwood trees were planted at a spacing of of 5m x 2.5m and the tengkawang tree were also planted at a spacing of 5m x 2.5m. This means that there were a total of 200 agarwood saplings and 200 tengkawang saplings in the plot. Model II was the combination of agarwood and tengkawang in one piece of land, in which 167 agarwood saplings were planted and 166 tengkawang saplings were planted in a different planting arrangement (at the planting distance of 5m x 3 m). Model III was rubber trees in an area of 0.25 ha with 119 saplings. The data for natural rubber were collected in series from the farmers. The measurement variables for agarwood and tenkawang included the diameter and height of trees using series measurement until they reached 30 years and then the results were simulated. The research findings showed that in Model I, agarwood was found to have higher maximum MAI while in Model II, tengkawang was found to have higher maximum MAI. This was the result of a silvicultural technique in which thinning, maintenance and intermediate harvest were carefully controlled. These two models were feasible for business because the values of their IRR were 14% and 13.3% respectively, while in Model III, rubber cultivation was not feasible for business because the value of its IRR was only 4.7%.

Long-term effects of single-tree selection on the frequency and population structure of root and butt rot in uneven-sized Norway spruce stands

Abstract The goal of this study was to assess the long-term effects of partial harvesting and supplementary soil scarification on the frequency of root and butt rot in managed uneven-sized Norway spruce stands. Frequency of rot and the population structure of the rot fungi were assessed on 1353 stumps after clear-cutting 21 years after a selection harvesting experiment. The initial experiment was comprised of three harvest strength (low, intermediate and high) of single-tree selection, removing approximately 25, 45 and 65% of the stand basal area. Uncut control plots were established at the same time. Supplementary soil scarification was applied in subplots within the single-tree selection plots, using a medium-sized excavator. After clear-cutting the stumps were analyzed with respect to rot caused by Heterobasidion parviporum, Armillaria spp., Stereum sanguinolentum as well as other rot fungi. Rot caused by Armillaria spp. was most common (8.6% of the stumps), while infection by H. parviporum (2.9%) or S. sanguinolentum (3.0%) was less frequent. The group “other rot” (5.4%) comprised 21 identified taxa, each occurring in 1–15 stumps. Significantly lower rot frequencies were found for the uncut control (16.3%) and intermediate harvest strength (15.7%), compared with low harvest strength (23.6%). A rot frequency of 21.0% was found in the high harvest strength. In two of three harvest strengths, the rot frequency was higher than for the uncut control. As the observed rot frequencies did not increase consistently with increasing harvest strength, the results do not completely support the initial expectations of increased rot after single-tree selection compared with the uncut control. However, since the probability of rot in individual stumps on plots treated with single-tree selection was significantly affected by the distance to the nearest strip road (H. parviporum) as well as dependent on the size of and distance to the nearest stump of trees cut during the experimental harvest (H. parviporum, S. sanguinolentum and total rot), it is evident that the single-tree selection harvesting was partially responsible for some of the observed rot. One of the selection criteria in the initial harvest was a sanitary removal of trees of poor vitality. Varying degrees of sanitation felling may therefore have offset the effects of new infections in wounds or spread of rot fungi through adjacent stumps. Supplementary soil scarification in small gaps of the residual stand had no significant effect on the frequency of rot, suggesting that such treatment may be used to facilitate regeneration in uneven-sized spruce stands on similar sites.

Radial Growth Response of Black Spruce Stands Ten Years after Experimental Shelterwoods and Seed-Tree Cuttings in Boreal Forest

Partial cutting is thought to be an alternative to achieve sustainable management in boreal forests. However, the effects of intermediate harvest intensity (45%–80%) on growth remain unknown in black spruce (Picea mariana (Mill.) B.S.P.) stands, one of the most widely distributed boreal species with great commercial interest. In this study, we analysed the effect of three experimental shelterwood and one seed-tree treatments on tree radial growth in even-aged black spruce stands, 10 years after intervention. Our results show that radial growth response 8–10 years after cutting was 41% to 62% higher than in untreated plots, with stand structure, treatment, tree position relative to skidding trails, growth before cutting and time having significant interactions. The stand structure conditioned tree growth after cutting, being doubled in younger and denser stands. Tree spatial position had a pronounced effect on radial growth; trees at the edge of the skidding trails showed twice the increase in growth compared to interior trees. Dominant trees before cutting located close to the skidding trails manifested the highest growth response after cutting. This research suggests that the studied treatments are effective to enhance radial wood production of black spruce especially in younger stands, and that the edge effect must be considered in silvicultural management planning.

Harvest timing and its population dynamic consequences in a discrete single-species model

The timing of harvesting is a key instrument in managing and exploiting biological populations and renewable resources. Yet, there is little theory on harvest timing, and even less is known about the impact of different harvest times on the stability of population dynamics, even though this may drive population variability and risk of extinction. Here, we employ the framework proposed by Seno to study how harvesting at specific moments in the reproductive season affects not only population size but also stability. For populations with overcompensation, intermediate harvest times tend to be stabilizing (by simplifying dynamics in the case of unimodal maps and by preventing bubbling in the case of bimodal maps). For populations with a strong Allee effect, however, intermediate harvest times can have a twofold effect. On the one hand, they facilitate population persistence (if harvesting effort is low). On the other hand, they provoke population extinction (if harvesting effort is high). Early harvesting, currently considered common sense to take advantage of compensatory effects, may cut into the breeding stock when the population has not yet surpassed the critical Allee threshold. The results in this paper highlight, for the first time, the crucial interplay between harvest timing and Allee effects. Moreover, they demonstrate that harvesting with the same effort but at different moments in time can dramatically alter the impact on the population.

Effect of rate of body weight gain in steers during the stocker phase. I. Growth, partitioning of fat among depots, and carcass characteristics of growing-finishing beef cattle1

Two experiments were conducted to examine the effect of growth rate to similar age or BW on fat deposition in stocker cattle grazing dormant native range (DNR) or winter wheat pasture (WP). In each experiment, fall-weaned Angus steers were randomly allotted to 1 of 4 stocker production programs: 1) control, 1.02 kg/d of a 40% CP cottonseed meal-based supplement during grazing of DNR (CON); 2) corn/soybean meal-based supplement fed at 1% of BW during grazing of DNR (CORN); 3) grazing WP at a high stocking rate to achieve a low rate of BW gain (LGWP); and 4) grazing WP at a low stocking rate to achieve a high rate of BW gain (HGWP). In Exp. 1, a subset of steers (3 steers per treatment) was harvested after winter grazing (138 d) at similar age. The remaining WP steers were transitioned into the finishing phase, whereas DNR steers were allowed to graze the same native range pastures for another 115 d without supplementation before entering the feedyard. In Exp. 2, steers grazed their respective pastures until each treatment reached an estimated HCW of 200 kg (262, 180, 142, and 74 d, respectively, for the CON, CORN, LGWP, and HGWP treatments), at which time a subset of steers (4 steers per treatment) were selected for intermediate harvest before finishing. In both experiments, the remaining steers were fed a finishing diet to a common 12th-rib fat thickness of 1.27 cm. In Exp. 1, winter grazing ADG was 0.19, 0.52, 0.68, and 1.37 ± 0.03 kg/d; and in Exp. 2, winter/summer grazing ADG was 0.46, 0.61, 0.83, and 1.29 ± 0.02 kg/d, respectively for CON, CORN, LGWP, and HGWP treatments. At intermediate harvest in Exp. 1, HGWP steers had greater (P < 0.01) 12th-rib fat thickness and marbling scores, compared with the other treatments. However, in Exp. 2, LGWP steers had greater (P < 0.01) marbling scores compared with HGWP steers, which were greater than DNR steers. At final harvest in Exp. 1, LGWP steers had greater (P < 0.01) 12th-rib fat thickness and smaller LM area, compared with the other treatments; however, there were no differences (P = 0.99) in final marbling scores. In Exp. 2, CON steers had lower (P < 0.05) 12th-rib fat thickness and tended (P = 0.10) to have greater marbling scores, compared with the other treatments. These data suggest that changes in the partitioning of fat among depots during the stocker phase may not be reflected after finishing when steers are fed to a common 12th-rib fat thickness.

Effect of rate of body weight gain of steers during the stocker phase. II. Visceral organ mass and body composition of growing-finishing beef cattle

Two experiments were conducted to examine the effect of rate of BW gain during the stocker phase on visceral organ mass and body composition of growing-finishing cattle that had grazed dormant native range (DNR) or winter wheat pasture (WP). In each experiment, fall-weaned steers were allotted randomly to 1 of these stocker production programs: 1) control, 1.02 kg · steer(-1) · d(-1) of a 40% CP cottonseed meal-based supplement during grazing of DNR (CON); 2) corn/soybean meal-based supplement fed at 1% of BW during grazing of DNR (CORN); 3) grazing WP at a high stocking rate to achieve a reduced rate of BW gain (LGWP); and 4) grazing WP at a low stocking rate to achieve an increased rate of BW gain (HGWP). In Exp. 1, 3 steers per treatment were harvested after winter grazing (138 d). The remaining WP steers were transitioned into a finishing phase and DNR steers were allowed to graze the same pastures for another 115 d before entering a feedyard. In Exp. 2, steers grazed respective pastures until each treatment reached an estimated HCW of 200 kg (262, 180, 142, and 74 d, respectively, for CON, CORN, LGWP, and HGWP treatments), at which time 4 steers per treatment were randomly selected for intermediate harvest before finishing. At the end of the finishing period, 4 additional steers from each treatment were randomly selected for final carcass measurements. All steers were fed to a common 12th rib fat thickness of 1.27 cm. After winter grazing in Exp. 1, HGWP steers had the greatest (P < 0.01) mesenteric/omental fat, total viscera, total splanchnic tissue mass, and carcass and empty body fat, compared with the other treatments. In Exp. 2 at intermediate harvest, WP steers had greater (P < 0.03) mesenteric/omental fat, total viscera, and total splanchnic tissue mass, compared with CORN steers, with CON steers being intermediate. Also, the WP steers had greater (P < 0.02) carcass and empty body fat, compared with CORN steers, with CON steers being intermediate. At final harvest in Exp. 2, LGWP steers had the least total viscera and total splanchnic tissue mass, compared with the other treatments. However, there were no differences (P > 0.53) among treatments for carcass or empty body fat. Stocker systems using WP or DNR result in cattle with differences in body fat and visceral organ mass before finishing; this may influence feedlot efficiency, even though there were no differences in body fat and visceral organ mass at the end of the finishing period.

Effects of starch- vs. fiber-based energy supplements during winter grazing on partitioning of fat among depots and adipose tissue gene expression in growing cattle and final carcass characteristics

Fifty-five normal-weaned Angus steers (268 ± 22 kg; 265 ± 16 d of age) were used to evaluate the effects of starch- vs. fiber-based energy supplements for stocker cattle grazing low-quality dormant native range on growth performance, body composition, and adipose tissue development of different fat depots. Steers were randomly allotted to 4 treatments: 1.02 kg·steer(-1)·d(-1) of a 40% CP cottonseed meal-based supplement (CON), corn/soybean meal-based supplement fed at 1% of BW (CORN), soybean hull/soybean meal-based supplement fed at 1% of BW (SBH), or dried distillers grains with solubles fed at 1% of BW (DDGS). All supplements were individually fed 5 d/wk during the 121-d winter grazing phase. After winter grazing, 3 steers per treatment were harvested to determine body composition and carcass characteristics, and collect subcutaneous (SC) and perirenal (PR) adipose tissue samples. The remaining steers grazed cool-season grass pastures for 74 d without supplementation before finishing. Steers were fed a common finishing diet for 113 d before harvest, at which time carcass characteristics were collected at a commercial abattoir. Energy supplementation increased (P < 0.01) winter grazing ADG compared with CON steers, and CORN steers had greater (P < 0.01) ADG than SBH and DDGS steers. Energy supplementation increased (P < 0.04) mesenteric/omental fat mass but did not influence (P > 0.13) 12th rib fat thickness or marbling score at intermediate harvest compared with CON steers. The mRNA expression of genes involved in lipogenesis and markers of adipogenesis were greater (P < 0.05) in PR adipose tissue of energy-supplemented steers compared with CON steers but not in SC adipose tissue. Fiber-supplemented steers had greater (P < 0.01) mRNA expression of fatty acid synthase and fatty acid binding protein 4 compared with CORN steers in PR adipose tissue but not SC adipose tissue. At final harvest, energy-supplemented steers had greater (P < 0.05) KPH and yield grade than CON steers, but no differences (P = 0.75) in marbling score were observed. Neither energy supplementation nor type of energy supplement influenced intramuscular fat deposition in stocker cattle grazing dormant native range. These data suggest that the total energy intake and stage of animal maturity during grazing supplementation were not great enough to influence marbling deposition.

Soil and plant responses to controlled traffic farming in Switzerland

A long-term tillage experiment in Tänikon, Switzerland showed that compared to ploughed plots, untilled plots developed a compact soil structure with decreased porosity and a trend towards lower oxygen concentration in the soil air. All these factors resulted in lower plant yields. To investigate the influence of wheeling on these plots, the shallow-tilled plots were converted to controlled traffic farming (CTF) with no-tillage in 2008. The hypothesis is that a sustainable improvement in soil structure and plant development is achievable in areas with no traffic. In a field trial with four repeated blocks, ‘CTF no-tillage’ was compared with ‘random trafficked mouldboard ploughing’ and ‘random trafficked no-tillage’. The crop rotation was winter wheat – winter barley – meadow, established on luvisol (23% clay, 34% silt, 42% sand) with an annual rainfall of 1190mm and an average annual temperature of 8.4 °C. An intensive monitoring programme was set up for various parameters: Soil-surface-level changes, penetration resistance, macropore volume, soil-air composition, matric potential, volumetric soil-water content, emergence rate, intermediate harvests and harvest yield. Results for 2008 to 2011 show that traffic has a clearly negative impact on soil structure in all variants, even when wheelings are done with low tyre-inflation pressure. Traffic-induced soil-surface-level changes were small, but nonetheless affected the soil’s physical parameters. Soil penetration resistance is higher and soil oxygen content after precipitations lower in the trafficked areas than in traffic-free zones. Yield effects were not as pronounced as in other published field trials. CTF and no-tillage achieved approximately the same yield levels, but routine ploughing resulted in the highest yields. CTF leads to a certain improvement in the soil structure, but the plant response showed that more improvement is necessary to optimise yields.

Fenología, producción y contenido de almidón en árboles de mango en Guanacaste, Costa Rica.

Phenology, production and starch content of mango trees in Guanacaste, Costa Rica. The objective of this work was to determine the seasonal variation of the starch content of mango trees and its relationships to phenology and fruit production. Trees of Tommy Atkins (TA) and Keitt (K) varieties were studied in Guanacaste, Costa Rica. The phenological stages recorded were: (1) appearance of vegetative buds, (2)fl owering, and (3) fruit production. The latter represented thetotal weight of fruits per tree. Starch content was determined through enzymatic hydrolysis of wood from roots, trunks and branches for four phenological stages during 2004 and 2005.Temperature and precipitation was also recorded. Starchcontent varied through out the study, and was influenced byfl ower and fruit production, with the highest concentration(TA: 11,7%, K: 14.4%) just before flowering (between Augustand November). The lowest concentration of starch (6.1%)was recorded at post harvest for both varieties (May). TheTommy Atkins variety had the highest production in 2006 with 208,5 kg/tree and the lowest production in 2005 with 34.9 kg. In contrast, peak production occurred in the Keittvariety in 2005 with 212.1 kg, and the lowest in 2004 with36.7 kg/tree. The highest harvest in both varieties could beassigned to “on” years and the lowest to “off” years, while 2004 in Tommy Atkins could be considered an intermediate harvest of 86.7 kg/tree.

Allocation and remobilisation of nitrogen in spring oilseed rape (Brassica napus L. cv. Mozart) as affected by N supply and elevated CO2

CO2 enrichment interacts with the resource economy of plants, but time-integrated studies on N partitioning between different plant parts, C:N ratios and N remobilisation are mostly lacking.The present study addressed the nitrogen use efficiency (NUE) in spring oilseed rape (OSR) grown at three N fertilisation levels and two CO2 concentrations (380 vs. 550μmolmol−1). N was supplied in three equal gifts at sowing, stem elongation and flowering. One of these gifts was labelled with 15NH415NO3 respectively. Six intermediate harvests and a final harvest were performed to determine dry mass, N concentrations, C:N, N recovery and δ15N signatures in the plant fractions root, main stem, branches, green and senescent leaves, pod walls and seeds.While N concentrations were lower and C:N higher in green leaves under CO2 enrichment, more N remained in the root until the final harvest. Under ambient CO2 concentrations the harvestable product (seeds) contained 50.7%, 44.5% and 41% of the total N supplied in the treatments that received 75, 150 and 225kgha−1N, respectively. Under elevated CO2 these values decreased to 47.4%, 34.5% and 15% reducing the NUE of the seeds by 2%, 33% and 65%, respectively. In CO2 exposed amply fertilised plants much of the N remained in the side stems due to strong outbranching and reduced seed set. However, N remobilisation was more affected by the different N supply than by the CO2 enrichment.The boosted growth of OSR under high availability of N disrupted the source:sink relationships so that benefits from the CO2 enrichment on stem and root growth could not be realised by yield formation.

Soil and plant responses to controlled traffic farming in Switzerland

A long-term tillage experiment in Tanikon, Switzerland showed that compared to ploughed plots, untilled plots developed a compact soil structure with decreased porosity and a trend towards lower oxygen concentration in the soil air. All these factors resulted in lower plant yields. To investigate the influence of wheeling on these plots, the shallow-tilled plots were converted to controlled traffic farming (CTF) with no-tillage in 2008. The hypothesis is that a sustainable improvement in soil structure and plant development is achievable in areas with no traffic. In a field trial with four repeated blocks, ‘CTF no-tillage’ was compared with ‘random trafficked mouldboard ploughing’ and ‘random trafficked no-tillage’. The crop rotation was winter wheat – winter barley – meadow, established on luvisol (23% clay, 34% silt, 42% sand) with an annual rainfall of 1190mm and an average annual temperature of 8.4 °C. An intensive monitoring programme was set up for various parameters: Soil-surface-level changes, penetration resistance, macropore volume, soil-air composition, matric potential, volumetric soil-water content, emergence rate, intermediate harvests and harvest yield. Results for 2008 to 2011 show that traffic has a clearly negative impact on soil structure in all variants, even when wheelings are done with low tyre-inflation pressure. Traffic-induced soil-surface-level changes were small, but nonetheless affected the soil’s physical parameters. Soil penetration resistance is higher and soil oxygen content after precipitations lower in the trafficked areas than in traffic-free zones. Yield effects were not as pronounced as in other published field trials. CTF and no-tillage achieved approximately the same yield levels, but routine ploughing resulted in the highest yields. CTF leads to a certain improvement in the soil structure, but the plant response showed that more improvement is necessary to optimise yields.