Long-term Effects of Weed Management on Earthworm Abundance in a Banana Plantation in Davao City, Southern Mindanao, Philippines

Earthworm densities have been regarded as reliable indicators of soil health. A long-term field experiment was conducted in two sites (15% and 25% slope) to compare the effects of manual and chemical weeding (using paraquat and glyphosate) and determine other factors that may affect earthworm populations in a banana plantation. Based on four years of field observation, no significant difference in earthworm count between manual and chemical plots (15% slope: F-ratio: 0.96, p = 0.43; 25% slope: F-ratio: 14.18, p = 0.06) were observed. The earthworm species composition was found to differ between the two sites. The 15% site tends to have a higher earthworm population compared to the 25%-slope site, likely because of the former’s higher soil organic matter content. Earthworm populations were on a declining trend in both treatments for both sites, but regression analyses show these trends to be insignificant. Rainfall, organic mulch, and weed cover were not significantly correlated with the earthworm counts. However, the declining pH in both sites could help explain the decline in earthworm populations. Pontocolex corethrurus showed significant avoidance response to normal glyphosate concentrations (8.055 × 10–3 mL per 350 g soil) (p = 0.03), but not to paraquat (1.5 × 10–3 g per 350 g soil) (p = 0.55). Experiments suggest that both weed management treatments do not pose a significant threat to earthworms under the conditions studied. The negative effect of declining pH needs further study

Impacts of Long-term Weed Management on the Diversity and Abundance of Grasses in Banana Plantation Slopes in Davao City, Philippines

Banana is one of the main export products in the Philippines. The growing demand for banana products generates a need for plantation expansion even in erosion-prone areas like slopes. Effective farming practices in slopes are therefore needed to conserve the soil and establish a sustainable production. One of these systems is weed management, which is a critical component of farming practice in sloping lands. A 3-year study was conducted to compare manual and chemical (paraquat and glyphosate) weed management on the abundance and diversity of grasses in a banana plantation. Counts, biomasses, seed bank, and diversity indices of grasses were compared in identical experiments in 15% and 25% slopes. From the seed banks, 7 grass species were observed: Cyperus brevifolius, Cynodon dactylon, Eleusine indica, Imperata cylindrica, Paspalum conjugatum, Digitaria ciliaris, and Digitaria longiflora. Generally, there was a decreasing trend in the seed bank counts in both manual and chemical plots of 15% and 25% slope. However, the differences between treatments were not significant. Chemical treatments reduced the general counts and biomass of monocot weeds, but this effect was generally not significant. Chemical treatments significantly reduced the counts of P. conjugatum in 15% slope and the biomass of E. indica in 25% slope in the field. C. dactylon was found to be the dominant species in the field because of its early establishment in the slopes, its spreading growth and its allelopathic properties, which suppressed other species. There was a significant increase in diversity in both treatments on two slopes, but chemical plots had a significantly higher diversity compared to the manual plots. Chemical weeding was also less expensive and less laborious than manual weeding

Yield and Response of First and Ratoon Crops of Eggplant (Solanum melongena) to the Eggplant Fruit and Shoot Borer (Leucinodes orbonalis) under an Integrated Pest Management System

Eggplant (Solanum melongena) is a highly valued crop with an average production of 10 t·ha–1 and contributes to nearly PhP2 billion in the Philippine economy using conventional farming methods. An integrated pest management system was designed to control the eggplant fruit and shoot borer (EFSB) for increased productivity with reduction on harmful pesticide inputs. Under a split plot in randomized complete block design, two eggplant varieties, i.e., hybrid Banate King F1 (BK) and open-pollinated Dumaguete Long Purple (DLP), were tested under four different pesticide treatments, namely, (1) control–no pesticide, (2) organic–Bird’s chilli extract, (3) synthetic–spinosad + flubendiamide, and (4) combination–Bird’s chilli extract + spinosad + flubendiamide. After data was obtained, the first crops were ratooned and tested under the same IPM system. Data on yield and EFSB damage of the ratoon crops were compared with the first crop as influenced by eggplant variety and pesticide treatment. All plants were grown on plots covered with polyethylene mulch sheets under a uniform fertilization and fungicide regimen. Multiple cropping with regular field sanitation and inspection were also incorporated in the IPM system. Results indicate that BK is a superior variety over DLP with a gross yield of about 40 t·ha–1 and a marketable yield of about 20 t·ha–1 in 22 harvests. Ratoon crops produced lower yield than first crops with only 2 t·ha–1 in 12 harvests. Among the pesticide treatments, synthetic or combination treatments are superior over the control (no pesticide) or organic treatments. Use of open-pollinated DLP and chilli spray is inferior to hybrid and synthetic or combination sprays. Chilli spray also tends to nullify the effectiveness of synthetic pesticides when used in combination. The designed IPM system produced higher yield than conventional methods, but all treatments only provided moderate control over EFSB damage with average yield losses of about 50% in first crops and about 60% in ratoon crops

Improving Fission-product Decay Data for Reactor Applications: Part I -- Decay Heat

Effort has been expended to assess the relative merits of undertaking further decay-data measurements of the main fission-product contributors to the decay heat of neutron-irradiated fissile fuel and related actinides by means of Total Absorption Gamma-ray Spectroscopy (TAGS/TAS) and Discrete Gamma-ray Spectroscopy (DGS). This review has been carried out following similar work performed under the auspices of OECD/WPEC-Subgroup 25 (2005-2007) and the International Atomic Energy Agency (2010, 2014), and various highly relevant TAGS measurements completed as a consequence of such assessments. We present our recommendations for new decay-data evaluations, along with possible requirements for total absorption and discrete high-resolution gamma-ray spectroscopy studies that cover approximately 120 fission products and various isomeric states.Comment: Submitted to European Physical Journal

Measurement of \u3csup\u3e17\u3c/sup\u3eF + p reactions with ANASEN

Reactions involving radioactive nuclei play an important role in stellar explosions, but those reactions involving short-lived nuclei have only limited experimental information available due to currently limited beam intensities. Several facilities are aiming to provide greater access to these unstable isotopes at higher beam intensities, but more efficient and selective techniques and devices are needed to properly study these important reactions. The Array for Nuclear Astrophysics Studies with Exotic Nuclei (ANASEN), a charged particle detector designed by Louisiana State University (LSU) and Florida State University (FSU), was created for this purpose. ANASEN is used to study the reactions important in the αp- and rp- processes with proton-rich exotic nuclei, providing essentially complete solid angle coverage through an array of 40 silicon-strip detectors backed with CsI scintillators, covering an area of roughly 1300 cm2. ANASEN also includes an active gas target/detector in a position-sensitive annular gas proportional counter, which allows direct measurement of (α,p) reactions in inverse kinematics. The first in-beam measurements with a partial implementation of ANASEN were performed at the RESOLUT radioactive beam facility of FSU during the summer of 2011. They included stable beam experiments and measurements of the 17F(p,p) 17F and 17F(p,α)14O reactions which are important to understanding the structure of 18Ne and the 14O(α,p)17F reaction rate. The performance of ANASEN and initial results from the 17F studies will be presented. © Published under licence by IOP Publishing Ltd

Key 19^{19}Ne states identified affecting γ\gamma-ray emission from 18^{18}F in novae

Detection of nuclear-decay $\gamma$ rays provides a sensitive thermometer of nova nucleosynthesis. The most intense $\gamma$-ray flux is thought to be annihilation radiation from the $\beta^+$ decay of $^{18}$F, which is destroyed prior to decay by the $^{18}$F($p$,$\alpha$)$^{15}$O reaction. Estimates of $^{18}$F production had been uncertain, however, because key near-threshold levels in the compound nucleus, $^{19}$Ne, had yet to be identified. This Letter reports the first measurement of the $^{19}$F($^{3}$He,$t\gamma$)$^{19}$Ne reaction, in which the placement of two long-sought 3/2$^+$ levels is suggested via triton-$\gamma$-$\gamma$ coincidences. The precise determination of their resonance energies reduces the upper limit of the rate by a factor of $1.5-17$ at nova temperatures and reduces the average uncertainty on the nova detection probability by a factor of 2.1.Comment: 6 pages, 4 figure

New γ\gamma-ray Transitions Observed in 19^{19}Ne with Implications for the 15^{15}O(α\alpha,γ\gamma)19^{19}Ne Reaction Rate

The $^{15}$O($\alpha$,$\gamma$)$^{19}$Ne reaction is responsible for breakout from the hot CNO cycle in Type I x-ray bursts. Understanding the properties of resonances between $E_x = 4$ and 5 MeV in $^{19}$Ne is crucial in the calculation of this reaction rate. The spins and parities of these states are well known, with the exception of the 4.14- and 4.20-MeV states, which have adopted spin-parities of 9/2$^-$ and 7/2$^-$, respectively. Gamma-ray transitions from these states were studied using triton-$\gamma$-$\gamma$ coincidences from the $^{19}$F($^{3}$He,$t\gamma$)$^{19}$Ne reaction measured with GODDESS (Gammasphere ORRUBA Dual Detectors for Experimental Structure Studies) at Argonne National Laboratory. The observed transitions from the 4.14- and 4.20-MeV states provide strong evidence that the $J^\pi$ values are actually 7/2$^-$ and 9/2$^-$, respectively. These assignments are consistent with the values in the $^{19}$F mirror nucleus and in contrast to previously accepted assignments

Building trust in agribusiness supply chains: A conceptual model of buyer-seller relationships in the seed potato industry in Asia

In the absence of a certified seed system, potato farmers in Asia must purchase replacement seed tubers from an informal seed system. With no third party assurance that the seed tubers purchased are of good quality, the farmer's decision to purchase seeds may be influenced by the long-standing relationships that have been established between buyers and sellers. Trust is the critical determinant of a good buyer-seller relationship. Through maintaining communication and the making of various relationship specific investments, a conceptual model is proposed which suggests that seed suppliers may engage in trust building behavior which should result in the preferred seed supplier enjoying a greater share of the farmer's patronage

Direct neutron capture cross section on Ge 80 and probing shape coexistence in neutron-rich nuclei

Results are presented from the first neutron-transfer measurement on Ge80 using an exotic beam from the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. Newly measured spins and spectroscopic factors of low-lying states of Ge81 are determined, and the neutron capture cross section on Ge80 was calculated in a direct-semidirect model to provide a more realistic (n,γ) reaction rate for r-process simulations. Furthermore, a region of shape coexistence around N≈50 is confirmed and implications for the magic nature of Ni78 are discussed