Sorption of isoxaflutole by five different soils varying in physical and chemical properties

Isoxaflutole is a new pre-emergence corn herbicide which controls both grass and broadleaf weeds. Experiments were performed in the laboratory to study the sorption of isoxaflutole in five different soils (Moorhead, MN; East Monroe, CO; Ellendale, MN; South Deerfield, MA; and Chelsea, MI) using the batch equilibration technique. Total initial isoxaflutole solution concentrations for each soil were 0.05, 0.15, 0.3. 0.8, 1.5, 2.0 and 4.0 mg litre⁻¹. Analysis of [ring-¹⁴C] isoxaflutole was performed using liquid scintillation counting, and sorption data were fitted with the Freundlich model. Isotherms of isoxaflutole in all the soils were non-linear as depicted by the exponent (n < 1.0), indicating differential distribution of sorption site energies in various soils. Since the isotherms were non-linear the data fit Freundlich's isotherm well, as was indicated by high values of the regression coefficient (r²). The Freundlich sorption coefficient ranged from 0.555 to 50.0 (litre ⁿmg ^l−nkg⁻¹). Multiple regression of the sorption constant, K_F against selected soil properties indicated that organic matter content was the best single predictor of isoxaflutole sorption (r² = 0.999) followed by soil pH (r² = 0.954). Clay content of the soils did not have a high correlation with K_F values (r² = 0.453), while the sorption of isoxaflutole was not influenced by the Ca²⁺ concentration in the soil solution. Isoxaflutole sorption increased with an increase in organic matter content of soils. Sorption of isoxaflutole decreased as the soil pH increased from 4.5 to 8.5, which was depicted by the reduction of K_F values. Sorption of isoxaflutole to the soils varied with differences in binding energies. At a particular net energy value (E*), the corresponding site energy distribution [F(E*)] values followed the order, Chelsea, MI > Moorhead, MN > East Monroe, CO > South Deerfield, MA > Ellendale, MN. The negative magnitude of Gibbs free energy of sorption (ΔG ^x) indicates the spontaneity of the given sorption process in the soils from Moorhead, MN; East Monroe, CO and Chelsea, MI. © 1999 Society of Chemical Industry     

Livelihood Improvements Through Agroforestry: Evidence from Northern Bangladesh

Agroforestry is one of the most sustainable land management systems practiced around the world due to the socioeconomic benefits that it brings to farmers. In Bangladesh, farmers practice agroforestry, applying indigenous knowledge. The present study was designed to identify the present status, management practices and its role in improving the livelihoods of farmers in northern Bangladesh. Data for the study were collected through quantitative and qualitative methods. A total of 29 tree and 38 agricultural crop species were planted by the102 farmers interviewed. Mangifera indica (relative prevalence 49%) is the most predominant species, followed by Eucalyptus camaldulensis (relative prevalence 35.4%). Farmers of northern Bangladesh plant trees in cropland for fruits (90%), fuel wood (87%) and timber production (79%). Fruit trees were planted with wider spacing while forest and fuel wood species were planted with narrower spacing. Farmer’s livelihoods improved enormously by practicing agroforestry as they have more access to food, fodder and fuel wood which is reflected by greater access to livelihood capitals (except social capital). However, farmers have experienced increased incidences of pests and diseases to the annual crops and trees. Agroforestry practices increases species diversity, ensure economic return and sustain farmer’s livelihoods.     

Improvement of Fertility in Artificially Inseminated Ewes Following Vaginal Treatment with Misoprostol Plus Terbutaline Sulphate

The effect of vaginal administration of misoprostol plus terbutaline sulphate 6 h prior to artificial insemination (AI) upon the site of AI (vaginal or cervical) and fertility was studied using a total of 87 estrous synchronized Serra da Estrela ewes (control n = 42 and treated n = 45). Artificial insemination was performed using refrigerated semen at 54–55 h after sponge removal. Lambing rate (fertility) and prolificacy were compared between control and treated ewes. The effect of the site of semen deposition on fertility was also evaluated. Prolificacy rate was not different between control (1.5) and treated (1.59) ewes. The proportion of cervical AI achieved in control (45.2%) and treated (37.8%) ewes was not significantly different. Overall, fertility was significantly lower in control than in treated ewes (42.9% vs 64.4%; p < 0.04). Fertility following vaginal AI was significantly lower for control for than treated ewes (30.4% vs 60.7%; p < 0.03) but the difference was smaller and not significant for cervical AI (control 57.9% vs 70.6%). It was concluded that vaginal administration of misoprostol plus terbutaline sulphate 6 h prior to artificial insemination did not affect the proportion of cervical inseminations but significantly improved the fertility of treated ewes. Although needing confirmation, it was hypothesized that drugs might have induced local secretory modifications leading to an increase of cervical ability to retain more viable spermatozoa for fertilization.     

Rapid,non-destructive carbon analysis of forest soils using neutron-induced gamma-ray spectroscopy

Forest soils are pivotal to understanding global carbon (C) cycling and evaluating policies for mitigating global change. However, they are very difficult to monitor because of the heterogeneity of soil characteristics, the difficulty of representative sampling, and the slow time scale of response to environmental change. Here we demonstrate that use of gamma-ray spectroscopy facilitates in situ non-destructive analysis of C and other elements in forest soils. In this approach the element-specific gamma-rays are induced by fast and thermal neutrons interacting with the nuclei of the elements present in the soil. Background gamma-rays emanating from naturally occurring radionuclides in the forest are recorded as well. We applied this approach in a mature northern hardwood forest on glacial till soils at the Bartlett Experimental Forest in New Hampshire, USA. The inelastic neutron scattering (INS) system yielded strong signals in gamma-ray counts/h, from C and other elements present in the soil matrix that included silicon, oxygen, hydrogen, iron, aluminum, manganese and potassium. The INS sensitivity for carbon was 20.656 counts h⁻¹ kg⁻¹ C m⁻² based on current net C gamma-ray counts and the data for the O horizon and mineral soil to a depth of 30 cm obtained from a nearby quantitative soil pit (7.35 kg C m⁻²). We estimate the minimum detectable change to be ∼0.34 kg C m⁻², which is ∼5% of the current soil C content, and the minimum detectable limit to be ∼0.23 kg C m⁻². Eight % reproducibility from 11 measurements was limited, in part, by the large variability in the system counting geometry due to the uneven forest microtopography. The INS approach has the potential to revolutionize belowground monitoring of C and other elements, because the possibility of detecting a 5% change in forest soils has not been possible with destructive sampling methods.     

Genetic diversity analysis in date palm (Phoenix dactylifera L.): a comparative assessment using ISSR and RAPD marker assays

SUMMARY

A comparative study was conducted to evaluate genetic diversity in 45 genotypes of date palm (Phoenix dactylifera L.), including both male and female plants, employing RAPD and ISSR marker systems. The data were analysed to calculate the total number of bands, the number of polymorphic bands, the percentage polymorphism, the average number of bands per primer, the effective multiplex ratio (EMR), the polymorphic information content (PIC), the marker index (MI), and genetic similarity coefficients. The 37 RAPD and 53 ISSR primers used generated 363 and 608 scorable amplified products, respectively, of which 95.0% and 90.9% were polymorphic. The ISSR markers produced more information than the RAPD markers due to their higher EMR and MI values. Jaccard similarity values among male plants, female plants, and between all male and all female plants varied between 0.72 – 0.80. The results indicate the effectiveness of these two marker systems for demonstrating genetic relationships among date palm genotypes.     

INTERACTION EFFECT OF POTASSIUM AND SULFUR FERTILIZATION ON PRODUCTIVITY AND MINERAL NUTRITION OF SUNNHEMP

The interactive effect of potassium (K) and sulfur (S) fertilization on productivity and mineral nutrition of sunnhemp (Crotalaria juncea L.) was evaluated in a field experiment during 2008 and 2009 cropping seasons at Uttar Pradesh, India. Potassium and sulfur fertilizers increased fiber yield and nutrient uptake of sunnhemp. It was observed that an application of K and S at 40 kg ha^?1 each significantly increased the total dry matter, fiber yield, and nutrient uptake of sunnhemp. The crop yield response to the added S was greater than for K and the nutrient use efficiency was also higher at lower levels of fertilizer addition. The increased levels of K and S improved the number of nodules and crude protein content of sunnhemp leaves.     

Formation of alkali soils by neutral salt solutions

It has been reported that large tracts of land under irrigation in the western part of United States contain enough soluble salts to depress crop production and thousands of acres have been abandoned because of salinity. In soils commonly called white alkali soils, containing accumulation of neutral salts in the form of chlorides or sulphates, 0.2% of salt will reduce yields of salt sensitive plants and 1.0% will cause marked yield reduction in most crops. If the drainage is poor and water table is maintained near the surface of the soil, evaporaLion will be high and the salt will accumulate. When large amount of soluble salts accumulate at the surface, the soil is termed as saline and has a pH value below 8.5. The soils containing alkali salts such as Na.COa or NaHC03 and having a pH value above 8.5 are called alkali soils or black alkali soils. Misra (1954) has reported that a gradual replacement of calcium ions and a subsequent increase in the exchangeable Na or K in the exchange complex of the soil, due to repeated leaching of the soils with dilute salt solutions of Na or K takes place which is similar to the repeated leaching of agricultural fields by irrigation.al water containing smaller amounts of soluble salts of Na or K. He has also reported that K-soils, which are also alkaline, are formed under similar conditions of leaching of the soil with K-salLs. Greater amounts of calcium were found in the filtrate when soluble salts were used instead of water alone for leaching the soil.     

Photosynthesis and Assimilate Partitioning in Mungbean in Response to Source-Sink Alteration

The effect of alteration in source-sink ratio by deflowering and defoliation technique on photosynthesis rate was examined in mungbean ( Vigna radiata [L.] Wilczek) var. PS 16. Deflowered plants where sink demand was decreased, maintained a higher rate of photosynthesis in spite of their higher starch content in the leaves. This treatment also increased the partitioning of assimilates to leaves, stem, roots and nodules indicating the existence of alternative sink capacity. The higher rate of photosynthesis of deflowered plants was associated initially with lower stomatal diffusive resistance and subsequently with higher leaf nitrogen content. Increase in sink demand for a particular leaf by excising other source leaves also increased the rate of photosynthesis. These results are discussed in relation to possible regulation through hormones.     

Animal medical genetics: a perspective on the epidemiology and control of inherited disorders

This perspective considers genetic disorders of domestic animal populations, in particular their epidemiology and control. Inherited disorders of animals share the same basic molecular biology as those of human beings, but they differ in their epidemiology due largely to the breed structure of the various species, human control of breeding and a greater influence of the founder effect, particularly due to extensive use of a limited number of sires, and inbreeding. Control of genetic disorders in animals is also more practical through extensive screening for disease, or heterozygous animals within defined breed populations, followed by exclusion of affected or carrier animals from breeding. This is assisted by the fact that, within a breed, many inherited monogenic disorders are associated with a single mutation. However some of the more important disorders may be inherited in a non-Mendelian manner, being influenced by multiple genes as well as environmental factors. These aspects are discussed and contrasted with similar aspects in human medical genetics.