Increasing soil salinity and degraded irrigation water quality are major challenges for agriculture. This study investigated the effects of irrigation water quality and incorporating compost (3% dry mass in soil) on minimizing soil salinization and promoting sustainable cropping systems. A greenhouse study used brackish water (electrical conductivity of 2010 µS/cm) and agricultural water (792 µS/cm) to irrigate Dundale pea and clay loam soil. Compost treatment enhanced soil water retention with soil moisture content above 0.280 m³/m³, increased plant carbon assimilation by ~30%, improved plant growth by >50%, and reduced NO₃⁻ leaching from the soil by 16% and 23.5% for agricultural and brackish water irrigation, respectively. Compared to no compost treatment, the compost-incorporated soil irrigated with brackish water showed the highest plant growth by increasing plant fresh weight by 64%, dry weight by 50%, root length by 121%, and plant height by 16%. Compost treatment reduced soil sodicity during brackish water irrigation by promoting the leaching of Cl⁻ and Na⁺ from the soil. Compost treatment provides an environmentally sustainable approach to managing soil salinity, remediating the impact of brackish water irrigation, improving soil organic matter, enhancing the availability of water and nutrients to plants, and increasing plant growth and carbon sequestration potential.

A real time, minimally invasive method to observe valve movement of bivalves using proximity sensors and a personal computer has been developed. The method is being evaluated as a tool to assess both episodic toxicity events and ambient toxicity. The method described minimizes contact with the animal to the anchoring of one valve and the placement of a small aluminum foil disk on the other valve, and allows the measurement of the distance that a clam's valves are open. Using proximity sensors and an aluminum foil target, valve movements of the Asiatic clam, Corbicula fluminea were measured and digitally recorded using a data acquisition board and a personal computer. One advantage of this method is its use of readily available stock electronics. In its final form, we envision an in situ biological monitoring system using C. fluminea deployed in aquatic systems in association with automated physical/chemical monitoring systems like those found at USGS gauging stations. A tool such as this could be used as a warning system to increase the probability of detecting toxic events as they occur.

We characterize the leaf spectra of tree species of an Andean cloud forest in Venezuela, grouped according to position in canopy, subcanopy and understory. We measured leaf reflectance and transmittance spectra in the 400–750 nm range using a high-resolution spectrometer. Both signals were subtracted from unity to calculate the absorbance signal. Nine spectral variables were calculated for each signal, three based on wide-bands and six based on features. We measured leaf mass per unit area of all species, and calculated efficiency of absorbance, as ratio of absorbance in photosynthetic range over leaf mass. Differences among groups were significant for several absorbance and transmittance variables, leaf mass, and efficiency of absorbance. The clearest differences are between canopy and understory species. There is strong correlation for at least one pair of band variables for each signal, and each band variable is strongly correlated with at least one feature variable for most signals. High canonical correlations are obtained between pairs of the three canonical axes for bands and the first three canonical axes for features. Absorbance variables produce species clusters having the closest correspondence to the species groups. Linear discriminant analysis shows that species groups can be sorted by all signals, particularly absorbance.

This study explores the effects of alternating current-induced electromagnetic field (EMF) on mitigating brackish water irrigation and soil salinization impacts. Greenhouse experiments were conducted to evaluate the effect of EMF on plant growth, soil properties, and leaching of ions under different conditions, including using brackish water and desalinated water for irrigation and soil compost incorporation. The experiment was performed with four types of irrigation water using soil columns representing field soil layers. EMF-treated brackish water maintained a sodium adsorption ratio of 2.7 by leaching Na⁺ from the soil. EMF-treated irrigation columns showed an increase in soil organic carbon by 7% over no EMF-treated columns. Compost treatment reduced the leaching of NO₃⁻ from the soil by more than 15% using EMF-treated irrigation water. EMF-treated brackish water and compost treatment enhanced plant growth by increasing wet weight by 63.6%, dry weight by 71.4%, plant height by 22.8%, and root length by 115.8% over no EMF and compost columns. EMF-treated agricultural water without compost also showed growth improvements. The findings suggest that EMF treatment, especially combined with compost, offers an effective, low-cost, and eco-friendly solution to mitigate soil salinization, promoting plant growth by improving nutrient availability and soil organic carbon.