Drought Estimation-and-Projection Using Standardized Supply-Demand-Water Index and Artificial Neural Networks for Upper Tana River Basin in Kenya

Drought occurrence, frequency and severity in the Upper Tana River basin (UTaRB) have critically affected water resource systems. To minimize the undesirable effects of drought, there is a need to quantify and project the drought trend. In this research, the drought was estimated and projected using Standardized Supply-Demand-Water Index (SSDI) and an Artificial Neural Network (ANN). Field meteorological data was used in which interpolated was conducted using kriging interpolation technique within ArcGIS environment. The results indicate those moderate, severe and extreme droughts at varying magnitudes as detected by the SSDI during 1972-2010 at different meteorological stations, with SSDI values equal or less than -2.0. In a spatial domain, the areas in south-eastern parts of the UTaRB exhibit the highest drought severity. Time-series forecasts and projection show that the best networks for SSDI exhibit respective ANNs architecture. The projected extreme droughts (values less than -2.00) and abundant water availability (SSDI values ³ 2.00) were estimated using Recursive Multi-Step Neural Networks (RMSNN). The findings can be integrated into planning the drought-mitigation-adaptation and early-warning systems in the UTaRB.

Pemanfaatan Sistem Embung Sebagai Sumber Air dan Pangan Keluarga di Desa Cikalong Tasikmalaya Jawa Barat

<p><strong><em>Utilizing the Pond as A Water and Food Source in Cikalong Village Tasikmalaya </em></strong><strong><em>West Java.</em></strong> Cikalong Village is administratively in the Tasikmalaya Regency, West Java, often experiencing drought every year, chiefly in the dry season, when the local people have difficulty obtaining water to meet their daily needs. The method used in the activity was a direct observation, interviews, and FGD (Focus Group Discussion). The number of people involved is 10-15 people, in which there are community leaders and farmers. This activity aims to determine the contribution and benefits of the pond, especially in the dry season which is prone to drought. Ponds can be an alternative solution, apart from being a water source, their function can also be developed for fish cultivation with an aquaculture system and vegetables with an aqua-plants system. Both systems are able to meet food needs on a family scale well, with the integration of various types of fish such as <em>Cyprinus carpio</em>, <em>Oreochromis mossambicus</em> and vegetables such as chili, leeks, tomatoes. The results of the activity showed that the benefits of making ponds around the house with sizes of 10x10 m, 5x5 m, and 3x3 m and in gardens with sizes 10x20 m to 20x20 are as water storage, fish cultivation and plant cultivation. The pond was a form of adaptation and mitigation of local communities in responding to the effects of drought properly. The Cikalong Village community can be categorized as a community that has a fairly high sensitivity to the surrounding environmental conditions in recognizing and mitigating drought problems.</p>

The Response of Antioxidant System of Drought-Stressed Green Pea (Pisum sativum L.) Affected by Watering and Foliar Spray with Silica Nanoparticles

Abiotic stress caused by drought impairs plant growth and reduces yields. This study aimed to investigate the impact of silica nanoparticles (SiO2 NPs) through the adverse effects of drought on the growth, oxidative stress, and antioxidative response of pea ‘Respect’. Pea plants were grown in a greenhouse before being watered (100 ± 1 mL per pot) or foliar sprayed (ca. 14 ± 0.5 mL plant−1) with suspensions containing SiO2 NPs (0, 12.5 ppm, 25 ppm, and 50 ppm) and were exposed to drought stress for 10 days. Drought stress was created by maintaining 30% of the soil moisture while the control was 80%. The growth parameters of pea grown under drought stress conditions were improved by spraying or watering plants with SiO2 NPs (12.5, 25, and 50 ppm). At drought stress, peas treated with SiO2 NPs (50 ppm) increased their relative water content by 29%, specific leaf area by 17%, and decreased root/shoot ratio by 4% as compared to plant non-treated with SiO2 NPs. In addition, spraying or watering of SiO2 NPs increased peas tolerance to drought by increasing the activity of antioxidant enzymes at least three times including catalase, ascorbate peroxidase, glutathione reductase, and superoxide dismutase, as well as reducing hydrogen peroxide and lipid peroxidation in plant tissue. It was observed the increase in total phenolic compounds and non-enzymatic antioxidant activity (DPPH, ABTS, FRAP) in peas treated with SiO2 NPs under drought stress. The physiological response of peas to drought and the effects of SiO2 NPs studied in this experiment based on the use of the concentration of 50 ppm nanoparticles can protect peas from the damaging effects of drought and could help reduce global food shortages.