Water consumption of cotton in the semi arid tracts of India

In the present study, evapotranspiration and other agrometeorological data for three different locations, viz., Akola. Bellary and Kovilpatti have been utilized to understand consumptive use and related aspects of cotton. Ratios of evapotranspiration to potential evapotranspiration (ET/PET) and evapotranspiration to total shortwave radiation (ET/Rs) increase gradually as the vegetative cover develops and shows year to year variation at same location. The energy summation indices have been worked out for all the three stations which indicate that the total yields are more dependent on consumptive water use by crop rather than energy summation indices.. The water use efficiency (WUE) of cotton crop also reveals wide variations in time and space.

Water use pattern and related agrometeorological indices of rabi & kharif sunflower (Helianthus annuus L.) at Deccan plateau

The agrometeorological data pertinent to estimation of water use and related agrometeorological indices of KBSH - II (1988 to 1991) and MORDEN varieties of sunflower (1992 and 1993) cultivated both in rabi and kharif seasons, were used to understand the comparative water use pattern and agrometeorological indices for getting an idea about the crop condition at Bangalore. The study revealed that mean weekly water use was higher in almost all the years during the kharif season than during the rabi season except in 1990 and the consumptive water use increased with development of the vegetative cover of the crop reaching a peak value in the vegetative growth stage. The ARI (agroclimatic rainfall index) and cumulative YMI (yield moisture index) were always higher during the kharif season than correspondingly those during the rabi season and showed yearly and seasonal variability in different growth stages which was due to the moisture stress condition of the soil as well as prevailing weather conditions of the atmosphere. In case of AI (aridity index), high values were observed at early and late crop growth stages during the kharif season which showed that the crop experienced less aridity between vegetative to seed formation stage. The water use efficiency (WUE) of the crop also revealed wide variation due to variety and season.

Numerical simulation of sea breeze in south Andamans

The air flow over the south Andaman island is simulated using a three dimensional numerical meso-scale model. Port Blair observations are used as initial data. The surface orography, soil moisture soil albedo variations and vegetations effects are included in the model. The combined effect of these factors on the development of sea/land breeze circulations is obtained quantitatively. The model simulated results are compared with the available observations. The principal results obtained are : (1) The meso-scale circulations induced by the differential heating of the island were intensified by topography. (2) The ground vegetative cover trans- port higher amount of turbulent heat fluxes: to the atmosphere and the meso-circulations appeared with higher intensities. (3) If we Include the lateral variations of flux with topographic and coastal asymmetries the induced meso-scale circulations appeared with different intensities along meridional direction and the inland penetration distances varied in y direction. The maximum Inland penetration of sea breeze was seen, where the inland was widest and terrain height was maximum. Stronger sea breeze was simulated over the central/northern parts of the island.

Factors contributory to fire occurrences in two populated areas in the American southwest

PurposeThis study aims to further understand the factors contributory to fire occurrences in two semi-arid regions in the American Southwest, Clark County in Nevada and Maricopa and Pinal Counties in Arizona.Design/methodology/approachStatistical and geographic information system analyses were employed to examine the spatial and temporal relationships of various natural and human-caused factors with fire incidences.FindingsAngström fire danger index, average amount of rainfall one month prior, extent of forests and grasslands, and proximities to secondary roads and population centers have significant relationships with fire events.Research limitations/implicationsThe importance of the factors contributory to fire occurrence is site-specific even in areas with similar climatic regimes and varies among different geographic regions; as such, researchers will need to conduct specific investigation of each study area.Practical implicationsThe findings of this study can be instrumental in facilitating fire managers to derive more informed strategies in fire prevention and management.Originality/valueWhile there are many studies on fire, most of them are conducted in wet regions with a lot of vegetative cover; not much work is done on arid areas. This paper considered and compared the spatial and temporal relationships of a wide range of natural and human-caused factors with fire events in two semi-arid areas. The intent was to assess the relative importance of these factors in areas even with similar climatic regimes. As our world is facing unprecedented changes in terms of climate and population growth, it is paramount to have an enhanced understanding of the impacts of these changes on fire regimes. The study areas are hot and dry, and they are located in the wildland–urban interfaces with rapid population growth and urbanization; as such, the research findings may contribute to existing literature.

Analysis of Vegetative Cover Vulnerability in Rohingya Refugee Camps of Bangladesh Utilizing Landsat and Per Capita Greening Area (PCGA) Datasets

The vegetative cover in and surrounding the Rohingya refugee camps in Ukhiya-Teknaf is highly vulnerable since millions of refugees moved into the area, which led to severe environmental degradation. In this research, we used a supervised image classification technique to quantify the vegetative cover changes both in Ukhiya-Teknaf and thirty-four refugee camps in three time-steps: one pre-refugee crisis (January 2017), and two post-refugee crisis (March 2018, and February 2019), in order to identify the factors behind the decline in vegetative cover. The vegetative cover vulnerability of the thirty-four refugee camps was assessed using the Per Capita Greening Area (PCGA) datasets and K-means classification techniques. The satellite-based monitoring result affirms a massive loss of vegetative cover, approximately 5482.2 hectares (14%), in Ukhiya-Teknaf and 1502.56 hectares (79.57%) among the thirty-four refugee camps, between 2017 and 2019. K-means classification revealed that the vegetative cover in about 82% of the refugee camps is highly vulnerable. In the end, a recommendation as to establishing the studied region as an ecological park is proposed and some guidelines discussed. This could protect and reserve forests from further deforestation in the area, and foster future discussion among policymakers and researchers.

IMPACT OF THE INVASIVE CUSCUTA CAMPESTRIS ON VEGETATIVE COVER AND PLANT BIODIVERSITY IN HOMA- BAY COUNTY

Purpose: This research paper focused on the impact of Cuscuta campestris on vegetative cover and plant biodiversity in Homa-Bay County. The specific objective was to investigate the impact on plant growth and development with indicator as photosynthetic capacity of preferred host plants and chlorophyll content and leaf weight as the parameters. Methodology: The study was conducted in hot-spot areas of invasion, Rachuonyo North, Homa Bay town and Suba North using Completely Randomized Experimental Block Design. The data was collected through field observation and laboratory analysis. The study used descriptive and correlation data analysis procedures to show the impact on photosynthetic capacity, ANOVA to determine statistical significant difference among the obtained results for each parameter of the infected and uninfected samples. Variance analysis were conducted using SPSS 20 (IBM Corp. Armonk, NY, USA) and differences between means tested by ANOVA. Values of P ≤ 0.05 were considered significantly different. Findings: The results showed that the invasion was more intense in Theveta peruvinia and Euphorbia tirucalli species. Mean leaf amounts of chlorophyll were observed to decline with chlorophyll a from 3.97 to 1.59 mg/g and chlorophyll b from 2.65 to 1.18 mg/g and total chlorophyll value from 6.62 to 2.76 mg/g on infection resulting to reduced photosynthetic efficiency and low organic material formation. Leaf wet and dry weight significantly decreased in both infected varieties. The mean wet weight of 17.61g in infected was significantly different, F (1, 4) = 235.74, p< .05, from the mean wet weight of 24.23g in the uninfected Yellow Oleander while the mean dry weight of 5.55g in infected was significantly different, F (1, 4) = 159.72, p< .05, from mean dry weight of 7.87g in uninfected Yellow Oleander. Similarly, significant difference, F (1, 4) = 714.64, p< .05, was observed in Calliandra calothyrsus variety. These demonstrated how C. campestris is detrimental causing ecological impacts with direct effects on plant biodiversity by reducing growth and development of infected host plant and even leading to death. Unique Contributions to Theory, Practice and Policy: The paper recommends intense sensitization of the community on the impacts of dodder from the findings for an enhanced understanding and need for management and control. The findings to be disseminated through workshops involving farmers, NGOs and community based organisations, academic conferences and publications to help create awareness on the impacts and mobilize the entire public on management and possible total eradication. Further research to investigate on nutrients of attraction in the preferred host plants with an aim of permanent solution for total eradication in order to restore the vegetative cover and plant biodiversity.

Integrating Sediment (dis)Connectivity into a Sediment Yield Model for Semi-Arid Catchments

Soil erosion-associated sedimentation has become a significant global threat to sustainable land and water resources management. Semi-arid regions that characterise much of southern Africa are particularly at risk due to extreme hydrological regimes and sparse vegetative cover. This study aims to address the need for an erosion and sediment delivery model that successfully incorporates our conceptual understanding of sedimentation processes in semi-arid regions, particularly sediment storage and connectivity within a catchment. Priorities of the Semi-arid Sediment Yield Model (SASYM) were simplicity and practical applicability for land and water resource management while adhering to basic geomorphic and hydrological principles. SASYM was able to represent multiple sediment storages within a catchment to effectively represent a change in landscape connectivity over geomorphic timeframes. SASYM used the Pitman rainfall–runoff model disaggregated to a daily timescale, the Modified Universal Soil Loss Equation (MUSLE), incorporating probability function theory and a representation of sediment storages and connectors across a semi-distributed catchment. SASYM was applied to a catchment in the Karoo, South Africa. Although there were limited observed data, there was a historical dataset available for the catchment through dam sedimentation history. SASYM was able to effectively present this history and provide evidence for landscape connectivity change.

Dryland Watershed Restoration With Rock Detention Structures: A Nature-based Solution to Mitigate Drought, Erosion, Flooding, and Atmospheric Carbon

Historic land degradation is an ongoing threat to the Sky Islands of southern Arizona, US, and northern Sonora, Mexico, an area designated as a globally significant biodiversity hotspot. Land degradation has reduced ecosystem services provisioning, released carbon from disturbed soils into the atmosphere, and significantly diminished resilience to climate change. Private land managers in the region have developed methods to reverse degradation and restore biodiversity and ecosystem function. Land managers have used rock detention structures (RDS), technology adapted from traditional Indigenous practices in the region, as a tool for reversing desertification and watershed degradation. The structures were installed primarily for erosion control and water management, but they have had positive impacts on multiple biophysical systems. In this study, we analyze watershed-scale installation of RDS as a nature-based solution for climate change mitigation and adaptation. Case studies include four properties that offer examples of structures that have been in place over a period ranging from 1 to 40 years. We reviewed journal articles and other studies conducted at the four sites, supplemented with interviews, to catalogue the nature-based solutions provided by RDS. This study documents positive impacts on overall stream flow, reduction in peak runoff during inundation events, and increased sedimentation, which increase resilience to drought, erosion, and flooding. Data suggest potential impacts for climate change mitigation, though further research is needed. In addition, results suggest that watershed restoration with RDS offers a host of co-benefits, including an increase in biodiversity and wildlife abundance, an increase in vegetative cover, and increased surface water provisioning over time to support the land-based livelihoods of downstream neighbors. In the discussion, we consider barriers to replication and scalability using the strategy of the UN Decade on Ecosystem Restoration as a guiding framework, discussing issues of awareness, legislation and policy, technical capacity, finance, and gaps in knowledge.