Growth Characteristics of Summer Cover Crop Grasses and their Relation to Soil Aggregate Stability and Wind Erosion Control in Arid Southwest

HighlightsFour summer cover crops under two irrigation regimes were tested for soil wind erosion control.Soil aggregate stability and wind erosion losses were improved with plant cover in the peak summer.Sorghum sudan is a prominent summer species for wind erosion control in the arid southwest. Abstract. Cover crops can have significant impacts on minimizing soil erosion by wind, which is a common problem in the arid southwest. A study was conducted at NMSU Leyendecker Plant Science Center, Las Cruces, New Mexico, to evaluate the impacts of selected summer cover crops on soil loss during wind erosion events. Four summer grass species [Japanese millet (Echinochloa esculenta), pearl millet (Pennisetum glaucum), brown top millet (Urochloa ramosa (L.) Nguyen), and sorghum sudangrass (Sorghum bicolor × S. bicolor var. Sudanese)] were randomly assigned to four blocks under two irrigation regimes (full-irrigation and deficit-irrigation). Results showed significant effect of grasses on horizontal soil flux compared to control under both irrigation regimes. When comparing the grasses, sorghum sudan grass performed better than the other tested summer cover crops for soil surface protection from wind erosion with its higher ground coverage, higher plant density, taller plant height and higher amount of biomass, while brown top millet was least effective in terms of plant and erosion control characteristics (P=0.05). Pearl millet and Japanese millet performed better than brown top millet, but was as effective as sorghum sudan as barriers against the wind erosion. Therefore, sorghum sudan is a prominent cover crop for summer in the arid zones of desert southwest. Producers of this region can be significantly benefited from the current research recommendations about cover crops choices for summer season. Keywords: Arid climates, Cover cropping, Summer grasses, Wind erosion control.

Evaluation of Uncertainty Intervals for Daily, Statistically Derived Streamflow Estimates at Ungaged Basins across the Continental U.S.

Streamflow estimation methods that transfer information from an index gage to an ungauged site are commonly used; however, uncertainty in daily streamflow estimates are often not adequately quantified. In this study, daily streamflow was simulated at 1331 validation streamgauges across the continental United States using four transfer-based streamflow estimation methods. Empirical 95 percent uncertainty intervals were computed for estimated daily streamflows. Uncertainty intervals were evaluated for reliability, sharpness, and overall ability to accurately quantify the uncertainty inherent in the estimated daily streamflow. Uncertainty intervals performed reliably in the Eastern U.S. and Pacific Northwest regions of the country, containing a median of 96 and 99 percent of the observed values respectively. Uncertainty intervals were less reliable in the Great Plains and arid Southwest regions, where uncertainty intervals contained a median of 83 and 94 percent of the observed streamflows respectively. Uncertainty interval performance was correlated with gage density and hydrologic similarity near the validation site, as well as the aridity and baseflow indices at the site.

Meteorological Macro-Imagineering: A Re-plumbed Freshwater Supply System for the USA’s Southwest? (Macro-Imagenharia Meteorológica: Um Sistema de Abastecimento de Água Doce para o Sudoeste dos EUA?)

<p>The macroproject proposed, encompassing the arid Southwest of the USA and northern Mexico, has the potential to more than pay for itself. If a radical volumetric enlargement were competently completed by correctly educated advocates of Macro-Imagineering, supplemented by geothermal power-plants, it could make benign an over-polluted aquatic “monster” — the present-day stagnant and putrid Salton Sea — through induced importation of diluting Gulf of California saltwater resulting in rapid areal increase of the inanimate “creature”, converting it from its presently degraded smelly status to an amply beneficial condition as an anthropogenic extension of Mexico’s Gulf of California! Formation by Macro-Engineering means of a sustainable human development around and thereon can result in profitable voluminous desalinated seawater exportation from the State ofCaliforniato adjacentArizona,Nevadaand nearbyUtahas well asMexicobordering theUSA’s Southwest. The key infrastructure permitting these developments is a centralized multi-segment photovoltaic-powered desalination factory resting atop named Introduction floating artificial islands covering most of a deliberately enlarged and robotized Salton Sea. A particular macroproject proposed, the Southwest Water Alliance Project (SWAP), is fashioned somewhat after NEOM, an announced ecopolis, but still structurally unspecified robot megacity, scheduled to be built in northern Saudi Arabia connected by a yet-to-be-constructed fixed sea-strait crossing linking Tabuk, Saudi Arabia to Sharm el-Sheikh on the Sinai Peninsula of bordering Egypt. </p><p class="-10"><strong>Key words: </strong>Seawater desalination, floating photovoltaic platforms, arid Southwest USA and Mexico development, Macro-Imagineering, Macro-Engineering.</p><div><span>===========================================================================</span></div><div> </div><div><p>O macroprojeto proposto, abrangendo o árido sudoeste dos EUA e norte do México, tem potencial para mais do que pagar por si mesmo. Se um aumento volumétrico radical fosse conduzido por defensores competentes da Macro-Imagineering, suplementado por usinas de energia geotérmica, seria possível tornar benigno um "monstro" aquático extremamente poluído — o atual e estagnado Mar de Salton — por meio de importações induzidas de água salgada diluente do Golfo da Califórnia, resultando em um rápido aumento de área da "criatura" inanimada, resgatando-a de seu estado atual degradado como uma extensão antropogênica do Golfo da Califórnia! Por meio da Macroengenharia é possível conduzir um desenvolvimento humano sustentável e lucrativo capaz de garantir uma expressiva exportação de água do mar dessalinizada do estado da Califórnia para os adjacentes Arizona, Nevada e Utah, além do México na fronteira com o sudoeste dos EUA. A principal infraestrutura que permite esse desenvolvimento é uma fábrica centralizada para dessalinização multissegmento baseada em energia fotovoltaica, formada por ilhas artificiais flutuantes que cobririam a maior parte do Mar de Salton em um sistema ampliado e robotizado. Em particular, um macroprojeto semelhante proposto é o <em>Southwest Water Alliance Project</em><em> </em>(SWAP) — criado um pouco depois do NEOM —, uma ecópolis anunciada, megacidade robótica estruturalmente ainda não especificada, programada para ser construída no norte da Arábia Saudita, conectada por uma passagem estreita ligando Tabuk, na Arábia Saudita, a Sharm el-Sheikh, na Península do Sinai (fronteira com o Egito).</p><p><strong>Palavras-chave: </strong>Dessalinização da água do mar, plataformas fotovoltaicas flutuantes, desenvolvimento do sudoeste dos EUA e do México, Macroengenharia.</p><p class="-10" align="left"> </p></div>