Consejos sobre la sequía: Recuperar los suelos salinos, sódicos y salino-sódicos

Los suelos afectados por la sal causan un crecimiento pobre en las plantas, dañan la producción de la cosecha y reducen la eficiencia en el uso del agua. Algunos suelos afectados por la sal presentan problemas físicos que reducen la filtración del agua e incrementan su escurrimiento en la superficie. La recuperación de los suelos afectados por la sal puede conducir a un mejor manejo del agua, un uso más eficiente del agua y la producción de los cultivos

Soil-landscape model helps predict potassium supply in vineyards

The Lodi Winegrape District is one of the largest in California and encompasses a wide diversity of wine-grape varieties, production systems and soils, which complicates grape nutrient management To identify regions within this district that have similar nutrient-management needs, we are developing a soil-landscape model based on soil survey information. Our current model identifies five regions within the Lodi district with presumed relationships between soil properties and potassium-supplying ability. Region 1 has weakly developed, clay-rich soils in basin alluvium; region 2 has weakly developed, coarser-textured soils on recent alluvial fans, flood plains and stream terraces; region 3 has moderately developed soils on low terraces derived from granitic alluvium; region 4 has highly developed soils on high terraces derived from mixed alluvium; and region 5 has weakly developed soils formed on undulating volcanic terrain. Field and lab studies of soils in these regions show that our model is reasonable in concept, but that it must be fine-tuned to account for differing degrees of soil variability within each region in order to make realistic nutrient-management predictions

Fate of nitrate in seepage from a restored wetland receiving agricultural tailwater

Constructed and restored wetlands are a common practice to filter agricultural runoff, which often contains high levels of pollutants, including nitrate. Seepage waters from wetlands have potential to contaminate groundwater. This study used soil and water monitoring and hydrologic and nitrogen mass balances to document the fate and transport of nitrate in seepage and surface waters from a restored flow-through wetland adjacent to the San Joaquin River, California. A 39% reduction in NO3-N concentration was observed between wetland surface water inflows (12.87±6.43mgL-1; mean±SD) and outflows (7.87±4.69mgL-1). Redox potentials were consistently below the nitrate reduction threshold (~250mV) at most sites throughout the irrigation season. In the upper 10cm of the main flowpath, denitrification potential (DNP) for soil incubations significantly increased from 151 to 2437mgNO3-Nm-2d-1 when nitrate was added, but showed no response to carbon additions indicating that denitrification was primarily limited by nitrate. Approximately 72% of the water entering the wetland became deep seepage, water that percolated beyond 1-m depth. The wetland was highly effective at removing nitrate (3866kgNO3-N) with an estimated 75% NO3-N removal efficiency calculated from a combined water and nitrate mass balance. The mass balance results were consistent with estimates of NO3-N removed (5085kgNO3-N) via denitrification potential. Results indicate that allowing seepage from wetlands does not necessarily pose an appreciable risk for groundwater nitrate contamination and seepage can facilitate greater nitrate removal via denitrification in soil compared to surface water transport alone

Consejos sobre la sequía: Recuperar los suelos salinos, sódicos y salino-sódicos

Los suelos afectados por la sal causan un crecimiento pobre en las plantas, dañan la producción de la cosecha y reducen la eficiencia en el uso del agua. Algunos suelos afectados por la sal presentan problemas físicos que reducen la filtración del agua e incrementan su escurrimiento en la superficie. La recuperación de los suelos afectados por la sal puede conducir a un mejor manejo del agua, un uso más eficiente del agua y la producción de los cultivos

Do constructed flow through wetlands improve water quality in the San Joaquin River?

The efficacy of using constructed wetlands (CW) to improve water quality of irrigation tailwaters was studied in the San Joaquin Valley, California. Two CWs were monitored during the 2004 and 2005 irrigation season, a new CW (W-1) and 12-year-old CW (W-2). Input/output waters from CW were collected weekly and analyzed for a variety of water quality contaminants. Organic carbon, nutrient and sediment retention efficiencies were evaluated from input/output concentrations. Results indicate that CW-2 was more a more efficient contaminant removal system for most water quality constituents. CWs were most effective at removing total suspended solids (TSS). Average TSS removal at CW-2 was 98% in 2004 and 83% in 2005. At CW-1, mean TSS removal was 90% in 2004 and 87% in 2005. Average total N removal efficiency was 41% in 2004 and 29% in 2005 for W-2, compared to 31% in 2004 and 21% in 2005 at W-1. Total P removal efficiency was 63% in 2004 and 24% in 2005 at W-2, compared to 27.5% in 2004 and 11% in 2005 at W-1. Chlorophyll-a, a measure of algal biomass, was higher at W-1, especially in input waters. Initially, in 2004, output concentration of chlorophyll- a increased, however over time, as emergent vegetation established, chlorophyll-a decreased to 35% of input levels. In 2005, CW-2 was a large source of algal biomass because vegetation was not present. Results demonstrate that CWs are effective at capturing sediment and nutrients from irrigation tailwaters, but may be a source of algae if not managed carefully

Ecology and Management of Annual Rangelands Series: Soils

The Ecology and Management of Annual Rangelands Series is a 9-part online publication that provides owners and leasees of California rangelands with a comprehensive source of information pertinent to the management and enjoyment of these lands. This information will help you formulate and implement strategies for achieving your personal goals as a landowner.Part 3 – Soils is an overview of how soils are classified. Researchers and managers like to organize the world they live in so that they can explain their environment. This publication will help you understand the soil taxonomy developed by soil scientists to help them classify soils and understand soil similarities and differences. Includes links to glossaries of terms so you can understand the terms used to define soil characteristics

Ecology and Management of Annual Rangelands Series: Soils

The Ecology and Management of Annual Rangelands Series is a 9-part online publication that provides owners and leasees of California rangelands with a comprehensive source of information pertinent to the management and enjoyment of these lands. This information will help you formulate and implement strategies for achieving your personal goals as a landowner.Part 3 – Soils is an overview of how soils are classified. Researchers and managers like to organize the world they live in so that they can explain their environment. This publication will help you understand the soil taxonomy developed by soil scientists to help them classify soils and understand soil similarities and differences. Includes links to glossaries of terms so you can understand the terms used to define soil characteristics

Using Wetlands to Remove Microbial Pollutants from Farm Discharge Water

Besides growing crops, a farmer is an active steward of the natural resources that support those crops. Just a few acres of wetlands on the farm can easily filter ag water for many harmful microbes introduced through livestock- or crop-related use

Soil health practices have different outcomes depending on local soil conditions

The amount of soil organic matter is a critical indicator of soil health. Applying compost or manure, growing cover crops, reducing tillage, and increasing crop diversity may increase soil organic matter. However, soil organic matter can vary dramatically in different environments, regardless of management practices. This calls for a framework to recommend place-based soil health practices and evaluate their outcomes. We used a new framework that groups soil survey data into seven regions in California's Central Valley and Central Coast. These regions either have performance limitations, such as root restrictive horizons, salinity, and shrink-swell behavior, or have relatively homogeneous, coarse-to-loamy soils ideal for agriculture. These inherent conditions affect a soil's response to practices designed to improve soil health. Looking at vineyards as an example, we find significant soil organic matter contrasts between soil health regions but not among contrasting management approaches within a given region. We also show that conservation practices improve or help maintain soil health in several long-term experiments, but inherent soil properties and types of cropping systems affect outcomes

Food, water, and fault lines: Remote sensing opportunities for earthquake-response management of agricultural water.

Earthquakes often cause destructive and unpredictable changes that can affect local hydrology (e.g. groundwater elevation or reduction) and thus disrupt land uses and human activities. Prolific agricultural regions overlie seismically active areas, emphasizing the importance to improve our understanding and monitoring of hydrologic and agricultural systems following a seismic event. A thorough data collection is necessary for adequate post-earthquake crop management response; however, the large spatial extent of earthquake's impact makes challenging the collection of robust data sets for identifying locations and magnitude of these impacts. Observing hydrologic responses to earthquakes is not a novel concept, yet there is a lack of methods and tools for assessing earthquake's impacts upon the regional hydrology and agricultural systems. The objective of this paper is to describe how remote sensing imagery, methods and tools allow detecting crop responses and damage incurred after earthquakes because a change in the regional hydrology. Many remote sensing datasets are long archived with extensive coverage and with well-documented methods to assess plant-water relations. We thus connect remote sensing of plant water relations to its utility in agriculture using a post-earthquake agrohydrologic remote sensing (PEARS) framework; specifically in agro-hydrologic relationships associated with recent earthquake events that will lead to improved water management