Recycled water causes no salinity or toxicity issues in Napa vineyards

In response to Napa Sanitation District's interest in expanding its delivery of recycled water to vineyards for irrigation, we conducted a feasibility study to assess the suitability of the water for this use. We adopted two approaches: comparing the water quality characteristics of the recycled water with those of other local sources of irrigation water, and evaluating soil samples from a vineyard that was irrigated for 8 years with the recycled water. Results indicate that the quality of the recycled water is suitable for irrigation, and also that long-term accumulation of salts and toxic ions have not occurred in the vineyards studied and are unlikely to occur. Nutrients in the recycled water may be beneficial to vineyards, though the levels of nitrogen may need to be reduced by planting cover crops in some vineyards

Subsurface drip irrigation: status of the technology in 2010

Subsurface drip irrigation (SDI), although a much smaller fraction of the microirrigated land area than surface drip irrigation, is growing at a much faster rate and is the subject of considerable research and educational efforts in the U.S. This article discusses the growth of SDI, highlights some of the research and extension efforts, and points out some of the challenges to SDI adoption and some of the future opportunities for SDI

Product architecture and the propagation of engineering change

The majority of design activities involve adapting a known solution to meet new requirements. Therefore understanding the issue of engineering changes is of vital importance if companies are to deliver product development projects on time and to budget. Making a change to a product is, in most cases, a relatively simple process. However, unexpected propagation of changes can occur. What may initially appear as a simple procedure can dramatically turn into an expensive redesign that requires alterations to a wide range of components. This paper investigates how product architecture influences change propagation and uses a design case study to highlight the complexity of this issue as faced by designers during product development

Spatial and temporal distribution of soil water balance for a drip-irrigated almond tree

Relatively little information is available on the spatial distribution of soil water under drip irrigation, and how it is affected by root distribution, emitter placement and irrigation amounts. We hypothesize that variables such as emitter position relative to the active roots as well as irrigation amount and frequency will affect the soil water regime in general, and specifically the spatial and temporal changes in soil water content as controlled by root water uptake and leaching. A better understanding of these interrelationships will provide alternative means for proper and efficient drip irrigation water management practices. Moreover, the present study will provide an extensive database which can serve as input for analytical or numerical modelling of drip-irrigated trees. We present the results of a field study in which the soil water regime of a surface drip irrigated almond tree is investigated. The experimental site (6.6 m X 4.8 m) was intensively instrumented with tensiometers and neutron probe access tubes to infer the three-dimensional distribution of soil water and root water uptake during the irrigation season. Drainage fluxes were estimated from measured hydraulic head gradients and hydraulic conductivity data. Unsaturated hydraulic conductivity were determined from in situ measurements by the instantaneous profile method, and in the laboratory using the multi-step outflow method. The water balance results showed that the applied water was not sufficient to match the actual tree Water use by evapotranspiration, causing soil water depletion around the tree as, the irrigation season progressed. Moreover, soil water content data demonstrated temporal changes in the water uptake patterns. The temporal occurrence of leaching justifies the need for soil water measurements in the scheduling and design of drip irrigation systems.This research was supported in part by Grant IS-2131-92RC from the U.S.-Israel Binational Agricultural Research and Development fund (BARD).Peer Reviewe

Reducing Runoff from Irrigated Lands: Managing Existing Sprinkler Irrigation Systems

If you experience runoff from an existing sprinkler-irrigated orchard, changing the design and set-up of the sprinkler system, the management of the sprinkler system, or the management of the orchard floor may reduce the amount

Reducing Runoff from Irrigated Lands: Storing Runoff from Winter Rains

This publication discusses the variables and feasibility of storage of winter rainwater in order to avoid impact by the Irrigated Lands Conditional Waiver under the California State Water Code

Reducing Runoff from Irrigated Lands: Tailwater Return Systems

Excess irrigation water that runs off a farm field (“tailwater”) is regulated by California law, since it may be carrying sediments, nutrients, and agricultural chemicals. Learn about options for safely recycling tailwater back into your farm operation

Reducing Runoff from Irrigated Lands: Measuring Irrigation Flows in a Pipeline

Minimizing the application of excess water requires knowing when and how much water to apply. Flow measurement is most easily done in a pipeline; this publication describes the four most commonly used flowmeters, their maintenance, and uses