Sustainable Irrigation
Conserving California's most precious resource — water — through precision drip systems, real-time sensor networks, and science-backed deficit irrigation strategies.
Every Drop
Precisely Placed
Water scarcity is the defining challenge of California agriculture. At Primex Farms, our irrigation infrastructure delivers water directly to the root zone — eliminating runoff, reducing evaporation, and cutting total water use by up to 40% compared to traditional flood irrigation methods. We coordinate with local water storage districts to match our seasonal demands with regional storage supply schedules.
In compliance with California's Sustainable Groundwater Management Act (SGMA), we actively monitor the local aquifer levels under our land. Our sustainable program includes dedicated groundwater banking recharge basins. During wet winter years, we divert excess storm runoff into these unlined spreading basins, allowing water to naturally filter down and replenish the depleted water tables, securing regional resilience for dry summer periods.
To maximize irrigation efficiency, our subsurface drip lines are buried 12 to 18 inches below the soil surface, preventing water from evaporating into the hot Central Valley air. Emitters are pressure-compensated, meaning that trees at the end of a line receive the exact same volume of water as those closest to the pump station, maintaining canopy consistency across variable terrain.
We pair subsurface drip systems with in-field soil moisture sensors and evapotranspiration-based scheduling software to make data-driven decisions every irrigation event.
Our Irrigation Toolkit
Subsurface Drip Lines
Buried emitter lines deliver water directly to the root zone, eliminating evaporative surface loss entirely.
ET-Based Scheduling
Daily evapotranspiration calculations from weather stations drive automated irrigation scheduling across all blocks.
Soil Moisture Sensors
Capacitance-based probes at multiple depths provide real-time root zone moisture data to growers and agronomists.
Tailwater Recycling
Any collected runoff water is captured, treated, and re-applied through our closed-loop recycling infrastructure.
Regulated Deficit Irrigation
Regulated Deficit Irrigation (RDI) allows us to strategically withhold water at specific growth stages where pistachio trees have high stress tolerance — reducing total water use without impacting yield.
UC Cooperative Extension research supports RDI for pistachios in California's Central Valley as a primary tool for reducing applied water during the hull-split phase without compromising nut quality or size.
Phase-specific stress application at shell hardening
Stem water potential monitoring weekly
Midday micro-climate temperature logging
Remote automated valve control via app
Water Savings Impact
California Water Law & SGMA Compliance
California's water law is a complex, layered system built on two distinct doctrines that govern access to different water sources. Surface water rights — rights to take water from rivers, streams, and canals — operate under the prior appropriation doctrine, which means that water rights are allocated in a hierarchical 'first in time, first in right' order, with older rights having priority access during shortage periods. Primex Farms holds a surface water supply contract with the Buena Vista Water Storage District (BVWSD), a Kern County water district that receives an annual allocation of State Water Project and Kern River water deliverable to member farms through an extensive canal network. This surface water supplements our groundwater supply, providing a more cost-effective water source during years when State Water Project allocations are available — though in drought years, SWP allocations to agricultural contractors have been cut to as low as 0–5% of contract amounts, making groundwater the primary supply.
Groundwater rights in California were historically unregulated — any landowner could drill a well and pump as much water as they desired from the underlying aquifer, regardless of impacts on neighboring well users or aquifer sustainability. This changed fundamentally with the Sustainable Groundwater Management Act (SGMA), signed into law in 2014, which requires that all critically overdrafted groundwater basins in California achieve 'sustainable' groundwater conditions by 2040. The Kern County Subbasin — the aquifer system underlying Primex Farms' orchards — was classified as critically overdrafted in 2014, meaning that for decades, total annual pumping had significantly exceeded natural recharge, causing measurable aquifer depletion, land subsidence, and increasing well depths throughout the region. Kern County is now managed under a complex multi-agency SGMA plan administered by the Kern Groundwater Authority (KGA), which sets annual extraction limits for member lands and requires all pumpers to report quarterly groundwater extraction volumes.
Primex Farms takes SGMA compliance extremely seriously, both because it is legally required and because we recognize that aquifer sustainability is existential to our own long-term operations. Our SGMA-compliant practices include quarterly metered groundwater extraction reporting to KGA using our calibrated turbine flow meters on all production wells, participation in KGA's voluntary fallowing program during years of high extraction stress (compensated financial agreements under which Primex Farms temporarily takes a portion of acreage out of production in exchange for water credit allocations), and active investment in on-farm recharge. Our recharge program uses a dedicated 8-acre spreading basin constructed on our lowest-elevation parcel, designed to receive and percolate winter floodwater from BVWSD canal deliveries — water that would otherwise flow uncontrolled to the valley floor. During the wet winters of 2022–23 and 2023–24, our spreading basin percolated an estimated combined total of 1,240 acre-feet of flood water into the local aquifer, partially offsetting our annual extraction and generating KGA groundwater credits.
The economics of water in California agriculture have shifted dramatically since SGMA implementation began. Water banking — the practice of storing excess surface water in the aquifer during wet years for later extraction during dry years — has become a formalized market in Kern County. The Kern Water Bank Authority manages one of the largest water banking projects in the western United States, and Primex Farms participates as a contracted water bank customer, paying a fee per acre-foot to deposit surface water during high-allocation years and withdraw banked water at a premium during drought years. The net economic value of water banking participation to Primex Farms depends on the ratio of wet-year deposit costs to dry-year withdrawal costs, but in the severe drought years of 2020–21 and 2021–22, having pre-purchased water bank credits provided supply certainty that allowed us to maintain full orchard irrigation at a time when spot water market prices in Kern County reached $400–600 per acre-foot — substantially above our bank withdrawal cost.
Looking forward, Primex Farms' water supply strategy is built around three pillars: efficiency maximization (reducing per-acre consumption through precision irrigation to create a buffer against future SGMA extraction limits), portfolio diversification (maintaining contractual access to surface water, groundwater, and water bank supplies so that no single source failure can jeopardize crop delivery), and advocacy (active participation in Kern Groundwater Authority governance to ensure that SGMA implementation policies reflect the practical realities of commercial pistachio production). As SGMA's mandatory extraction limits become progressively more restrictive through the 2030 decade, Primex Farms is committed to meeting our compliance obligations without sacrificing the crop quality and yield reliability that our buyers depend on — a goal that will require continued innovation in both technology and operational practice.
Sensor Network & Precision Scheduling
Primex Farms operates a comprehensive soil moisture and plant water status monitoring network across all irrigated orchard blocks. Our soil moisture monitoring system uses a combination of granular matrix sensors (Watermark-style) at 12-inch, 24-inch, and 36-inch depths and time-domain reflectometry (TDR) probes at 18-inch depth, providing a complete picture of the soil moisture profile from the shallow root zone through the deep moisture reservoir. Sensor data is telemetered wirelessly at 15-minute intervals to our cloud-hosted farm management platform, where our irrigation engineers review soil moisture depletion curves each morning to identify blocks where root-zone moisture has depleted to the target refill threshold and irrigation events should be scheduled for that day.
In addition to soil moisture monitoring, Primex Farms uses stem water potential (ψstem) measurements to directly assess plant water stress — a more direct indicator of the crop's physiological water status than soil measurements alone. Stem water potential is measured using a pressure chamber (Scholander bomb) on a subset of representative trees in each orchard block between noon and 2 PM on clear days, when stomata are fully open and plant water demand is at its maximum. Target ψstem thresholds for pistachio at each growth stage are based on UC Cooperative Extension research: during kernel fill (mid-July through August), Primex Farms targets ψstem between -10 and -12 bar, a range that indicates mild stress that has been shown to improve kernel quality (increasing sugar concentration and flavor intensity) without reducing yield. During the less critical pre-harvest period (August–September), a slightly higher stress level of -12 to -16 bar is acceptable and can help advance hull split.
The irrigation control system at Primex Farms uses a central SCADA (Supervisory Control and Data Acquisition) platform that integrates data from all soil moisture sensors, weather station data from two on-farm CIMIS-linked stations, flow meter readings from all pump stations and sub-main manifolds, and fertilizer injection system setpoints. This integration allows our irrigation engineers to execute complex fertigation programs — irrigation events during which liquid fertilizer is injected into the water stream at precise concentrations and timings — through the central software interface rather than requiring manual valve operation and injection system adjustment in the field. The SCADA platform also monitors pump energy consumption in real time, alerting engineers to elevated power draw that might indicate declining well yield, partial impeller wear, or manifold blockage — early warning that allows preventive maintenance before a pump failure during the critical summer irrigation season.
Drip lateral maintenance is a critical and ongoing operational task at Primex Farms. Our subsurface drip system — with emitters buried 24 inches deep at 18-inch in-row spacing — has a design life of 15–20 years when properly maintained, but requires annual inspection and maintenance to prevent emitter plugging by calcium carbonate precipitation (a common problem in the alkaline groundwater of Kern County), biological fouling by iron-oxidizing bacteria, and root intrusion. Our maintenance protocol includes quarterly acid flushing of all drip laterals with 50–100 ppm sulfuric acid injected through the system — a concentration sufficient to dissolve calcite deposits without damaging emitter membranes. Annual lateral inspection is performed using a combination of pressure uniformity testing (measuring emitter discharge rates at the beginning, middle, and end of each lateral) and physical line-pulling inspection of 2% of emitter locations per year on a rotating block schedule.
Pressure management across the drip system is critical for achieving distribution uniformity above 95%. Our pump stations are equipped with variable-speed pump drives that maintain constant system header pressure at the design operating point (typically 30–35 PSI at the pump outlet) regardless of the number of drip zones operating simultaneously. Pressure-regulating valves at each zone inlet reduce pressure from the mainline to the designed drip lateral operating pressure of 12–15 PSI, and pressure-vacuum breaker assemblies at each zone prevent water hammer shock during zone opening and closing that could dislodge emitters or split thin-wall lateral tubing. Zone valve control through the SCADA system allows split-zone irrigation runs during peak demand periods when the pump's flow capacity limits simultaneous operation of all zones.
Looking at the future of irrigation technology at Primex Farms, we are currently piloting a machine-learning irrigation scheduling algorithm that integrates real-time soil moisture sensor data with 10-day weather forecast inputs from the National Weather Service, satellite-based canopy NDVI (Normalized Difference Vegetation Index) measurements updated weekly, and historical yield response curves from our block-level production database. The algorithm generates daily irrigation volume recommendations for each block that aim to maintain root-zone moisture at the target depletion fraction while pre-loading the soil profile before forecasted heat events to buffer the crop against peak transpiration stress — a capability that would be nearly impossible to execute through manual calculation on a farm of our scale. Early pilot results show a 7–12% reduction in total irrigation volume for equivalent crop outcomes compared with our previous manual scheduling methodology, a saving that translates to approximately 280–480 acre-feet of water per season across our full irrigated acreage.