Hansen Trust Report

Study of Agricultural Nitrates

Las PosasBasin, VenturaCounty

Steven Bachman, PhD

September, 2003

Supported by the Hansen Trust
and
Calleguas Municipal Water District

Table of Contents

Table of Contents

Conclusions

Background and Purpose of Study

Cooperation with other Studies

Procedures

Field Results

Laboratory Results

Nitrate Trends

Chloride Trends

Educational Outreach and Best management Practices

Continuing Work Effort

Recommendations

Acknowledgements

Appendix A – Table of Water Quality Analyses...... A-

Appendix B – Water Quality Charts...... B-

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Study of Agricultural NitratesSteven Bachman, PhD

Conclusions

Analyses of the nitrogen compounds in soil moisture within and below the crops’ root zone indicate that nitrate is by far the most pervasive of these compounds present in the soil water samples. Nitrate levels are above the drinking water maximum contaminant level in the majority of the samples. In contrast, other nitrogen species were relatively low in concentration or were non-detected. Nitrate is apparently being applied in excess of plant demand on a variety of crops.

The overall nitrate results indicate that current fertilizer applications are not “perfectly tuned” to plant demand. Nitrate concentrations at all lysimeter depths are generally above optimum levels. However, the nitrate levels in the soil water can be reduced rapidly when fertilizer applications are reduced. In a plot of peppers, reduction in fertilizer application near the time of crop maturity reduced nitrate by more than 90% in the soil water within a month. Thus, significant improvement in nitrate loading to the soil can be achieved by more closely matching fertilizer application to the maturity of the crop.

Early results from this study have prompted a larger effort at characterizing agricultural loading of nutrients and reducing this loading. This effort has included outreach programs and the procurement of grant funding for further characterization and testing of management strategies to reduce this nutrient loading.

Background and Purpose of Study

In some areas of VenturaCounty, nitrates are elevated in both surface water and groundwater. This has prompted the Regional Water Quality Control Board to instigate a ban on septic systems in the El Rio area and to focus on nitrogen loading from wastewater treatment plants and from agriculture. Agricultural nitrates have been assumed to be a major contributor to surface and ground water contamination.

Irrigation and fertilization practices have changed substantially in the last several years. Increased use of low-pressure irrigation systems has replaced gravity flow methods and there is increased use of foliar nutrient application and fertigation. These new methods have certainly altered the fate of applied nitrogen. The concern prompting this pilot study is that for the purpose of allocating nutrient loading in the watershed, the Regional Board will likely use generalized data from some other area that will not reflect current practices of VenturaCounty growers.

As nitrogen is applied to crops, several processes occur. A portion of the nitrogen is used by plants, a portion runs off the field with tail waters, and a portion percolates into the unsaturated zone and possibly into groundwater. Depending on the local conditions, both tail water and a portion of the groundwater may reach surface water tributaries. The nitrogen in this water undergoes a variety of chemical transformations, resulting in various proportions of nitrogen, ammonia, nitrate and nitrite.

This study examined the component of irrigation and rain water that percolates to the root zone and beyond. Several questions were addressed:

• What is the concentration of nitrogen components at various depths at and below the root zone?
• Do nitrogen levels vary with crop and soil?
• Do nitrogen levels vary with season, according to irrigation and rainfall patterns?
• Are nitrogen levels sufficiently high to potentially impact surface water and groundwater quality?
• Can current agricultural management practices be modified to reduce nitrogen loading?
• Do the results of this study warrant expanded study and more-widespread modification of current agricultural management practices?

Cooperation with other Studies

Larry Walker Associates (LWA) sampled surface water in Arroyo Las Posas tributaries concurrently with this study. LWA chose sites that overlapped with this study, and sampled during the same general periods. There was generally little or no flow in these tributaries except during the rainy portion of the year. The LWA study, done in conjunction with other Calleguas Creek Watershed studies, will be available on the watershed web site at

Procedures

Eight sampling sites were used in the study (Fig. 1). Three were in avocado groves, two in citrus orchards, and three were rotated through row crops (carrots and peppers). Three lysimeters were installed at each site at depths of two, four, and six feet. Halfway through the study, the two-foot lysimeters were reinstalled to eight inches deep to better correlate with the crop root zone.

Figure 1. Lysimeter sites in the Las Posas Basin.

Each lysimeter was installed by auguring a hole slightly wider than the lysimeter. A slurry of silica flour was poured into the bottom of the auger hole, the lysimeter was set into the slurry, and additional silica flour was poured around the lower tip of the lysimeter to provide a good contact between the ceramic tip and the soil. The remainder of the hole was then filled with bentonite pellets to preclude downward movement of water around the lysimeter. When lysimeters were required to be reset in the row crops because of seasonalcrop rotation, a jacking device borrowed from UC Cooperative Extension was used to extract the lysimeters.

The lysimeters were sampled eight times during a one-year period. During the winter, sampling was targeted to rain events. Sampling was accomplished by applying a vacuum to the lysimeter and allowing sufficient time for soil moisture to be pulled into the lysimeter tube. A flexible sampling tube was then inserted into the lysimeter to extractthe sample. Each sample was split between an empty sample bottle (for most analyses) and one containing a sulfuric acidpreservative (for ammonia and nitrogen). If there was insufficient sample for a split, the complete sample was poured into the empty bottle. Samples were chilled in the field and delivered to the testing laboratory within a few hours of sampling, accompanied by a standard chain of custody form. Irrigation source water was also sampled when practical. All analyses were performed by FGL Environmental in Santa Paula.

Laboratory analyses included nitrate, nitrite, ammonia, organic nitrogen, and Kjeldahl nitrogen. In addition, chloride and electrical conductivity were analyzed for a qualitative sense of the rate of deep percolation. The results were analyzed using an Access database, Excel spreadsheets, and ArcGIS software.

Growers participating in the study were not given any results until the last months of the study so that current management practices could be tested over most of the year-long study period. After results were shared with the growers, there was some modification of fertilizer practices (discussed in a following section).

Field Results

Descriptions of the sample sites, sequencing of sampling, and resetting of lysimeters are described in an Access database and Excel spreadsheet attached to this report on a CD. This information includes:

- Installation date

- Hole depth and diameter

- UTM coordinates of sample site

- Crop

- Terrain

- Vacuum time for each sample

- Sample dates

- Volume extracted for each sample

The quantity of soil water extracted during each sample event varied considerably (Appendix A). In general, sample size was larger during the rainy season. Sample size also varied by crop; avocados, for which irrigation must be controlled carefully to prevent root rot, yielded small amounts of water. In fact, there was little or no soil water available to sample at deeper depths at avocado sites during the drier portion of the year. In contrast, citrus and row crops yielded much larger quantities of soil water (up to one liter per sample).

Laboratory Results

Analyses of the nitrogen compounds indicate that nitrate is by far the most pervasive of these compounds present in the soil water samples (Appendix A). Nitrate concentrations varied from about 1 mg/L NO3to as much as 1400 mg/L NO3; 75% of the nitrate results were in the 45 to 300 mg/L NO3range (the drinking water maximum contaminant level for nitrate is 45 mg/L NO3). In contrast, other nitrogen species were relatively low in concentration or were non-detected.

Chloride concentrations varied from near the detection level to in excess of 5,000 mg/L; over 75% of the samples were below a concentration of 100 mg/L. Individual sites had a variety of irrigation source water. Sites with high chloride concentrations in source water also had the highest concentrations in soil water. Electrical conductivity ranged from 534 to 9,230 umhos/cm[1].

The results of the analyses were entered in an Access database and queried to Excel files to prepare time-series charts. The Excel spreadsheet appears in Appendix A and the nitrate and chloride charts are included in the main text or in Appendix B. All the digital files are available on the included CD.

Nitrate Trends

Nitrate is the most prevalent of the nitrogen compounds present in the samples analyzed in this study. Thus, it represents the best tracer for how efficiently fertilizer is being applied and being used by the crops. Nitrate in excess of crop demand can reach both groundwater and surface waters. In groundwater, nitrate concentrations in groundwater in excess of 45 mg/L NO3 violate primary drinking water standards; high nitrates in surface water bodies are a nutrient source that promotes algal growth to the detriment of other species.

If application of fertilizer was perfectly tuned to crop demand, nitrate within the root zone (lysimeter samples at eight inches depth) would increase following fertilizer application and decrease as the plant used the nitrate. There would be relatively low levels of nitrate below the root zone. Nitrate sampled at lysimeter depths of four to six feet is effectively nitrate that has escaped the crops’ root zone and is likely to affect groundwater and/or surface water as it percolates deeper or runs into surface water bodies.

The overall nitrate results indicate that current fertilizer applications are not “perfectly tuned” as described in the previous paragraph. Nitrate concentrations at all lysimeter depths are generally above optimum levels, and nitrate at depths below the root zone are generally equal to or higher than concentrations within the root zone (Fig. 2). Winter rains might also be expected to leach nitrates from the upper soil horizons into lower soil horizons, but that trend was not apparent in the results.

Figure 2a. Nitrate concentrations from two lysimeter sites. L4-08 is a sample from eight inches deep, L4-2,4,6 are from two, four and six feet, respectively.

Figure 2b. Nitrate concentrations from two lysimeter sites.

The highest nitrate readings were from row crops (carrots and peppers). These row crops were irrigated by both overhead sprinklers (carrots) and by drip tape (peppers). The largest time variation (and highest concentrations) of nitrate occurred in the peppers (Figure 3), where fertilizer was applied in the irrigation water at each irrigation. This variation is discussed further in the section Educational Outreach and Best Management Practices.

Figure 3. Nitrate concentrations from pepper field.

Chloride Trends

Chloride can be used as a tracer of evaporation and plant uptake of water. Chloride is conservative in these reactions – that is, water is removed and the chloride is left behind. Chloride thus increases in concentration as irrigation water or rainfall moves through the root zone and water is consumed by the crop. Irrigation is generally thought to increase chloride concentrations in a groundwater basin as water is removed, chloride is left behind, and recharge to the basin continues to introduce new sources of chloride. Within the soil horizons, rising concentrations of chloride require periodic leaching of the salts.

As expected, chloride concentrations in this study are higher at deeper lysimeter depths (Fig. 4). This is particularly true in the avocados, where irrigation is controlled to prevent root rot and there is less water to leach the chloride. In fact, it was difficult to extract significant soil moisture from the four and six foot lysimeters in the avocados.

Most chloride levels analyzed were relatively low (less than 100 mg/L). Some of the row crops had the highest chloride concentrations, in part because of a differing source of irrigation water. However, the high concentrations of chloride in lysimeters at station 8 (Appendix B) cannot be completely explained in this way, and remain an enigma.

Figure 4. Chloride concentrations from two lysimeter sites.

Educational Outreach and Best management Practices

Growers in this study were informed of results more than halfway into the study period. The higher nitrates in the row crops were of concern to the growers, which prompted several conversations about the current irrigation and fertilizer practices. The ability to reduce nitrates was highlighted from the results in the peppers (Fig. 3), where nitrates decreasedby more than 90% in the last measurement period. The higher nitrates in these peppers occurred when the plants were smaller and needed fewer nitrates. As the plants became larger (with a higher need for nitrate) and applied fertilizer was reduced as the peppers set, nitrate at shallower lysimeter depths decreased sharply. The current fertilizer plan in the peppers is based on maximizing crop yield; when the effects of unwanted nitrate loading are also factored into fertilizer plan, it is apparent that early fertilizing could be scaled back. Thus, an effective Best Management Practice (BMP) would be to more closely tailor fertilizer application to changing plant requirements.

This study provided one of the seeds that led to further discussions within the VenturaCounty agricultural community about potential agricultural effects on surface water and groundwater. The study coincided with significant regulatory action on Total Maximum Daily Loads (TMDLs) in the local watersheds. When an AgriculturalOversight Committee was formulated to deal with TMDLs that would affect agriculture, one of the first discussions dealt withthe need to have local data such as this study provided. In fact, the study became a model for planning future work.

The committee discussions resulted in a series of seminars for growers on the TMDL process and how it might affect agriculture. These seminars were sponsored by the Ventura County Farm Bureau and the Association of Water Agencies of Ventura County (AWA). Among the topics was a presentation on the techniques of this study in answering questions of agricultural loading. This study was also the front page article in the Fall 2003 AWA newsletter.

An additional result of these outreach efforts within the agricultural community was the decision to apply for grant monies to broaden the work of this study into the entire Calleguas Creek and Santa Clara River watersheds. This effort is described in the section Continuing Work Effort.

Continuing Work Effort

As discussed above, there is a continuing effort in VenturaCounty to expand on the type of work accomplished in this study. The major water agencies (United Water Conservation District and Calleguas Municipal Water District) have teamed with the Ventura County Farm Bureau to apply for grant monies. The first of this work has been funded througha Proposition 13 grant from the State Water Resources Control Board; a second grant application has been short-listed. These grants includecollecting baseline information on nitrogen compounds and pesticides in agricultural soil water and direct runoff from fields, as well as a three-year program of fine-tuning management strategies and re-testing for improvements. If completely funded, this work would be done at 65 sites within the Santa ClaraRiver and Calleguas Creek watersheds. There is also a significant effort in the work plans for educational outreach to involve many growers in the work and to share results of the study.

Recommendations

The results of this study indicate that current fertilizer management practices need to be further refined to reduce nitrate loading into groundwater and surface waters. The funded work discussed above will help in this effort. However, the ultimate success of the effort will be with growers themselves. A permitting process for agricultural runoff proposed by the Los Angeles Regional Water Quality Control Board will likely increase awareness of the issue. VenturaCounty growers have historically solved water problems by themselves, so it is recommended that growers become involved in the funded studies to preclude any future onerous permitting process.

Acknowledgements

The Hansen Trust, administered by UC Davis, provided the funds for this project. Calleguas Municipal Water District paid for all chemical analyses, which effectively matched the funding from the Hansen Trust. Ben Faber of UC Cooperative Extension and Darrell Nelson of FGL Environmental were instrumental in helping set up this study. Sam McIntyre of Somis Pacific was most helpful in providing study sites, installing the lysimeters, and pulling vehicles out of the mud. Craig Underwood assisted in providing study sites and installing lysimeters.

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Study of Agricultural NitratesSteven Bachman, PhD

Appendix A – Table of Water Quality Analyses

Lysimeter / Sample Date / Vacuum Time / Volume extracted / Laboratory / Nitrate(NO3)mg/L / Nitrite mg/L / Ammonia-N mg/L / Nitrogen-total mg/L / Nitrogen, Organic ppm / Chloride mg/L / Nitrate+Nitrite (N) / Kjeldahl Nitrogen / Conductivity
L2-2 / 10/10/2002 / 8 days / 500+ mL / FGL / 499 / 4.9 / 0.4 / 4.2 / 21 / 113 / 2.7
L2-4 / 10/10/2002 / 8 days / 500+ mL / FGL / 155 / 1.4 / -0.1 / 36.1 / 22 / 35 / 1.1
L1-2 / 10/21/2002 / 19 days / 400 mL / FGL / 72.3 / -0.3 / -0.1 / 1.5 / 29 / 1.5
L4-2 / 10/21/2002 / 11 days / 350mL / FGL / 104 / 0.8 / 0.2 / 0.5 / 56 / 0.7
L4-4 / 10/21/2002 / 11 days / 300mL / FGL / 246 / 1.2 / 0.2 / -0.5 / 19 / 0.5
L5-2 / 10/21/2002 / 19 days / 50mL / FGL / 42.7 / -0.3 / -0.14 / 1.4 / 95 / 1.4
L5-4 / 10/21/2002 / 19 days / 40mL / FGL / 32.3 / 1 / -0.16 / 1.1 / 34 / 1.1
L4-6 / 10/23/2002 / 2 days / 200mL / FGL / 113 / -0.3 / 0.1 / 0.5 / 27 / 0.6
L6-6 / 10/23/2002 / 2 days / 30mL / FGL / 130 / 0.6 / 0.1 / 0.6 / 37 / 0.7
L2-6 / 10/24/2002 / 3 days / 200 mL / FGL / 120 / -0.3 / 0.2 / -0.5 / 27 / 0.6
L1-4 / 11/1/2002 / 8 days / 60mL / FGL / -0.3 / 0.2 / 1.3 / 37 / 1.5
L1-6 / 11/1/2002 / 8 days / 30-40mL / FGL / 279 / -3 / 0.1 / 1.2 / 78 / 1.3
L3-2 / 11/1/2002 / 8 days / 45mL / FGL / 89 / -3 / 0.2 / 3.8 / 101 / 4
L3-6 / 11/1/2002 / 8 days / 20mL / FGL / 109 / -0.3 / 57
L5-6 / 11/1/2002 / 9 days / 600mL / FGL / 180 / -0.3 / 0.1 / 1.2 / 48 / 1.3
L1-2 / 11/15/2002 / FGL / 18 / -0.3 / 0.4 / 1 / 24 / 1.4
L1-4 / 11/15/2002 / FGL / 92 / -0.3 / -0.2 / 1.2 / 25 / 1.2
L1-6 / 11/15/2002 / FGL / 300 / -1.5 / -0.2 / 1.2 / 260 / 1.2
L2-2 / 11/16/2002 / FGL / 66 / -0.3 / -0.2 / 1.4 / 19 / 1.4
L2-4 / 11/16/2002 / FGL / 138 / 0.5 / 0.7 / 0.7 / 25 / 0.7
L2-6 / 11/16/2002 / FGL / 70 / -0.3 / -0.2 / -0.5 / 25 / -0.5
L3-2 / 11/16/2002 / FGL / 167 / -0.3 / -0.2 / 7 / 83 / 7
L3-4 / 11/16/2002 / FGL / 74.9 / -0.3 / -0.2 / 1.2 / 124 / 1.2
L4-2 / 11/16/2002 / FGL / 209 / -0.3 / -0.2 / -0.5 / 70 / -0.5
L4-4 / 11/16/2002 / FGL / 202 / -0.3 / -0.2 / -0.5 / 17 / -0.5
L4-6 / 11/16/2002 / FGL / 137 / -0.3 / -0.2 / -0.5 / 24 / -0.5
L5-2 / 11/16/2002 / FGL / 4.1 / -0.3 / -0.2 / 0.9 / 81 / 0.9
Lysimeter / Sample Date / Vacuum Time / Volume extracted / Laboratory / Nitrate(NO3)mg/L / Nitrite mg/L / Ammonia-N mg/L / Nitrogen-total mg/L / Nitrogen, Organic ppm / Chloride mg/L / Nitrate+Nitrite (N) / Kjeldahl Nitrogen / Conductivity
L5-4 / 11/16/2002 / FGL / 0.4 / 0.9 / -0.2 / 0.6 / 29 / 0.6
L5-6 / 11/16/2002 / FGL / 125 / -0.3 / -0.2 / -0.5 / 42 / -0.5
L6-2 / 11/16/2002 / FGL / 175 / -0.3 / -0.2 / 1 / 17 / 1
L6-4 / 11/16/2002 / FGL / 1.7 / -0.3 / -0.2 / -0.5 / 14 / -0.5
L6-6 / 11/16/2002 / FGL / 52 / -0.3 / -0.2 / -0.5 / 35 / -0.5
L1-2 / 12/30/2002 / 12 days / 300mL / FGL / 179 / -0.3 / 0.1 / 1.5 / 21 / 1.6 / 746
L1-4 / 12/30/2002 / 12 days / 60mL / FGL / 310 / -0.3 / -0.1 / 1.1 / 17 / 1.1 / 882
L1-6 / 12/30/2002 / 12 days / 40mL / FGL / 172 / -0.3 / -0.1 / 0.7 / 180 / 0.7 / 3600
L2-2 / 12/30/2002 / 12 days / 500mL / FGL / 81 / -0.3 / 0.2 / 1.1 / 21 / 1.3 / 795
L2-4 / 12/30/2002 / 12 days / 900mL / FGL / 108 / -0.3 / -0.1 / 0.9 / 22 / 0.9 / 809
L2-6 / 12/30/2002 / 12 days / 800mL / FGL / 86.2 / -0.3 / -0.1 / -0.5 / 26 / -0.5 / 827
L3-2 / 12/30/2002 / 12 days / 400mL / FGL / 131 / -0.3 / -0.1 / 3.4 / 53 / 3.4 / 1450
L3-4 / 12/30/2002 / 12 days / 700mL / FGL / 95 / -0.3 / -0.1 / 2.2 / 160 / 2.2 / 2910
L4-2 / 12/30/2002 / 12 days / 400mL / FGL / 234 / -0.3 / -0.1 / 0.7 / 65 / 0.7 / 2310
L4-4 / 12/30/2002 / 12 days / 300mL / FGL / 163 / -0.3 / -0.1 / -0.5 / 19 / -0.5 / 1370
L4-6 / 12/30/2002 / 12 days / 800mL / FGL / 154 / -0.3 / 0.1 / -0.5 / 24 / -0.5 / 1700
L5-2 / 12/30/2002 / 12 days / 500mL / FGL / 76.6 / -0.3 / -0.1 / 0.7 / 37 / 0.7 / 1820
L5-4 / 12/30/2002 / 12 days / 150mL / FGL / 39.9 / -0.3 / -0.1 / 0.5 / 36 / 0.5 / 2140
L5-6 / 12/30/2002 / 12 days / 1000mL / FGL / 120 / -0.3 / -0.1 / 0.5 / 42 / 0.5 / 3490
L1-2 / 2/19/2003 / 13 days / 300mL / FGL / 140 / -0.3 / -0.1 / 1.6 / 22 / 1.6
L1-4 / 2/19/2003 / 13 days / 30mL / FGL / 190 / 24
L1-6 / 2/19/2003 / 13 days / 20mL / FGL / 201 / 260
L2-2 / 2/19/2003 / 13 days / 500mL / FGL / 69.6 / -0.3 / -0.1 / 0.9 / 26 / 0.9
L2-4 / 2/19/2003 / 13 days / 850mL / FGL / 105 / -0.3 / -0.1 / 1.1 / 26 / 1.1
L2-6 / 2/19/2003 / 13 days / 700mL / FGL / 124 / -0.3 / -0.1 / 0.6 / 27 / 0.6
L3-2 / 2/19/2003 / 13 days / 400mL / FGL / 64.5 / -0.3 / -0.1 / 3.9 / 36 / 3.9
L3-4 / 2/19/2003 / 13 days / 800mL / FGL / 122 / -3 / -0.1 / 1.7 / 190 / 1.7
L4-2 / 2/19/2003 / 13 days / 400mL / FGL / 176 / -0.3 / -0.1 / -0.5 / 46 / -0.5
L4-4 / 2/19/2003 / 13 days / 500mL / FGL / 139 / -0.3 / -0.1 / -0.5 / 23 / -0.5
L4-6 / 2/19/2003 / 13 days / 1100mL / FGL / 183 / -0.3 / -0.1 / -0.5 / 27 / 0.5
Lysimeter / Sample Date / Vacuum Time / Volume extracted / Laboratory / Nitrate(NO3)mg/L / Nitrite mg/L / Ammonia-N mg/L / Nitrogen-total mg/L / Nitrogen, Organic ppm / Chloride mg/L / Nitrate+Nitrite (N) / Kjeldahl Nitrogen / Conductivity
L5-2 / 2/19/2003 / 13 days / 350mL / FGL / 102 / -0.3 / -0.1 / -1 / 30 / -1
L5-4 / 2/19/2003 / 13 days / 50mL / FGL / 64.2 / -0.3 / -0.1 / 0.7 / 36 / 0.7
L5-6 / 2/19/2003 / 13 days / 800mL / FGL / 94 / -0.3 / -0.1 / -0.5 / 40 / -0.5
L7-2 / 3/21/2003 / 17 days / 500mL / FGL / 529 / -0.3 / 0.3 / 1.5 / 102 / 1.8 / 2540
L7-4 / 3/21/2003 / 17 days / 1000mL / FGL / 736 / -0.3 / 0.5 / 0.8 / 220 / 1.3 / 3650
L7-6 / 3/21/2003 / 17 days / 1200mL / FGL / 557 / -0.3 / 0.4 / -0.5 / 240 / 0.7 / 3300
L1-2 / 3/26/2003 / 7 days / 120mL / FGL / 101 / -0.3 / 0.2 / 1.3 / 14 / 1.5 / 535
L2-2 / 3/26/2003 / 7 days / 400mL / FGL / 78 / -0.3 / 0.2 / 1 / 33 / 1.2 / 918
L2-4 / 3/26/2003 / 7 days / 1000mL / FGL / 83 / -0.3 / 0.1 / 1.1 / 27 / 1.2 / 803
L2-6 / 3/26/2003 / 7 days / 350mL / FGL / 143 / -0.3 / -0.1 / 3 / 27 / 3 / 810
L3-2 / 3/26/2003 / 7 days / 500mL / FGL / 14 / -0.3 / -0.1 / 3.9 / 24 / 3.9 / 868
L3-4 / 3/26/2003 / 7 days / 800mL / FGL / 57 / -0.3 / -0.1 / 2.5 / 98 / 2.5 / 2110
L3-6 / 3/26/2003 / 7 days / 40mL / FGL / 180 / -0.3 / 180 / 6170
L4-2 / 3/28/2003 / 7 days / 200mL / FGL / 104 / -0.3 / -0.1 / 0.6 / 27 / 0.6 / 1370
L4-4 / 3/28/2003 / 7 days / 300mL / FGL / 111 / -0.3 / -0.1 / 0.7 / 24 / 0.7 / 1190
L4-6 / 3/28/2003 / 7 days / 800mL / FGL / 168 / -0.3 / 0.1 / -0.5 / 26 / 0.5 / 1740
L5-2 / 3/28/2003 / 7 days / 400mL / FGL / 93 / -0.3 / -0.1 / 1.1 / 32 / 1.1 / 1240
L5-4 / 3/28/2003 / 7 days / 80mL / FGL / 86 / -0.3 / -0.1 / 0.7 / 38 / 0.7 / 1910
L5-6 / 3/28/2003 / 7 days / 500mL / FGL / 213 / -0.3 / -0.1 / 0.7 / 45 / 0.7 / 2720
L1-08 / 5/27/2003 / 8 days / 400mL / FGL / 113 / -0.3 / 0.2 / 1.9 / 14 / 2.1 / 614
L1-4 / 5/27/2003 / 14 days / 75mL / FGL / 59.7 / -0.3 / 17 / 534
L1-6 / 5/27/2003 / 14 days / 50mL / FGL / 290 / -0.3 / 290 / 4640
L2-08 / 5/27/2003 / 8 days / 500mL / FGL / 111 / -0.3 / 0.1 / 2.4 / 15 / 2.5 / 941
L2-4 / 5/27/2003 / 14 days / 950mL / FGL / 73.9 / -0.3 / 0.1 / 1.2 / 25 / 1.3 / 840
L2-6 / 5/27/2003 / 14 days / 700mL / FGL / 117 / -0.3 / -0.1 / -0.5 / 28 / -0.5 / 816
L2-IRR / 5/27/2003 / NA / 1000mL / FGL / 0 / -0.1 / 9 / 528
L3-08 / 5/27/2003 / 8 days / 550mL / FGL / 416 / -0.3 / -0.1 / 2.5 / 34 / 2.5 / 1790
L3-4 / 5/27/2003 / 14 days / 50mL / FGL / 63.7 / -0.3 / 120 / 2500
L3-6 / 5/27/2003 / 14 days / 50mL / FGL / 183 / -0.3 / -0.1 / 1.8 / 240 / 1.8 / 5000
Lysimeter / Sample Date / Vacuum Time / Volume extracted / Laboratory / Nitrate(NO3)mg/L / Nitrite mg/L / Ammonia-N mg/L / Nitrogen-total mg/L / Nitrogen, Organic ppm / Chloride mg/L / Nitrate+Nitrite (N) / Kjeldahl Nitrogen / Conductivity
L4-08 / 5/27/2003 / 8 days / 300mL / FGL / 252 / -0.3 / 0.2 / 2.1 / 24 / 2.3 / 2370
L4-4 / 5/27/2003 / 14 days / 550mL / FGL / 97 / -0.3 / -0.1 / -0.5 / 23 / -0.5 / 1220
L4-6 / 5/27/2003 / 14 days / 950mL / FGL / 165 / -0.3 / -0.1 / -0.5 / 29 / -0.5 / 1800
L5-08 / 5/27/2003 / 8 days / 200mL / FGL / 156 / -0.3 / 0.2 / 1.3 / 8 / 1.5 / 598
L5-4 / 5/27/2003 / 14 days / 150mL / FGL / 95 / -0.3 / 0.1 / -0.5 / 34 / 0.5 / 1870
L5-6 / 5/27/2003 / 14 days / 700mL / FGL / 99 / -0.3 / -0.1 / -0.5 / 46 / -0.5 / 2760
L5-IRR / 5/27/2003 / NA / 1000mL / FGL / 0 / -0.1 / 9 / 723
L7-6 / 5/27/2003 / 14 days / 900mL / FGL / 490 / -0.3 / -0.1 / -0.5 / 270 / -0.5 / 3610
L8-08 / 6/19/2003 / 6 days / 400mL / FGL / 464 / 5 / 1.1 / 1.6 / 440 / 2.7 / 5140
L8-4 / 6/19/2003 / 6 days / 700mL / FGL / 1070 / -3 / 0.4 / 0.6 / 1100 / 1 / 7270
L8-6 / 6/19/2003 / 6 days / 800mL / FGL / 445 / -0.3 / 0.1 / -0.5 / 530 / -0.5 / 5150
L1-08 / 7/7/2003 / 10 days / 475mL / FGL / 172 / -0.6 / 0.2 / -0.5 / 15 / -0.5 / 717
L1-4 / 7/7/2003 / 10 days / 50mL / FGL / 262 / -0.6 / 23 / 914
L1-6 / 7/7/2003 / 10 days / 20mL / FGL / 311 / -1.5 / 357 / 4860
L2-08 / 7/7/2003 / 10 days / 500mL / FGL / 23.3 / -0.3 / 0.1 / -0.5 / 19 / -0.5 / 836
L2-4 / 7/7/2003 / 10 days / 1100mL / FGL / 257 / 0.3 / 0.3 / -0.5 / 28 / 0.6 / 1080
L2-6 / 7/7/2003 / 10 days / 500mL / FGL / 119 / -0.3 / -0.1 / 1.8 / 34 / 1.8 / 821
L3-08 / 7/7/2003 / 10 days / 100mL / FGL / 46.7 / -0.3 / 0.1 / 3.6 / 45 / 3.7 / 1710
L4-4 / 7/7/2003 / 10 days / 400mL / FGL / 174 / -0.3 / 0.2 / -0.5 / 21 / -0.5 / 1110
L4-6 / 7/7/2003 / 10 days / 950mL / FGL / 178 / -0.3 / 0.2 / -0.5 / 32 / -0.5 / 1740
L5-08 / 7/7/2003 / 10 days / 450mL / FGL / 71.3 / -0.3 / 0.3 / 1.3 / 14 / 1.6 / 819
L5-4 / 7/7/2003 / 10 days / 100mL / FGL / 103 / -0.3 / 30 / 1730
L5-6 / 7/7/2003 / 10 days / 900mL / FGL / 111 / -0.3 / 0.3 / -0.5 / 46 / 0.6 / 2500
L8-08 / 7/7/2003 / 10 days / 100mL / FGL / 581 / -3 / 1.5 / 1.6 / 420 / 3.1 / 5640
L8-4 / 7/7/2003 / 10 days / 650mL / FGL / 1390 / -6 / 0.2 / 0.5 / 1400 / 0.7 / 8690
L8-6 / 7/7/2003 / 10 days / 950mL / FGL / 600 / -3 / 0.2 / 0.7 / 740 / 0.9 / 6110
L1-08 / 8/12/2003 / 14 days / 500mL / FGL / 150 / -30 / 0.2 / 1.5 / -100 / 1.7 / 21300
L1-4 / 8/12/2003 / 14 days / 150mL / FGL / 219 / -0.3 / 0.2 / 1.4 / 47 / 1.6 / 1140
L2-08 / 8/12/2003 / 14 days / 300mL / FGL / 34 / -0.3 / -0.1 / 2 / 23 / 2 / 860
Lysimeter / Sample Date / Vacuum Time / Volume extracted / Laboratory / Nitrate(NO3)mg/L / Nitrite mg/L / Ammonia-N mg/L / Nitrogen-total mg/L / Nitrogen, Organic ppm / Chloride mg/L / Nitrate+Nitrite (N) / Kjeldahl Nitrogen / Conductivity
L2-4 / 8/12/2003 / 14 days / 900mL / FGL / 90 / -0.3 / 0.1 / -2.5 / 23 / -2.5 / 973
L2-6 / 8/12/2003 / 14 days / 800mL / FGL / 112 / -0.3 / -0.1 / 0.6 / 30 / 0.6 / 806
L3-08 / 8/12/2003 / 14 days / 40mL / FGL / 33.8 / -3 / 130 / 2320
L4-4 / 8/12/2003 / 14 days / 650mL / FGL / 122 / -0.3 / -0.1 / -0.5 / 19 / -0.5 / 971
L4-6 / 8/12/2003 / 14 days / 1100mL / FGL / 170 / -0.3 / 0.2 / -0.5 / 35 / -0.5 / 1710
L5-08 / 8/12/2003 / 14 days / 500mL / FGL / 58.5 / -0.3 / -0.1 / 0.7 / 15 / 0.7 / 840
L5-4 / 8/12/2003 / 14 days / 240mL / FGL / 53.9 / -0.3 / 0.1 / -0.5 / 18 / -0.5 / 1450
L5-6 / 8/12/2003 / 14 days / 1000mL / FGL / 78 / -0.3 / -0.1 / 0.6 / 29 / 0.6 / 2180
L8-08 / 8/12/2003 / 14 days / 280mL / FGL / 75.7 / -6 / 0.1 / -0.5 / 490 / -0.5 / 5210
L8-4 / 8/12/2003 / 14 days / 700mL / FGL / 40 / -15 / 0.2 / -0.5 / 5240 / -0.5 / 9230
L8-6 / 8/12/2003 / 14 days / 1200mL / FGL / 729 / -6 / 0.1 / 0.5 / 960 / 0.6 / 6900

Note: A negative value represents a non-detect, with the absolute value representing the “Practical Quantitation Limit” (detection limit) of the analytical test.