Hanford Turlock Woodland

Transcription

1 Denele Analytical Since 1968 Joe Mullinax Plant Pathologist Hanford Turlock Woodland Soil H20 Seed Nematodes ELAP Plant Tissue Manure Feeds-Invitro Plant Pathology Environmental Foods

2 Denele Respiration Rate D.R.R. Why we need advanced research grade tests like the D.R.R. Fertilizer is expensive Improved plant health Regulatory aspects

3 Basic Concept Accurate N Release estimation is dependent on accurate Microbial activity number. Unlike K where microbial activity does not have a large effect on K release rate. CO 2 and Nitrogen release Microbial Activity Tests 1. More of an art than a science. 2. Lab to lab difference. 3. Time of year Microbial Respiration Soil Organic Matter

4 D.R.R. Need to adapt CO 2 -respiration method for repeatability and laboratory standardization. We have succeeded in developing an accurate respiration test for our Western soils. Proved high r 2 with existing methods (GC, IR and base-trap methods).

5 Laboratory methods for Soil C0 2 Respiration are time consuming and cumbersome. Methods to predict mineralization of N from SOM have not been widely adopted in the industry. Denele gas tube, PSNT, ISNT, 7d-Anaerobic N-min Other calculations: SOM x factor lacked consistency and does not work in Western semi-arid soils

6 Soil Re-hydration Benefits Research shows tight correlation to biomass Drying-rewetting mimics natural systems The majority of nutrient cycling is due to the drying/rewetting effect. Plants nutritional status increases following an irrigation event. * Alfalfa Effect As the time from irrigation to cut increases, the nutritional status decreases.

7 Drying-Rewetting CO 2 Pulse Rewetting soil activates microbial mineralization Consistent with repeated d/w cycles Source: Fierer and Schimel 2003 Soil Sc Soc Am J 67

8 Comparison to other CO 2 methods Base Trap Titration Infrared cell (IRGA)

9 How does 1d test compare with traditional 28d basal respiration?

10 TX SOIL CO 2 RESPONSE TO MANURE Compost field applications linearly correlated to 24h CO 2 burst by two methods Base Trap CO 2 KIT CO 2 Chart 1

11 7d N-min vs. Microburst CO 2 Burst: Relationship consistently about 1:1

12 N-Min from Manured soils 30 Net N- Release in Relation to 24-h CO2 Burst Following Compost Applications (Com_Appl n-avail = 3ppm) 25 mg/kg 20 y = x R 2 = 0.981** Inorganic-N increase CO 2 -C burst mg/kg

13 Background N- release from SOM correlates to CO 2 - Burst Yield correlating to respiration test Annual Compost Bio Co2 Yield Meat LB Almonds Turlock 10 Ton Ton

14 D.R.R. Limitations of the quick test 1. Abiotic C0 2 not calculated Total C0 2 - Abiotic C0 2 = Biological C0 2 * Merced Effect: Not all soil C0 2 release is from microbial activity 2. Incubation temp 68 degrees Temp hr Co2 Bio Activity 24hr

15 San Joaquin Soil Temperature over 10 years (degrees Fahrenheit) AT 4-INCH DEPTH1 At 20-Inch Depth Month Maximum Minimum Average Average2 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mar-Oct Average

16 Ammonia 1. Ammonia needs to be calculated. Ammonia analyzer to be subtracted from nitrogen release rate. 2. Calculations on a sliding scale for microbial activity. * As the microbial activity increases, the available N decreases to represent the microbial N portion. If this is not done, all soils with C0 2 would theoretically release N. But, we know some typically high Carbon soils bind the available N.

17 D.R.R. Sample Report

18 D.R.R. Fast, inexpensive, repeatable Method to determine: Microbial activity Available Carbon Nitrogen release rate In conjunction with the soil test for a complete N.M.P.

19 Soil Analysis Sample Report

20 Summary 1. The D.R.R. addresses deficiencies in quick tests. 2. Correlates to yield. 3. D.R.R. shows repeatability and accuracy in 4 years of trials and is accepted as an N release rate. 4. Recognized by USDA-NRCS. 5. Calibrated to Western soils and temperatures. 6. Offered by DENELE ANALYTICAL Lab. Gee Whizz Info: Anhydrous Increase UN32 No response No response Can 17 Decreased