Jornada Basin LTER Research

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Dataset: Soil nutrient distribution in long-term NPP plots - 1991


   Download data: File nppsn91.dat
   File description including attribute definitions: data_JornadaStudy_398_npp_soil_nutrient_distribution_1991
   Original Investigator: Ross Virginia
   Data contact: John Anderson
   Duration: 1991 - 1991
   Dataset ID: 210398002
   Abstract:

Soil nutrient distribution in NPP quads in the Mesquite, Grassland, Playa, Creosotebush, and Tarbush plant communities sampled at 3 spatial scales of grids. Soils were sampled from the NPP (biomass plots). Each of the five vegetation types (mesquite, grassland, playa, creosote, tarbush) had three sites (with low, medium, and high production levels). At 14 of 15 sites a grid of 70 by 70 meters was set out. Within this 49 plots of 10 by 10 meters were placed and labeled (numbered) in serpentine design. At the 15th site, Playa College, 48 plots of 10 by 10 meters were laid out in three long rows of 16 plots per row. At all sites the soil sample of 0-10 cm depth was taken 1 meter from the NE marker bar at a diagonal (heading toward the SW marker). 70m x 70m layout of NPP quads where 1 is in NE corner. 43 42 29 28 15 14 1 44 41 30 27 16 13 2 45 40 31 26 17 12 3 46 39 32 25 18 11 4 47 38 33 24 19 10 5 48 37 34 23 20 9 6 49 36 35 22 21 8 7 160m x 30m layout of P-COLL NPP quads where 1 is in NE corner. 33 32 1 34 31 2 35 30 3 36 29 4 37 28 5 38 27 6 39 26 7 40 25 8 41 24 9 42 23 10 43 22 11 44 21 12 45 20 13 46 19 14 47 18 15 48 17 16 At one of each of the five vegetation types another set of 49 soils (#101-149) was taken from within one of the 10 by 10 meter plots. Using a 7 by 7 meter grid (bounded by the southern east-west boundary line and the western north-south boundary line[#149 is in the SW corner]) soils were sampled 1 meter apart using a serpentine design. 7m x 7m layout within single 10m x 10m NPP plot. 143 142 129 128 115 114 101 144 141 130 127 116 113 102 145 140 131 126 117 112 103 146 139 132 125 118 111 104 147 138 133 124 119 110 105 148 137 134 123 120 109 106 149 136 135 122 121 108 107


   Additional information:

Northern Chihuahuan Desert 37 kilometers N of Las Cruces, New Mexico on the NMSU College Ranch and the USDA Jornada Exp. Range. See project documentation for more complete description. Vegetation: We are studying 5 vegetation communities that are dominant on the Jornada and are hypothesized to differ in their degree of desertification: 1) remnant black grama (Bouteloua eriopoda) grasslands; 2) playas or low-lying areas with heavy soils ( which are periodically flooded) and dominated by tobosa (Hilaria mutica) and burrograss (Scleropogon brevifolius); 3) tarbush stands (Flourencia cernua); 4) mesquite dunes (Prosopis glandulosa); 5) creosotebush-dominated bajadas (Larrea tridentata). For each community type, three permanent plots representing a range of primary productivity have been established to examine patterns of NPP, soil moisture, plant nutrients as a function of climatic variation. These are the 15 NPP sites (3 sites in each of the 5 vegetation communities described above.

   Methods:

data sheets, electronic spreadsheet (Microsoft Excel 2.2)

   Methods:

Sampling: Soils were sampled from the NPP or biomass plots. Each of the five vegetation types (mesquite, grassland, playa, creosote, tarbush) had three sites (with low, medium, and high production levels). At 14 of 15 sites a grid of 70 by 70 meters was set out. Within this 49 plots of 10 by 10 meters were placed and labeled (numbered) in serpentine design. At the 15th site, Playa College, 48 plots of 10 by 10 meters were laid out in three long rows of 16 plots per row. (It could have been 4 long rows of 12 plots per row-- check with John Anderson). At all sites the soil sample of 0-10 cm depth was taken 1 meter from the NE marker bar at a diagonal (heading toward the SW marker). At one of each of the five vegetation types another set of 49 soils (#101-149) was taken from within one of the 10 by 10 meter plots. Using a 7 by 7 meter grid (bounded by the southern east-wet boundary line and the western north-south boundary line[#149 is in the SW corner]) soils were sampled 1 meter apart using a serpentine design. Nutrient Analysis: Soils were kept in plastic bags and stored in a partly cooled housetrailer in New Mexico over a two week period. %H2O--Gravimetric water In San Diego, soil subsamples were taken from the plastic bags, placed in soil cans and dried at 105�C for two days. Saturation % Soils were air dried and seived to 2mm. One hundred grams of soil was weighed into a disposable drinking cup. Using a 250 ml buret, water was added. The soil was stirred to take up the water, which was added until saturation was attained. The amount of water required was recorded. Saturation %= (mls water/ wt of soil) X 100. One * or two * * in column next to sat% indicates sample was a little too wet and too wet, respectively. It may be necessary to subtract 0.5 ml and 1.0 ml from the amount of water. See references for discription of what saturation looks/is like in different soils. References: Rhoades, J.D., 1982. Soluble Salts. in A.L. Page(ed.). Methods of Soil Analysis Part 2- Chemical and Microbiological Properties. Soluble Salts. Agronomy 9 (2): 167-179. Am. Soc. of Agron., Madison, Wis. Richards, LA, ed. 1954. Diagnosis and improvement of saline and alkali soils. Chapter 2. Determination of the properties of saline and alkali soils. pg. 7-33. USDA Handbook #60. Soil pH--2:1 To ten grams of 2mm seived soil, 20 mls of RO (reverse osmosis-purified) water was added. It was stirred and left to sit for 10 min. The pH was read on the liquid above the soil. Soil TKN One gram (0.5 g for PS and PC) of 2 mm seived air-dried soil was digested using microkjeldahl method with 40 tube heating block. A mercury-potassium sulfate catalyst was used. The digest went for two hours after clearing at 375�C. Digests were analyzed colorimetrically on a Technicon autoanalyzer. References: Total N by Kjeldahl digestion block techniques.(Bremner and Mulvaney, 1982) Bremner, J.M., and C.S. Mulvaney. 1982. Nitrogen--Total. In A.L. Page (ed.). Methods of soil analysis. Chemical and microbiological properties. Agronomy 9 (2):595-694. Am. Soc. of Agron., Madison, Wis. Technicon Industrial Method No. 329-74W/B TKN-->NH4------>ammonia-salicylate complex TP--->PO4------->phosphomolybdenum complex

   Maintenance:

One time