Quintin Salas/B2Mrs. PetriAp Environmental Science/Lab Report30 October 2017MeasuringPrimary Productivity – Grass Plants I. Title:”Measuring Primary Productivity – Grass Plants” II. Name:Quintin Salas III. Date: October30th, 2017 IV.
Purpose: Togrow grass plants over a one-week period in order to calculate productivityrates using two methods of collection. And to understand the concepts of netproductivity, respiration rates, gross productivity, and standing biomass. V. Hypothesis: Thethree pots with the sand and dirt mixture (experiment 1) and the three potswith the clay and dirt mixture (experiment 2) will not grow exponentiallycompared to the three pots with the plain soil. This is due to the fact thatthe sand and clay might retain more water than the soil. VI. Experimental Set-up: 1. Control– Soil2.
Experiment#1 – Adding sand to the soil3. Experiment#2 – Adding clay to the soilVII. Procedure: Your assigned task is to calculate the primary productivity of oneweek of grass growth. The basic instructions for each method are listed belowunder the letters A and B.
After you complete step3 in part A and step 2 in part B, you must choose under what conditions yourgrass will grow. There are various light sources, fertilizer, and punches foraeration for your use.A.1. Using flat A, measure the grass length from the top of the soil to the tipof the grass plants.2.
Remove the grass plants entirely from one plot of eachcolumn. Dust as much of the soil as possible from the plants. Weigh and recordthe plant mass content from each plot.3. Cover with aluminum foil one plot from each of thecolumns.4. Allow the contents of the flats to continue to grow for another week.5.
Remove the grass plants from the uncovered plots. Weigh and record thisweight. 6.
Removethe foil from the covered plots. Describe the appearance of the grass and thenremove the grass plants. Weigh and record this weight. B.1.
Using flat B, measure the grass length from the top of the soil to the tipof the grass. 2. Cover each plotwith foil and leave to grow.3. Allow grass in the flat to grow for one week.4. Uncover the foil covered plots and describe appearance.
Measure height ofgrass. VIII. Data Table: (see attached paper)IX. Calculations:A. Control GroupMeasurement #2 (g) = 36.2g-Measurement #1 (g) =32.7gNet Primary Productivity(g) = 3.
5g Uncovered Measurement #1(g) = 32.7g- Covered Measurement #2(g) = 40.0gRespiration (g) = -7.3g Net Primary Productivity(g) = 3.
5g+ Respiration (g) =-7.3gGross Primary Productivity(g) = -3.8g B. Uncovered Measurement #2= 26.7g- Uncovered Measurement#1 = 11.9gNet productivity = 14.8g Covered Measurement #2 = 2.
3g- Uncovered Measurement#1 = 11.9gRespiration = -9.6g Net Productivity = 14.8g+ Respiration = -9.
6gGross Productivity = 5.2g C. Uncovered Measurement #2(g) = 35g + Uncovered Measurement #1 (g) = 9.6g Net Primary Productivity (g) = 25.4g X.
Conclusions:The data supported the hypothesis because the grass grown in the sandand clay mixtures did not grow as much as the grass grown in the soil pot. Thegrass grown in the soil weighs 36.2 grams while the grass grown in the clayweighs 26.7 grams and the grass grown in the sand weighs 35 grams.XI.
Questions:1. Why in part A was oneset of plots harvested and the weight of the grass taken at the beginning ofthe experiment? It is the starting biomass of the grass plants.2. What do the plotswith the foil covering represent?Nonphotosynthesizing plants, they are only respiring.3. Compare thedifference in appearance between the foil-covered and the noncovered grass. Ifthere is a difference in appearance, explain the difference.Grass that is covered has become yellowed due to loss or lackof continued production of chlorophyll.
4. If there was growthin the covered plots in part B, account for why that growth might have takenplace even though there was no sunlight reaching the plant.Any growth that might have occurred would have been doneusing the plant’s carbohydrate storage; however, this growth should be very slight,if at all. Usually, the plant will be somewhat reduced and curled.
XII. Errors:1. Failure to grow. Ifsufficient growth of grass or diatoms is not demonstrated in one week, theexperimental time for growth may be extend.2. Failure to coverplants for measurement of respiration3.
Mistakes in weighing4. Mistakes incalculations5. Failure to makeinitial measurements XIII. Applications: This could help people understand why their grass at their house doesnot grow well. It provides examples to how grass needs sunlight to grow usingphotosynthesis and if they have something over the grass such as a pool or atall tree shading said grass, than it can only go through with respirationwhich causes the grass to turn yellowish.