Carolan Homework 1

Agron181 Spring2022 Homework 1 – Quantifying inputs, outputs, and crop residue (30 pts) Assigned: Thurs, 27 Jan Due: Thurs, 3 Feb, 12:40 pm Learning Outcome: students will be able to identify and quantify the components of water, carbon, nitrogen, phosphorus, or potassium cycles that enter, cycle, or leave an agroecosystem. Download the Homework assignment. You can either 1. type your answers in red font, save the document and upload to Canvas as a doc, docx, pdf document OR 2. Download the homework file, answer question by writing legibly with a pencil/pen, scan, and upload to Canvas as a pdf document. “Legibly”, if we cannot read it, we cannot grade it. You may use your notes and seek help during office hours or contact mwiedenh@iastate.edu . This is not a group assignment; please work as an individual. Name: _____ Jessica Carolan ___________________________________________ 1. Review the narrative (DelsonFarmNarrative) on Canvas about the cornfield (agroecosystem) called the homeplace on the Delson Farm in 2016. (6 pts) Make of list of the components that are inputs, outputs, and are cycling in this agroecosystem. Inputs: rainfall, 26 lb/A of granular potash, 2 lb/A of zinc sulfate, 50 lb/A of monoammonium phosphate, 170 lb/A of UAN corn seed, 2 pts crop oil concentrate, 170 lb/A urea ammonium nitrate. Outputs: 235 bu/A of corn. Cycling: corn stalks, stover 2. For the agroecosystem “homeplace” on the Delson Farm during the 2016-growing season , quantify the selected components you are assigned for the nitrogen, phosphate, potash, carbon, and water cycles. Review HW1_Resources: Table 1. Nutrient content in corn grain and corn stover on Canvas. Show your calculations. A. N, P, K cycles: calculate the amount of N, P 2 O 5 , and K 2 O on an acre bases, express the answer in lb/A units for a. all soil nutrient inputs (4 pts) Last name begins with the letters A-E: fertilizer that contain nitrogen 13.6 lb N 205.5 Bu ------------- x ------------- = 69.87 lb. N/A 40 Bu A

Last name begins with the letters F-M: fertilizer that contain P 2 O 5 Last name begins with the letters N-Z: fertilizer that contain K 2 O b. grain at harvest (output) (4 pts) Last name begins with the letters N-Z: amount of nitrogen in corn grain Last name begins with the letters A-E: amount of P 2 O 5 in corn grain 211.5/100(32)= 67.68 P 2 0 5 /A Last name begins with the letters F-M: amount of K 2 O in corn grain c. corn stover at harvest (potential for cycling nutrients) (4 pts) Last name begins with the letters F-M: amount of nitrogen in corn stover Last name begins with the letters N-Z: amount of P 2 O 5 in corn stover Last name begins with the letters A-E: amount of K 2 O in corn stover 211.5/40=5.2875(18)=95.17 K 2 0 lbs/A B. Water cycle: calculate the amount of water on a per acre basis, express the answer in lb/A units for: All students: entering the farm ecosystem (input) (2 pts) 43.31 rainfall 27154 8.34 9,808,171.43 lb water ------------------ x ----------- x ---------- = ----------------------- A in. 901 A All students: leaving the farm via the harvested grain (output) (2 pts) 1,974 lb. water/A C. Carbon cycle: calculate the amount of carbon on a per acre basis, express the answer in lb/A units for All students: the grain (2 pts) 5000.8 lb. C/A All students: crop residue at harvest (2 pts) 3407.6 lb. C/A 3. You are a crop consultant working with farmers in either Montana, North Dakota, Arkansas, or Texas. Review yields of several selected crops in Tables 2 and 3, HW 1_Resources. The farmers have hired you to determine the amount of fertilizer that they should apply in order to replace the amount of N, phosphate (P 2 O 5 ), and potash (K 2 O) that will be removed by the crop. Review Table 4, HW 1_Resources, which provides the removal amounts of N, P 2 O 5 , and K 2 O for the selected crops. You only have to complete one row, i.e. the row that you were assigned. (4 pts) Nitrogen Potash 0.9 lb. N 48 Bu 43.2 lb. N 0.3 lb. K 2 0 48 Bu 14.4 K 2 0 0------------ x ----------- = -------------- -------------- x --------- = ------------