name _________________________             AGRO 1033, T2, S2007


____    Which of the following is NOT a C4 crop with regard to photosynthesis?

            A. corn                                                             B. soybean

            C. sugarcane                                                    D. grain sorghum


____    Carbon dioxide losses from plants occur from both:

            A. respiration and mitosis                                  B. respiration and photorespiration

            C. photorespiration and photosynthesis C. photorespiration and photolysis


____    Gaseous diffusion into leaves is regulated by what leaf structures?

            A. golgi valves                                      B. vascular bundles

            C. chloroplasts                                                 D. stomates


____    The ideal soil pH for growing crops is around:

            A. 3.5                          B. 4.5                           C. 6.5                          D. 8.5


____    Photorespiration is higher in:

            A. C3 than C4 crops                                        B. C4 than C3 crops

            C. C.A.M. than C3 crops                                 D. C.A.M. than C5 crops


____    Loess is a:

            A. starch storage organ in plants                        B. by-product of photosynthesis

            C. soil parent material                                       D. term describing soil texture


____    A 50 lb bag of 10-26-8 fertilizer has how many lbs of P?

            A. 10                           B. 26                            C. 4                             D. 13


____    The grade of a 16-24-8 fertilizer is:

            A. 16-24-8                                                      B. 8-12-4

            C. 2-3-1<ratio!                                                D. 2-3-1


____    Conservation tillage soil management:

            A. should be approved by the USDA prior to implementation

            B. must leave 90% or more residues on the soil surface

            C. do not involve any disturbance of the soil by implements

            D. must leave 30% or more residue on the soil surface


____    Which one of these nutrients is considered a plant micro-nutrient?

            A. C                             B. Zn                            C. N                            D. P


____    Red and gray colors in soils are due to the effect of what on soil color?

            A. Fe                                                               B. N                            

            C. organic matter                                              C. temperature



name______________________________    AGRO 1033, T2, F2007


____    The ‘Calvin cycle’ of plants is located in what cell organ?

            A. mitochondria                                                B. vacuoles

            C. chloroplasts                                                 D. nucleus


____    Potassium is taken up by plants as:

            A. KCl                         B. K+                           C. KNO3                     D. KH2PO3


____    Plant nutrients such as Ca and Mg are referred to as:

            A. secondary nutrients                          B. primary nutrients      

            C. micronutrients                                              D. non-essential nutrients


____    In C3 plants, the majority of the chloroplasts are located in the:

            A. vascular bundle                                            B. guard cells

            C. palisade mesophyll                                       D. spongy mesophyll


____    If a farmer needed to apply 90 lbs N/acre, how much 45-0-0 would be needed?

            A. 90                           B. 45                            C. 200                         D. 400


____    What nutrient listed below do plants get primarily from the air?

            A. H                             B. P                             C. S                             D. C


____    In plants, the ‘source’ is considered a leaf and the ‘sink’might be a:

            A. growing soybean seed                                  B. lower, mature leaf

            C. mature root                                                  D. photoperiod interval


____    The letter designation of the topsoil horizon is:

            A. A                             B. B                             C. C                             D. R


____    The letter designation of a soil horizon found in forest ecosystems but not in

            prairie ecosystems is most likely:

            A. A                             B. C                             C.  E                            D. R


____    Soil parent material formed from rock weathered in place is called:

            A. alluvium                                                       B. residium

            C. lacustrine                                                     D. rock till


____    The cation exchange capacity of a soil is a measure of:

            A. pH                                                               B. soil fertility

            C. soil tilth                                                        D. soil drainage


____    RuBP carboxylase/oxygenase is:

            A. a protein enzyme in photosynthesis   B. a protein enzyme in respiration

            C. a toxic compound to plant cells                     D. not found in C4 plants


name___________________________          AGRO 1033, T2, S2007




1. What distinguishes the agronomic definition of soil from the geologist’s definition?

    (2 pts)  soil is seen also as a medium for growing crops



2. What can a corn farmer do to improve the photosynthetic capacity of the corn crop to

     help increase yields?  (5 pts)

many things: Examples:  - select high yielding varieties

                                                - plant at proper row width and seeding rate

                                                - fertilize according to soil tests and at the right time

                                                - irrigate if possible

                                                - control foliar damaging insects and disease






3. List below five factors that affect photosynthesis of field crops.  (10 pts)


There are many: Examples:        - sunlight, photoperiod, leaf area , growth stage,

            water, soil nutrients, carbon dioxide, type of crop (C3 or C4), others







4. Complete the unbalanced reactions where indicated:  (10 pts)



__CO2__     +    __H2O__    ---------------------------->   ____C6H12O6____  +   O2

                                                                sunlight, chloroplasts



_H2O__    +   CO2    ----------------->  ___C6H12O6____  +  __CO2____  + O2

                                                O2, RuBPcarboxylase/oxygenase



__C6H12O6____ + ___O2____  ----------------->  __H2O___  +  CO2   +  __ATP’s_





5. If a farmer has an acid soil that needs to be improved, what should he/she do and

    when?  (3 pts)

lime, at least 3-6 months ahead of crop



6. What are three benefits of no-till and conservation tillage practices?  (6 pts)


Many!  Reduce soil erosion, improve water quality, increase water infiltration,

  improve soil aggregation, improve soil organic matter


7. What are four of the five factors of soil formation?  (8 pts)

1. Parent Material

2. Climate

3. Topography

4. Organisms (both plant and soil)

5. Time!



8. When a crop is irrigated, it is also fertilized.  How so?  (2 pts)


Trick question here: it supplies the plants with H and O nutrients!



9. Why do C4 crops have a greater potential for dry matter production per acre than C3

     crops?  (2 pts)


Less carbon losses from photorespiration.



10. List below a plant available form of the nutrients indicated:  (5 pts)


            N: NH4+, NO3-


            P: H2PO4-, HPO42-


            K: K+


            Ca: Ca2+



11. In planning a soil fertility program for a crop, what is THE MOST important thing to

      do?   (2 pts)