Gce Model Questions Vol1 2019 Agricultural Science Question 24

Practice objective / multiple choice question 24 from the 2019 Gce Model Questions Vol1 Agricultural Science examination.

Gce Model Questions Vol1 2019 Agricultural Science Objective / Multiple Choice Medium Difficulty
Question 24 GCE_MODEL_QUESTIONS_VOL1 • 2019 • AGRICULTURAL_SCIENCE • objective

A farmer rotates wheat and a legume (soybean) over a 4‑year cycle. Wheat removes \(120\) kg N ha⁻¹ each season, while the legume adds \(80\) kg N ha⁻¹ through fixation. The farmer wants the soil N to never fall below \(150\) kg ha⁻¹. Starting soil N is \(200\) kg ha⁻¹. Determine the minimum number of legume years required in the 4‑year cycle to satisfy this condition, give one possible crop sequence, and compute the average annual change in soil N over the cycle.

Answer Options

A. At least 3 legume years (e.g., L‑W‑L‑L); average annual N decrease = -5 kg ha⁻¹
B. At least 4 legume years (e.g., L‑L‑L‑L); average annual N increase = 40 kg ha⁻¹
Correct Answer C. At least 3 legume years (e.g., L‑L‑L‑W); average annual N increase = 30 kg ha⁻¹
D. At least 2 legume years (e.g., L‑L‑W‑W); average annual N increase = 10 kg ha⁻¹
Correct Answer
C
Correct Option:
At least 3 legume years (e.g., L‑L‑L‑W); average annual N increase = 30 kg ha⁻¹

About This Question

This is Gce Model Questions Vol1 2019 Agricultural Science Question 24. It is one of the objective questions from the 2019 Gce Model Questions Vol1 Agricultural Science examination.

Difficulty level: Medium .

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