Class 9 Science Chapter 1 Crop Production and Management: 17 Important Questions with Solutions

The rationalized Class 9 Science syllabus keeps Crop Production and Management as core content because agriculture touches every student's life in India. Board examiners test this chapter across all three question types: objective (MCQ, 1-mark), subjective (2-mark, 3-mark), and descriptive (5-mark). The chapter emphasizes **application over memorisation**—you need to explain *why* farmers use certain practices, not just name them. Recent board papers (2023–2024) show a consistent 15–20 marks dedicated to this chapter. Questions frequently link multiple subtopics: for example, "Explain how manure and fertilisers together improve soil and crop yield" bridges two concepts. HOTS (Higher-Order Thinking Skills) questions ask you to compare, analyze, or solve real farming scenarios. Many students lose marks by confusing manure with fertilisers, or by not explaining the steps of harvesting and storage properly. This guide follows the exact 2024-25 NCERT structure: soil preparation, sowing, manuring, irrigation, weeding, harvesting, and storage. Every question reflects patterns seen in actual board papers, so practising these builds exam-day confidence and conceptual clarity.

**Question 1:** Which of the following is an organic fertiliser? (A) Urea (B) Ammonium nitrate (C) Compost (D) Potassium nitrate **Answer:** (C) Compost **Explanation:** Compost is decomposed organic matter from plant and animal waste. Urea, ammonium nitrate, and potassium nitrate are inorganic (synthetic) fertilisers manufactured chemically. --- **Question 2:** The process of removing water-logged soil is called: (A) Irrigation (B) Drainage (C) Aeration (D) Mulching **Answer:** (B) Drainage **Explanation:** Excess water in soil must be removed through drainage to prevent root rot and fungal diseases. Irrigation adds water; aeration improves soil structure; mulching conserves moisture. --- **Question 3:** Which irrigation method is most water-efficient? (A) Flood irrigation (B) Sprinkler irrigation (C) Drip irrigation (D) Basin irrigation **Answer:** (C) Drip irrigation **Explanation:** Drip irrigation delivers water directly to plant roots through pipes with small holes, minimizing evaporation and runoff. It conserves 30–50% more water than flood or sprinkler methods. --- **Question 4:** Manure differs from fertiliser because manure: (A) is chemical in origin (B) is organic and improves soil structure (C) acts faster than fertiliser (D) requires no decomposition **Answer:** (B) is organic and improves soil structure **Explanation:** Manure (cow dung, compost, farm waste) enriches soil with organic matter and nutrients while improving its physical properties. Fertilisers are chemical salts that provide quick nutrition but do not improve soil structure. --- **Question 5:** Harvesting is best done when crops: (A) are fully mature and grains are hard (B) show initial grain formation (C) begin to wilt (D) are still green **Answer:** (A) are fully mature and grains are hard **Explanation:** Harvesting at full maturity maximises grain yield and quality. Early harvesting results in low yield and soft, unharvestable grain.

**Question 1:** Differentiate between manure and fertiliser. Give one example of each. **Answer:** | Feature | Manure | Fertiliser | |---------|--------|----------| | Origin | Organic (animal waste, decomposed plants) | Chemical (synthetic compounds) | | Nutrient content | Low (2–3%) | High (10–50%) | | Soil improvement | Improves texture and water retention | No structural improvement | | **Example** | **Cow dung, compost** | **Urea, NPK (10:26:26)** | --- **Question 2:** Why is levelling of the field important before sowing seeds? **Answer:** Levelling ensures: 1. **Uniform water distribution**: Water does not accumulate in low areas or drain from high areas, preventing waterlogging and drought zones. 2. **Even seed placement**: Seeds are sown at uniform depth, ensuring simultaneous germination and growth. 3. **Reduced weeds**: Uniform soil conditions reduce weed growth. Without levelling, crop yield is uneven and water is wasted. --- **Question 3:** State the advantages of drip irrigation over traditional flood irrigation. **Answer:** 1. **Water conservation**: Uses 30–50% less water; ideal for dry regions. 2. **Reduced labour**: Automatic and requires minimal human intervention. 3. **Precise nutrient delivery**: Fertilisers can be mixed with water (fertigation) for targeted feeding. 4. **Lower disease incidence**: Keeps foliage dry, preventing fungal infections. 5. **Cost-effective long-term**: Initial investment high, but operational costs are low. --- **Question 4:** Name two methods of crop storage. Which is preferred for long-term storage in India? **Answer:** Two methods: 1. **Granaries/godowns**: Traditional structures with good ventilation. 2. **Cold storage**: Temperature and humidity-controlled rooms. **Long-term preference:** Cold storage is preferred because it slows respiration, microbial growth, and pest activity, keeping grains fresh for months or years. Temperature is typically 4–10°C with 60–70% relative humidity. --- **Question 5:** Explain why weeding is essential during crop growth. What tool is commonly used? **Answer:** **Importance of weeding:** 1. Weeds compete with crops for water, nutrients, and sunlight, reducing yield by 20–40%. 2. Weeds host pests and diseases. 3. They produce allelopathic chemicals that inhibit crop growth. **Common tool:** Hand hoe or khurpi (a small, curved blade attached to a handle) is used for manual weeding in smallholder farms, while herbicides (e.g., 2,4-D) are used in large-scale farming.

**Question 1:** Describe the process of soil preparation for sowing seeds. Why is it important? **Answer:** **Process:** 1. **Ploughing**: Turning over soil with a plough or tractor to break compacted layers, kill weeds, and expose buried organic matter to decomposition. 2. **Harrowing**: Breaking soil clods into smaller, finer particles using a harrow, creating a smooth seedbed. 3. **Levelling**: Making the field surface even to ensure uniform water distribution. 4. **Manuring**: Adding manure or compost to enrich soil before sowing. **Importance:** - **Aeration**: Loosened soil allows root penetration and air circulation. - **Nutrient availability**: Organic matter decomposes, releasing nutrients. - **Water retention**: Well-prepared soil holds moisture without waterlogging. - **Uniform germination**: Fine seedbed ensures seeds make good contact with soil. Without proper soil preparation, seed germination is poor and crop yield is reduced by 30–50%. --- **Question 2:** Compare sprinkler irrigation and drip irrigation in terms of water efficiency, suitability, and cost. Which would you recommend for a drought-prone region and why? **Answer:** | Aspect | Sprinkler | Drip | |--------|-----------|------| | **Water efficiency** | 60–70% (evaporation losses) | 90–95% (direct to roots) | | **Suitability** | Flat fields, vegetables, cereals | Orchards, vegetables, hilly terrain | | **Cost** | Moderate initial, low operational | High initial, minimal operational | | **Spacing** | Suitable for 0.5–1 acre plots | Best for 1–5 acre plots | **Recommendation for drought region:** **Drip irrigation** is ideal because: 1. Saves 30–50% more water than sprinkler. 2. Delivers water directly to roots, reducing waste. 3. Long-term savings justify high initial investment. 4. Suitable for marginal rainfall areas (e.g., Rajasthan, Maharashtra). --- **Question 3:** Explain the steps of harvesting and what precautions should be taken. Name two methods of harvesting. **Answer:** **Steps of harvesting:** 1. **Timing**: Harvest when crops are fully mature—grains hard and moisture ≈12–15%. 2. **Cutting**: Use sickles, scythes, or mechanical harvesters to cut crops close to the ground. 3. **Bundling**: Tie cut crops into bundles for easy transport. 4. **Transportation**: Move bundles to threshing floor. **Precautions:** - **Avoid shattering**: Don't delay harvest; mature grains fall to ground if over-ripe. - **Weather monitoring**: Harvest during dry weather to prevent moisture damage. - **Careful handling**: Minimize grain breakage and wastage. **Two methods:** 1. **Manual harvesting**: Using sickles; labour-intensive but suitable for small farms. 2. **Mechanical harvesting**: Using combine harvesters; efficient for large areas, saves time (1 hectare in 1–2 hours vs 4–5 days manual). --- **Question 4:** Describe two storage methods for grains. What are the main causes of grain loss during storage, and how can they be prevented? **Answer:** **Two storage methods:** 1. **Granaries/godowns**: Single or double-walled structures with ventilation holes; suitable for short-term (3–6 months) storage in temperate regions. 2. **Silos**: Large, cylindrical, airtight structures; ideal for long-term storage in humid climates. **Causes of grain loss and prevention:** | Cause | Prevention | |-------|----------| | **Moisture** | Dry grains before storage (moisture <12%); store in dry rooms | | **Pests (insects, rodents)** | Use pesticides (neem, phosphine gas); seal storage structures | | **Microbial growth (fungi, bacteria)** | Maintain 60–70% relative humidity; use fungicides if needed | | **Respiration** | Keep temperature low (4–10°C in cold storage) to slow metabolic activity | Proper storage can prevent 20–30% post-harvest loss, ensuring food security and farmer income.

**Question 1:** Explain the complete process of crop production from soil preparation to storage. How does each step ensure better yield and quality? **Full Solution:** Crop production is a systematic process with seven key stages: **1. Soil Preparation (Impact on yield: +15–20%)** - Ploughing breaks soil, increases aeration, and exposes organic matter. - Harrowing creates a fine seedbed for uniform germination. - Levelling ensures even water distribution, preventing waterlogging and drought zones. - **Benefit:** Better root growth and nutrient uptake. **2. Sowing (Impact on yield: +10–15%)** - Seeds are sown at correct depth (2–3 cm for wheat, 4–5 cm for rice) and spacing (15–20 cm rows). - Proper spacing reduces plant competition and disease spread. - **Benefit:** Optimal plant density (20–30 plants/m² for cereals) maximizes biomass production. **3. Manuring (Impact on yield: +20–30%)** - Organic manure (5–10 tonnes/hectare) improves soil structure, water retention, and microbial activity. - Chemical fertilisers (N:P:K ratios like 10:26:26) provide quick nutrients. - Combined use balances long-term soil health with immediate nutrient availability. - **Benefit:** Doubling grain output per hectare (example: 30 bags/hectare to 60 bags/hectare with proper fertilisation). **4. Irrigation (Impact on yield: +25–35%)** - Drip or sprinkler methods deliver water at critical growth stages (germination, tillering, grain filling). - Irrigation frequency depends on rainfall and crop type (wheat: 3–4 times; rice: continuous flooding). - **Benefit:** Prevents drought stress, enabling plants to reach genetic yield potential. **5. Weeding (Impact on yield: +20–40%)** - Manual or chemical weeding at 30–45 days after sowing removes competing plants. - Reduces pest and disease incidence. - **Benefit:** Crops get 100% access to water, nutrients, and light. **6. Harvesting (Impact on quality: ensures maturity)** - Harvested when grains are hard (moisture ≈12–15%) to maximise output and quality. - Mechanical harvesting reduces shattering losses (grain dropping). - **Benefit:** Maximum yield; grains suitable for long storage. **7. Storage (Protects 80–90% of harvest)** - Grains dried to <12% moisture and stored at 4–10°C in sealed structures. - Prevents pest, mould, and respiration losses. - **Benefit:** Grain remains viable for months; farmer income secured. **Overall impact:** Following all steps can increase yield from 30 bags/hectare (poor management) to 70–80 bags/hectare (best practice), a 130–165% improvement. Quality grains command 10–15% higher prices in markets. --- **Question 2:** A farmer in Maharashtra (semi-arid region) has 5 hectares of land with erratic rainfall (400–600 mm annually). He currently uses flood irrigation but faces water scarcity. As an agricultural advisor, suggest a complete management plan including irrigation method, manuring strategy, and crop selection. Justify each choice. **Full Solution:** **Irrigation method:** **Shift to drip irrigation** - **Justification:** Drip saves 30–50% water compared to flood. With 500 mm annual rainfall and only 1–2 irrigation cycles feasible, drip targets water directly to roots, preventing evaporation losses (25–30% in flood irrigation). - **Calculation example:** 5 hectares flooded = 50 mm per irrigation × 5 ha = 2.5 million litres per cycle. Drip irrigation: 25 mm per cycle = 1.25 million litres. **Water saved per cycle = 1.25 million litres. Over 4 cycles/year = 5 million litres saved annually—enough for 2 additional harvests in dry years.** - **Cost:** Initial investment ₹80,000–₹1,00,000 per hectare recovered in 2–3 years through increased yield and reduced water bills. **Manuring strategy:** **Mixed organic-inorganic approach** - **Organic:** Apply 4 tonnes farmyard manure/hectare every 2 years to build soil carbon and water-holding capacity (critical in semi-arid zones). Compost from crop residue adds nitrogen cheaply. - **Inorganic:** Use NPK 10:26:26 at 50 kg/hectare for immediate nutrient supply. Avoid excess nitrogen in low-rainfall zones (promotes vegetative growth, depleting soil water). - **Justification:** Semi-arid soils have low organic matter (0.3–0.5%). Building soil carbon improves water retention by 5–10%, reducing irrigation frequency. **Crop selection:** **Grow millets (pearl millet, sorghum) and pulses (chickpea)** - **Why not wheat/rice?** Both require 500–1,200 mm water; rainfall is insufficient even with irrigation. - **Millets:** Drought-tolerant, yield 2–3 tonnes/hectare with 300–400 mm water. Grain price: ₹3,000–₹3,500/quintal. Profit per hectare: ₹60,000–₹80,000. - **Chickpea (rabi crop):** Grows on residual soil moisture; no irrigation needed. Yield 2 tonnes/hectare. Profit: ₹50,000–₹70,000/hectare. - **Benefit:** Millet + chickpea rotation maintains soil nitrogen (legumes fix atmospheric N₂), reduces pest cycles, and diversifies income. **Complete 5-hectare plan:** - 3 hectares millet (drip irrigation, 2 cycles/year) = ₹2,40,000 annual income. - 2 hectares chickpea (rain-fed + residual moisture) = ₹1,20,000 annual income. - **Total annual income: ₹3,60,000** vs ₹2,00,000 with current flood irrigation wheat (high water loss, low yield in semi-arid zones). - **Water saved:** 50% reduction, freeing water for domestic use or additional area irrigation. --- **Question 3:** During monsoon, a farmer's paddy field is waterlogged for 10 days. Explain the effects on crop and soil, and suggest immediate and long-term solutions. **Full Solution:** **Immediate effects (within 10 days of waterlogging):** 1. **On crop:** - **Root hypoxia:** Soil pores fill with water, oxygen becomes depleted. Roots cannot respire, weakening nutrient uptake. - **Symptom:** Yellowing of leaves (especially older leaves), stunted growth. - **Yield loss:** 20–40% if waterlogging occurs during tillering (critical growth stage). - **Plant death:** If waterlogging lasts >14–21 days, anaerobic respiration produces ethanol, killing roots; entire crop may perish. 2. **On soil:** - **Anaerobic decomposition:** Without oxygen, organic matter decomposes incompletely, producing toxic gases (H₂S, methane), lowering soil pH. - **Nutrient immobilization:** Beneficial microbes die; nitrogen-fixing bacteria (Azotobacter) and phosphate-solubilizing bacteria are inhibited. - **Soil compaction:** Waterlogged soil becomes dense and airless, reducing permeability. - **Iron toxicity:** Excess water causes iron reduction, releasing Fe²⁺ ions that are toxic to rice in high concentrations (>300 ppm). Symptoms: "bronze leaf disease" (brown leaf tips). **Immediate solutions (first 3 days):** - **Drainage:** Open field channels to let water escape. Use pump sets if natural drainage is slow. - **Aeration:** After water recedes, apply gypsum (2 tonnes/hectare) to improve soil structure and break compaction. - **Monitoring:** Check soil pH; if <5.5, apply lime to neutralise acidity. **Long-term solutions (for future seasons):** 1. **Field drainage system:** - Install permanent drainage channels every 50–100 metres with a main outfall drain. Cost: ₹25,000–₹40,000 per hectare, but protects against all future monsoon waterlogging. - Benefit: Water drains in 24–48 hours instead of 10 days. 2. **Soil improvement:** - Raise field beds by 15–20 cm above surrounding area (bed-and-furrow system) to reduce water retention. - Add 5 tonnes compost/hectare annually to increase soil organic matter, improving porosity and aeration even in wet conditions. 3. **Crop management:** - Select waterlogging-tolerant rice varieties (e.g., Swarna Sub-1, CR1009) that have submergence-tolerant genes (SUB1 gene). These survive 10–14 days underwater without yield loss. - Adjust sowing date: Sow 2–3 weeks later so monsoon peak is less likely to coincide with critical growth stages. 4. **Integrated approach for 5 hectares:** - **Year 1:** Invest in drainage channels (₹1,50,000) and switch to tolerant varieties. Reduce yield loss from 40% to 10%. - **Years 2–5:** Add compost annually. Yield stabilizes at 90% of optimal, generating consistent ₹1,50,000–₹1,80,000/hectare annually. **Quantitative outcome:** Without intervention, waterlogging loses ₹80,000–₹1,20,000 per season. Drainage + variety selection costs ₹30,000 one-time, saves 25–30% yield loss annually = ₹2,00,000 saved over 5 years. **Investment payback: 1.5 years.**

**Case-Study Question:** Rajesh, a farmer from Punjab, grows wheat on 4 hectares. Last year (2023), his yield was only 40 bags/hectare (total 160 bags, ≈8 tonnes) despite using chemical fertilisers. His neighbour, Priya, uses integrated crop management (manure + controlled fertiliser + drip irrigation) and harvests 65 bags/hectare (260 bags, ≈13 tonnes) from the same soil type and climate. Both farmers irrigate, but Rajesh uses flood irrigation. Analyse why Priya's yield is 63% higher and recommend changes for Rajesh. **Analysis Steps:** **Step 1: Identify yield-determining factors** Yield (Y) depends on: Y = Crop variety × Soil fertility × Water availability × Weed management × Pest/disease control × Harvest timing Assuming both use similar wheat variety and climate, the variables are soil management, irrigation method, and practices. **Step 2: Compare Rajesh's vs Priya's approaches** | Factor | Rajesh (40 bags/ha) | Priya (65 bags/ha) | Impact | |--------|-------------------|------------------|--------| | **Soil preparation** | Ploughing + harrowing only | Ploughing + harrowing + manure (5 t/ha) | Priya: +15–20% yield from improved soil structure | | **Manuring** | Urea 100 kg/ha only; no organic input | FYM 5 t/ha + NPK 80 kg/ha | Priya: +10% yield from balanced N:P:K; improved water retention (+5%) | | **Irrigation** | Flood (25 mm per irrigation); 4 times/season | Drip (15 mm per irrigation); 6 times/season, precise timing | Priya: +15–20% from reduced water stress, no waterlogging, targeted nutrition | | **Water use efficiency** | 60% (flooding = evaporation, runoff) | 92% (drip = direct to roots) | Priya: 32% less water for same area; enables 6 vs 4 irrigations | | **Weeding** | Manual, done once at 45 DAS | Manual + pre-emergent herbicide; twice (30 DAS, 60 DAS) | Priya: +10% from reduced weed competition | | **Fertiliser use** | 100 kg urea only; deficient in P, K | 80 kg NPK (balanced); includes micronutrients | Priya: Better grain filling, fewer empty spikelets | **Step 3: Quantify yield loss in Rajesh's system** - **Soil fertility loss:** No manure = low organic matter (OM ≈0.4%). Priya's 5 t/ha manure adds 2.5% OM annually. Result: Nutrient availability ↓ by 15–20% → yield loss ≈8 bags/ha. - **Water stress:** Flood irrigation waterloggs soil 2–3 times/season, causing temporary oxygen stress. Root hypoxia → 10–15% yield loss = 4–6 bags/ha. - **Weed competition:** Single weeding at 45 DAS allows 35–45 days weed growth. Weeds consume 20–30% of water and nutrients → 8–10 bags/ha loss. - **Imbalanced nutrition:** Urea only supplies nitrogen. Deficiency of P (for root growth) and K (for disease resistance, grain hardness) → 5–8 bags/ha loss. - **Total loss due to poor practices = 25 bags/ha** (8 + 5 + 8 + 4). Rajesh's yield: 40 bags/ha = baseline 65 bags/ha minus 25 bags loss. **Step 4: Recommendations for Rajesh (costed)** 1. **Introduce farmyard manure:** 5 tonnes/hectare annually, cost ₹2,500/tonne = ₹12,500/ha/year. **Expected gain: +8 bags/ha = ₹2,400–₹3,000/ha (at ₹300–₹375/bag grain rate).** Payback: 4–5 months. 2. **Switch to drip irrigation:** Initial investment ₹80,000/ha; operational cost ₹5,000/ha/year. Saves 10 mm water per irrigation × 4 irrigations = 40 mm total = 2 million litres for 4 ha. **Expected gain: +8 bags/ha = ₹2,400–₹3,000/ha.** Payback: 2–3 years. 3. **Use balanced NPK (10:26:26):** 80 kg/ha instead of 100 kg urea. Cost ₹1,600/ha (only ₹200 more than urea). **Expected gain: +5 bags/ha = ₹1,500–₹1,875/ha.** Payback: immediate. 4. **Double weeding:** Add second weeding at 60 DAS, cost ₹500/ha labour. **Expected gain: +8 bags/ha = ₹2,400–₹3,000/ha.** Payback: immediate. **5-year implementation plan:** - **Year 1:** Introduce manure + double weeding + switch to NPK. Cost: ₹13,000/ha. Expected yield: 53 bags/ha. Gain: ₹3,900/ha profit. - **Years 2–3:** Gradually install drip irrigation (1–2 ha/year). By Year 3, all 4 ha under drip. - **Year 3 onwards:** Expected yield stabilises at 62–65 bags/ha, matching Priya's performance. **Annual profit increase: ₹60,000–₹80,000 for 4 hectares.** **Conclusion:** Rajesh's low yield is not due to crop variety or climate, but management inefficiency. Integrated practices (manure + irrigation efficiency + balanced nutrition + weed control) unlock a 60% yield increase at modest cost, demonstrating that even small farms can achieve high productivity.

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**Yield Calculation:** Yield (bags/hectare) = (Total grain weight / Weight per bag) / Area in hectares Example: 5,200 kg grain ÷ 50 kg/bag ÷ 1 hectare = 104 bags/hectare **Irrigation water requirement:** Water needed (mm) = Crop water demand (ETo × Kc) − Effective rainfall Where ETo = evapotranspiration (climate-dependent, 4–8 mm/day), Kc = crop coefficient (0.4–1.2) Example: Wheat, ETo = 5 mm/day, Kc = 0.8 → Daily water = 4 mm; with 100 mm monsoon, need 300–400 mm from irrigation. **Fertiliser dose (NPK):** For wheat: N = 100–120 kg/ha, P = 60 kg/ha, K = 40 kg/ha Urea (46% N): 100 kg N ÷ 0.46 ≈ 217 kg urea/ha DAP (18% P, 46% N): 60 kg P ÷ 0.18 ≈ 333 kg DAP/ha Muriate of Potash (50% K): 40 kg K ÷ 0.50 = 80 kg MOP/ha **Grain moisture for safe storage:**nOptimal: <12% (prevents fungal growth) Risk zone: 12–14% (slow microbial activity begins) Danger: >14% (rapid mould growth; grain loses viability) **Soil organic matter improvement:** Adding 5 tonnes FYM/ha annually increases OM by 0.5–1% over 3 years. OM↑ by 1% increases water-holding capacity by 15–20 mm/metre depth. **Critical growth stages for irrigation in wheat:** 1. Germination (0–7 days after sowing): Soil must be moist. 2. Tillering (30–60 DAS): 1st irrigation; critical for shoot formation. 3. Grain filling (60–100 DAS): 3rd–4th irrigation; determines grain weight. Skip this, yield ↓ 20–30%. **Weed competitiveness timeline:** First 45 days after sowing are critical. If weeds are controlled within this window, yield loss is <5%. Delay beyond 60 DAS, loss increases to 20–40%.