Manures and Fertilizers Questions and Answers

Answer: B

Poultry manure has the highest content of nitrogen, phosphorus and potassium among the organic manures listed, which is why it is used as a concentrated manure.

Farm yard manure, town compost and NADEP compost have lower nutrient levels.

Poultry manure is richer than farmyard manure, as the nitrogen and phosphorus in bird droppings are high, and it is used as a concentrated organic manure. Town compost and NADEP compost are lower in nutrients.

Answer: D

The potassic fertilizer is MOP (muriate of potash).

Muriate of potash is potassium chloride, containing about 60 per cent K₂O, and is the most widely used potassium fertilizer.

Urea is a nitrogen fertilizer, SSP (single super phosphate) a phosphatic fertilizer, and DAP (diammonium phosphate) supplies nitrogen and phosphorus but no potassium.

SSP supplies phosphorus with some sulphur and calcium, while DAP (18 per cent N and 46 per cent P2O5) is the most widely used phosphatic fertilizer in India.

Answer: D

The method that does not exist is Aquatic placement.

Fertilizer placement methods put the fertilizer where roots can use it. Deep placement puts it in the reduced zone of flooded rice soils, contact placement puts it close to the seed, and subsoil placement puts it in the subsoil of strongly acidic or deep-rooted situations. Others include band, plough-sole and pellet placement.

There is no fertilizer method called aquatic placement; the word refers to water, not to a position in the soil, and is the distractor.

Answer: A

The consumption of chemical fertilizer in 2018-19 was 62 kg/ha (NPK).

The Economic Review of Tripura 2019-20 gives the per-hectare use of NPK as 62.00 kg for 2018-19, the same figure as for 2019-20, and describes the rise from 25 kg per hectare to 62 kg per hectare over the years. The one lower year in the series is 2017-18, at 45.50 kg.

So 47 and 50 kg/ha are too low for 2018-19, and 72 kg/ha is above anything the series reports.

Answer: C

The main function of a bio-fertilizer is to increase biological process.

Bio-fertilizers are preparations of living micro-organisms, such as Rhizobium, Azotobacter, Azospirillum, blue-green algae and phosphate-solubilising bacteria. Applied to seed or soil, they step up biological processes such as nitrogen fixation, solubilisation of phosphorus and production of growth substances, making nutrients available to the crop.

They do not act through chemical reactions as mineral fertilizers do, and their effect on plant physiology or photosynthesis is indirect, through better nutrition.

Answer: D

The answer is None of these: green manure crops mainly belong to the legume family, Leguminosae (Fabaceae).

Common green manures such as sunnhemp, dhaincha (Sesbania), cowpea, horse gram and Glyricidia are legumes. Their root nodules host Rhizobium bacteria that fix atmospheric nitrogen, so ploughing them in adds both organic matter and nitrogen to the soil.

Compositae (the sunflower family) and Solanaceae (the potato and tomato family) are not used as green manures, and Jacobaea is a genus of ragworts, not a family of green manure plants.

Answer: A

Agronomic efficiency is expressed in Kg/kg.

Agronomic efficiency of a nutrient is the extra yield obtained per unit of nutrient applied:

\[ AE = \frac{Y_{f} - Y_{0}}{F} \]

where \(Y_{f}\) is the yield with fertiliser, \(Y_{0}\) the yield without it and \(F\) the amount of nutrient applied. It is read as kilograms of grain per kilogram of nutrient, so its unit is kg/kg.

Kg/ha is a unit of yield or application rate, and kg/day is a rate of growth or production, so neither expresses efficiency.

Answer: C

The correct formula of urea is \(\text{H}_{2}\text{NCONH}_{2}\).

Urea is carbonyl diamide: a carbon atom double-bonded to oxygen and joined to two amino groups, \(\text{CO(NH}_{2})_{2}\). Written in a line, that is \(\text{H}_{2}\text{N-CO-NH}_{2}\), with the formula \(\text{CH}_{4}\text{N}_{2}\text{O}\). It contains about 46% nitrogen, the highest of the common solid fertilisers.

\(\text{H}_{2}\text{NCO}_{2}\text{NH}_{2}\) has an extra oxygen, HNCONH has too few hydrogens, and \(\text{H}_{4}\text{NCONH}_{4}\) has far too many; none of them is a real formula for urea.

Answer: A

Muriate of potash is not typically produced in India.

Muriate of potash (potassium chloride) is made from mined potash ores, and India has no commercially exploited potash deposits. Practically all the MOP used in the country is imported, from countries such as Canada, Russia, Belarus and Israel, and potash in complex fertilisers is also imported.

The other three are made in India on a large scale. Urea is produced from natural gas or naphtha in many plants. Single super phosphate and DAP are manufactured domestically, though partly from imported rock phosphate and phosphoric acid.