Rice is a crop which is sown in rainy season, i.e. from June to September, as it is a kharif crop. The other three crops are rabi crops and are sown in winter season.

Crop rotation is a method of replenishing soil with nutrients. This can be done by growing different crops alternately.

Ploughing does not reduce the population of pests in the soil. The other statements are correct.

Sprinkler system is a modern method of irrigation.

Earthworms increase the soil fertility.

Farmers with small holdings of land separate grains from chaff by the method called winnowing.

Leaves of a neem plant are used to mix with grains to keep insects away, because of their insecticidal property.

2,4-D is a weedicide that can kill unwanted plants (weeds) growing in the field.

Drip system will be the best method to be adopted for watering fruit plants, gardens and trees. This system provides water to plants drop by drop and water is not wasted at all. Sprinkler system is best for sandy soil. Lever system and pulley system, being traditional methods, are less efficient. 

Wheat, gram and pea need low temperatures for their growth whereas paddy requires the presence of large amount of water. Therefore, paddy is grown in a rainy season.

Agricultural practices are the processes adopted in the field such as preparing the soil, adding nutrients for the growth of crops and cutting down the crop i.e. harvesting, whereas selling grains in a market does not involve any field process and is thus not an agricultural practice. 

Cultivator, sickle and plough are the tools used for the preparation of soil whereas khurpi helps in the removal of weeds and is adopted as a manual method of removing weeds.

Pushkar is a camel fair in Rajasthan.

Fertilisers do not provide humus to soil. The rest of the statements are true regarding fertilisers.

Broadcasting is a method of seeding that involves scattering of seeds by hand or mechanically over a relatively large area.