Using manure and fertilizers as an agriculture practice is important as continuous growth of crops makes the soil poorer in certain nutrients. These both are added to the soil in the form of nutrients for the healthy growth of plants. Manure replenishes the soil with nutrients and also improves water retaining capacity whereas fertilizers make soil rich in a particular nutrient. They also help farmers to get better yield of crops.

Water is essential for plants. It helps in germination of seeds because seeds cannot germinate under dry conditions. Nutrients dissolves in water get transported to each part of the plant. It protects the crop from frost and hot air currents. Water is important for proper growth and development of flowers, fruits and seeds of plants. Along with water, minerals and fertilizers are also absorbed. Plants contain nearly 90% water. The time and frequency of irrigation varies from crop to crop, soil to soil and season to season.

Disadvantages of fertilizers:
(i) They become source of water pollution.
(ii) They make soil less fertile.
(iii) They do not provide any humus to the soil.

Advantages of manure:
(i) It enhances the water holding capacity of the soil.
(ii) It makes the soil porous due to which exchange of gases becomes easy.
(iii) It increases the number of friendly microbes.
(iv) It improves the texture of the soil.

The activities practised during cultivation of crops are:
(i) preparation of soil,
(ii) sowing
(iii) adding manure and fertilizers
(iv) irrigation     
(v) protecting from weeds
(vi) harvesting
(vii) storage

Differences between fertilizer and manure:

(i) Manures are organic substances while fertilizers are chemical substances.
(ii) Manures are prepared in fields, while fertilizers are prepared in factories.
(iii) Manures contain all the nutrients, while fertilizers are rich in certain nutrients.
(iv) Manures provide humus, while fertilizers do not provide it.

If despite favourable climatic conditions, farmer's crop failed to give good yield, the possibilities may be
(i) he did not use good quality and healthy seeds.
(ii) his field was not well irrigated.
(iii) manures/fertilisers were not timely and properly applied.
(iv) weeds were not removed.
(v) seeds were not sown at appropriate distance.
(vi) the soil was not ploughed and levelled properly.

Some of the common tools used by a gardener or farmer in a field are
(i) Khurpi is used for the manual removal of unwanted plants.
(ii) Sickle is used in manual harvesting of crop.
(iii) Shovel is a tool for digging, liftingand moving soil, sand, gravels,etc.
(iv) Plough is used for tilling soil, adding fertilisers to crops, removal of weeds and scrapping of soil.

The unwanted plants (weeds) grow on the land alongside the main field. Their seeds get disseminated by various agencies like water, air, insects, birds and reach to the main field and lie there. These seeds germinate and crop up as a weed plants along with our main crop.

Advantages of using chemical fertilisers over manures are
(i) Fertilisers are nutrient specific and provide specific nutrient to soil in desired quantity.
(ii) These, being readily soluble in water, can be absorbed easily by the crop plants. If it is used in excess, it causes tremendous changes in the chemical nature of soil and makes it less fertile.

The levelling of ploughed field is beneficial because of following reasons:
(i) It prevents the top fertile soil from being carried away by strong winds or water.
(ii) It helps in uniform distribution of water in the fields during irrigation.
(iii) It also prevents loss of moisture from the ploughed soil.

Weeds are the undesirable (unwanted) plants that may grow naturally along with the crop. They are hazardous to the crops as they compete with the crop for food, nutrients, water and sunlight. Hence, they must be controlled. The process of controlling or removing weeds from the field is known as weeding. There are several methods to remove weeds such as tilling in which weeds are uprooted. They are removed manually by cutting with the help of khurpi. They are also controlled by chemicals known as weedicides which kill the weeds, e.g. 2,4-D.

Soil is the source for plants from which they derive their mineral nutrients, essential for their growth. If crops are grown continuously in the same field, for a long period of time, the soil becomes poorer in nutrients. Thus, soil gets deficient in nutrients and the field becomes infertile.

Preparation of soil - It is the first step before sowing the crop. In this, the soil is ploughed to loosen it and make it aerated which allows the roots to breathe easily. This also helps earthworms and microbes in the soil that bring the nutrient rich soil to the top. The process of loosening and turning of soil is called tilling or ploughing, which is followed by levelling and manuring.