*5.2.1 Weather and soil*

Carrot is a cold-weather crop, but can also thrive well in warm climates. Optimum temperature for good growth is 16–20°C, temperatures beyond 28°C will drastically reduce its growth. Carrot grows well in sandy soil, when planted in rows of at least 10 cm apart on a raised seedbed, it starts to germinate at about 1–3 weeks and can be harvested at any size, but better when it has turned bright orange for enhanced flavor. There are several varieties of carrot that are cultivated in Nigeria with a high rate of productivity, some of which include the Danvers variety which is larger in size and requires a balanced level of soil fertility to grow well. Other varieties include Chantanay, Nantes, Armsterdam, among others. Carrots are well adapted to a wide variety of soils, although deep, loose, well-drained soils rich in humus are suitable for commercial carrot farming. In Nigeria, the best soil for cultivation of carrots is loamy or sandy loam soils rich in humus [70].

#### *5.2.2 Land preparation*

Soil should be properly prepared by repeated deep plowing (at least 20–30 cm deep), harrowing, leveling, and cleaning will enhance desired yield. The soil must be loose, friable, deep, and well-drained in order to enhance effective germination of seeds. Because carrot seeds are very small and delicate, a fine seedbed of convenient size should be prepared before sowing. Carrots are taproots that penetrate and grow downwards so while cultivating the carrots, you should avoid rocky or stony areas to prevent stunted growth. It is advisable to make ridges for planting carrots, which should be higher than those for planting a crop like maize. Ridges are necessary at a considerable height level for the maximum penetration of the carrot.

#### *5.2.3 Planting*

Carrots are propagated using seeds, clean, disease-free and viable seeds from reliable sources will enhance good productivity. Complete seeds germination takes approximately 7–21 days. Seeds are lightly covered with soil after planting.

*Nigeria Root Vegetables: Production, Utilization, Breeding, Biotechnology and Constraints DOI: http://dx.doi.org/10.5772/intechopen.106861*

Some farmers irrigate the field about 24 h prior to sowing to ensure that enough water is present in the soil at the time of sowing. The Fertilizer recommendations should be based on soil analysis.

#### *5.2.4 Irrigation*

Light irrigation should be done immediately after sowing while subsequent irrigations are applied as necessary. Excess water makes carrot to be light colored, short with large diameter.

#### *5.2.5 Harvest*

In case of special markets, carrots can be harvested early when they have not fully developed; or else, they should be allowed to reach full maturity stage in the soil. But they will become hard and unfit for consumption if they are retained in the full maturity stage. Carrots are harvested when the roots are ca. 1.8 cm or larger in diameter at the upper end. After harvesting, carrots are carefully washed, sorted by size then packaged for future endeavors.

#### **5.3 Turmeric (***Curcuma longa***)**

Turmeric (*Curcuma Longa* Linn) is a type of root vegetable belonging to the same family (Zingiberaceae) as ginger [71]. It is a tropical perennial plant, originated from India and Indonesia, which is widely cultivated throughout the tropical regions of the world. It is one of the most essential spices used as a culinary ingredient world wide for which it is referred to as the "golden spice of life" [72]. World production level of turmeric is 11–16 tonnes annually. Nigeria being the fourth largest world producer, produces about 3% of the world annual production [73]. About 76 cultivars of turmeric exist in the gene bank of the National Root Crop Research Institute (NRCRI), Umudike with some being evaluated in multilocational trials [74]. The prevailing favorable edaphic and climatic conditions in Nigeria place the country in a position to play a leading role in turmeric production. Turmeric is cultivated both under rain fed and irrigated conditions.

#### *5.3.1 Soil requirement*

Turmeric also thrives well in deep soil tilt with heavy manure for high yields. Fertile and friable, well-drained, loamy soil ranging from sandy loam to clay loam with high organic matter are required for turmeric cultivation [75]. Moreover, flat land with gentle or no slope is equally recommended.

#### *5.3.2 Land preparation/planting*

This commences with selection and clearing of the site followed by bed preparation because turmeric thrives well on beds, ridges or even on mounds at the onset of rains possibly around April or when the rains must have stabilized around May or June. Bed size of 3 × 2 m is advised so as to reduce human movement on the beds during farming operations. Seedbed can be prepared using tractor or manually using a spade or a hoe. Turmeric is propagated by rhizomes using mother rhizomes as

planting material [76], planting distance of 30 x 50 cm [77] at a depth of 10 cm to give optimum yield [78] is recommended. The rhizomes are about 10–15 g with one or two buds [79] therefore, about 1 ton of setts are needed to plant 1 ha.

### *5.3.3 Mulching*

Mulching is important in cultivation of turmeric, the first mulching should be done immediately after planting followed by a second mulching at 8 weeks after planting. Mulching aids moisture conservation, enhances germination, controls weeds, modifies soil temperature, adds nutrients to the soil and improves soil fertility for optimum yield. Mulching can be done with elephant grass (straw) at the rate of 12 t/ha [78].
