Effect of Planting Material and Variety on Productivity and Survival of Napier Grass (pennisetum purpureum schumach) in the Coastal Lowlands of Kenya

ABSTRACT

A study to determine a suitable planting method for multiplication of planting materials of Napier grass varieties was done at the Kenya Agricultural Research Institute (KARI) Msabaha in coastal lowland (CL) agro-ecological zone 4 (CL4). The experimental design was split-plot with a factorial arrangement of three Napier grass varieties: var. Bana (Bana), var. French Cameroon (French Cameroon) and var. Gold Coast (Gold Coast) as the main plot and three types of planting material consisting of stem cuttings with different numbers of nodes (one, two, three nodes) as sub plots which were replicated three times. Data on the number of stools, number of stems per stool and the total number of nodes per treatment of the three Napier grass varieties were collected 11 months after planting. Plant counts and forage dry matter yield data was collected thereafter every two months for one year. Napier grass, established using three and two-node cuttings, maintained a 37% higher amount of surviving plants and a 43% higher amount of forage dry matter, respectively, than the one-node cuttings. Bana and Gold Coast produced a higher (p<0.05) dry matter yield than French Cameroon, while Bana and French Cameroon produced a higher number of planting material per acre. The three-and two-node cuttings proved to be suitable planting materials for long-term dry matter productivity for all three Napier grass varieties.

KEYWORDS:

• Napier grass
• planting materials
• multiplication methods

Introduction

In the coastal lowlands of Kenya, farmers practise mixed farming (Waaijenberg, 1994). They grow maize and cassava crops as staples for food security and keep local cattle, exotic dairy/crosses and local goats (Thorpe et al., 1992). They rely on natural pastures (Reynolds et al., 1993), which are often low in quality and supply, and mainly under a free grazing system (Muinga et al., 1998). Milk production is low, ranging from 1.0 to 6.4 kg day⁻¹ for local and exotic/cross cattle; and 1.0 to 2.0 kg day⁻¹ for local and exotic/cross goats, respectively (Ramadhan et al., 2008). Despite the introduction of various fodder production technologies on-centre and on-farm (Njunie and Ogora, 1990; Mwatate et al., 1998; Ramadhan and Njunie, 2001), cultivated forages contributed less than 40% and 25% of dairy cattle feeding during the rainy and dry seasons, respectively (Muinga et al., 1998). Bana is a popular Napier grass variety introduced in smallholder dairy farms in the region. The area planted with cultivated fodder has been declining (Ramadhan et al., 2008). Lack of planting materials contributed to low adoption of planted forages and low profitability of farm enterprises (Mureithi et al., 1998). A study was therefore carried out to determine suitable methods of multiplying Napier grass planting materials in order to overcome a shortage of Napier grass planting material on-farm. These methods are aimed at improving profits from the sale of Napier grass planting material and increasing fodder for feeding dairy cattle.

Materials and methods

Study area

The trial was carried out at KARI, Msabaha 3°16′S, 40°03′ E over a five-season period starting from the long rain of 2011 and ending after the long rain season of 2013. The soils at Msabaha centre are well drained, deep, low in available nutrients and have low to moderate moisture storage capacity. The topsoil texture is sandy loam to sandy clay loam with a low organic matter content. The site is in the cashew nut-cassava zone (Jaetzold and Schmidt, 1983). There are two distinct rainfall patterns in the area: a long rainy season from April to June and a short rainy season from October to December. The mean temperature ranges from a minimum of 24–27 °C in May–July to a maximum of 30–32 °C in January–April.

Experimental design

Three Napier grass varieties were planted using three types of node cuttings (one, two or three node(s)) during the 2011 long rainy season. The Napier grass node cuttings were planted in 27 plots, each measuring 3 m × 2.5 m and spaced 1.0 m × 0.5 m. The experimental design was split plot, consisting of three Napier grass varieties – Bana, Gold Coast and French Cameroon – as the main plots and three types of Napier grass node stem cuttings comprised of either one, two or three node(s), as a sub plot. The experiment was replicated three times. The plots were kept free of weeds and di-ammonium phosphate (DAP) was applied at a rate of 20 kg P ha⁻¹six weeks after planting and calcium ammonium nitrate (CAN) was applied at a rate of 75 kg N ha⁻¹ in two splits per year.

Data collection methods

Data were collected to determine the optimum number of nodes in Napier grass planting material that would maintain plant survival and increase the dry matter production of the three Napier grass varieties. The data included the number of live (surviving) stools, the number of stems per stool and the total number of nodes per unit treatment plot, 11 months after planting (MAP). Thereafter, data on the fresh weight of Napier grasses and the number of surviving stools was taken in each plot on average every two months for a year. Data were collected from surviving plants in a net plot of 2.5 m × 3 m (a maximum of 15 plants per plot). A 200 g sample was taken, oven dried at 105 °C to a constant weight and the percentage dry matter calculated to determine the forage dry matter production. Data were analysed using the SAS GLM procedure (SAS, 1997) and means separated using least significant difference (LSD).

Results

Plant survival

Establishment of grass using two or three node stem cuttings resulted in a higher number (p<0.05) of surviving plants than one node stem cutting (Table 1). Bana grass maintained a higher (p<0.05) number of surviving plants across all cuts, compared to French Cameroon.

Table 1. Number of surviving plants across different types of node cuttings and varieties of Napier grass at subsequent harvestings at Kenya Agricultural Research Institute, Msabaha

Number of nodes in Napier grass cutting	Second harvest	Third harvest	Fourth harvest	Fifth harvest	Sixth harvest	Seventh harvest	Average harvest
Three	10^a	8^a	10^a	10^a	8^a	7^a	9^a
Two	9^a	10^a	10^a	10^a	9^a	9^a	10^a
One	6^a	5^b	5^b	5^b	5^b	5^a	6^b
LSD	4	3	2	3	2	4	2
CV	50	33	22	32	36	25	23
Variety of Napier grass
Bana	11^a	11^a	11^a	10^a	10^a	10^a	10^a
Gold Coast	9^ab	8^ab	9^ab	9^ab	7^ab	6^b	8^b
French Cameroon	6^b	6^b	6^b	7^b	5^b	6^b	6^c
LSD	3	4	3	3	4	2	2.3
CV	50	33	22	32	36	25	23

Values with differing letters within column are different (p<0.05).

Note: Dates of harvesting for the second = 4 July 2012, third = 12 September 2012, fourth = 21 November 2012, fifth = 6 February 2013, sixth = 11 April 2013 and seventh = 4 July 2013.

Dry matter production

Dry matter production of Napier grasses tended to decline with time of harvests and, overall, French Cameroon produced lower cumulative dry matter (p<0.05) compared to Bana (Table 2). The Napier grass with greater than two node cuttings produced higher (p<0.05) total dry matter yield than that with one node cutting.

Table 2. Dry matter yield (tonne/ha) of varieties and different types of node cuttings of Napier grass at subsequent harvestings at Kenya Agricultural Research Institute, Msabaha

Variety of Napier grass
	Second Harvest	Third Harvest	Fourth Harvest	Fifth Harvest	Sixth Harvest	Seventh Harvest	Total Yield
Bana	2.4^a	2.1^a	1.3^a	2.1^a	0.6^a	0.7^a	14.4^a
Gold Coast	2.4^a	1.4^a	1.1^a	1.5^a	0.3^a	0.5^b	12.2^ab
French Cameroon	2.5^a	1.9^a	1.2^a	2.2^a	0.6^a	0.8^a	9.9^b
LSD	1.91	1.45	0.64	1.52	0.44	0.14	2.63
CV	50	51	55	57	48	45	14
Napier grass node(s) cutting
Three	2.7^a	1.8^a	1.4^a	2.0^a	0.7^a	0.7^a	14.1^a
Two	2.6^a	1.8^a	1.2^a	2.1^a	0.5^a	0.7^a	13.8^a
One	2.0^a	1.8^a	1.0^a	1.7^a	0.4^a	0.6^a	8.5^b
LSD	1.54	0.83	0.68	0.87	0.44	0.35	1.63
CV	50	51	55	57	48	45	14

Values with differing letters within column are different (p<0.05).

Production of stem cutting planting materials

Bana and Gold Coast produced a higher (p<0.05) number of stools but lower number of stems per stool than French Cameroon (Table 3).

Table 3. Number of stools, number of stems per stool, and total number of nodes per hectare of three Napier grass varieties and three types of Napier grass node treatments at first harvest (11 months after planting) at Kenya Agricultural Research Institute, Msabaha

Treatments	Number of stools	Stem per stool	Total node counts (number in millions/ha)
Napier variety
Bana	11^a	7^b	3.236^ab
Gold Coast	10^a	6^b	2.100^b
French Cameroon	6^b	17^a	3.466^a
LSD	2	7	0.129
Napier node cutting	C
Three	11^a	9^ab	3.667^a
Two	10^a	7^b	2.721^b
One	6^b	13^a	2.412^b
LSD	3	5	0.818
CV	20	29	21

Values with differing letters within column are different (p<0.05).

Note: Date of first cutting = 25 April 2012.

Three and two node cutting treatments produced a higher number of stools than the one node treatment. Results also indicated that French Cameroon produced a higher (p<0.05) total number of nodes per ha than Gold Coast while there were no differences (p>0.05) between French Cameroon and Bana in the number of nodes produced. The three node cutting treatment produced the highest total number of nodes per ha (Table 3).

Discussion

Napier grass selection for dry matter production

Results showed that Bana produced higher dry matter yield than French Cameroon. The low yield of French Cameroon could be attributed to the low number of surviving plants during the growing seasons compared to other Napier varieties (Table 2). In contrast, Wandera (1997) reported that the production of French Cameroon and Bana was similar in Kitale but Bana out yielded French Cameroon in the Embu region. He reasoned that the production potential of different fodder grasses varied from region to region, as influenced by the rainfall pattern and age of the stand. Bana was the most productive grass in higher rainfall areas (agro-ecological zones CL3 and CL4) in the coastal region but produced lower dry matter yield than drought resistant Napier grass varieties such as ex-Matuga and Pakistan hybrid, when planted in the coastal semi-arid lands (Njunie and Ramadhan. 2011; Ramadhan and Njunie, 2011). In the current study, Bana produced (p=0.05) similar amounts of planting material as French Cameroon, although the latter had low numbers of surviving plants. It was observed that French Cameroon produced a large number of nodes per hectare, compared to Gold Coast (Table 3).

Napier planting material selection

Napier grass, planted using two- or three-node cutting, maintained higher numbers of surviving plants than when using one-node cutting (Table 1). Sumran et al. (2009) reported that Napier grass could be established using two-node cutting under irrigation conditions, producing up to 67 t ha^-1 fresh weight material. On average in the current study, survival of one-node plantings declined by 37%. Similarly, the one-node plantings showed a 43% decline in dry matter compared with the two or three-node plantings (Table 2). Farmers should, therefore, continue to establish Napier grass using the current recommended size of three-node cuttings. Although the establishment of Napier grass is labour intensive, planting three-node cuttings will ensure high survival rates, sustained high dry matter production and a high number of Napier grass planting material (Table 3).

Conclusion

Three-node cutting is suitable for long-term dry matter productivity and survival of all three Napier grass varieties. However, Bana and Gold Coast varieties are recommended as they maintain higher dry matter yield.

ORCID

A. Ramadhan http://orcid.org/0000-0001-5019-1368

M. N. Njunie http://orcid.org/0000-0002-7752-1299

K. K. Lewa http://orcid.org/0000-0001-7945-0570