The effect of intercropping lablab (lablab purpureus l.) And cowpea (vigna unguiculata l.) At different planting Densities with napier grass (pennisetum purpureum) on Yield and nutritional qulities

Abstract

This study was conducted with the objectives of determining the effect of intercropping lablab (Lablab purpureus L.) and cowpea (Vigna unguiculata L.) at different planting densities with napier grass (Pennisetum purpureum) on yield and nutritional qualities and changes in the soil chemical properties due to legumes inter-cropping effects. The field study was conducted at Haro sabu Agricultural Research site. The experimental design was factorial combination arrangement in randomized complete block design (RCBD) with three inter and intra spaces (i.e. 1m ×0.5m, 0.75m × 0.5m, 0.5m× 0.5m) and intercropping with two tropical legumes (i.e. lablab and cowpea) with three replications. Treatments were T1= Pure Napier grass at 1m row spacing, T2= Napier grass intercropped with lablab at 0.75m row spacing, T3= Napier grass intercropped with cowpea at 0.5m row spacing, T4= Napier grass intercropped with cowpea at 1m row spacing, T5= Napier grass intercropped with lablab at 0.5m row spacing, T6= Pure Napier grass at 0.75m row spacing, T7= Napier grass intercropped with lablab at 1m row spacing, T8= Napier grass intercropped with cowpea at 0.75m row spacing, T9= Pure Napier grass at 0.5m row spacing and totally nine treatments were used. Soil samples were collected before and after forage harvested. Agronomic parameters, biomass yield, chemical analysis, in vitro dry and organic matter digestibility (IVDMD, IVOMD) and in sacco DMD and OMD of forage samples were determined. Results showed that intercropping increased the soil pH value from 5.8 (before planting) to 6.0 (after planting) for T2 and organic carbon increased from 3.72 (before planting) to 4.11 (after planting) for T7 and total nitrogen increased from 0.31 to 0.35 for T5 and T7. There was no significant (p> 0.05) effect of intercropping on agronomic parameters of Napier grass such as plant height (PH) and number of leaves per tiller (NLPT). However, number of tillers per plant (NTPP), leaf length (LL) and total number of leaves per tiller (NLPT) were significantly affected by intercropping at different planting densities of Napier grass (p<0.05). Intercropping of lablab and cowpea had significant effect (p<0.05) on dry matter yield, total dry matter yield and total crude protein yield (TCPY) of the Napier grass and but had no significant effect (p>0.05) on crude protein yield. Intercropping at different planting densities significantly affected the proximate composition of Napier grass such as Ash, CP, OM and NDF. However, the DM, ADF, ADL, Hemicelluloses and cellulose contents of the Napier grass was not significantly (P>0.05) affected. Napier grass intercropped at different planting densities with lablab and cowpea had significant effect (P<0.05) on the in vitro dry and organic matter digestibility (IVDMD, IVOMD) and increased digestibility. The OM degradation constant (a, b, c and PD (a + b), were significantly different (P<0.05) but ‘ED’ were not and for DM degradation ‘c’ and ‘b’ was not significant (P>0.05) for Napier grass intercropped with lablab and cowpea at different planting densities. In conclusion, Napier grass intercropped with lablab and cowpea at a planting density of 24 plants m-2 (1m×0.5m space) could be a better choice for high yield and forage quality in the current study. However, it is suggested to do on animal performance trial of this result based on animal feeding practice and economic feasibility in order to come up with sound recommendations.