EFFECTS OF TIMES OF SOWING COWPEA INTO PINEAPPLE-PEPPER INTERCROP ON COMPONENT CROP YIELDS AND MIXTURE PRODUCTIVITY IN AKURE, NIGERIA

Abstract

Four experiments were conducted in the rainy and late seasons of 2011 and 2012 at the Teaching and Research Farms of the Federal College of Agriculture, Akure (FECA) and the Federal University of Technology, Akure (FUTA) in a humid rainforest zone of Nigeria. The main objective was to determine the effects of time of sowing cowpea into pineapple-pepper intercrops on growth and yield of the component crops in the intercropping system. The experiments which were laid out as a randomized complete block design with three replications, adopted the additive series of intercropping system. Experimental treatments were based on varying time of sowing cowpea into pineapple-pepper intercrops at three-week intervals in addition to the sole crops of cowpea, pepper and pineapple. Experiments conducted in the rainy-season planting comprised of four dates of sowing cowpea into pineapple-pepper intercrop namely: sowing cowpea at the time of transplanting pepper seedlings into pineapple, and sowing at 3, 6 and 9 weeks after transplanting (WAT) pepper, pineapple-pepper intercrop alone and the sole crops of pineapple, pepper and cowpea. Experiment conducted in the late-season planting comprised of two dates of sowing cowpea into pineapple-pepper intercrop at 3 weeks intervals: sowing cowpea at the time of transplanting pepper seedlings into pineapple and sowing at 3 weeks after transplanting pepper into pineapple, pineapple-pepper intercrop alone and sole crops of pineapple, pepper and cowpea. The growth of the component crops in the intercrops were measured using growth indicators such as leaf area, number of leaves per plant and plant biomass yield, dry matter accumulation (root, stem and leaf dry weights) and yield of the component crops at maturity. The crop mixture productivity was determined using indices of relative yield (RY), relative yield total (RYT) and land equivalent ratio (LER). The soil physical and chemical properties were also determined before planting and at crop maturity. Partial budget analysis, benefit cost ratio, rate of return on investment and profit margin were used to evaluate the profitability of pineapple based intercropping systems. Data collected from the experiments were subjected to two way analysis of variance using Statistical Analysis System (SAS), while significant treatment means were separated using Tukey’s Honestly Significant Difference (HSD) test at 5% probability. The results showed that cowpea biomass and yield components declined with delayed sowing for both the rainy and late season crops; while the pepper biomass and yield components increased with delayed sowing of cowpea. Cowpea seed yield declined significantly (P=0.05) with its delayed sowing in the rainy season experiment of 2011. Seed yield of cowpea sown at 6 and 9 WAT into pineapple- pepper intercrop during the rainy season of 2011 were 79.84 and 75.49 % lower than the seed yields of sole cowpea and cowpea sown at the time of transplanting pepper into pineapple. Delayed sowing of cowpea by 3 weeks in the late season of 2011 and 2012 reduced seed yields by 53 and 59 %, respectively. About 95 % pepper fruit yield reduction was recorded when cowpea was sown at the time of transplanting pepper into pineapple in the rainy season of 2011 while 86, 79, 59 % pepper fruit yield reduction was recorded when cowpea was sown at 3, 6 and 9 WAT pepper. Sowing cowpea at the time of transplanting pepper and at 3 WAT resulted in 94 and 92 % yield reduction of pepper in the rainy season of 2012 while delayed sowing of cowpea at 6 and 9 WAT resulted in 63 and 38 % yield reduction. Up to 92 % yield reduction of pepper was recorded when cowpea was sown at the time of transplanting pepper in the late-season planting. Delaying the introduction cowpea into pineapple-pepper intercrop by 3 weeks resulted in 62 and 57 % yield reduction of pepper in 2011 and 2012 late-season planting, respectively. Pineapple growth indices were not significantly affected by either pepper or cowpea as the intercrops. However, significantly lower pineapple fruit yield (12.79 t/ha) which was up to 73% lower than fruit yield obtained from pineapple with delay sowing of cowpea in the rainy season planting of 2011. Yield reduction in the rainy season of 2012 was not more than 25 % when cowpea was sown simultaneously with pepper. Yield reduction up to 18 and 39 % were recorded when cowpea was sown simultaneously with pepper in the late season of 2011 and 2012, respectively. The highest Net Benefits of N871, 472 was obtained when cowpea was sown at 9 WAT in the rainy season planting in 2011 while the Net Benefit (N1,955,937) was obtained in pineapple-pepper alone in the rainy-season planting in 2012. The benefit cost ratio (BCR) for pineapple-pepper-cowpea intercrop ranged from 1.16 to 1.91 in the rainy season planting while the BCR ranged from 1.7 to 1.99 to 2.62 in the late-season planting. Higher profit margin of 41 to 62 % was obtained in the rainy and late-season planting in 2012. Delay in sowing cowpea into pineapple-pepper intercrop up to 6 WAT pepper better utilized growth resources in addition to the spread and diversified sources of income, products variants to the farmer and the possibility of farmers making income/returns from short duration annual crops such as pepper and cowpea when intercropped at the early stage of the establishment of pineapple. The study confirmed the appropriateness of intercropping pineapple with pepper with delayed introduction of cowpea to take advantage of the growth resources (soil moisture, nutrients and light) that would have been under-utilized.