Effect of Population Density and Sowing Date of Pumpkin on Soil Hydrothermal Regime, Weed Control and Crop Growth in a Yam–pumpkin Intercrop

Abstract

Pumpkin (Cucurbita maxima) is used for live mulch and edible apical shoots, seeds and fruits, and requires that a strategy for using it as ground cover in intercropping with food crops be developed while sustaining reasonable apical and fruit yields. Field experiments were conducted in 1999–2001 to investigate the effects of population density (5000, 10 000 and 15 000 plants ha−1) and sowing date (March, April and May) of pumpkin on the soil hydrothermal regime, earthworm casts, weed control, and crop growth and yields in a Yam–pumpkin intercrop. Growing pumpkin between yam mounds reduced maximum diurnal soil temperature by 4.3–8.1 °C, weeding frequency by 52% and weed dry biomass by 50–67%, while soil moisture was conserved by 48–62 g kg−1, earthworm casts were increased by 58–68% and yam tuber yield by 30–52%, irrespective of population density or sowing date, compared with yam monoculture. Intercropping had no effect on the growth and fruit yields of pumpkin, but leaf area index and apical shoot and fruit yields increased by 30–49% as the plant population increased to 10 000 plants ha−1, beyond which there was no further significant increase. Furthermore, apical shoot and fruit yields were remarkably reduced when pumpkin was sown beyond April. Increasing pumpkin population up to 10 000–15 000 plants ha−1 reduced soil temperatures by 0.7–1.2 °C, weeding frequency by 15–35% and weed dry biomass by 36–57%, conserved soil moisture by 46–63 g kg−1, and increased earthworm casts by 20% compared to 5000 plants ha−1 in both cropping systems. Although the sowing date did not affect earthworm casts and weeding frequency, pumpkin sown in March or April reduced soil temperatures by 2.6–4.0 °C and weeds by 27%, and conserved soil moisture by 15–37 g kg−1, compared with May-sown plants. Intercropping pumpkin up to 10 000 plants ha−1 with yam at an optimal sowing date target in March-April is recommended for maximum development and productivity, and when pumpkin is used for live mulch in yam plots to reduce supra-optimal soil temperature, excessive evaporation and weed growth.

Intercropping Sunflower with Soyabeans Enhances Total Crop Productivity

“…Conditions of the 2002 cropping season were more favourable for soyabean and sunflower production because they were wetter and cooler than in 2001. Although changes in microclimate due to intercropping were not investigated in this study, Olasantan (2007) and Olasantan et al (2007) revealed that substantial variations in soil moisture, light interception, and air, canopy and soil temperatures under intercropping were favourably modified to benefit the growth of component crops. However, lack of appreciable yield reduction of Record and Isaanka in the mixtures suggests that these varieties have some level of compatibility with soyabean, especially TGx 1440-1E and TGx 1448-2E, compared with var.…”

Effect of Variety Selection on Growth,Development and Yield of White Yam in Southwestern Nigeria

“…The selection of variety is among the factors that contributes to the realization of a successful cropping [1][2] [9]. Hence, the fact that the total rainfall (1177.2 and 1201.6mm for 2007 and 2008 experimental years respectively) recorded at the study site fell within the range of optimum annual rainfall (1000-1500mm) reported for yam growth is not enough criteria for suitable crop variety selection in the study area.…”

“…The A horizon of the soil is an Oxic Paleudulf of the Iwo series with 83% sand, 5% silt and 12 % clay with a pH of 6 considered tolerable by yam cultivation [9]. …”

“…Hence, for successful cropping, it is pertinent to identify the characteristic of variety and then synchronize the crop growth cycle with the period of effective water availability particularly because the rainfall in the area is characterized by an unpredictable distribution, variability and seasonality. The selection of cultivar (variety) has been noted to be among the factor that contributes to the realization of a successful cropping [1][2] [9]. This study intend therefore to confirm the agro-climatic potential of the study area for three white yam varieties in order to determine the appropriate variety that will synchronize the crop growth cycle with period of effective water availability.…”

Assessment of the effect of Cadmium, Copper and Lead on Soils prorperties with reference to cultivated land use in the Tropical Wet-and Dry Climate

“…The study area is characterized by a tropical climate with distinct wet and dry seasons with bimodal rainfall pattern and mean annual air temperature of about 30 o C. The soil at the experimental site was categorized as a well-drained tropical ferruginous soil. The A horizon of the soil is an Oxic Paleudulf of the Iwo series with 83% sand, 5% silt and 12 % clay with a pH of 6 considered tolerable by yam (Olasantan, 2007). …”