Estimation of yields of orange fleshed sweetpotato promises a bright future for food security and nutrition in Karamoja

The introduction of orange-fleshed sweetpotato by the International Potato Centre (CIP), in collaboration with the World Food Program (WFP) and other partners, has been met with a remarkably positive reception in this predominantly pastoralist community. Despite sweetpotato being new to some communities in the area, with some households planting it for the first time in 2021, consumption has already seen a shift. While previously relied upon for market purchases, sweetpotato is now finding its way onto dinner plates from own farm production itself.

Given this exciting development, and the ongoing search for homegrown solutions to the persistant food insecurity in the sub-region, we embarked on a study to determine the potential yields of sweetpotato in this community. Establishing these values is crucial for guiding future interventions from both local and international actors. For schools, knowing potential yields informs the area and quantity they need to produce for consistent student consumption in the school meal program. Farmers too benefit from this knowledge, as it empowers them to plan their production to ensure they have enough to sustain themselves for a substantial portion of the year. Crop cut yield estimates also informs stakeholders such as extensionist on planning and appropriate agronomic guidance for improved crop yields.

The crop cut method, which involves determining yield from a specific unit within a plot was adopted over the recall methods which are commonly used and yet are prone to errors especially in estimating the crop area and quantity harvested. The crop cut area was 6 msq which was demarcated, and harvests were made in only that unit. This activity, in which CIP, WFP with its partner Andre Food International (AFI) participated, was undertaken in four districts in Karamoja. Rengen and Nakapiripirit primary schools in Moroto and Nakapiripirit districts, respectively were selected for the crop cut study. In these schools, OFSP was planted on at least one acre. At the same time, households around these schools received vines and messages on how to plant and manage the crop. In each district, at farmer level, crop cuts targeted 52 plots and from 52 farmers, thus one plot per farmer. At school level, four crop cuts were done, giving a total of 240 crop cuts from both farmer and school managed plots. Harvesting was done between 90 to 120 days after planting. This is the maturity period for most of the varieties that were distributed. Care was taken to ensure that within the sampled units, there were no piece meal harvests that were made prior the exercise.

Harvests in the demarcated units were made, and measurement taken were total yield, weight of marketable roots, weight of unmarketable roots, number of roots affected by weevils and weight of vines produced. Additionally, the yield of the varieties distributed in Karamoja, i.e., NASPOT 8, NASPOT 13 and Kakamega, were determined.

Orange fleshed sweetpotato crop cut harvest displayed by the research team at Namalu Primary school, Nakapiripirit. Credit Julius A, 2022

And results were exciting! An average yield of 8.4MT/ha was obtained in Karamoja, which is significantly higher than the National average of 4.8MT/ha. This implies that Karamoja can indeed produce sweetpotato to feed its people. Further analysis revealed that yields obtained in schools were more than double those obtained from farmer plots (Table 1 and Table 2). This is attributed to the observance to the Good Agronomic Practices (GAP) which were best followed in schools than at farmer plots. Indeed, yields were generally higher in plots where GAP such as planting in big heaps (>30cm high) and planting three vines per heap were followed during planting. As expected, yields varied in the districts, with Moroto experiencing the lowest yields. This is because the district experienced adverse drought conditions. Farmers in this district consumed the leaves that were surviving the dry season, and thus poor yields can be attributed to poor root formation arising from lack of rain and lack of enough photosynthetic area since most leaves were plucked off and consumed as relish. NASPOT 8 registered the highest yield (9.3MT/ha) compared to 8.6 MT/ha for NASPOT 13 and 7.6 MT/ha for Kakamega.

From this crop cut investigation, it can be deduced that sweetpotato can grow well in Karamoja and the potential yield is high if farmers adopt good agronomic practices. Further, the yields show that sweetpotato can withstand adverse climate conditions and give high yields. This is because during the period of investigation 47% of the plots had no rain at least for a week after planting, with some areas receiving rains after four weeks of planting, and there was no other source of water since none of the plots were irrigated. The consumption of leaves was unintended outcome but shows the multipurpose role of sweetpotato in this rain deficient sub-region.

Table 1: Yield of sweetpotato from crop cut plots

Table 2: Yield per district (MT/ha)

View project report here.