E. Omondi

The Effect of Intercropping Annual Ryegrass with Pinto Beans in Mitigating Iron Deficiency in Calcareous Soils

Dry beans are grown extensively throughout the western Great Plains. The high-pH soils prevalent in this region limit the availability of many micronutrients, especially iron. In 2002 a Goshen County, Wyoming farmer observed that pinto beans intercropped with annual ryegrass did not exhibit iron-deficiency chlorosis and produced higher yields than beans grown without the ryegrass. Field studies were conducted on the same farm in 2006 to determine if a ryegrass intercrop results in increased iron concentration in pinto beans. Treatments included bean–ryegrass intercrop, beans planted in ryegrass residue incorporated in the soil, and beans planted alone. Soil iron concentration increased for all treatments (p<0.10) over the first 76 days of the experiment. There was also significantly more soil organic matter and significantly lower soil pH (p<0.10) in plots with ryegrass compared to beans alone. Iron concentration declined, though not significantly, in bean leaves over the study period with a steep decline over the first sampling interval in the monoculture plots compared to bean–ryegrass plots.

A social networks approach for strengthening participation in technology innovation: lessons learnt from the Mount Elgon region of Kenya and Uganda

Participatory approaches to agricultural technology development have not yet fully lived up to their promise to incorporate farmer knowledge. This paper introduces a social networks approach (SNA) to improve participatory research processes for co-innovation. Drawing upon findings from a collaborative project developing conservation agricultural production systems for smallholders in western Kenya and eastern Uganda, the paper explores farmer support networks to improve participation in technological innovation and development. Key research themes include: identifying farmers’ agricultural production networks; the local articulation of agricultural production networks and mindsets; using networks to facilitate meaningful participation in technology development; and disadvantages and advantages of using a social network approach. The introduction of SNA improved participatory research by building external and internal legitimacy for determining who participates, discouraging participatory attrition, and providing a meaningful forum for participation of all stakeholders. As a result, the introduction of SNA is demonstrated to show strong promise for improving processes of participatory technology development in agriculture.

Weed Dynamics during Transition to Conservation Agriculture in Western Kenya Maize Production

Weed competition is a significant problem in maize (Zea mays, L.) production in Sub-Saharan Africa. Better understanding of weed management and costs in maize intercropped with beans (Phaseolus vulgaris, L.) during transition to conservation agricultural systems is needed. Changes in weed population and maize growth were assessed for a period of three years at Bungoma where crops are grown twice per year and at Trans-Nzoia where crops are grown once per year. Treatments included three tillage practices: minimum (MT), no-till (NT) and conventional (CT) applied to three cropping systems: continuous maize/bean intercropping (TYPICAL), maize/bean intercropping with relayed mucuna after bean harvest (RELAY) and maize, bean and mucuna planted in a strip intercropping arrangement (STRIP). Herbicides were used in NT, shallow hand hoeing and herbicides were used in MT and deep hoeing with no herbicides were used in CT. Weed and maize performance in the maize phase of each cropping system were assessed at both locations and costs of weed control were estimated at Manor House only. Weed density of grass and forb species declined significantly under MT and NT at Manor House and of grass species only at Mabanga. The greatest declines of more than 50% were observed as early as within one year of the transition to MT and NT in STRIP and TYPICAL cropping systems at Manor House. Transitioning to conservation based systems resulted in a decline of four out of five most dominant weed species. At the same time, no negative impact of MT or NT on maize growth was observed. Corresponding costs of weed management were reduced by

Volunteer Corn (Zea mays) Interference in Dry Edible Bean (Phaseolus vulgaris)

148.40 ha-1 in MT and

Interplanting Annual Ryegrass, Wheat, Oat, and Corn to Mitigate Iron Deficiency in Dry Beans

149.60 ha-1 in NT compared with CT. In conclusion, farmers can benefit from effective and less expensive weed management alternatives early in the process of transitioning to reduced tillage operations.

Performance of a local open pollinated maize variety and a common hybrid variety under intensive small-scale farming practices

Volunteer corn can affect dry bean by reducing yields; expanding the life cycle of insects, mites, and pathogens; interfering with harvest; and contaminating bean seed. Field studies were conducted at Lingle, WY, and Scottsbluff, NE, to determine the relationship between volunteer corn density and dry bean yield, establish the proper time of volunteer corn removal, and determine whether dry bean yield was affected by the method used to remove volunteer corn. Volunteer corn reduced dry bean yields, as recorded in other crops. Growing conditions for each location were different, as indicated by the accumulated growing degree days (GDD): Lingle 2008 (990), Lingle 2009 (780), and Scottsbluff 2009 (957). No difference in dry bean yields was observed between hand removal of volunteer corn and herbicide application. Dry bean yield loss increased with longer periods of volunteer corn competition and ranged from 1.2 to 1.8% yield loss for every 100 GDD that control was delayed. Control measures should be implemented 15 to 20 d after planting when volunteer corn densities are close to 1 plant m−2. Dry bean yield losses also increased as volunteer corn densities increased, with losses from 6.5 to 19.3% for 1 volunteer corn plant m−2. Based on 2015 prices, the cost of controlling volunteer corn would be the equivalent of 102 kg ha−1 of dry bean, and potential losses above 4% would justify control and should not be delayed beyond 15 to 20 d after planting Nomenclature: Dry bean, Phaseolus vulgaris L.; volunteer corn, Zea mays L.

Development and transfer of conservation agriculture production systems (CAPS) for small-holder farms in eastern Uganda and western Kenya

This study evaluated whether grass intercropping can be used to alleviate Fe deficiency chlorosis in dry beans (Phaseolus vulgaris L.) grown in high pH, calcareous soils with low organic matter. Field studies were conducted at the University of Wyoming Sustainable Agriculture Research and Extension Center in 2009 and 2010. Black- and navy beans were grown alone or intercropped with annual ryegrass (Lolium multiflorum Lam.), oat (Avena sativa L.), corn (Zea mays L.), or spring wheat (Triticum aestivum L.) in a two-factor factorial strip-plot randomized complete block design. All four grass species increased chlorophyll intensity in dry beans. However, grass species did not increase iron (Fe) concentration in dry bean tissues suggesting inefficient utilization of Fe present in the dry bean tissues. In 2009, nitrate-nitrogen (NO3-N) and manganese (Mn) concentration in bean tissue were greater in bean monoculture than in grass intercropped beans. Bean monoculture also had greater soil NO3-N concentrations than grass intercropped treatments. In 2009, grass intercrops reduced dry bean yield >25% compared to bean monoculture. Annual ryegrass was the least competitive of the four annual grass species. This suggests that competition from grasses for nutrients, water, or light may have outweighed benefits accruing from grass intercropping. Additional studies are required to determine the appropriate grass and dry bean densities, as well as the optimum time of grass removal.

Conservation agriculture effects on earthworm populations in Western Kenya and Eastern Uganda soils.

Given that the majority of maize farmers in Kenya are small-scale, improvement in maize production must focus on increased production per unit area. While hybrid maize varieties outperform local open pollinated varieties under conventional farming practices, their relative performance has not been tested under small-scale intensive production practices. A study was conducted in 2013 in Kitale, western Kenya, to evaluate performance of ‘Namba Nane’; a local open pollinated maize variety, alongside a high yielding hybrid, ‘Hybrid 614D’ under a small-scale, intensive farming practice that utilizes deep tillage and compost/manure. Each variety was subjected to conventional and diagonal offset close spacing. The grain yield of the hybrid (12.8 tons ha) was not statistically different from that of ‘Namba Nane’ (10.2 tons ha), even though the number of rows per cob and number of ears per plant of the former were significantly greater than those of latter. However, yields of both varieties were about twice the published potential yield of improved hybrid maize (6 tons ha) grown with conventional practices. Seed kernels of ‘Namba Nane’ weighed 1.6 times more than those of ‘Hybrid 614D’. Diagonal off-set close spacing under this technology increased the maize grain yield of both varieties 1.3 times. The cost of producing ‘Namba Nane’ under the technology was significantly less than producing the hybrid and twice more profitable (gross margin). Growing ‘Namba Nane’ using small-scale, intensive farming practices may be a viable option for most small-scale, resource-challenged farmers to increase economic yields.