Strategies to improve cropland soils in North Korea using pasture leys

In the Democratic People's Republic of Korea (DPRK), soil fertility decline is a major factor that prevents the national grain production goal from being realised. The strategic use of legume-based pasture leys as rotations in intensive single and double cropping systems has proven to be a sound, low-cost means to boost soil fertility in other parts of northeast Asia. However, using pasture species in this way is a new technology in DPRK and there is some reluctance by cooperative farm managers to devote any of their cropland to ley pastures, irrespective of soil condition, because of a fear of failure to meet grain production targets set by the Government. Audits of five cooperatives in the Miru Hills upland maize cropping area indicated that some of the land currently used for livestock forage production may be used to introduce pasture leys without affecting crop production if the current fodder production systems can be redesigned to enable the same amount of forage to be produced on a smaller land area. This paper shows that this can be achieved by replacing the current grain-type maize system with a combination of cold tolerant cereals (i.e. oats and triticale), multi-cut sorghums and forage maize that have higher potential productivity. Using realistic assumptions, it was estimated that 4.5 ha in every 10 ha currently used for greenchop maize and maize grain to support livestock enterprises could be released to establish ley pastures without any change in greenchop or grain output if 1 ha each of cold tolerant oats, winter hardy triticale, hybrid forage maize and multi-cut sorghum were sown instead of the grain maize cultivars. The strategy becomes even more attractive when the quality of these new forages and the production from ley pastures are taken into account. While there is a need for further testing, refinement and demonstrations of this strategy, the analysis presented highlights the potential to rapidly integrate ley pastures into the cooperative farm structure without any disruption of the cropping activities. However, while the potential impacts of introduced pastures and forages on livestock production are readily apparent, their impact on soil fertility and subsequent crop production remain the prime objective of an extensive on-going monitoring program.