Editorial: Conservation agriculture: knowledge frontiers around the world

International audienc

Crop Yields Response To Conservation Farming And Spatial-Temporal Effects In Zambia

We examined crop yields along a wide environmental gradient and spatial dynamics in soil organic matter in response to conservation farming (CF) in Zambia. Maize yields from farmer managed CF and traditional farming (TF) were not significantly different with over 280 on-farm trials with varying soil properties, management practices and environmental covariates. Principle component analysis (PCA) identified inappropriate management practices (planting and insufficient weeding), of which 25% of total variability were major factors restricting CF yields. TF yields were limited by both amount and types of inputs that explained 26 % of total variability. With addition of different organic and inorganic amendments, average CF yield ranged from 1 to 4 t ha-1, with highest in wetter region (3.4±7.9 t ha-1) and lowest (2.1±6.8 t ha-1) in degraded plateaus. Combined additions of inorganic fertilizer (NP-K at 200-100-100 kg ha-1) with biochar and manure achieved the highest effect in degraded plateau with yield increase of 320% and 300% respectively as compared to organic matter additions of manure (46%) and gliricidia (24%) in the same region. PCA established pre-existing soil fertility is the major factor in all sites for improved yields and nutrient uptake with organic additions (P<0.05). Compost additions (P=0.001), and manure with or without inorganic fertilizer additions (P=0.02) led to greater yields with finer soil texture but not with biochar additions. iii Additions of biochar with inorganic fertilizer in wetter region enhanced maize Ca uptake (P=0.03) at lower pH (P=0.005) and higher rainfall (P=0.05). Total soil organic C (SOC) and N contents were initially 8% and 12% greater in planting basins than in rows over 10-year chronosequence under CF. Both SOC and N contents increased to a greater extent in basins than in rows with increasing years indicating greater SOM accrual. Mineralization of C per unit SOC in basins (R2=0.83) increased with years under CF indicating an accumulation of more labile SOC, whereas no changes were observed in rows. Potential mineralized N (PMN) increased in both basins (R2=0.60) and rows (R2=0.79) although more rapidly in basins than in rows. Greater stability of SOC was observed in areas receiving crop residues only. i

Post-harvest losses and food safety in tomatoes produced in Laikipia County

Kenya is one of the main producers of tomato within Africa south of the Sahara, with an estimated market value of USD 237 million as of 2012, most of which was produced for the national market (Sibomana et al., 2016). Within Laikipia, the total value of tomato production was estimated as 148.5 million KSh in 2014 (Ministry of Agriculture). Due to their softness and perishability, tomatoes have significant potential for both quality and quantity losses postharvest.Non-PRIFPRI1; Voice for Change Partnership; 2 Promoting Healthy Diets and Nutrition for all; 3 Building Inclusive and Efficient Markets, Trade Systems, and Food Industry; CRP2; CRP4; DCAMTID; A4NH; PIMCGIAR Research Program on Agriculture for Nutrition and Health (A4NH); CGIAR Research Program on Policies, Institutions, and Markets (PIM

Food safety in tomatoes produced in Laikipia county

Kenya is one of the main producers of tomato within Africa south of the Sahara, with an estimated market value of USD 237 million as of 2012. Tomatoes are vulnerable to a number of pests. As a result, pesticides are commonly applied to tomato in Kenya. The fleshy nature of tomato means that chemicals can easily soak into the edible part of the crop, leading to potentially high residual levels of pesticides.Non-PRIFPRI1; Voice for Change PartnershipMTI

Editorial: Conservation agriculture: knowledge frontiers around the world

International audienc

Conservation agriculture and ecosystem services: An overview. Agriculture, Ecosystems and Environment 187

a b s t r a c t Conservation agriculture (CA) changes soil properties and processes compared to conventional agriculture. These changes can, in turn, affect the delivery of ecosystem services, including climate regulation through carbon sequestration and greenhouse gas emissions, and regulation and provision of water through soil physical, chemical and biological properties. Conservation agriculture can also affect the underlying biodiversity that supports many ecosystem services. In this overview, we summarize the current status of the science, the gaps in understanding, and highlight some research priorities for ecosystem services in conservational agriculture. The review is based on global literature but also addresses the potential and limitations of conservation agriculture for low productivity, smallholder farming systems, particularly in Sub Saharan Africa and South Asia. There is clear evidence that topsoil organic matter increases with conservation agriculture and with it other soil properties and processes that reduce erosion and runoff and increase water quality. The impacts on other ecosystem services are less clear. Only about half the 100+ studies comparing soil carbon sequestration with no-till and conventional tillage indicated increased sequestration with no till; this is despite continued claims that conservation agriculture sequesters soil carbon. The same can be said for other ecosystem services. Some studies report higher greenhouse gas emissions (nitrous oxide and methane) with conservation agriculture compared to conventional, while others find lower emissions. Soil moisture retention can be higher with conservation agriculture, resulting in higher and more stable yields during dry seasons but the amounts of residues and soil organic matter levels required to attain higher soil moisture content is not known. Biodiversity is higher in CA compared to conventional practices. In general, this higher diversity can be related to increased ecosystem services such as pest control or pollination but strong evidence of cause and effect or good estimates of magnitude of impact are few and these effects are not consistent. The delivery of ecosystem services with conservation agriculture will vary with the climate, soils and crop rotations but there is insufficient information to support a predictive understanding of where conservation agriculture results in better delivery of ecosystem services compared to conventional practices. Establishing a set of strategically located experimental sites that compare CA with conventional agriculture on a range of soil-climate types would facilitate establishing a predictive understanding of the relative controls of different factors (soil, climate, and management) on ES outcomes, and ultimately in assessing the feasibility of CA or CA practices in different sites and socioeconomic situations. The feasibility of conservation agriculture for recuperating degraded soils and increasing crop yields on low productivity, smallholder farming systems in the tropics and subtropics is discussed. It is clear that the biggest obstacle to improving soils and other ES through conservation agriculture in these situations is the lack of residues produced and the competition for alternate, higher value use of residues. This limitation, as well as others, point to a phased approach to promoting conservation agriculture in these regions and careful consideration of the feasibility of conservation agriculture based on evidence in different agroecological and socioeconomic conditions