Research - Posters

Poster - Methodologies for Strengthening Informal Indigenous Vegetable Seed Systems in Northern Thailand and Cambodia - 20 មករា 2017

Poster - Moringa Fertility Trial - 20 មករា 2016

Moringa is known for its ability to grow in a wide range of soils. We hypothesized, however, that moringa leaf production can be increased by applying fertility inputs at the base of the trees.

We wanted to know:

• Do moringa trees benefit from fertility inputs?
• If so, how many grams of nitrogen (from NPK fertilizer) per tree are needed to maximize moringa leaf yield in a sandy soil?
• Does it make any difference, in terms of moringa yield, if NPK fertilizer is combined with compost?

Moringa trees responded favorably to added fertility. In comparison to no fertility, the largest increase (73%) in moringa yield occurred with 25 g of N per tree, regardless of whether or not compost was applied. However, with the data averaged across NPK-N rates, compost increased leaf yield by 23%. It seems best, therefore, to combine NPK fertilize with compost.

Poster - 2-4-2 Maize/Legume Intercropping Trial Update (2016) - 20 វិច្ឆិកា 2016

The 2:4 maize–double cowpea system consists of a repeating sequence of 4 rows of cowpea alternated with 2 rows of maize. Maize and cowpea are  planted on the same day. The second cowpea crop is planted after the first has been harvested (about 60 days after planting).¹ The objective of this trial is to gain first-hand experience while evaluating the feasibility of implementing 2-4-2 with other legumes. Jack bean produced the most (4.3 t/ha) dry matter. Cowpea and velvet bean produced 1.8 and 2.8 t/ha dry matter, respectively. Soil fertility and subsequent maize growth were apparently influenced by the amount of leguminous mulch produced and left on the ground. Maize grew taller with jack bean than cowpea, likely an effect of higher biomass with jack bean. This intercropping pattern shows promise as a way for farmers to intercrop maize with aggressive legumes.

¹H.A. Ajeigbe, B.B. Singh, A. Musa, J.O. Adeosun, R.S. Adamu, and D. Chikoye. 2010. Improved cowpea–cereal cropping systems: cereal–double cowpea system for the northern Guinea savanna zone. pp 17

Poster - Oxalates Present in Monstera Fruit and Plant Matter

Plants contain oxalates for a few reasons. The first is that plants do not have an excretory system like animals, so oxalates allow plants the ability to bind up excess calcium (Webb 1999).Plants high in oxalates can have negative effects on the ability of animals to absorb calcium after eating taro leaves as forage (Hang 2011). In humans, eating foods with a high amounts of oxalates can increase kidney stone formation (Juajun2012).The second reason oxalates are said to occur in plants is to prevent herbivory (Webb 1999). Oxalate crystal shapes (raphidesand styloids) are like small needles and can be found in plants such as Monsteradeliciosaand Colocasiaesculenta.Consumption of plants containing raphidesand styloids cause an unwanted reaction. The crystals within plant matter from monsteraare said to cause oral and skin irritation (Morton 1987). Plants containing high levels of oxalates are able to be consumed if processed correctly or harvested at the right time.

Poster - Cyantesmo Paper for Detecting Cyanide

Some tropical crops contain cyanogenic glycosides, toxic substances that release hydrocyanic acid (HCN; also referred to as cyanide) when cells are crushed. Consuming these plants without cooking them can cause cyanide poisoning, with varying effects depending on cyanide levels and how long a person or animal has been eating that plant. Cassava roots and leaves contain cyanogenic glycosides, so people whose diets are heavily dependent on cassava are especially at risk. Traditional methods to process and detoxify cassava roots include fermentation, prolonged soaking and boiling. Chaya leaves also contain cyanogenic glycosides; it is best to cook chayaleaves before eating them, to boil off the HCN rather than ingesting it. To determine if a plant is safe to consume, either by humans or livestock, a simple cyanide screening test is very helpful. At the 2014 ECHO International Conference in Florida, Dr. Ray Smith provided ECHO with sample strips of Cyantesmopaper for screening plant material for HCN.

Poster - Soil Salinity Measurement Trial

Salt buildup typically occurs in dry areas where evaporation exceeds precipitation. Over time, as water evaporates, the minerals left behind begin to accumulate. Plants need a certain amount of soluble salts, but when the salt content of soil water is greater than that of the water inside plant cells, the plant roots cannot absorb the soil water.

The degree of salinity at which yields decline depends on the crop. Quinoa (Chenopodiumquinoa), for example, is quite tolerant of salinity, whereas many annual vegetable crops are much more sensitive. Farmers in salt-prone areas need to know the salinity of their soils.

Poster - Seed Storage: Effectiveness of containers on temperature and relative humidity control

After modifications to the ECHO Global Seed Bank storage unit, seed storage techniques already in use were assessed for effectiveness in achieving appropriate seed storing conditions within the renovated cooling and dehydrating system. Seed type influenced the effect of container on relative humidity. In comparison to that with non-sealed containers, sealed containers reduced humidity when filled with bean but not maize seed. Humidity fluctuation was less with sealed than non-sealed containers. The same was true for bean seeds. Air temperature around the seeds was unaffected by seed type or container. Fluctuation of air temperature, however, was  significantly less in a bucket than in any of the other containers.