ECHO Asia Notes - Được xuất bản bằng tiếng Việt

Testing Seed Viability Using Simple Germination Tests

Editor: Abram serves as the Coordinator of Sustainability Research and as an Instructor with the International Sustainable Development Studies Institute in Chiang Mai. He also assists the ECHO Asia Impact Center as a technical advisor.

Introduction and Background

Saving your own seeds is a cost-effective way to access crop seed for future planting and to help maintain the planet's plant biodiversity. Whether you plant your own saved seeds, give them away to friends and neighbors, or distribute them through your organization, knowing the viability of your seeds is important. As a follow-up to the article in the January 2011 EC HO Asia Notes, Issue 8, titled "Building your own seed germination chamber for testing seed viability" ( www.echonet.org/repository#1003:d:Build Your Own Seed Germination C abinet), this article will explore the details of several low-cost methods for testing seed viability.

The Use of Green Manure/Cover Crops for Relay Cropping in Northern Thailand - 01-07-2011

This article is from ECHO Asia Note #10

Introduction

During the late rainy season, the permanent hill fields that surround a cluster of hilltribe villages in the Chiang Dao district of northern Thailand radiate various hues of green. These verdant fields, belonging to ethnic Lisu, Lahu, Akha, Palaung and Karen farmers, are covered in a patchwork of green manure/cover crops (gm/ccs) that include rice bean (Vigna umbellata), cowpea/black bean (Vigna unguiculata), lablab bean (Lablab purpureus), peanut (Arachis hypogaea) and jack bean (Canavalia ensiformis).

The extensive plantings of gm/ccs are part of a legume-maize relay cropping system that local farmers developed in the early 1980s. Relay cropping is a type of intercropping with two or more crops grown simultaneously during part of their life cycles. The second crop is often planted after the first crop has reached its reproductive phase, but before it is ready to harvest (Van Keer, et al.).

Preparation of Modified Mat Nurseries (MMN) for Improved Rice Seedling Production

This article is from ECHO Asia Note #9

Editor: The System of Rice Intensification (SRI), an unconventional approach to rice production that has spread throughout many parts of the world since the late 1990s, is comprised of a set of flexible management practices. CEDAC, based in Cambodia, summarizes these as follows:

Shallow (1-2 cm) transplanting of strong, young seedlings that are uprooted and quickly moved from moist but well-drained seedbeds.
Transplanting of 1-2 seedlings per hill at wider-than-usual spacings, between 25 x 25 cm (9.84 x 9.84 in.) and 50 x 50 cm (19.66 x 19.66 in.), ideally in a square pattern or in straight rows to facilitate weeding.
Alternate flooding and drying of the field during the period of vegetative growth.
Early and frequent mechanized weeding to control weeds and to aerate the soil.
Adding nutrients to the soil, preferably in organic form.

Biochar - An Organic House for Soil Microbes - 01-04-2011

This article is from ECHO Asia Note #9

Rick Burnette wrote an article for Issue 6 (July 2010) of ECHO Asia Notes, titled "Charcoal Production in 200-Liter Horizontal Drum Kilns." My article takes the charring process a step further by exploring the rapidly re-emerging world of biochar. Biochar is a form of charcoal, produced through the process of pyrolysis from a wide range of feedstocks. Basically any organic matter can be charred, but agriculture and forestry wastes are most commonly used due to the available volume. Biochar differs most significantly from charcoal in its primary use; rather than fuel, it is primarily used for the amendment of soils (enhancing their fertility) and sequestration of carbon (reducing the amount of CO2 released into the atmosphere).

Biochar has received a lot of interest internationally over the last few years, especially in light of the rising demand for food and fuel crops, and of raging debates on how to radically slow down runaway climate change. With strong voices on both sides of the debate-that is, both in favor of and against the widespread production and application of biochar-I would like to step back to the beginning of the story, hopefully putting things into perspective again.

Build Your Own Seed Germination Cabinet for Testing Seed Viability

This article is from ECHO Asia Note #8

Editor: Abram serves as a Post-Doctoral Research Fellow and Instructor with the International Sustainable Development Studies Institute in Chiang Mai. He also assists the ECHO Asia Regional Office as a technical advisor.

Introduction and Background

Saving your own seeds is a cost-effective way to access crop seed for future planting and to help maintain the planet's plant biodiversity. Whether you plant your own saved seeds, give them away to friends and neighbors, or distribute them through your organization, knowing the viability of your seeds is important.

Zanthoxylum: A Low-Profile Asian Crop with Great Potential - 01-01-2011

This article is from ECHO Asia Note #8

Introduction

The genus Zanthoxylum (family Rutaceae) contains a fascinating group of plants found around the world from the tropics to temperate zones. With over 200 species, ranging from small shrubs to large trees, Zanthoxylum spp. are characterized by sharp thorns on either the stem or leaves. Various Zanthoxylum spp. are well recognized as Asian spices, including Sichuan pepper or hua jiao in China, sansho in Japan and chopi and sancho in Korea (Austin and Felger 2008). In South and Southeast Asia, various parts of Zanthoxylum plants are used as a spice in stews, marinades and soups.

Recent literature shows that the anaesthetizing effect of alpha-hydroxysanshool, a compound produced by Zanthoxylum, has potential as a commercial product to reduce skin irritation. This same compound also induces the numbing sensation experienced by eating certain (central to western) Chinese cuisines containing Sichuan pepper. In South Asia and Africa, Zanthoxylum is used in traditional remedies for toothaches, malaria and diarrhoea. A scan of scholarly publications indicates that some scientists are also interested in investigating Zanthoxylum spp. as a source of medicinal compounds to be used against major diseases including malaria and diarrhoea.

An Introduction to Wood Vinegar

This article is from ECHO Asia Note #7

Prakrit Khamduangdao was looking for an alternative to agricultural chemicals to control pests in his vegetable farm. However, he was not completely satisfied with various botanical pest control measures being promoted in northern Thailand. He reports that even though certain natural insect repellents were beneficial, their effects were too limited. Additionally, finding adequate amounts of necessary raw plant materials and processing them into sprays was laborious and time consuming.

When Mr. Prakrit first heard about wood vinegar in 2000 he was intrigued. Compelled by the idea of a natural by-product of charcoal production that can control pests and diseases of crops, he bought his first bottle. Having used the product, Mr. Prakrit was pleased with the ease of mixing and application. Ultimately, after observing much fewer insect pests and fungal diseases on his crops, he became convinced of the effectiveness of wood vinegar.

Charcoal Production in 200-Liter Horizontal Drum Kilns

This article is from ECHO Asia Note #7

Editor: Due to the length of this article, only a portion is included in ECHO Asia Notes. The full article, including illustrated steps related to the assembly of 200- liter drum kilns as well as charcoal and wood vinegar production, can be accessed via the web link here.

Until recently, firewood was taken for granted in northern Thailand. With vast forests full of many types of trees, upland households could afford to be choosy concerning the wood they used for cooking.

However, in recent years, more and more communities are facing restricted access to forest products due to the establishment of national parks. In many areas, deforestation caused by agricultural activities, such as the encroachment of large plantations, is also resulting in declining access to firewood.

Gardening without Digging

This article is from ECHO Asia Note #6

One of the easiest and most effective ways to improve and build soil fertility in any gardening situation is to use a method known as sheet mulching. Thick layers of mulch are placed directly on the soil, simulating the thick leaf litter and humus found in natural forest systems. Sheet mulch provides multiple benefits, including water retention, weed suppression, slow release of nutrients and increase of beneficial soil organisms.

I first was introduced to this method through a sweet old lady called Esther Deans. She had written a book called 'Growing without digging', and was one of the first people in Australia to promote this type of garden. Her simple method enabled anyone to quickly create an extremely productive garden in any soil, even directly over weeds or lawn. The somewhat chaotic garden in illustration 1 is one of my early mulch gardens, made on shallow sandy soil over solid rock!

The Recent Introduction of Niger Seed (Guizotia abyssinica) Production in Northern Thailand - 01-07-2010

This article is from ECHO Asia Note #6

The arrival of a new crop

No one seems to know why members of the Lisu hilltribe in northern Thailand refer to a certain field crop with brilliant yellow flowers as Japanese sesame. The seeds of this crop yield quality cooking oil, but the plant looks nothing like true sesame (Sesamum indicum).

Traditionally, the Lisu have used at least a few sources of cooking oil, including the seed of roselle (Hibiscus sabdariffa) and even opium (Papaver somniferum). But when tens of thousands of Lisus began to migrate into northern Thailand from the Burma-China border during the 1960s, they apparently left the so-called Japanese sesame behind.