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ECHO Tech Notes are subject-specific publications about topics important to those working in the tropics and subtropics. Our material is authored by ECHO staff and outside writers, all with experience and knowledge of their subject. These documents are free for your use and will hopefully serve a valuable role in your working library of resources in agricultural development!

97 Các Số trong Ấn phẩm này (Hiển thị vấn đề 79 - 70) |

TN #79 Nutrient Quantity vs Access - 01-01-2014

In order to achieve high levels of agricultural productivity in the tropics at the lowest possible economic and ecological costs, we need to properly understand the relationship between nutrients in the soil and crop productivity. For this to happen, the current understanding needs to change. The conventional view of the relationship between soil nutrients and crop productivity in the tropics is leading to both damaging agricultural policies and inefficient and damaging farm-level practices. There is no need to use the huge quantities of chemical fertilizers that are so often recommended. In fact, often times the use of such fertilizers is unnecessary, expensive and harmful to the environment, especially because farmers often stop using organic matter when they use chemical fertilizers.

Much of the theory described here was originally developed by Drs. Artur and Ana Primavesi. For a much more in-depth analysis of the chemical and biological issues described in this article, the best book at present is Ana Primavesi’s The Ecological Management of the Soil (available in Spanish and Portuguese). This article will discuss the conventional concept of soil fertility and some of its shortcomings; a new conception of soil fertility; and how the new theory can be put into practice.

Cite this article as:

Bunch, R. and ECHO staff 2014. Nutrient Quantity vs Access. ECHO Technical Note no. 79.

TN #78 Zai Pit System - 01-01-2013

“Zai” is a term that farmers in northern Burkina Faso use to refer to small planting pits that typically measure 20-30 cm in width, are 10-20 cm deep and spaced 60-80 cm apart.  In the Tahoua region of Niger, the haussa word “tassa” is used. English terms used to decribe zai pits include “planting pockets”, “planting basins”, “micro pits” and “small water harvesting pits.” Seeds are sown into the pits after filling them with one to three handfuls of organic material such as manure, compost, or dry plant biomass. The following quotes provide further detail.

What’s Inside:

  • Introduction
  • Historical background
  • Technical Details
  • How to optimize the zai system
  • Other plant basin systems
  • References

Cite this article as:

Motis, T. 2013. Zai Pit System. ECHO Technical Note no. 78.

TN #77 An Introduction to Wood Vinegar - 01-08-2013

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.

What’s Inside:

Uses of Wood Vinegar

Wood Vinegar Production

Composition and Characteristics of Wood Vinegar

Wood Vinegar Concerns?

Cite this article as:

Burnette, R. 2013. An Introduction to Wood Vinegar. ECHO Technical Note no. 77.

TN #76 Charcoal Production in 200-Liter Horizontal Drum Kilns - 05-02-2016

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.

In upland communities, commercial types of cooking fuel like propane are not readily accessible or affordable.  With limited options, communities and development organizations have begun considering alternative fuels.

Cite this article as:

Burnette, R. 2013. Charcoal Production in 200-Liter Horizontal Drum Kilns. ECHO Technical Note no. 76.

TN #75 Biochar: An Organic House for Soil Microbes - 01-06-2013

Rick Burnette wrote an article for Issue 7 (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.

Cite this article as:

Hugill, B. 2013. Biochar: An Organic House for Soil Microbes. ECHO Technical Note no. 75.

TN #74 Agriculture Components for Small Institutions - 01-01-2013

The ECHO Asia Regional Office receives frequent inquiries from small organizations seeking input and other assistance related to their agricultural initiatives, including questions such as the following:

  • How many acres would it take to grow enough food (other than rice) to feed 38 people year round?
  • What crops are most likely to be grown for that purpose?
  • How would you quantify the amount of labor that such an endeavor would require?

Essentially, many inquirers are asking, “How realistic is it to combine agricultural components into small institutions, and are there any examples of effective efforts?”

This technical document goes through how to approach answers, proposes some potential benificial practice and shares lessons learned.

What’s Inside:

  • An Effective Farm for Children
  • Realistic Expectations at Suan Aden
  • Good Management – Clear Priorities
  • Lessons Learned
  • Agricultural Options for Institutions with Land Constraints
  • Outreach Potential

Cite this article as:

Burnette, R. 2013. Agriculture Components for Small Institutions. ECHO Technical Note no. 74.

TN #73 Lablab (Lablab purpureus) New Staple Crop for the Sudano Sahel - 20-01-2013

About 98% of agricultural production in the Sudano Sahelian region of West and Central Africa is based on rainfed crops. With a mean annual rainfall of 300 to 800 mm/year, the number of staple crops is very limited. It includes two grain crops: pearl millet (Pennisetum glaucum) for sandy soils and grain sorghum (Sorghum bicolor) for heavier soils. (Corn is grown in high rainfall regions.) Two pulses are also produced: cowpeas (Vigna unguiculata) and groundnuts (Arachis hypogaea).

All five crop species are sown at the beginning of the rainy season and harvested three to four months later. Average yields of these crops are only 20% of potential for three main reasons:

  1. The very low fertility of Sudano Sahelian soils combined with the fact that farmers do not add chemical fertilizers
  2. Sporadic rainfall and frequent droughts
  3. Diseases and pests that attack these crops

In the Sudano Sahel, an agro-pastoral system is practiced. The relative importance of the livestock component increases as we advance to regions of lower rainfall. Animal feed production is a very important component of the production system. It is provided by the hay produced from cowpeas and groundnut stems, and by sorghum and millet straw.

Cite this article as:

Pasternak, D. 2013. Lablab (Lablab purpureus). ECHO Technical Note no. 73.

TN #72 Sloping Agricultural Land Technology (SALT) - 01-01-2012

Asia makes up less than one third (30%) of the world’s land area and yet carries over half (56%) of the world’s
population. Moreover, the average population density of Asia becomes a significant long-term problem when food production is considered. Some countries in Asia have a population density of up to eight people per hectare. In addition, the Food and Agriculture Organization (FAO) of the United Nations predicts that the world have to double its food production by the year 2030 to feed its exploding population. However, Asia, when compared to the rest of the world, has very little land that is suitable for cultivation that has not already been exploited.

To compound the problem, much of the land now under cultivation in Asia has been classified as degraded or as having undergone moderate-to-severe erosion. According to FAO, many Asian countries now have 20% or more of their lands considered “degraded,” with some countries approaching 50%.

What’s Inside:

  • The Problem: Deforestation
  • leading to soil erosion
  • Introduction to SALT
  • The Ten Steps of SALT
  • Advantages of SALT Farming
  • Conclusion

Cite this article as:

Mindinao Baptist Rural Life Center 2012. Sloping Agricultural Land Technology (SALT). ECHO Technical Note no. 72.

TN #71 Foundations for Farming (FFF) - 01-01-2012

Dawn Berkelaar, working with Dr. Martin Price and Danny Blank, featured this farming system in EDN 98. At that time, the technique was known as “Farming God’s Way” (FGW). Subsequently, the name was changed to “Foundations for Farming” (FFF); however, it continues to also be promoted as FGW. FGW and FFF Internet URL’s, links to much more detail, are given at the conclusion of this section. The article from EDN 98 is summarized here using the name, FFF.

What’s Inside:

  • History and Background
  • Principles
  • Step-by-Step Instructions
  • Success Stories
  • Conclusion

Cite this article as:

Berkelaar, D. 2012. Foundations for Farming (FFF). ECHO Technical Note no. 71.

TN #70 Water Harvesting through Sand Dams - 01-01-2011

A sand dam is a reinforced concrete wall built across a seasonal river to hold underground water in sand (see above photo of Nzaaya Muisyo sand dam, Eastern province, Kenya). It is initially built one meter high and up to 90 meters across. During the heavy and erratic seasonal rains, the water and silt flow over the dam while the heavier sand settles to the bottom. Over one to three seasons of rain, the dam fills up with sand which acts as a storage tank for water. In good quality sand, the sand dam volume is approximately 35% water (Beimers et al., 2001). Most of this water does not evaporate as it is protected by the sand. Evaporation decreases by 90% at 60 cm below the surface (Borst et al., 2006). 

The sand dam is always built on bed rock. A natural aquifer is formed under the sand as water accumulates. Often there is already an aquifer present and the sand dam simply increases the water in it. Over time, the aquifer increases in size and the water table of the surrounding area rises. 

What’s Inside: 

  • What is a Sand Dam? 
  • Where Does the Water Come From? 
  • Where and When is it Best to Build? 
  • What Permits do I Need? 
  • How is a Sand Dam Designed, Constructed, and Maintained? 
  • Terracing around Sand Dams 

Cite this article as:

Stern, J. H. and A. Stern 2011. Water Harvesting through Sand Dams. ECHO Technical Note no. 70.