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Agro-chemical properties of cultivated soils and Cyanobacteria in rice fields of Dak Lak province

Under low temperature conditions, soil here was acidic, content of humus was at the middle level, quality of substrate and other physical and chemical factors influence the decomposition of Cyanobacteria. Exploration on Cyanobacteria in Ea Sup, Krong Pak and Lak districts (Dak Lak province) showed 62 species from 15 genera, 6 families, and 3 orders of Cyanobacteria. The structure of Cyanobacteria communities is depends on season.

Applying the holding moisture, microorganism preparation Lipomycin M. to enhance water capacity of hilly lands in Me Linh, Vinh Phuc

The study’s results showed that the yeast of Lipomyces in microorganism preparation Lipomycin M. is able to grow well in hilly lands of Me Linh district, Vinh Phuc province. Lipomycin M. has safe properties for soil animal and eco-system. The number of earthworms and soil mesofauna are enhanced in 1.5-2.0 times after 4 months of applying Lipomycin M. The results from the field experiments showed that Lipomycin M. is able to enhance water-holding capacity of hilly lands from 10-16% in comparison with controlled ones after 30 days.

Chemo-remediation of heavy metals contaminated soils using Vietnamese bentonite

Composting household organic waste as bio-organic fertilizer for clean vegetable production

The objectives of the research are to complete the process of composting household organic waste with microorganism to produce bio-organic fertilizer; to evaluate the quality of the compost products through compost sample analyzing and testing this fertilizer for clean vegetable production at farmer level. The main contents of the research are: to collect and separate of organic waste at household; to construct house for organic waste composting; to compost organic waste with 3 isolated and selected microorganisms with high digestion powers for nitrogen fixing and for phosphorus and cellulose solving; to analyze the quality of the composting products as organic fertilizer; to test bio-organic fertilizer for clean vegetables on farmer's fields. During 2004 and 2005, total 9 tanks were composted in which the volume of one tank around 9 tons of fresh organic waste. Up to now, it has produced about 10 tons of high quality compost as bio-organic fertilizer for clean vegetable production: cabbages, tomato, carrot and beans.

Effect of bentonite on improving crop yield and rehabilitation of degraded light texture soil

The results of experiments on using bentonite show that: on Arenosols (Thanh Hoa and Nghe An), Haplic Acrisols (Bac Giang), and degraded Ferralit Acrisols (Ha Tay) using 10-30 tons of bentonite per hectare for different annual crop species, the effect of bentonite on crop yield increasing sharply not only for the first crop yield from 15% to 32% (on average), but also for the next crop. On Arenosols, yields of sesame increased from 10% to 28%, corn yield increased from 9% to 12% in both site Nghe An and Thanh Hoa provinces. On Haplic Acrisols at Bac Giang province for the four crop rotations per year (spring peanut-summer rice-winter corn-spring peanut), spring peanut yield in the 4th rotation still increasing from 9% to 27%. On the Ferralit Acrisols, tea yield also increased from 9% to 16% compare with unapplied bentonite (control).

Effectiveness and sustainability of advantage upland programs

The objectives of the study are to research current situations of sustainable upland programs in the Northern mountainous region, and to evaluate difficulties and opportunities to expand of these programs. Both qualitative (farmer approach) and quantitative (soil analysis) methods were used. The results shown that advantage upland programs applied in this region have given good results to improve soil quality and economic effectiveness. However, there are a lot of difficulties caused to many farmers giving up their upland models. This is because many programs only concentrated on technology, but not on farmers' needs. Also, there is lack of market aspect when developing these programs.

Effects of re-use wastewater on heavy metals accumulation in the soil and rice in Nam Dinh town

Re-use wastewater for irrigation could bring back more economic return to farmers. In the controversy, it also could cause soil and agricultural product contamination. A study carried out in My Loc district, Nam Dinh province, where rice is irrigated by wastewater from Nam Dinh town in more than 20 years to determine effects of wastewater on soils and rice in the area. The results showed that, wastewater is rich in organic matter, phosphate, values of DO, COD, and BODs is over the accepted level of Vietnamese Standards (TCVN 5942-1995). The content of heavy metals (Cu, Pb, Zn, Ni, As) is under accepted level of Vietnamese Standards (TCVN 5942-1995) for surface water. However, in wastewater site they are higher than in non-wastewater site. Particularly, content of Cd in wastewater is 5-32 times higher than in non-wastewater (the Red River water), and over Vietnamese Standards (TCVN 5942-1995) from 1.3 to 8 times, even, over the Standards of FAO/WHO for irrigating water for agriculture.

Endomycorrhiza (Vesicular arbuscular mycorrhizae) and microorganism populations in Doan Hung pomelo soil

Analyze of study results showed that the spores of Endomycorrhiza appear in almost 32 soil samples taken from Doan Hung district. It's estimated that average of one gram of soil number of spore is less one. Size of spores (40-90 mm) and size (90-250 mm) are more abundant than >250 mm spore. Clear and Stain root with Tryphan blue determined contamination of fungi to root of host tree mainly vesicles. Spore germination ratio is 16%; percentage colonization (Mycorrhizal root length) is 26%. Aerobic microbiological population analyses indicate that total bacteria are higher than fungus, yeast and actinomycet total. Beneficial microbiological population (free nitrogen fixing, phosphate solubilization, cellulose decomposition and extra cellular polysaccharides excreting) is also found but low number.

Evaluation of land resources and recommendations for suitable land use types of sustainable agricultural production in Pho Yen district, Thai Nguyen province

The objective of this study is to evaluate land resources in order to identify suitable land use types for a sustainable agricultural production in Pho Yen district of Thai Nguyen province. Land evaluation program was carried out under guidelines for land evaluation from FAO framework since 1976. The results of the study indicated that there are 36 land mapping units. There are 5 optimum land utilization types, which are recommended to Pho Yen district such as rice-rice, rice- rice winter rained crops (e.g., corn, sweet potato), rice rained crop, and spring rained crops-rice-winter rained crops, vegetable-rained crops. It is estimated that the land use rate of cultivation rotation land per year will be increased from 1.8 times in 2003 to 2.3 times in 2010.

Farming systems development based on improving of land use efficiency in Dinh Tuong, Yen Dinh, Thanh Hoa

This paper aims to develop farming systems in Dinh Tuong commune based on economic efficiency of land use. The results showed that the farming systems in Dinh Tuong are diverse by the combination of rice with winter crops, beans or short growing season industrial crops. The systems of aubergine, summer-august soybean, winter vegetables and sugar cane, winter vegetables give the income of 61,96 million VND and 53,78 million VND/ha/year, respectively, are considered as systems of highest economic efficiency. The systems of spring corn, summer soybean, winter vegetables and spring peanuts, summer-august soybean, winter vegetables also give high income of 38,5 and 42,5 million VND/ha/year. However, the systems of spring rice, summer rice, and winter corn and spring rice, summer rice give low income at 25,3 and 17,5 million VND/ha/year, respectively.

Impact of cultivation methods and rainfall intensity on infiltration capactity of sloping land

The research was carried out on Dong Cao watershed, Hoa Binh province. The results were as followed: infiltration capacity of the soil is closely depends on rainfall intensity (close correlation): the more rainfall intensity the less water infiltration, because of surface soil compaction and crust formation reduced infiltration rate. The least water infiltration rate is on the cassava-cultivated area where soil surface is disturbed, poor/no structure, easily crust formation. In Eucalyptus cultivated area water infiltration rate is also not much higher than on cassava area, because under the Eucalyptus's canopy, soil surface is bare and compact by the raindrops and water drops formed from the leaves falling down resulting in reducing infiltration rate. Fallow and fodder plantation areas are the best methods, they stimulating infiltration rate of the soil, resulting from covering density reducing surface runoff and promoting surface water infiltration.

Isolation and selection of root fungus, Arbuscular mycorrhizae, to inoculate for crops

The Arbuscular mycorrhizae strains that were isolated and selected are grow fast with high vitality. Their spore has globes or sub-globes shape, sometimes oblong. The color of spore was white to yellow brown and orange brown with size distribution from 100 to 400 mm. Inoculation of Arbuscular mycorrhizae for crops promote the plant growth and stimulates the colonization of Arbuscular mycorrhizae fungi resulting in the enhancement of the plant vitality and tolerance with disadvantage condition of environment. The two strains of selected Arbuscular mycorrhizae as Gigaspora sp. 1 and Glomus sp. 2 proved more predominance. They have fast growth ability, their mycelium grow strong, the germination and vitality are high as well as given superiority effect in host plants, hence, they could inoculate for crops.

Land evaluation for land use planning and transferring agricultural plants structure in Cu- Jut district, Dak Nong province

The total area of Cu-Jut district, Dak Nong province is 71,889 hectares. There are 31 land mapping units in the area. Based on the studied results, 6 perspective land utilization types have been found. The studied results provided scientific and practical bases for land use planning in Cu-Jut district, Dak Nong province.

Land management and use regulated by 2003 Land Law

Litterfall production, leaf litter decomposition and sesarmid breakdown of leaf of two mangrove species Rhizophora apiculata and Ceriops tagal in Tam Giang forest enterprise, Ca Mau province

Physical properties of the soils under long-term tea growing

The objective of this study is to investigate physical properties of tea growing soils. The study was conducted in Dong Hy district of Thai Nguyen province. Tea fields were selected including 10, 25 and 40 years old tea crops and forest soil nearby was considered as a control plot. The study results shown that after 40 years of growing tea, soil texture changed little. However, other soil properties such as bulk density, total porosity, soil resistance, plant available water capacity and mean weight diameter were significantly changed in line with soil degradation. Most changes were at a surface soil layer. These changes of soil properties would affect negatively to the crop yield.

Phyto-remediation of cadmium and zinc contaminated soils

Potassium fractions and soil potassium supply extracted by resin capsule in major soil groups in the Mekong River Delta

The objective of the study was to investigate potassium fractions in 27 soil samples of non-acid alluvial soils, saline-intruded soils, sulfate acid soils, sandy soils and old-alluvial soils in the Mekong River Delta. Soil potassium fractions including total potassium by concentrated acid HFHClO4, non-exchangeable potassium by HNO3 1N boiling, exchangeable potassium by ammonium acetate 1N pH7, and soil potassium supply by resin capsule were investigated. Average total, non-exchangeable and exchangeable potassium were highest in saline intruded soils, lower in alluvial soils, sulfate acid soils, old alluvial soils, and lowest in sandy soils. Resin potassium at 1 day (RAQ1) and at 14 days (RAQ14) was at low to medium range. Soil potassium management in alluvial soils should be concerned because potassium fractions were at medium levels and cropping is now being intensified. Resin potassium can be used to study soil potassium supply to plants because of its good correlation with non-exchangeable and exchangeable ones.

Recommendations for a better vegetable production in Dong Anh peri-urban district, Hanoi city

The paper presents several recommendations for a better vegetable production in Dong Anh district, Hanoi city: improving nursery production; specializing an area for vegetables so that soil is not yearly disturbed; encouraging the uses of environmentally friendly pesticides such as pyrethroid and biological ones; and encouraging the adoption of new vegetable varieties which are more resistant to pests and diseases as well as better in quality.

Research on rational fertilizer regime for yellow tobacco growing in Bac Son district, Lang Son province

The studied results have shown that using fertilizer for yellow tobacco based on the soil analytical data gave the same quality, yield and economical efficiency of tobacco in comparison with the control treatment. However, the fertilizer dosage has been reduced by 5 kg of nitrogen, 10 kg of phosphorus and 10 kg of potassium per hectare respectively compared with the control treatment. Using combination fertilizer made by the Tobacco Technical and Economic Institute gave higher quality and yield of tobacco.

Research on several theoretical models of soil water movement under localized irrigation

The article presents some results on theoretical models of soil water movement under localized irrigation especially under trickle irrigation. Based on differential equations on soil water movement, researchers over the world have tried to find out the laws of soil water movement under localized irrigation. It can be said that all models mentioned in the article are useful for designing localized irrigation systems. Apart from that, in order to approach real situation of localized irrigation, field experiment must be done.

Researching soil moisture dynamics of main land use - types in Yen Chau district, Son La province

Yen Chau district located in mountainous and hilly region of Son La province. With the typical climate characteristic that is very dry in the winter season and heavy rain in the summer, the change of soil moisture in hilly land is clearly and it is impacting on the growth of annual crops and fruit trees. Therefore the study of soil moisture dynamics through the year under different land use types is very important for determining different measures of soil conservation and crop as well as tree planting. The study results shown that the soil moisture under the cover crops and fruit trees keeping in all year especially in the dry season is higher than on the barren land and fallow land.

Soil properties and land use of sloping land in Hanh Dzich commune, Que Phong district, Nghe An province (North Central Vietnam)

The sloping land in Hanh Dzich commune have some good properties as: high soil depth, fine loamy, moderate organic matter content, but strong acidic, very low exchangeable calcium, high aluminum contents. Enlarging the terrace rice in valley for nearly twenty years is a right process: strengthen food security, decrease of slash and burn cultivation, control deforestation. Income from sloping land farming is low. Unfertilized, monoculture of cassava is the most popular farming in sloping land. Cattle rising are important source of cash income. Planting grass, establishing community grazing in each hamlet is necessary for developing cattle rising.

Some results from initial research on activated sludge and its effects for wastewater treatment

The composition of alkaline - earth alkaline ions in surface layer of rice field in the Red River Delta

There are tidal dominant part and wave dominant part in the coastal area of the Red River Delta. Rice field of these two areas has been affected by salinity intrusion in the dry season. It is very important to improve stability economy, based on the consideration of aquaculture, agriculture and environment in these salt-effected soil area. Soil salinity and the participation of calcium, magnesium and sodium in the salt-effected soil have been researched in this study. The alkaline ion concentration adsorbed on soil particle of Nam Dinh saline soil and Hai Phong sulfate acid soil has been clarified. It is reported that sodium adsorption was the main reason for salinity in the saline soil, but it may not true in the sulfate acid soil. As a result, it is needed to carry out a further study about this topic in order to find out the optimal way to use the natural resource in the salt-effected soil areas of the Red River Delta.

The effect of handicraft development on agricultural production in Phu Xuyen district, Ha Tay province

Changing the rural economic structure have created new jobs and improved income of farmers. Development of handicraft is an effective method. However it has caused several negative effects on development process in the rural area. This paper focuses on analyzing the effects of handicraft development on agricultural production in Son Ha commune, Phu Xuyen district, Ha Tay province. The research results showed that the quick development of handicraft in Son Ha has created new jobs and opportunities to improve farmers' income and rural economic development. But it decreased the interest of farmers to agricultural production and increased the gap between the rich and the poor. The process of land use exchange raised problems of land management. This needs to solve for sustainable economic development in the commune.

The effect of intensification on heavy metals concentration in soils and leaf vegetables in peri-urban of Hanoi

In recent years, along with rapid increase in the rate of industrialization, agriculture has changed quite fast, the area of rice is taken place by vegetable cultivation area which has a quite large area on the peri-urban areas of Hanoi as: Gia Lam, Tu Liem and Dong Anh districts. The results of the study on the effects of intensification on heavy metals concentration in soils and leaf vegetables in peri-urban of Hanoi indicated that the rate of intensification of vegetable cultivated area in the peri-urban areas of Hanoi is very rapid; it is estimated with double in the Red River Delta. However, it has trend to accumulate a lot of heavy metals on the soil as Cu, Pb, Zn, Cd, especially in the area where is effected by industrial and urban waste, as well as high intensification. The intensification of fertilizer for vegetable is very high in peri-urban of Hanoi.

The effect of keeping in situ all organic residues available on robust coffee farm in Dak Lak province

The research results shown that: The amount of on-farm organic residues obtained from pruning coffee trees and shade tree, from falling of-coffee leaves and others, clipping and weeding grasses, etc was from 20 to 25 tons of fresh weight per hectare per year. The nutrient properties of the residues were different from kinds of the sources and were quite high to compare with those of in farmyard manure, Tephrosia candida, and Eupatorium odoratum. Returning these residues to the soil could improve soil fertility and soil structure through positive changes of the chemical and physical contents such as porosity, aggregation, water-holding capacity, P2O5 fixing, etc, leading to increase in chemical fertilizers-use efficiency. Keeping all the materials in place not only stimulated the development of coffee root system, reduced amount of dropped berries, increased bean size, but also increased coffee yield by 29 - 80% in comparison with the control treatment (without application of the residues).

The initial study of the New System of Rice Intensification (NSRI)

The New System of Rice Intensification (NSRI) is a system of farming practices that help rice plants to achieve their potential by following changes: Water management-from keeping standing water in the rice field until harvesting to no continuously standing water. The rice plant during its growth stage only needs to have soil that is moist, but not saturated; Early transplanting of seedlings before they are 15 days old, and as early as 8 or 10 days (2 leaves) instead of transplanting older seedlings with 4, 5 or 6 weeks old (5 or 6 leaves); Wider spacing, 1 or 2 plants per hill replaces 3 or 4 plants per hill; Seedlings are placed into the soil when they are transplanted and try do not make them vulnerable when moving them from nursery to the field; Application of more organic manure and etc. The experiments and trials were conducted in different seasons and provinces of Quang Nam, Thua Thien Hue, Quang Tri, Thanh Hoa and Hanoi indicated that rice yield of hybrid varieties was 20% and of purebred varieties 40% higher in NSRI than in conventional farming practices. NSRI is not only increases rice yield but also increases income by reducing external inputs such as fertilizer, pesticides, irrigation water and etc. NSRI also gives opportunities in transforming of crops system.

The integrated model of ALES-GIS in evaluating ecological suitability of landscape for cultivated crops (A case study in coffee and rubber growing area of Dak Lak and Dak Nong provinces)

The integrated model of ALES-GIS (Automaticed Land Evaluation System-Geography Information System) has 3 parts: (a) The data input including ecological requirement of crop and landscape map linking with landscape property matrix; (b) ALES and GIS software interacted with evaluation experts; (c) The data output that evaluating matrix linking with ecological suitability maps. The advantage of the model is not only evaluates landscape suitability exactly but also rapidly. The results of the integrated model of ALES - GIS application in landscape evaluation for cultivated crops, of coffee and rubber shows that: in Dak Lak and Dak Nong territories, there are 483,119 ha suitable for rubber, 791,615 ha for coffee.

The role of residues to nutrient balance for four-cropping system on degraded soil in Bac Giang province

Warning on cadmium pollution in soil and vegetables at intensive vegetable growing in Minh Khai commune, Tu Liem district, Hanoi

Minh Khai commune of Tu Liem district, Hanoi city is a peri-urban area with high intensive level of vegetable cultivation. Farmers applied a large amount of chicken excrement into the soil for vegetables. The paper presents the research on cadmium pollution in soil and vegetables growing area in Minh Khai commune. The results of this research show that, soil was polluted with cadmium (6.2 times higher than Vietnamese Standards). Vegetables (cabbages, salads, water morning glories) growing in this area also contained high concentration of cadmium (content of this element exceeded from 12.4 to 40.2 times in comparison with Vietnamese Standards for vegetables). Chicken excrement was initially determined as main source of cadmium pollution in soil and vegetables this area.