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Assessment of effects of shrimp hatching activities on the quality of soil environment in Thai Thuy coastal zone, Thai Binh province

Recently, shrimp hatching activities have been increasingly developing in the coastal zone due to an enormous economic benefit, and it contributes to considerably increase export turn-over of aquatic products in our country. Besides, shrimp hatching activities, in whole country in general, and in Thai Thuy coastal zone in the particular, have been causing positive impacts on soil and water environment. In Thai Thuy, the initial research show that the shrimp hatching activities mainly include 3 modes: advanced extensive aquaculture, semi-intensive aquaculture, and intensive aquaculture. The results of analysis of physico-chemical parameters in the soil samples indicated that the effected level of shrimp hatching activities on the environment depends on the intensive level of aquacultural activities. The highest pollution was found on the lagoon with intensive aquaculture mode, then on semi-intensive aquaculture and advanced extensive aquaculture.

Cation exchange capacity and composition of exchageable cations in degraded soil, means improve cation exchange capacity of soil influence of cation exchange capacity on rice yield

Cation exchange capacity (CEe) and exchangeable cations is one of the most important properties of soil fertility. In degraded soils, CEC is very low in surface layer and increase in deeper layer. Therefore they are also poor in exchangeable cations special Mg2+ and K+. On farm mix subsoil with surface soil layer increase CEC of soil. With 50% subsoil and 50% surface soil inrrease CEC 7.4% compare surface soil. When apply FYM increase CEC of soil from 10-20%. Due to CEC of soil remain nutrients for rice, it has strong correlation with rice yield r= 0,78. Organic matters ( straw, FYM, azola) and laterite stone grinded can improve cation exchange capacity of soil. Straw, FYM increase CEC better than azola.

Cultivation of watermelon on severely acid sulfate soils in the Mekong delta

Alleviating soil toxicities and introducing new crop for diversification on severely acid sulfate soils can give opportunities to farmers in improving their income and standard living. New raised beds were constructed to grow watermelon on an severely acid sulfate soil, Typic Sulfaquepts, at Tien Giang province. Three consecutive crops were executed arranging in treatments of local lime and Agri-Stabi, a new production of lime material. Residual effect of lime was tested at the second and the third crop. Some selected chemical soil properties were measured. Fruit yield was recorded and economic effciency was evaluated. In the first crop, watermelon could not survive without supply of lime although sufficient of nutrients N, P, K. Local lime and Agri-Stabi give very positive effect on increasing soil pH, reducing aluminium exchangeable, improving growth and fruit yield. Residual effect of lime resulted in maintain fruit yield significantly higher in comparison with the control. After three crops, fruit yield was improved, Al in soils gradually declined due to leaching acidity. However, lime application and residual effect give the highest production and profit after three crops. Therefore, in severely acid sulfate soil, watermelon can growth and give high fruit yield, high benefit if liming of 2 tons per ha is done in the condition of sufficient major nutrients.

Determination of acid sulfate soils' acidification for agriculture development and rural construction in Mekong delta

Acid sulfate soils (ASS) occupy one-third of total area in the Mekong delta, which cover some 1.6 million ha, mainly in the Plain of Reeds, Long Xuyen Quadrangle, and Ca Mau Peninsula. Disturbance by excavation or drainage of ASS for flood mitigation, urban development and agricultural production can result large areas acidified with significant environmental, social and economic impacts. Field techniques are useful exploratory tools, but are indicative only and definitely not quantitative. Acid and sulfur trails in ASS can be quantified by SPOCAS method, which is relatively quick and simple performance. The acid and sulfur trail of ASS in the Mekong delta varied in depth and location. Some good regressions have been found among SPOCAS components. The results from analysis of TPA, TM and Spos have provided a basis of liming.

Effect of copper, lead, zinc, cadmium on rice seedlings in alluvial soil of Red river

Used root growth inhibition measure method of TCVN 5962-1995 for studying effect of copper, lead, Zinc, Cadmium on seedling at concentrations: Cu2: 50; 70; 100; 500 ppm; Pb2+ : 50; 100; 500; 1000; 1500 ppm: Zn2+: 200; 500; 1000; 1500 ppm; Cd2+: 1; 5; 50; 100; 200 ppm. Experiments have been conducted over 16 days with three replications. Results indicated that: - At copper concetration of 75 ppm, rice seedlings were slightly affected: young leaves were cholorotic growth was stunted; - At Zinc concentration of 200 ppm, young leaves were chlorotic, have had grey spots, leaf tips become dried. At concentration of 1000 ppm after 16 days rice seedlings stopped growth; - At lead concentration of 100 ppm, leaf tips have had yellow spots and at 1500 ppm leaves were become chlorotic and dried, rice seedlings stopped growth. At cadmium concentration of 10 ppm root system started under go negative effect and at 100 ppm rice seedlings were died. In the mean while conduced analysis of total and available contents of experiment soil samples for finding - out correlation between their contents in the soil and they effect to rice seedlings.

Effect of heavy metals (copper, lead) on earthworms (pheretima morrisi) and cabbage (brassica juncea)

Development of industrial, agricultural productions and handicraft activities have strongly affected on soil environment and caused soil pollution, especially by heavy metals. This study aimed to assess the effect of Cu2+, Pb2+ on growth of earthworms and cabbage: - Experiments were applied on alluvial soils of Red River Delta with three replication according to TCVN 5962-1995 (ISO 11269 - 1/1993). The copper, lead concentrations were applied: 0; 50; 100; 200; 500; 1000 ppm. The following results were find out. For earthworms: After 7, 14, 21 days, the effect of copper on earth worms were very evident. The more, the copper concentration, the more the effect. At concentration of 500 ppm, after 7 days, almost earthworms were deal, and at 1000 ppm the died totally; - Effect of lead on earthworms were not evident at all conducted concentration. After 7 days LC50 was found 2500 ppm; - The accumulation of Cu2+, Pb2+ after 35 days in the earthworms was increased with copper and lead concentrations used. At the same concentration, copper was accumulated more than lead one. For Cabbage: - Ter 7, 14,21 days copper effected considerably on plant height, root loony and leavers amount. After 7 days at concentration of 200 ppm root was become black, and after 14 days at concentration of 500 ppm appeared necrotic of the stems; - At lead concentration from 0 to 1000 ppm was not effected on growth of cabbage. At Pb2 concentration of 1300 ppm after 7 days, lead was effected on this cabbage.

Evaluation of land use effect and trend to use of cultivated land towards commodity agriculture in Gia Loc district, Hai Duong province

Gia Loc is district, which is popular in agricultural development with vegetable based croping systems. Vegetables give high economic value. In the future use types with 2 vegetable crops - 1 rice crop 1 will be expanded to maintain fertility of the soil for sustainable agriculture.

Impact of micro-organic fertilizers on alluvial rice soil in Dong Trieu, Quang Ninh

The objective of this study is to evaluate impacts on alluvial rice soil of apply two micro-organic fertilizers, one is from Song Gianh Company (Song Gianh fertilizer) and the other from Hanoi Agricultural University (Ha Noi fertilizer). The study was placed in Dong Trieu, Quang Ninh with amount of fertilizer application was 500 kg per ha. The study results indicated that: - Both these two fertilizers (Song Gianh and Hanoi fertilizer) increased rice yield to 8.2 and 12%, respectively; - Application of these fertilizers resulted in improving OM, total N, P, K and available P; - Quantity of inorganic fertilizers applied were reduced to 25 - 50% compared to control, but rice yield still remained; - Every 1000 VND for buying fertilizer, it gained a net-benefit in rice crop as 2840 VND for Song Gianh and 4680 VND for Hanoi fertilizer.

Increasing income hectare agricultural land in Yen Chau district, son La province

Yen Chau is a mountainous district of Son La. The territory of Yen Chau is 84,367 ha. In which 20.13% of the total area is agricultural land. The average income per ha of land is still low and not equally with its potential because of low land use rate and production efficiency. Therefore, in order to increase income per ha of agricultural land it is necessary to carry out and conducting solutions are as follows: Adjustment of land use planning; promoting extension service; building up production, model; improving skill for labour; applying new tecnology; improving infrastructure; mobilizing capital to invest in order to develop production; expanding output market.

Land use planning in Kon Plong district, Kontum province, Tay Nguyen area

Kon Plong is the one district of Kontum province. It is very important strategic area as the Northeast bordered with main economic area of Central of Vietnam (Quang Ngai and Quang Nam), West is Dakto, Dakha and Kontum town, East is Gia Lai province. The district is rich in land resource and area of natural forest covered most of the total area, which functioned as protector for some hydropower plants such as Yaly, Thach Nham etc. According to statistical year book, existing land used in 2002 is 106,0555.33 ha (77.6%) and the remaining unused land is 30,104.67 ha (22.11%). Even though, its economic and basic infrastructural conditions are still poor, population density is 12 persons/km2 with 98% of total population belong to ethnic minority groups. Land use planning up to 2010: Of the total natural area 136,160 ha, agriculture land will be 12,000 ha (8.23%), increases of 7645.66 ha; forest land will be 120,147.35 ha (88.24%) increase 18,216.35 ha, area for specific uses: 3,639.17 ha (2.36%) increase 3,233.66 ha; resident area 340.54 ha (0.25%) increase 176.06 ha; abundant land will reduce by 29,271.73 ha, equal to 832.94 ha (0.61%). Coefficient of land used in 2002 was 1.77 times and in 2010 it will reach 2.3 times.

Major characteristics of materials using in banana and pineapple nursery gardens

The results of study shown that different materials using in banana and pineaple nursery gardens have different physical and chemical characteristics. Among studied materirals, husk ashes are suitable to grow of banana and pineaple seedlings multiplied by cell plants. These ashes have the important characteristics as following: 1. Bulk density is 0.16 g/cm3, particle density is 1.04, porosity is 84.62%, equivalent to 14 and 15%, 36 and 35%, 1.34 and 1.45 times compared to Song Cau alluvial soils and red yellow soils respectively; 2. pHKcI is 7, organic matter is 7.58% ; while those of other materials are from 5.2 (pH) and from 0.58 to 1.29% (OM); 3. Available N, P, K are all higher to those of other materials; particular available P is as high as 30 mg/100g, while P of other materials is only from 1-10 mg/100g.

Morphological and geochemical characteristics of old-alluvial soils (OASs) in Vietnam

Study on OASs morphological and geochemical characteristics may gather some main problems: - OASs soil group is one of few other soil groups in Vietnam having the most variable, special and attractive morphologies, depend on microrelief, vegetations, production way, water regime... in the soils; - The superiority of Kaolinite and strongly clay decomposition and leaching decrease or dim out the presence of many 2:1 clays. Even Kaolinite can be also destroyed. Danger of being degenerated of the soils are very urgent; However, with the establishment of "climax-under forest", "climax-flooding"... combine with other technical and technological means in agriculture and forestery prodution. the OASs progressive evolution will be sustainable.

Nitrogen mineralization capacity as influenced by insecticide, fungicide and herbicide on soils of rice and upland crop

To determine the effects of pesticide and cropping systems on nitrogen mineralization capacity of soils, an experiment was carried out in laboratory. Top soils of intensive 3 rice and upland crop in Tien Giang province were collected, dried, and ground through 2 mm sieve then used as a medium for N mineralization under aerobic incubations. Inseticide Monitor 70 DD, fungicide Anvil 5 SC, and herbicide Sofit 300 ND were applied into soil samples at the normal rate. The total mineralized N of rice soils is higher than of soils of upland crop. However, percentage of mineralized N (on basis of total soil N) is lower and nitrification process occurs later in the soils of rice compared with the soils of upland crop. The insecticide Monitor lower down N mineralization process in the soils of upland crop, but no effect on rice soils. The fungicide Anvil lower down N mineralization in a short period in the soils of upland crop, but no effect on rice soils. The herbicide Sofit has no effect on both soils of rice and upland crop.

Organic carbon and nitrogen dynamic in the soils under tea plantations

This study was undertaken to quantify changes in OC and N in soils under long-term tea cultivation following forest clearance. Soil samples were collected at 0-10, 10-20, 20-40, 40-60 and 60-80 cm depth. Soil OC and total N contents decreased in response to cultivation with lowest OC and N total content occurring in the 40-yr-old tea soils. The decrease in OC and total N was greatest during the first 10 years of cultivation, reaching a steady state after 25 years of continous tea production. The changes in OC and total N were mainly at the surface 0-40 cm layer, but in subsoil layers (40-80 cm depth) there were exhibited no significant change during 40 years of tea cultivation. The decrease in OC resulted in increasing bulk density, decreasing mean weight diameter, plant available water capacity, and CEC.

Potassium and sulphur dynamic in the soils under tea plantations

This study was undertaken to quantify changes in K and S in soils under long-term tea cultivation following forest clearance. Soil samples were collected at 0-10, 10-20, 20-40, 40-60 and 60-80 cm deepth. Total soil K contents decreased in response to cultivation, whereas available K and total S increased or unchanged. The changes in K and S were mainly at the surface 0-40 cm layer, but in subsoil layers (40-80 cm deepth) there were exhibited no significant change during 40 years of tea cultivation. Fertilization has a great impact on soil properties. This is an important approach to maintain soil nutrients, especially, K and S content in the tea soils. It is neccesary to apply K fertilizers for tea cultivation. In the other hand, S element is already supplied to the soils during apply fertilizers containing S such as K2S04.

Quantitative investigation of the main groups of microorganisms and the yeast lipomyces in some soil samples from Me Linh, Vinh Phuc

Microorganisms have an important role in soil ecosystem. Based on their quantitative and qualitative investigation in different soil ecosystems, microorganisms can be used as a biological indicator and suitable measure should be taken into account improving quality of soil. Our experimental part focus on quantitative investigation of some main groups of microorganisms and the soil yeast Lypomyces in some hill soil samples. The result shows that the quantity & different groups of microorganisms is not too high, but there is no big difference between them. The yeast Lypomyces are found in all soil samples and their quantity is rather high. in top-hill and middle-hill soil samples, 100% soil particles are coagulated by extracellular polysaccharide of Lypomyces. This extracellular polysaccharide can be used in reducing transpiration evapotraspiration and raising soil moisture, so moisture-keeping product containing Lypomyces should be soon produced and applied in dry slopping land in Vietnam.

Soil physical and chemical degradation of citrus plantation in the Mekong delta

Making raised beds for cultivating fruit trees are necessary to avoid submergence due to high flood period in the Mekong Delta. Some selected chemical and physical soil properties were studied to clarify whether there are soil degradation and soil constraints of raised bed in citrus plantation. Six citrus plantations were selected in a range of 7, 9, 16, 26 and 33 years old raised bed. Experimental results showed that increasing the age of raised beds, soil degradation were clearly found. Raised beds of 26 and 33 years old have soil pH below 5, very poor in organic matter and phosphorus available, low total nitrogen and organic labile nitrogen, low base saturation. Zinc concentration was in a level of inadequate for the requirement of citrus plant. Soil penetration resistant of these raised bed was in a range of soil compaction. Water permeability in soil of old raised bed, 26 and 33 years, was low compared to raised bed of 7, 9, 16 years old. Therefore, soil raised bed from over 26 years old need to be improved of soil pH, soil nutrients and reclaimed soil compaction.

Some evaluations for irrigation water resources in agricultural land use of Kak Lak province

Dak Lak is the bigest province in Vietnam. Its total area of 1.959.950 ha. Many minority people are living here. The water resource for irrigation of Dak Lak province is very great. But, one of problems is poor management and lack of facility for providing effective water resource informations. At present time all irrigation water resousces at the studied area are satisfied only 30 - 40% of water supply demants agricultural development of a year.

Terrace rice in the Northern of Vietnam

Terrace rice is a construction levelling the slope land for rice cultivation. Comparing with the upland rice cultivation, the terrace rice has many advantages: erosion control, eliminating the fallow period, multiple croped, intensification as irrigated rice, high yield... Though 73% natural area of Vietnam is slope land but the terrace rice only concentrates on the mountainous region in the north side of Fansipan range (North Vietnam). The area of upland rice (slash and burn cultivation) decreases. There are many reasons: low yield, soil degradation, weed control, low cultivation factor, low income. Although terrace rice has so many advantages but the enlargement of its area in Vietnam for the last twenty years had been modest. The reasons may be high labor requirement for leveling, the competition of income between rice and other upland crops. However the food demand in the world is still increasing and the demand-suply equilibrium during the past decads maybe broken. In future, the leap of rice yield that had reached as in the "green revolution" of 1970s and 1980s is difficult in reatity The capacity for enlarging rice area in the palains had reached to limit, while the threat of global warming and of the higher frequeny of natural disaster. Therefore the enlargement of terrace rice area in the mountainous regions need to be more interested.

The application of some scientific and technological solutions to contribute soil environment improvement after eucalyctus exploitation in Lam Thao district, Phu Tho province

The frutis (litchi) has been growed after Eucatyptus exploitation applied some scientific-technologies by digging water resevoirs combining with green cover such as: Tephrosia candida, peanut, mueuna... The results of experiments indicated that green cover contribute to protection of soil from erosion, maintaining humidity and providing nutrient for fruit trees through left biomass.

The characteristics of soil and water environment in coastal zone warps of Nghia Hung district, Nam Dinh province

The article presents some results of field works, analyses and assessment for quality of soil, surface and underground water in coastal zone warps of Nghia Hung district, Nam Dinh province, achieved by the authors during the time from September 2002 to April 2003. The investment results proves that: local underground water is a large reserves and surface water in irrigation channels and aquaculture lagoons is being polluted by human production and social activities; coastal zone sea water has hight content of Cu, Zn, Fe: soil environment in interior fields is still unpoluted; soil environment in coastal zone warps is being polluted by heavy metals and pesticides.

The current status of using fertilizer for vegetables production in Dong Anh district, Hanoi

An experiment was carried out in Dong Anh district, results showed that: Animal manure was used with 11 to 14 ton per ha. It's only 55 -70% of standard. But N fertilizer was using higher than standard about 2,5 - 4 times. However, P and K fertilizers only lower than standard. Results indicated that: NO-3 in vegetables higher than standard 2-3 times.

The effects and residual effects of phosphorus fertilizers for peanut grown on rhodic ferralsols in Tay Nguyen

Soil phosphorus is considered a yield-limiting factor of peanut (Arachis hypogaea) grown on rhodic ferralsols, which is rich in total P but poor in available P. So application of P to peatnut is one of the best farm management practices to increase peanut yield. On the rhodic ferralsols, generally, the effects and residual effects of fused magnesium phosphate (FMP) for peanut were higher than those of superphosphate (SSP). The average fertilizer efficiency of FMP was 7.71 kg dried pod per 1kg P2O5 applied that was larger than that of SSP (6.79kg dried pod peanut). The peanut yields obtained one year after one year of application of SSP (T2-1) and FMP (T3-1) were not significant differences from the control treatment (P - omission). However, after two years of P addition, trpatments T2-2 and T3-2, the residual effects of SSP and FMP on the growth, development and yield of peanut were recorded in two years later and these parameters significantly differed from the control treatment (T1) and only one year P applied treatments (T2-1 and T3-1). General speaking, it is better to apply phosphorus fertilizer in the forms of FMP for peanut grown on Rhodic Ferralsols than SSP.

The effects of coffee pulp/husk application to robusta coffee grown in rhodic ferrasols in Tay Nguyen of Vietnam

Coffee pulp/husk is very abundomt in the coffee-producing provinces through raw processing of coffee cherries. The data obtained from analysing coffee pulp/husk shown that there were 1.85 kg N, O.19 kg p2O5, 3.56 kg K2O and O.37 kg S contained in 100kg of dried coffee pulp/husk. So application of this matter to the coffee farm not only improved soil fertility and soil structure but also released a considerable amount of nutrients to provide for the crop. On the other hand, this matter can be used as a material to cover soil surface of coffee farm during the dry season in order to reduce water loss through evaporation. The application of about 6000 kg of coffee pulp/husk per hectare per year can reduce the amount of chemical fertilizers used by 28 N, 8 P2O5 and 42 K2O compared to those of the pulp/husk-unapplied coffee farm (V1). The coffee yield of the pulp/husk-applied coffee farm as the same as yield of the coffee farm with 1200 kg FYM mixed with 1600 kg pulp/husk applied to one hectare per year. The coffee pulp/husk should be used as a type of organic fertilizer for coffee farms.

The environmental effect of using wood land in Hoanh Bo district, quang Ninh province

The most land in Quang Ninh is the wood land or clearing land and land for agriculture is not much (less than 10 %). The article above shows the active role of the dense vegetation which covers the land. It also gives an overal view of the variety of botanical composition and physical - chemical properties of soil under impact of humans. Valueing the effect of using various kinds of vegetation is based on generation of vegatation and physical - chemical properties of soil which are considered as criteria to measure the levels of environmental degeneration.

The situation and solution to use sloping land in Dia Linh, Ba Be district, Bac Kan province

Dia Linh is a mountainous commune of Ba Be. In Dia Linh still exiting subsistence production system with the feature is shifting cultivation (slash and burn) which is mix with new and model system. There are many challenges in the area have to solve such as misuse of sloping land had led to strong soil erosion and negative impact on environment. To find out the model cultivation system, which bases on the traditional cultivation methods and suitable to the capacity and condition of farmer is necessary for the area. The solutions for more benefit using of sloping land are as follow: guide the farmer to choose the suitable cultivation system on sloping land, increasing using of new technologies, expanding output market, improving infrastructure, promoting capital to invest for production and soil erosion control.

Using organic manure derived from sugarcane residue to improve crop yield

Enormous amount of waste residue (filter residue) from sugar factory has been polluted for the environment surrounding. Experimental results showed that the rate of composting of this material was enhanced by mixing with sugarcane dregs with ratio of 1:1. After one month, the nutrient quality of this compost was rather high compared to other materials and it was decomposed stably. Application of 10 Mg.ha-1 of this compost in combination with inorganic fertilizer resulted in increasing double of maize biomass grown in pots. Therefore, filter residue derived from sugar production of factory can be used efficiently as organic manure to improve upland crop yield, improve soil properties and minimize environmental pollution.

Verifying the role of water superabsorbent polymers on several properties and productivity of winter crop in degraded soil area

The water superabsorbent polymers applied in degraded soil area of Soc Son improved some chemical and physical properties of soil, increased water holding capacity, maintained soil moisure and agregation. They increased sorption capacity of potassium of soil and phosphorus displacement. Water superabsorbent polymers at a rate of 50 kg/ha, provided plants with better growth and higher yield. The productivity of dry seed increased 23% for peanut, 20% for soybeans, 11% for corn.