Improving of soil carrying capacity for better living.

Soil is the most important resource for food production. The increase in world population puts pressure on the soil resource to continuously provide food security for the population. The per capita arable land is 0.22 ha per capita and it is expected to reduce due to population increase, land degradation processes and competition for non-agriculture land use. The agricultural sector has been successful to continuously supply food for the growing population. This is brought about by the green revolution resulting from technological improvement through advancement in scientific knowledge. With more constraints and greater challenges the agriculture sector requires more efficient and productive technology. Since horizontal increase through expansion of arable land is restricted the increase in food production has to be achieved vertically by increasing soil productivity. The use of fertilizer for improvement of soil productivity is one of the widely practices worldwide. The use of fertilizer has no doubt increased the soil productivity; however it has also created serious environmental problems. As an example, the efficiency of N fertilizer is often low due to losses and the N that leaks to the environment causes serious environmental problems such as ground water pollution, emission of greenhouse gases, eutrophication and nitrate pollution. For sustainable fertilizer management, the loss has to be minimized to subsequently increase fertilizer efficiency. Application of balanced plant nutrients had been shown to increase soil productivity. Addition of small amount of micronutrients in certain soils can result in tremendous yield increase. Other technologies that increase soil productivity and reduce its degradation will enhance the soil carrying capacity. The public awareness on the importance of soil resource for food production and human survival should be provided through the education system. Research for public good on sustainable soil management must be given top priority alongside the market driven research, to ensure the agriculture sector continues to supply us with food from the growing population

Ammonia Volatilization from Malaysian Soils Following Application of Urea

Surface application of urea often results in high ammonia volatilization loss. Information on ammonia volatilization in tropical acid soils is limited. This study was carried out to determine ammonia volatilization loss from surface applied urea in Malaysian soils and to study the ejects of soil properties on the rate of loss. Measurement of urease activity and ammonia volatilization loss in the laboratory was carried out on topsoil (0-15 cm) of 22 soils commonly found in Malaysia using a force-draft technique. Ammonia volatilization loss was recorded daily for seven days. Ammonia volatilization loss from the 22 soils studied ranged from 0.5 to 53% of N applied with most soils having values around 35 %. The ammonia loss in acid sulfate soil was low. Most of the loss occurred during the first 34 days after urea application. The urease acitivity of soils ranged from 12.20 to 150.50 uglg Nih and was not affected by soil texture and C content. Urease acitivity had a significant e1Ject on ammonia volatilization los

Recovery of Field-Applied Fertilizer Nitrogen by Rice

Field estimation of the recovery of fertilizer N applied to rice COryza sativa L.) was carried out as an appraisal of the prevailing fertilizer management practice. The study was carried out on a farmers field for two growing seasons. Soil samples at three depths, 0-15 cm, 15-30 cm and 30-45 cm and water samples were collected every two weeks during the growing season. The plant recovery of fertilizer N was estimated by the difference between the N treated plots and the controls. Although this method could overestimate the fertilizer N recovery due to priming effect, under the conditions in the study the effect was assumed to be minimal. An increase in ammonium N content in the soil was not observed even immediately after N application. The removal of fertilizer N from the soil through either plant uptake or loss processes was very rapid. Higher ammonium N was only detected in the water samples early in the growing season but not at the mid-season after the second N application. The recovery of fertilizer N in the plant were 36% and 30% during the main and off-seasons respectively. Most of the N was in the grain. About 69 kg of the 95 kg of the total N removed by the crops per hectare was derived from the soil. More than 64% of the fertilizer N applied was either lost or immobilized in the soil

Effect of Air-Flow Rates on Laboratory Measurement of NH3 Volatilization

The effect of air-flow rates on the volatilization loss of NH3 from urea was studied on two soil types. In both soils, the volatilization loss increased with increasing air flow rates up to 14 volume/min. Further increase in air-flow rate to more than 14 volume/min. did not significantly increase volatilization loss ofNH3" It is suggested that volatilization loss should be measured at an air flow rate of14 volume/ min

Effects of water management on nitrogen fertiliser uptake and recovery efficiency in rice

A planthouse experiment was carried out to determine the uptake and recovery efficiency of nitrogen fertilizer applied to rice varieties, MR 84 and Siam, grown under flooded, non-flooded (NF)-saturated and NF-field capacity water management conditions. The total nitrogen uptake and nitrogen fertilizer uptake of rice were higher under flooded and NF-saturated than under NF-field capacity condition irrespective of rice varieties. On average, the recovery efficiency of applied nitrogen fertilizer was 47.7, 43.2 and 30.4% under flooded, NF-saturated and NF-field capacity conditions, respectively. Recovery efficiency of applied nitrogen fertilizer was higher for MR 84 than Siam regardless of water management treatments. Recovery efficiency of nitrogen fertilizer from soil was 26.1, 26.9 and 18.5% for flooded, NF-saturated and NF-field capacity conditions, respectively. On the contrary, under NF-field capacity condition, the amount of nitrogen fertilizer losses from the plant-soil system was the highest (51.1%), followed by NF-saturated condition (29.9%) and flooded condition (26.2%)

From the soil to the table

Soil is the most important resource for food production. The increase in the world population puts pressure on the soil resource to continuously provide food security for the population. The per capita arable land is 0.29 ha per capita and it is expected to reduce due to population increase, land degradation processes and competition for non-agriculture land use. The agricultural sector has been successful to continuously supply food for the growing population. This is brought about by the green revolution resulting from technological improvement through advancement in scientific knowledge. With more constraints and greater challenges the agriculture sector requires more efficient and productive technology. Since horizontal increase through expansion of arable land is restricted the increase in food production has to be achieved vertically by increasing soil productivity. The use of fertilizer for improvement of soil productivity is widely practiced and N fertilizer is the most important fertilizer use world wide. The use of N fertilizer has no doubt increase the soil productivity; however it has also created serious environmental problems. The efficiency of N fertilizer is often low due to losses through denitrification, volatilization, and leaching and clay fixation. The N that leaks to the environment causes serious environmental problems such as ground water pollution, emission of greenhouse gases, eutrophication and nitrate pollution. For sustainable N management, the N loss has to be minimized to subsequently increase N fertilizer efficiency. Co-applying urea with selected cations, micronutrients and urease inhibitors can effectively improve urea efficiency. It was also shown that rice yield was not affected when irrigation was applied only at soil saturation level instead of continuous flooding at 5-10cm as currently practiced. Thus, potentially, tremendous amount of irrigation water can be saved and more area of land can be used for rice production .The public awareness on the importance of soil resource for food production and human survival should be provided through the education system. Research for public good on sustainable soil management must be given top priority alongside the market driven research, to ensure the agriculture sector continue to supply us with food from the soil to the table

Response of non-flooded rice to nitrogen rate

Nitrogen and water supply are important factors that influence rice growth and yield. The grain yield response to N application rate was significantly quadratic in nature irrespective of water management practices. A higher yield response to N application rate was observed under flooded as compared to non-flooded (NF)- saturated and non-flooded (NF)-field capacity conditions. The estimated N rates for maximum yield were 99, 105 and 126 kg/ha for flooded, NF-saturated and NF-field capacity conditions, respectively. The higher amount of N needed for maximum rice yield under NF-field capacity conditions was probably due to greater N losses as a result of alternate wetting and drying of soil as well as the reduced root system. However, the optimum N rate for maximum yield did not differ very much between flooded and NF-saturated conditions indicating the close similarity in N requirement under both water management practices. The dry shoot biomass response to N rate was quadratic but it was not significant under flooded and NF-saturated conditions. However, a significant quadratic response was observed for dry root biomass under flooded and NF-saturated conditions. The dry shoot and root biomass response to N rate was significantly linear under NF-field capacity conditions

Role of zinc in plant nutrition- a review

Zinc is plant micronutrient which is involved in many physiological functions its inadequate supply will reduce crop yields. Zinc deficiency is the most wide spread micronutrient deficiency problem, almost all crops and calcareous, sandy soils, peat soils, and soils with high phosphorus and silicon are expected to be deficient. Zinc deficiencies can affect plant by stunting its growth, decreasing number of tillers, chlorosis and smaller leaves, increasing crop maturity period, spikelet sterility and inferior quality of harvested products. Beside its role in crop production Zn plays a part in the basic roles of cellular functions in all living organisms and is involved in improving the human immune system, due to its insufficient intake, human body will suffer from hair and memory loss, skin problems and weakness in body muscles

A 15N tracer study to evaluate the effects of nitrogen and copper fertilization on fertilizer nitrogen efficiency in rice production

In the study of the effects of nitrogen and copper fertilization on rice yield when four rates of N (0, 60, 120 and 180 kg N/ha) as 15N labelled urea and three rates of Cu (0, 5 and 10 kg Cu/ha) were applied, grain yield increased significantly with increasing N rates upto 120 kg N/ha. The recovery of fertilizer N was around 40% irrespective of N and Cu rates. Copper application at 10 kg/ha increased grain yield by 0.53 t/ha insignificantly. Cu content in the straw was below the critical deficiency level of 6 mg/kg. Thus higher rate of Cu fertilizer (above 10 kg/ha) in soil increase rice yield and fertilizer N efficiency if Cu is applied as basal. Alternately, Cu may be applied as foliar spray on standing crop to avoid Cu adsorption in the soil