Evaluating the Cu and Zn status of various rice soils of Peninsular Malaysia

Malaysia is taking efforts to be self.sufficient in rice production. However, the country is facing low availability of Cu and Zn in its soils. Even though these elements are required in small quantities for normal plant growth, their role in maximising yield is very impressive. The present study was conducted to assess the micronutrient Cu and Zn contents in selected paddy soils of Malaysia. Investigations carried out showed that marine alluvium [Guar, Sedaka, Keranji, Kuala Kedah, Kangkong, Sedu, Rotan and Kundur (Kedah)] and reverine alluvium; [Chempaka, Lubok Itek, Lating, Batu Hitam and Machang soil series (Kelantan)] were low in Cu and Zn contents. All soils were acidic in nature, with their pH values ranging from 4.3 to 6.5. Based on the results, extractable Cu and Zn concentration of soil varied within the range of 0.09.1.70 and 0.51.2.10 mg kg-1 in the soil series of Kuala Kedah and LubukItek, respectively. It was manifested that the micronutrient contents were below the critical level (Cu 0.1.1.0 mg kg-1 and Zn 0.5.3.0 mg kg-1)according to the method of extracting analysis; Mehlich.I. The sampling depth has shown a variation and the subsurface soil sampling exhibited lesser Cu and Zn contents as compared to the surface soil sampling. Findings of the research indicate that micronutrient deficiency occurs in the main rice regions of Malaysia, and this can be corrected by applying micronutrient fertiliser

Consequences of Cu and Zn coated urea to minimize ammonia volatilization

Nitrogen (N) losses from agricultural fields are commonly observed particularly from urea. The rate of urea hydrolysis is accelerated as it remains in conventional form and about 70% of applied urea losses in different forms to atmosphere. Ammonia volatilization is persuasive loss among all the losses from urea. Therefore to minimize ammonia (NH3) volatilization the micronutrient coated urea is applied to enhance N-efficiency and its uptake. This study is an application of micronutrient coated urea with zinc (Zn) and copper (Cu) for two soil series of Malaysia. A laboratory experiment was designed according to the force draft technique for trapping the NH3 loss. The results have manifested that the rate of ammonia volatilization was 16% from uncoated urea and 8% from coated urea with micronutrients during the first two weeks of observations. After the six weeks of observations it was perceived that the ammonia losses for both soil series were gradually decreased with time. The mean comparison by using Tukey’s range test has shown the positive effect of micronutrient coated urea in comparison with the conventional urea. However the urea coated with the combination of both micronutrients Cu and Zn has shown significant difference in contrast to the coating urea with single micronutrient. The overall results revealed the efficacy of micronutrient coated urea on both of the soil series to maximize N-uptake and reduce NH3 volatilization

Effects of Cu and Zn coated urea on rice production in acidic and alkaline soils

Acidic soils of Malaysia and alkaline soils of Pakistan are in incidence of micronutrient insufficiency. Despite of that urea is considered as the most broadly used nitrogen (N) fertilizer. Unfortunately, its application is associated with losses such as emissions of ammonia (NH3) and nitrous oxide (N2O) gases. In couple to the economic loss, such N losses may threaten atmospheric quality and results in poor plant synchrony. Application of both urease and nitrification inhibitors is encouraged as an approach to mitigate these gaseous losses. The rate of urea hydrolysis is accelerated as it remains in conventional form and about 70% of applied urea losses. Ammonia volatilization (NH3) is a substantial loss of urea. Therefore, to minimize NH3 volatilization and to supply the adequate Cu and Zn was the major aim of this research. Copper and Zn status were evaluated in selected paddy soils of Malaysia and Pakistan. Based on the results, Kuala Kedah and Chempaka soil series were below the critical level (Cu 0.1-1.0 mg kg-1 and Zn 0.5-3.0 mg kg-1) according to the method Mehlich-I in Malaysia, whereas in Pakistan Rustum soil series was below the critical level on Zn ( AB-DTPA 0.5 mg kg-1). Soils deficient in Cu and Zn were selected for this current study. The research was based on trials conducted at: (1) laboratory; (2) glass house; and (3) field conditions. Copper and Zn coated urea was prepared manually, where micronutrient fertilizer sources copper sulphate (3 and 5 kg ha-1) and zinc sulphate (7 and 10 kg ha-1) were used. Palm stearin was used as coating material to overlap Cu and Zn on urea. The specific aims of this study were to evaluate the effect of Cu and Zn coated urea on: (1) NH3 volatilization loss; (2) yield components of rice under acidic and alkaline soils; and (3) fluctuation of soil Eh and pH. In this regard a laboratory study was conducted on two acidic soil series of Malaysia. Results revealed that 50% less NH3 volatilization loss was observed under Cu and Zn coated urea treated soils as compared to common urea. After the positive results found in laboratory testing of Cu and Zn coated urea, a glass house study was designed to evaluate its effect on rice and Cu and Zn availability. Copper (3 and 5 kg ha-1) and Zn (7 and 10 kg ha-1) either alone or in combinations were applied as surface application or coated with urea followed by recommended doses of P and K (70 kg ha-1). Results manifested that Cu and Zn coated urea controlled fluctuating pH, Eh and facilitated Cu and Zn availability. The Cu and Zn had positive effect on growth, yield and nutrients concentration in rice plants. There was 40.9% yield increment over control under acidic soils. To confirm the results of glass house, a filed study was conducted on alkaline soils of Pakistan. Copper and Zn were applied all in coated form either alone or in the combinations (Cu3, Cu5, Zn10 and Zn15 kg ha-1) followed by the recommended doses of P (70 kg ha-1) and K (50 kg ha-1). Copper and Zn coated urea showed the positive response on the growth and yield of rice (50% grain yield increment was obtained over control). Coated urea increased the Cu, Zn and N contents in soil and plants

Consequences of micronutrient coated urea for maximizing N-uptake

Nitrogen (N) losses from agricultural fields are commonly observed particularly from urea. To minimize ammonia (NH3) voltalization the micronutrient coated urea is applied to enhance N-efficiency. This study is an application of micronutrient coated urea with zinc (Zn) and copper (Cu) for two soil series of Malaysia. A laboratory experiment was designed according to the force draft technique for trapping the NH3 loss. The results manifested the rate of ammonia voltalization is 16% for uncoated urea and 8% for coated urea with micronutrients during first two weeks of the observation. It was observed that the ammonia loss gradually decreased with the time for both soil series. The mean comparison has shown the positive effect of Zn and Cu coated urea in comparison with the other treatments. The overall results revealed the efficacy of micronutrient coated urea on both soil series to maximize N-uptake and reduce NH3 voltalization