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%)

Traceability approach for managing changes involving software testing artefacts

Software change is inevitable for software product to remain relevant and reusable. As software evolves over time due to specific changes at any point in time during software development and maintenance, the managing aspect of changes may get more complicated and risky. The outdated links would cause the affected artefacts to be not updated timely and effectively. Most of the existing traceability approaches and tools are dedicated and limited to high level artefacts such as requirements and fewer capability made available to address the lower level artefacts such as classes and codes. Most maintainers limit their links to begin at the requirement perspective but there is no valid traceability link being made to support the fine grained level involving testing components. This thesis proposes a new traceability approach to manage changes with the emphasis on the integration of the development artefacts and testing artefacts. The working artefacts cover requirements, packages, classes, methods, test case, and codes. The proposed approach provides a know-how solution to the IEEE 829:2010 standards associated to testing that demands for the support at testing perspective. This approach has the capability to horizontally and vertically manage artefacts from requirement down to code and vice versa. The proposed traceability approach was applied to a case study of a software development project called On- Board Automobile (OBA) with a complete set of documentation including test cases. The evaluation results prove that the proposed traceability approach is significant and useful in managing software changes involving testing artefacts

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

Concepts in waste management: A preliminary study

This paper aims to discuss and highlight the basic concepts in waste management studies. Effective MSW management consists of a mix of policy instruments to achieve the policy objectives. Understanding the factors that have effects on public pro-environmental attitudes and behavior is important for helping decision makers to strengthen the existing policy frameworks for the future. Ensuring successful implementation of recycling and waste separation at source requires high participation from the household. Thus, this paper will discuss the relevant concepts in waste management studies that are relevant to assess the waste separation behavior from the socio-psychological model perspective. Understanding the factors that influence public waste separation behavior is useful to strengthen the existing policy framework

Effects of elemental sulphur application rates on soil Al3+ solubility and its concentration in maize plants (Zea mays L.)

A greenhouse experiment was conducted to elucidate the influence of soil acidification due to application of different doses of elemental sulphur (0, 0.5, 1.0 and 2.0 g S kg-1 soil) on Al3+ solubility at 0, 20 and 40 days after incubation. Maize plants were grown after soil treatment with the elemental S and were allowed to grow for 45 days. The results showed that addition of elemental sulphur significantly increased the soil acidity; each g S decreased soil pH for 1.52 units. The Al3+ concentration in soil remained rather unchanged from the pH value of 7.3 to around 5 and experienced a 22000-time increase at the pH value of 4. Soil acidification from the background of 7.03 to 6.29 resulted in 41.83% increase in root Al3+ concentration and it was not significantly affected with further soil acidification. Soil acidification progressively decreased Al3+ concentration in the stem but it failed to affect Al3+ concentration in the leaves. The optimum rate of sulphur for maize without the risk of Al3+ toxicity under greenhouse conditions was 0.82 g S kg-1 soil. Further evaluation under field conditions is required

Effect of elemental sulphur timing and application rates on soil P release and concentration in maize

High pH soil accounts for more that 30 percent of world's soils and poses problems to plant nutrient availability. As a cheap and readily available source of soil acidulates, elemental sulphur may be a useful material for alleviating some alkaline soil problems. To elucidate the role of elemental sulphur as a soil amendment for plant production in a high pH soil, maize plants were grown under greenhouse conditions for 45 days after 0, 20 and 40 days of soil incubation at different rates of elemental sulphur (0, 0.5, 1 and 2 g S kg-1 of soil). Soils were sampled two times (before and after planting) and subjected to soil pH and available P determination. The results showed with each unit increase in S rate, soil pH decreases by 1.52 units. In addition, while sulphur application increased available P before planting, it failed to increase P supply to maize at harvest. Supporting the role of elemental S on soil P availability, with increasing S application rate the P concentration in maize root, stem and leaves was successively decreased. This relationship can be explained by the dilution of P in increasing leaf biomass and the similar concomitant increase of both zinc and manganese nutrient concentrations with increasing sulphur application rate. Overall, soil acidification by elemental sulphur application resulted in P reduction in soil labile pools and intensified P deficiency in maize

Application of boron and zinc in the tropical soils and its effect on maize (Zea mays) growth and soil microbial environment.

An experiment was conducted at glasshouse of Universiti Putra Malaysia with boron (B) and zinc (Zn) deficient soil (Serdang series) to evaluate the effect of B and Zn on maize crop and the behavior of soil microbial communities with various levels of boron and zinc. Among the six tested soil series, Malawi soil was found the most deficient in boron (0.06 ppm). Four levels of B from Borax as 0, 0.5, 1.0, and 1.5 kg ha -1 and two levels of Zn from Zinc Sulphate, 0 and 5 kg ha -1 were applied. The highest plant height (109 cm), root length (30.67 cm), leaf area index, chlorophyll content, shoot (5.38 g) and root dry weight (0.23 g) were obtained at B 0.5 + Zn 5.0 kg ha -1 treatment. The interaction effect between boron × zinc in the soil was significant. Antagonistic effect occurred for B uptake at higher rates of B with 5 kg ha -1 of Zn application. The addition of B at lower level alone or in combination with Zn significantly increased soil bacterial population. The highest rhizosphere bacterial population was found at B 0.5 + Zn 5 kg ha -1 treatment. The addition of B 1.0 kg ha -1 with zinc Zn 5 kg ha -1 showed a toxic effect on soil bacterial population. Although B produced substantial biomass yield increment with extended rates, the excess amount caused toxicity in the soil bacterial environment. It can be concluded that 0.5 kg ha -1 of B in combination with 5 kg ha -1 Zn can exhibit higher yield of maize and is friendly to this particular soil environment

Field evaluation of newly-developed controlled release fertilizer on rice production and nitrogen uptake

Implementation of sound fertilizer management in rice cultivation is essential in optimizing productivity and profitability. The use of controlled release fertilizer (CRF) to improve crop production in various cropping systems has been widely explored, with new approaches and materials continually being studied to produce new CRF. A field study was carried out to determine the efficiency of local CRFs on rice production and N uptake using MR220 CL1 rice variety. Ten different types of CRFs consisting of two groups namely biochar impregnated urea (BIU 300-5, BIU 300-10, BIU 700-5 and BIU 700-10) and palm stearin (PS) coated urea with nitrification inhibitors (PS, PS+DMPP-100, PS+DMPP-50, PS+DMPP-150, PS+Cu and PS+Zn) were used as treatments. Plant height, SPAD reading, 1000-grain weight and harvest index (HI) showed significant improvement in rice treated with both biochar impregnated and palm stearin coated urea. With respect to grain yield, BIU 300-10, BIU 700-5, BIU 700-10, PS+DMPP-100, PS+DMPP-50, PS+DMPP-150 and PS+Cu treatments significantly increased rice yield. The CRFs mostly showed significantly higher N uptake in rice, especially in rice grains, however, there was no significant difference among treatments in soil residual ammonium (NH4+-N). The newly-developed CRFs showed huge potential as an alternative for common urea, especially BIU 700-5, BIU 700-10, PS+DMPP-100 and PS+DMPP-50, in increasing rice grain yield. With proper approaches, these CRFs can contribute in improving rice production to provide sufficient food for ever increasing population

Rice growth and nitrogen uptake as influenced by water management

Rice (Oryza sativa L.) is grown in Malaysia mainly under flood irrigation. As water becomes increasingly scarce, demand for available water from urban and industrial sectors is likely to receive priority over irrigation. It is, therefore, necessary to adopt rice production practices that reduce water input without any adverse effects on rice growth and yield. A greenhouse study was conducted to evaluate the effects of water management practices on the growth and nitrogen (N) uptake of rice. The three water management practices studied on rice variety MR 84 and Siam were flooded, non flooded (NF)-saturated and NF field capacity. Nitrogen in the form of 15N-labelled urea (2.52% atom excess) was applied at a rate of 100 kg ha-1 in three splits. Tiller production, plant height, root growth and grain yield were adversely affected when rice was grown under NF-field capacity soil condition. Grain yield was 57.6 and 54.4% lower under NF-field capacity than flooded and NF-saturated soil condition , respectively. The lower grain yield from NF-field capacity soil resulted from few panicles, less spikelets per panicle and lower 1000-grain weight. However, maintaining soil at a NF-saturated level did not seriously affect rice growth. Rice growth, grain yield and N uptake from NF- saturated soil were comparable to rice grown under flooded condition. A lower nitrogen uptake and fertilizer N recovery under NF-field capacity were attributed to smaller root system, lower above-ground dry matter yield and greater N losses from alternate wetting and drying soil condition. These results showed that irrigated rice could be grown under reduced water input at saturated soil condition throughout the growth period without affecting growth, N uptake and yield

Effects of copper, nickel, and its alloy as catalysts for graphene growth via chemical vapor deposition method: a review

Enormous characteristics exhibited by two-dimensional carbon-based nanomaterial, graphene attract current researchers in integrating this advanced material into the development of next-generation electronic, optoelectronic, photonic, and photovoltaic devices. The ultimate aim was to synthesis a single layer of graphene with large-size domain with less defect formation. The solid state of the graphene promises ultra-high performance in the devices due to ultra-high electron mobility. Within a decade, previous researchers have narrowed down their studies by applying different types of metal species as catalyst substrate in chemical vapor deposition method. The crucial part was to determine the characteristics of carbon precipitation and diffusion onto the metal surfaces. Each metal-based catalyst and its alloy revealed different behavior according to its carbon solubility and intrinsic properties. Until now, copper, nickel, and its alloy combination provide tremendous finding in the synthetization of graphene. Currently, researchers are still exploring the ideal parameters related to feeding gases, growth temperatures, and working pressures which are essential to each catalyst metals characteristic such as copper, nickel, and its alloy