Christopher B.S. Teh

Universiti Putra Malaysia | UPM · Department of Land Management

Plant height is a key indicator of healthy growth. Given the role of soil texture in productivity, the effects of sand, silt, and clay on the height and diameter of oil palm (OP) were investigated. In the four OP plantations, measurements of total and trunk heights and trunk diameters were taken from two OP clusters: tall and short. A Pro II Laser...

Most asbestos-related studies have focused on asbestos exposure risks, their associated health implications, and waste management issues. Our research introduced a unique perspective that has rarely been explored: the impact of environmental factors on asbestos cement products. The novelty of the study is that, in contrast to previous research, in...

Oil palm is commonly replanted once reaching the end of its productive lifespan. This cyclical planting practice in oil palm plantations could have long-term implications for the humification and properties of tropical peat soil. This study aimed to investigate the changes observed across successive generations of oil palm plantations in Sarawak, M...

Oil palm model for a wide range of planting densities and soil textures in Malaysian growing conditions. For latest updates, please visit the model's Github repo.

This chapter is a collection of selected abstracts presented at the 10th Asian-Australasian Conference on Precision Agriculture, held from October 24th to 26th in Putrajaya, Malaysia. It aims to emphasize the transformative potential of technology in precision agriculture and smart farming. The featured studies highlight the transformative impact o...

A semi-mechanistic oil palm growth and yield model called Sawit.jl was developed to account for a wide range of planting densities and soil textures under Malaysia’s climate conditions. The model comprises components related to meteorology, photosynthesis, energy balance, soil water content, and crop growth. The model simulates instantaneous meteor...

A semi-mechanistic oil palm growth and yield model, called Sawit.jl, was developed to account for a wide range of planting densities and soil textures under Malaysia’s climate conditions. The model comprises components related to meteorology, photosynthesis, energy balance, soil water, and crop growth. The model simulates instantaneous meteorologic...

Washed rice water (WRW) is the leftover water after washing rice grains and is usually discarded. However, WRW contains nutrients leached from rice, making it a potential plant fertilizer. Reusing WRW promotes better water governance, particularly in the face of increased freshwater needs due to population expansion and climate change. Recent exper...

This is a review paper about mitigation measures of land degradation in Malaysia. Land degradation in Malaysia is caused by the extreme amounts of seasonal rainfall, which severely affects the non-vegetated areas (particularly hilly sloping land), resulting in severe soil erosion. The chapter initially explores the types and causes of land degradat...

Washed rice water (WRW) is often used as liquid plant fertilizer. However, there is no study on nutrient leaching of soils due to frequent WRW application. Therefore, a column study was undertaken to evaluate the rate of nutrient leaching losses, nutrient retention, and recovery of elements in leachates of three different soil textures irrigated wi...

The wastewater after washing rice grains is known as washed rice water (WRW). WRW is often recommended for reuse as plant fertilizer, but little is known about the difference in the nutrient and microbial contents of WRW between white and brown rice. The study aims to answer this question and determine how much the nutrient contents in the WRW woul...

The sprinkler irrigation system is the most widely used system for rubber irrigation in a nursery. However, the method is associated with high water loss during irrigation. In view of this, an experiment was conducted to assess the effect of different irrigation systems on the growth dynamics, leaf ratio analyses, water productivity, and water use...

Plant growth is referred to as the irreversible changes with time which are mainly in size, often in form, and occasionally in number (Hunt, 2012). Plant growth quality and quantity depend on cell division, differentiation, and enlargement, which are ultimately affected by water stress (Correia et al., 2001; Cabuslay et al., 2002). Water stress als...

The benefits of washed rice water (WRW) as a plant fertilizer, particularly over a consecutive application period, are not well studied. An experiment was therefore carried out to determine: the continuous effects of applying unfermented (F0) and 3-day fermented (F3) WRW on the: (1) soil chemical properties, soil bacterial count, and the growth and...

Recent advances in oil-palm breeding and agronomic practices may have influenced the dry-matter production and nutrient demand of tenera oil palm since the last comprehensive studies published some three decades ago. This has raised concerns, since updated knowledge of nutrient requirements at various stages of oil palm growth is essential for form...

Supplementary data to "Standing Biomass, Dry-Matter Production, and Nutrient Demand of Tenera Oil Palm", 2022, Agronomy

Conversion of native lands into agricultural use, coupled with poor land management practices, generally leads to changes in soil properties. Understanding the undesirable effects of land-use and land-cover (LULC) changes on soil properties is essential when planning for sustainable land management. This study was conducted in Al Jabal Al Akhdar re...

Sixty frequently asked questions (FAQ) on gardening are answered by an agriculturist. This book is written for two purposes. First, it is to fulfill a need by gardeners who wish to understand how better to manage their gardens to have healthy and thriving plants. And second, it is to educate gardeners not only on the mechanics but also on the scien...

Washed rice water (WRW) is said to be a beneficial plant fertilizer because of its nutrient content. However, rigorous scientific studies to ascertain its efficiency are lacking. The purpose of this study was to determine the effect of fermenting WRW on the bacterial population and identification, and to measure how fermentation affects the nutrien...

The wastewater from washed rice water (WRW) is often recommended as a source of plant nutrients in most Asian countries, even though most current research on WRW lack scientific rigor, particularly on the effects of rice washing intensity, volumetric water-to-rice ratio (W:R), and condition of the WRW before plant application. This research was thu...

Recently, washed rice water (WRW) is used as plant fertilizer particularly in Asian countries. However, the current findings failed to analyse the microbial content of WRW that could be found as a result of fermentation. The objective of the study was to determine nutrient and microbial content of washed rice water (WRW) from white rice (WR) and br...

Sprinkler system of irrigation is the conventional method of irrigating rubber seedlings in nursery. However, the main disadvantage of the system is, it wastes higher amount of water during irrigation and water is expensive nowadays. Given an experiment was carried out to assess the effect of irrigation systems on plant growth and leaf ratio analys...

A significant wastewater source in every household is washed rice water (WRW) because it contains leached nutrients (from washing the rice prior to cooking) that could be used as fertilizer. The paper reviewed the current understanding of the potential use of WRW as a plant nutrient source. WRW was shown to increase vegetables growth, such as water...

The under-utilized legume Mucuna bracteata is a potential biomass resource in Malaysia. A 24-month study was conducted under 10-year-old mature oil palm trees to determine the effects of several harvesting frequencies of M. bracteata on the legume biomass and soil properties. The experimental design was a randomized complete block design (RCBD) for...

This study analysed the net rainfall components under different ages and leaf area index (LAI) of the oil palm to determine the contribution of net rainfall towards water requirements of the palm. We hypothesised that older palms, with their higher LAI, would have lower net rainfall due to higher interception of rain. The study was conducted in oil...

Soil Conference Proceedings

This paper compares leaching loss differences between straight and compound fertilisers under mature oil palm on two different soil types.

The conventional system of raising rubber seedlings in nurseries is the soil-polybag growing system with sprinkler irrigation. The drawback of this system is associated with high water wastage and labour. The soil-polybag growing system also causes root restriction and root coiling which reduce the seedlings growth and lower field survival rate upo...

The region of Al-Jabal Al-Akhdar in northeastern Libya has undergone rapid, wide-ranging changes in the land use and land cover (LULC) intensified by the conversion of natural resources for food purpose, urbanization, and other socioeconomic benefits. This study examined the use of geographic information system (GIS) and remote sensing techniques t...

The Farquhar-von Caemmerer-Berry C3 photosynthesis (FvCB) model is used to model photosynthesis of oil palm. However, some model parameters and their temperature dependencies are not known for oil palm. Hence, the aim of this study was to determine the intercellular photocompensation point (Ci*), rate of leaf day respiration in the light (Rd), the...

Hourly values of air temperature, relative humidity and solar irradiance are often not available in most of the oil palm growing areas in Malaysia, thus limiting research in studying how these weather variables affect oil palm growth and yield. Therefore, a study was carried out to determine the accuracy of some selected models to estimate hourly v...

Constructing a silt pit is one of the most widely adopted and effective practices used in oil palm plantations to conserve soil and water. The objective of this study was to utilize the HYDRUS-2D/3D to determine the optimal dimensions of silt pit and optimise the simulation results employing the multiple linear regression (MLR) and/or artificial ne...

Go to the following link for full description and latest version: https://github.com/cbsteh/Goodness-of-fit-model-indexes-for-Excel

Soil and water conservation under oil palm

Growth response of difference aerobic rice varieties to water stress

Effect of several harvesting frequencies on Mucuna bracteata on soil properties under mature oil palm.

The AquaCrop model, calibrated for 2002 and validated for 2003, is used to simulate sugar beet root dry yield, dry biomass, water productivity based on irrigation (WP i ), and water productivity based on total water input (WP i+p ) in an experimental field of the Karaj Sugar Beet Seed Institute (Karaj, Iran). Three irrigation treatments including f...

Malaysia experiences high total rainfall intensity, which increases soil erosion on steep slopes and causes a reduction in soil fertility, polluting fresh and groundwater, and the degradation of adjacent lands. Although Malaysia has high rainfall, oil palm may still experience water stress due to high rainfall intensity which results in fast downsl...

Bah, A. Husni, M. H. A., Teh, C. B. S., & Rafii, M. Y. (2013). Response of corn (Zea mays) to conventional and controlled-release fertilizers applications. In J. Hamdan & J. Shamshudin (Eds.), Advances in Tropical Soil Science (Vol. 2, pp. 70-82). Serdang, Malaysia: Universiti Putra Malaysia.

The development and use of a soil water model to predict the soil water flow and content under oil palm would be useful as a tool for more effective oil palm water management. Although many soil water models exist, none of them has been specifically developed, applied, and validated for oil palm. Consequently, the purpose of this study is to develo...

Earth is faced with dramatic changes in the weather systems, which leads to climate change. Climate change affects water resources and crop production. In this study, five and seven general circulation models (GCMs) were respectively collected via the IPCC Fourth and Fifth Assessment Reports. Emission scenarios including B1, A1B, and A2 for AR4 and...

This course focuses on the physical aspects and processes in agriculture, and this course can be divided into two. The first part is related to their climate components and modeling, and the second part is related to climate change. The first part discusses important climate components (air temperature, air humidity, wind speed, sunshine intensity...

The growth of rubber seedlings is greatly influenced by various conditions such as irrigation, soil or substrate quality, drainage and fertilization. BX-1 system (Rb 900 and BX-1 growing media) is a new nursery planting system introduced by Humibox Sdn. Bhd, with the main purpose of replacing the traditional (polybag with soil) way of raising seedl...

Rubber seedlings raised in the soil-polybag system experience root coiling and restriction and the overhead sprinkler results in much water wastage. The objective of the study was to determine the influence of root trainers and three irrigation systems on rubber seedlings grown in a peat-based medium. The irrigation systems were the overhead sprink...

Many net rainfall models have been developed, but they are often complex, data demanding and usable only for a specific vegetation type. The focus of this study was to develop and validate two simple equations (a two- and a three-coefficient equation) for nearly full canopies of oil palm, rubber and pine trees. Throughfall and stemflow data from se...

The first semi-mechanistic oil palm model was OPSIM (van Kraalingen, 1985). It was developed by taking into account some aspects of oil palm physiology and the physical processes and causal relationships between the environment and crop. OPSIM was later modified by Gerristma (1988) in order to propose a more rigorous approach to estimate oil palm p...

Dear Plant Doctor, a series of urban gardening Q&A articles in Star2 Section, The Star newspaper, Mar.-Dec. 2017

This study was conducted to understand the effects of fertiliser type (straights, compounds and controlled-release fertilisers) on N, P, K and Mg losses by surface runoff. The study was conducted in a mature oil palm field using three 20 m by 6 m erosion plots containing two palms per plot with the soil type being Typic Kandiudults and slopes rangi...

As published in: 1) TEH, C.B.S. 2017. Modeling soil water flow in Python and Excel. Universiti Putra Malaysia, Serdang, and 2) TEH, C.B.S. 2018. Development and validation of an unsaturated soil water flow model for oil palm. Pertanika Journal of Tropical Agriculture, 41(2): 787-800.

As published in: TEH, C.B.S. & CHEAH, S.S. 2018. Modelling crop growth and yield in palm oil cultivation. In: Rival, A. (Ed.) Achieving sustainable cultivation of oil palm. Vol. 1. Burleigh Dodds Science Publishing: Cambridge, UK. pp. 183-227.

Build a complete and working soil water model in either Python or Microsoft Excel. With this book, you will: 1) understand how and why water flows in the soil and what factors affect its flow; 2) how the soil water flow can be described as a set of mathematical equations; and 3) how these equations can be implemented into a computer program in Pyth...

Studies on nutrients leaching losses of tropical peat soil is limited especially in relation to the water table depths. Tropical peat soil is formed as the results of organic matter accumulation in' a situation where the organic matter production is higher than the rate of its decomposition under anaerobic or extreme acidic condition and low temper...

The main purpose of this study were to determine whether two recycled materials, a wastewater treatment plant sludge (SW204) and a spent active carbon (SW411), were effective and safe to be used in the environment as a soil conditioner and to increase plant growth. Two test crops were used: kangkung (Ipomoea reptans) and cow grass (Axonopus compres...

Mohamad Taram, E., Maulan, S., & Teh, C. B. S*. (2016). Morphology of plants root system along riverbank as a key for ecological balancer. In N. Baharuddin, S. F. Abd. Shukor & S. Abu Bakar (Eds.), Sustainable Tropical Environmental Design Exhibition. STEdex 15/16 (Vol. 7, pp. 70-73). Serdang, Malaysia: Uni. Putra Malaysia.

Teh, C. B. S.* (2016). Development of a spreadsheet software for students who are non-computer programmers to build and run mathematical models. In A. S. Md. Yunus, M. H. Zakaria & N. A. Man (Eds.), Extended Abstracts of GIPP (Incentive Research Grant for Teaching and Learning) (No. 1, pp. 111-117). Serdang, Malaysia: Centre of Academic Development...

Course module for the Long Distance Learning Program of Uni. Putra Malaysia

The BX-1 system (consisting of the BX-1 media and RB 900 tube) is a new planting system introduced by a private company to replace the growth of plants in soil-filled polybags. Different irrigation systems influence plant growth differently. The main objective of this study was to compare and determine the best of three water irrigation systems: ov...

Hypothetically, leafy vegetables need water and nitrogen (N) simultaneously in their applications for good growth. Therefore, this study was conducted to determine the effects of four watering frequencies (watering once a day, once a week, and once in every two weeks, and no watering) and five levels of N (0, 34, 68, 136, and 272 kg N ha-1) on the...

Oil palm is Indonesia’s largest source of agriculture biomass. In 2013, Indonesia is estimated to have produced 570 mil. t of oil palm biomass, among which 299 mil. t is OPF (oil palm fronds), 134 mil. t is OPT (oil palm trunk), and 28 mil. t is EFB (empty fruit bunches). This biomass are conventionally applied in the oil palm plantations as soil m...

Teh, C. B. S.* (2015). Can we build agriculture models in Excel? In C. I. Fauziah, C. B. S. Teh, M. M. Hanafi, A. Rosazlin, A. B. Rosenani, J. Shamsuddin, A. P. Qurban & K. Wan Rasidah (Eds.), In Soil Science Conference of Malaysia: Soil Security for Sustainable Food Production (pp. 99-102). Putrajaya, Malaysia: Malaysian Society of Soil Science.

Teh, C. B. S.* (2015). Response of oil palm due to climate change: Simulations and challenges. In Proceedings of the International Seminar on Gearing Oil Palm Breeding and Agronomy for Climate Change (pp. 17-24). Bangi, Malaysia: Malaysian Palm Oil Board.

This book is for agriculturists, many of whom are either novices or non-computer programmers, about how they can build their mathematical models in Microsoft Excel. Of all modeling platforms, spreadsheets like Excel require the least proficiency in computer programming. This book introduces an Excel add-in called BuildIt (available for free as down...

The Rb 900 planting tubes and BX-1 media is a new planting system introduced by Humibox Sdn. Bhd. to replace growing plants in polybags filled with soils. The main objective of this study was to compare three water irrigation systems (overhead sprinkler, drip irrigation, and the capillary wick system) and to determine the best water delivery system...

Most agriculturists receive no to very little formal training in computer programming. Consequently, they often struggle to translate their agriculture models into computer programs that can be correctly understood and executed by a computer. For them, computer programming often becomes a tedious and time-consuming drudgery that distracts them from...