Modelling of Solar Radiation Interception and Biomass Production in an Intercropping System of Rubber with Banana and Pineapple

Simulation modelling is a powerful approach for studying complex intercropping systems in entirety and a complementary tool to conventional field experiments. This study aimed to: 1) construct a dynamic model to simulate the biological productivity of an immature rubber (R), banana (8) and pineapple (P) intercropping system based on the interception and utilisation of incident solar radiation (SR), 2) evaluate growth and yield of the intercrop components using the model, 3) compare production for various cropping scenarios and 4) investigate the likelihood and effects of water stress on crop growth using a simple water budget. A FORTRAN computer model, SURHIS (Sharing and Utilisation of Radiation intercepted in a Hedgerow-Intercropping System), was developed for simulating daily SR interception and growth of R-B-P intercropping system. SR interception was modelled using a modified Monsi-Saeki equation by including a clump factor to account for the loss in intercepted SR resulting from the wide row spacing between the crops. Crop growth was modelled based on the net biomass resulting from the difference between crop photosynthesis and respi ration. Simulation results showed that increments in the leaf area index (LAI) had a greater effect on SR interception by component crops compared to height increments. Changes in height affected only fractional interception, whereas LAI increments affected both fractional and total interception. The crop growth modules were suffiCiently accurate in estimating LAI and dry matter yield (OMY) but less precise for crop height. The girth of rubber was estimated with good accuracy. The general trend in overestimation for later part of the simulation period can be attributed to model assumptions for potential production conditions

Vermicomposting of Durian husk fruit waste using indigenous sabah earthworm species: a preliminary study

Vermicomposting as a form of recycling and adding value to waste is now a widespread activity in agriculture. This preliminary study was conducted to evaluate different types of durian husk waste materials namely, fresh shredded (FS), dry shredded (OS), fresh chipped (FC) and fresh whole (FW) durian husks (un-processed) vermicomposted using local blue worms, Perionyx excavafus, with and without cow dung. The objectives of the study were to produce vermicomposts from the wastes, characterize the chemical properties of the composts and evaluate the composting efficiency (CE). The experiment was carried out in the vermished at the Field Laboratory of School of Sustainable Agriculture, Universiti Malaysia Sabah. Each treatment (i.e the various durian husk wastes, with and without cow dung) was replicated three times in a completely randomized design (CRO). The parameters of the study were nitrogen (N), carbon (C), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and pH of the vermicompost as well as composting efficiency. All data were analyzed using two-way ANOVA and Tukey's test was used for means separation. In comparison to the raw materials, after vermicomposting, pH, N, K, Mg and Ca content of the compost increased by 9 to 13 %, 76 to 93 %, 64 to 75 %, 120 to 167 %, 178 to 265 % respectively while DC decreased by 23 to 34 %. The results of pH, CE, N, DC, P, K, Ca and Mg for FS vermicompost was 6.7,85.68 %, 0.64 %, 41.5 %, 79.5 mg kg-1, 124.5 mg kg-1, 215 mg kg-1 and 81.5 mg kg-1 respectively. In the case of OS vermicompost, the results were 7.01, 26.35 %, 0.09 %, 42.5 %, 77.3 mg kg-1, 142 mg kg-1, 203 mg kg-1 and 69.5 mg kg-1 respectively. For FC vermicompost. the results were 7.3, 53.98 %, 0.096 %, 38.23 %, 55.24 mg kg-1 , 89.3 mg kg-1, 320.5 mg kg-1 and 75.5 mg kg-1 respectively. The study indicated that treatments amended with cow dung were more suitable for vermicomposting. The shredded durian husk amended with cow dung was the best compost compared to the other treatments

Using seaweed base organic fertilizer as yield booster at volcanic soil: Effect on soil quality and yield of patchouli (Pogostemon cablin)

Patchouli (Pogostemon cablin Benth.) is a bushy herb and native to tropical region of Asia, and now cultivated for its essential oil which usually used in perfume productions. It is also widely been used throughout the world to treat skin conditions, relieving depression, controlling appetite, and antifungal agents. It is cultivating commercially in Tawau, Sabah for export purposes and the average oil production is up to 26–29 mt per acre in 2016. As they enter the second and third harvesting cycle, the production starts to decline and reach 2.6 mt of oil per acre. This drop-in yield is thought to be either due to soil variabilities, low nutrient levels in volcanic soil, and diseases. Soil nutrient analysis and leaf coloration patterns are studied before conducting the study. Seaweed extract, banana peel, the mixture of Seaweed extract and banana peel, and pre-formulated 12-12-12 (N-P-K) organic fertilizer (PFF) fertilizer treatments were engaged in the Patchouli plot field experiment. Besides, the agronomical practice for the cultivation of Patchouli is well documented. The pre-study showed that the study plot has a very low conductivity level, a very low organic Carbon level and low Cation Exchange Capacity (CEC) level. Meanwhile, there were no diseases or nematode occurrences in the area. Plant height, soil pH, and soil conductivity were studied with all the four treatments that have shown a positive significant impact compared with standard estate practice. The treatments using seaweed and seaweed mixture had the highest significant level with a slight reduction in soil pH. Whereas plant height data analysis showed that the seaweed mixture was significantly different compared with other treatments at a 0.05 level. Hence, we recommend the Patchouli plantation to use organic fertilizers including the mixture of seaweed since it is cheap and easily available in Sabah

Growth response of oil palm sending from decanter cake application as fertiliser substitute in nursery

Sustainable waste management is essential to safeguard the environment and corporate interests. Stringent regulations on quality of palm oil mill effluent (POME) discharge led to the introduction of more decanter machines, which increased output of dried POME solid namely oil palm decanter cake (OPDC). Therefore, a field experiment was planned to investigate how OPDC can be directly used as fertiliser for oil palm (OP) seedling to meet the needs of the plants. In polythene bags as planting media, topsoil was combined with OPDC at ratios of 10%, 20%, 30%, and 50%. This was followed by a reduction in inorganic fertiliser at levels of 25%, 50%, a predetermined nutrient deficiency input, and up to 100% for planting medium at a ratio of 50% OPDC to topsoil. Null hypothesis was tested by comparing vegetative development i.e., seedling’s girth, height, rachis length, frond production, petiole size and true leaf area at 3rd, 6th , and 9 th month after planting (MAP). OP seedlings able to tolerate OPDC application up to 50% mixture ratio with topsoil from transplanting up to twelve months old of biological age. Growth response in treatments up to 50% and nil fertiliser input showed comparable results (P>0.005) against control in all parameters evaluated across three, six and nine months of growing period. Despite of full manuring input, OPDC application on OP seedlings has neither caused leaf phytotoxicity nor deficiency. In conclusion, OPDC can be applied directly to OP seedling as a fertiliser alternative with equal growth performance to standard method

Brief review on climate change and tropical peatlands

In 2008, the very extensive tropical peats were estimated to be about 182 million ha spanning South America, Asia and Africa. About 20.3% (36.9 million ha) of this area exist in Asia. Peats are classified based on their degree of decomposition, namely Fibrists, Hemists, Saprists and Folists. This makes them different in characteristics. The activities of microorganisms vary in different types of peat due to, for example, the sapric layer of well humified peat can provide water and food to microorganisms during heat stress. In another scenario, deeper peat is older and typically has lower levels of labile carbon to provide substrate for microbes compared to surface peat. A complete understanding of the microbial communities in different layers of peat is essential as microorganisms play major roles in peat decomposition and are important to ecosystem processes. These peats are a very important global carbon (C) store or reserve and could severely impact climate change if not managed well. Peatlands can store as much as 40 to 90 Gt C. Mis-management of peats could severely impact the environment particularly the emission of carbon into the atmosphere. For instance, clearing of peatlands using fire has been reported to release an estimated 88 t C ha−1 to the atmosphere. There are several factors which influence the environmental consequences of tropical peat especially in relation to climate change. The main influences are: (i) changes in temperature, (ii) changes in precipitation or rainfall, (iii) changes in atmospheric composition, and (iv) fire and haze. This paper is a brief review on these four influences in relation to climate change. It is apparent from the brief review that there is a need for continued short and long-term research to better understand tropical peats and how they affect our climate. This will hopefully provide the basis for predicting better what could happen under various scenarios

Soil Nitrogen Fractions, Nitrogen Use Efficiency and Yield of Zea mays L. Grown on a Tropical Acid Soil Treated with Composts and Clinoptilolite Zeolite

High nitrogen use efficiency (NUE) is important for improving crop yield. There are many nitrogen (N) fractions in soil and their uptake by crops varies. Most of the N that is taken up by plants is not native to the soil but usually from fertilizer added to the soil. However, the unbalanced use of fertilizers is currently an important issue that needs to be addressed. The objectives of this work were to determine the effects of using the recommended chemical fertilizers together with inorganic and organic amendments on (i) soil organic and inorganic N fractions, (ii) N uptake and use efficiency, and (iii) maize (Zea mays L.) dry matter production and ear yield. A randomized complete block design field trial, using maize as a test crop, was done with seven fertilizer treatments, each replicated thrice for two crop cycles. The treatments included different combinations of urea N, clinoptilolite zeolite (CZ), rice straw compost, and paddy husk compost. The variables of the study were soil N fractions, ear yield, and N use efficiency. Generally, the combined use of the recommended chemical fertilizers with CZ and organic amendments resulted in significantly higher soil N fractions, N use efficiency, and ear yield of maize for both crops. The two treatments with a 50% reduction in recommended chemical fertilizers, CZ, and rice straw compost or paddy husk compost (treatments four and six) are recommended instead of the 100% recommended chemical fertilizer treatment (treatment one). The organic materials used for these two treatments are abundantly available and will reduce the economic and environmental costs of applying large quantities of chemical fertilizers alone

Brief review on climate change and tropical peatlands

In 2008, the very extensive tropical peats were estimated to be about 182 million ha spanning South America, Asia and Africa. About 20.3% (36.9 million ha) of this area exist in Asia. Peats are classified based on their degree of decomposition, namely Fibrists, Hemists, Saprists and Folists. This makes them different in characteristics. The activities of microorganisms vary in different types of peat due to, for example, the sapric layer of well humified peat can provide water and food to microorganisms during heat stress. In another scenario, deeper peat is older and typically has lower levels of labile carbon to provide substrate for microbes compared to surface peat. A complete understanding of the microbial communities in different layers of peat is essential as microorganisms play major roles in peat decomposition and are important to ecosystem processes. These peats are a very important global carbon (C) store or reserve and could severely impact climate change if not managed well. Peatlands can store as much as 40 to 90 Gt C. Mis-management of peats could severely impact the environment particularly the emission of carbon into the atmosphere. For instance, clearing of peatlands using fire has been reported to release an estimated 88 t C ha−1 to the atmosphere. There are several factors which influence the environmental consequences of tropical peat especially in relation to climate change. The main influences are: (i) changes in temperature, (ii) changes in precipitation or rainfall, (iii) changes in atmospheric composition, and (iv) fire and haze. This paper is a brief review on these four influences in relation to climate change. It is apparent from the brief review that there is a need for continued short and long-term research to better understand tropical peats and how they affect our climate. This will hopefully provide the basis for predicting better what could happen under various scenarios

Evaluation of Varietal Performance for Yield and Yield Contributing Attributes of Local Brinjal (Solanum melongena L.) Germplasm Collections

Brinjal is the second most important vegetable crop after Tomato in relation to its total production. Better production from any crop can only be achieved from a better variety. But in most cases the producers especially the rural farmers are not aware about the selection of high yielding varieties. Without any justification they just buy those seeds are easily available in nearby shops resulting harvest a poor yield with very unsatisfactory return.   In this regard five different brinjal (Solanum melongena L.) germplasm collections were evaluated for their major yield and yield contributing attributes along with total chlorophyll content as physiological parameter. The study was conducted in rain shelter 10, at the Faculty of Sustainable Agriculture, Universiti Malaysia Sabah, arranged in Complete Randomized Design (CRD) with five replications. Research findings revealed significant variations for all the measured parameters among different brinjal cultivars. Round purple brinjal (V1=Mte2) had the highest fruit weight (238.60g; which is about 88.14% increased fruit weight over V4), followed by long red purple brinjal (V2=H117) with 167.50g (about 83.10% increased fruit weight over V4), long green brinjal (V3=H249) with 119.70g (about 76.36% increased fruit weight over V4) and the lowest fruit weight (28.30g) was found in brinjal variety V4 (Telunjuk), respectively. On the other hand red purple brinjal (V2) was the longest (24.23 cm) in size with 5.60 cm in diameter, but the highest fruit diameter (12.24 cm) was recorded in V3 brinjal. Long red purple brinjal (V2) showed the shortest days to 50% flowering with 49 days compared to Kermit brinjal (V5) which took the longest 61 days to 50% flowering. The highest total leaf chlorophyll content was detected in V5 (51.02 nmol/mg) while the lowest (44.06 nmol/mg) was in V3. From the correlation analysis significant correlation were detected among days to 1st flowering and days to 50% flowering; plant height and fruit diameter, while significant but negative correlation was seen among numbers of leaves and fruit diameter; plant height and fruit weight with chlorophyll content. From the cluster analysis primarily; V1, V2, and V3 were grouped into one cluster while V4 and V5 into another clusters, while in secondary clustering V1 alone in one group, V2 and V3 in 2nd group and finally V4 and V5 were in third groups which indicated a significant diversity among cultivars. On an average; considering varietal performance for yield and yield contributing attributes of five (5) different brinjal cultivars, it was revealed that the fruits of V1 gained the highest weight, while the fruits of V2 had the highest length and the fruits of V3 gained the highest diameter. Regarding earliness; variety V2 was the earliest among all 5 varieties, which is one of the desirable characteristics for any crops; especially in vegetables