High Rainfall Regions Research Articles

Spatio-Temporal Drought Characterization in Kenya from 1987 to 2016

Kenya is a drought, famine and hunger prone country, with considerable impact on agriculture, human health and livestock due to its eco-climatic conditions. It contains only a few regions of high and regular rainfall where arid and semi-arid lands cover 80% of the territory, therefore periodical droughts are part of the climate system. Some drought studies undertaken in Kenya used Standardized Precipitation Index (SPI) which could not fully account for drought severity status as the role of temperature increase on drought conditions was not taken into account. This study has tried to fill the gap by using Standardized Precipitation Evapotranspiration Index (SPEI), which includes precipitation, a temperature component and evapotranspiration in its computations. SPEI and the Normalized Difference Vegetation Index Anomaly (NDVI) were applied to characterize drought in Kenya from 1987 to 2016, investigate the drought severity and duration in the same period, assess drought trends together with mapping of spatial distribution of drought in identified months, assessment of Agricultural, meteorological and socio-economic activities. Correlation analysis was done to understand the response of climate and satellite based drought monitoring indices results and the crop yield data. The results and analysis obtained from the study showed that the years 1987, 1998, 2000, 2001, 2005, 2006, 2008, 2009, 2010, 2011 and 2015 were considered as drought years based on their SPEI and NDVI anomaly results. They were classified as extremely dry, very dry and moderately dry for meteorological drought and slight, moderate, severe and very severe for Agricultural drought. SPEI results can be rated as being superior as the element of temperature variation is taken into consideration.

Germination ecology of Sonchus oleraceus L. in the northern region of Australia

In Australia, Sonchus oleraceus has been emerging as a major weed in conservation agricultural systems. The effect of environmental factors on germination and emergence of S. oleraceus was assessed on populations collected from Gatton (SOG) and St. George (SOS) regions of Australia, which are high and low rainfall regions respectively. Germination of both populations responded similarly to various environmental factors studied. Although S. oleraceus seeds germinated under a broad range of temperatures (15/5, 20/10, 25/15 and 30/20°C day/night), germination was lower at 15/5°C. There was only 47–53% germination under dark conditions compared with 62–87% under alternating light–dark. Germination was only 2 and 3% at –0.8 MPa osmotic potential for SOG and SOS populations respectively, and no germination occurred at –1 MPa. Germination was 6 and 8% at 200 mM NaCl for SOG and SOS populations respectively. Although S. oleraceus seed germination exceeded 80% for pH 6–7, germination was reduced at pH outside this range. Germination was 83 and 87% for SOG and SOS populations respectively at the soil surface; and emergence decreased with increasing depth, with none from seeds buried at 6 cm depth. Wheat residue amount within the range of 0–2000 kg ha–1 did not alter germination; however, germination was significantly reduced when the crop residue amount increased to 4000 kg ha–1 and the lowest germination was at 6000 kg ha–1. The potential to germinate under diverse environmental conditions correlates with the widespread occurrence of this weed in the northern region of Australia. High residue amounts and occasional tillage leading to deep burial of seeds may reduce its emergence and incidence.

Economic impact of weather advisory services: a case of Varuna Mitra scheme in Karnataka

Despite the existence of various forecast services in India, the accuracy in their prediction is limited. To address this, the Karnataka State Natural Disaster Monitoring Centre launched a scheme Varuna Mitra in 2010, which is considered superior to others on two counts: one, it is an interactive service, and two, it provides location specific weather forecast up to the panchayat level for a period of three days on a 12-hour cycle. In this paper, we have assessed the impact of Varuna Mitra from 1350 sample farmers distributed across nine districts of high, moderate and low rainfall regions. Data were collected with and without information from farmers for 2016–17 to examine the impact of the service. The calls were found to have increased at an annual rate of 61.55% from 6,565 in 2011 to 10.42 lakh in 2016. Results indicate a reduction in the cost of cultivation and post-harvest losses, improvements in the crop yields and net incomes. Overall, the farmers could realise incremental net gain of Rs 5,106 per acre from the forecast and Rs 18,005 in terms of per capita income.

Legume crop rotation suppressed nitrifying microbial community in a sugarcane cropping soil

Nitrifying microorganisms play an important role in nitrogen (N) cycling in agricultural soils as nitrification leads to accumulation of nitrate (NO3−) that is readily lost through leaching and denitrification, particularly in high rainfall regions. Legume crop rotation in sugarcane farming systems can suppress soil pathogens and improve soil health, but its effects on soil nitrifying microorganisms are not well understood. Using shotgun metagenomic sequencing, we investigated the impact of two legume break crops, peanut (Arachis hypogaea) and soybean (Glycine max), on the nitrifying communities in a sugarcane cropping soil. Cropping with either legume substantially increased abundances of soil bacteria and archaea and altered the microbial community composition, but did not significantly alter species richness and evenness relative to a bare fallow treatment. The ammonia oxidisers were mostly archaeal rather than bacterial, and were 24–44% less abundant in the legume cropping soils compared to the bare fallow. Furthermore, abundances of the archaeal amoA gene encoding ammonia monooxygenase in the soybean and peanut cropping soils were only 30–35% of that in the bare fallow. These results warrant further investigation into the mechanisms driving responses of ammonia oxidising communities and their nitrification capacity in soil during legume cropping.

Aerosols cause intraseasonal short-term suppression of Indian monsoon rainfall

Aerosol abundance over South Asia during the summer monsoon season, includes dust and sea-salt, as well as, anthropogenic pollution particles. Using observations during 2000–2009, here we uncover repeated short-term rainfall suppression caused by coincident aerosols, acting through atmospheric stabilization, reduction in convection and increased moisture divergence, leading to the aggravation of monsoon break conditions. In high aerosol-low rainfall regions extending across India, both in deficient and normal monsoon years, enhancements in aerosols levels, estimated as aerosol optical depth and absorbing aerosol index, acted to suppress daily rainfall anomaly, several times in a season, with lags of a few days. A higher frequency of prolonged rainfall breaks, longer than seven days, occurred in these regions. Previous studies point to monsoon rainfall weakening linked to an asymmetric inter-hemispheric energy balance change attributed to aerosols, and short-term rainfall enhancement from radiative effects of aerosols. In contrast, this study uncovers intraseasonal short-term rainfall suppression, from coincident aerosol forcing over the monsoon region, leading to aggravation of monsoon break spells. Prolonged and intense breaks in the monsoon in India are associated with rainfall deficits, which have been linked to reduced food grain production in the latter half of the twentieth century.

Use of standardized precipitation evapotranspiration index to investigate drought relative to maize, in the Luvuvhu River catchment area, South Africa

Drought frequency and severity analysis during the growing period of maize was carried out by means of the Standardized Precipitation Evapotranspiration Index (SPEI) based on climatic data from seven weather stations (1975–2014). The index was aggregated at different time scales following three consecutive planting dates (October, November and December), relative to the average start of the rainy season in the area. Temporal analysis of droughts was conducted and trends were evaluated using the non-parametric Spearman's Rank Correlation test. The relative frequency distributions of the different drought categories were plotted for each growth stage of maize, with respect to the three planting dates. Results revealed an average drought occurrence of once every two seasons. The 1991/92 drought was identified as the most extreme drought during the analysis period; and generally there were no significant trends across the catchment, except for weak increasing SPEI at Levubu, Lwamondo and Thohoyandou with Spearman's ρ values of 0.4. This implies that the severity of drought decreased over time in these regions following the respective planting dates. The study further revealed that planting a 120-day maturing maize crop in December would pose a high risk of frequent severe-extreme droughts (SPEI -1.5 to ≤ −2) during the flowering to grain-filling stage at the high and moderate rainfall regions, while results at the low rainfall region indicated this risk following planting in October.

Species Diversity, Stand Structure, and Species Distribution across a Precipitation Gradient in Tropical Forests in Myanmar

An understanding of how species diversity, structural pattern, and species distribution vary across different environmental regions is crucially important for tropical ecology. In this study, we explored how these ecological parameters vary across various rainfall regions in the tropics with annual rainfall levels ranging from 843 to 2035 mm. Diversity, similarity, structure, and forest classification, and their correspondence with rainfall regions were tested. We found that species diversity, site class, and structural complexity increased with rainfall, with differences of 1000 mm having significant effects on diversity. The structure and heterogeneity of forests were higher in the high rainfall regions than the low rainfall regions. The forest structure was significantly correlated with rainfall, and the structure differed substantially where annual rainfall differed among sites by approximately 200 or 400 mm. Forests could be classified into two types according to whether they had high annual rainfall (1411–2035 mm) or low annual rainfall (843–1029 mm). In addition, the dominance of species changed noticeably from high- to low-rainfall regions, with Tectona hamiltoniana and Terminalia oliveri only being abundant in the low rainfall region. Species diversity and richness were significantly correlated with rainfall and average temperature. These findings will provide invaluable information for forest management and ecological phytogeography.

Phylogenetic analysis of Mangifera from central region of Sumatra using trnL-F intergenic spacer

Fitmawati, Fauziah R, Hayati I, Sofiyanti N, Inoue E, Matra DD. 2017. Phylogenetic analysis of Mangifera from central region of Sumatra using trnL-F intergenic spacer. Biodiversitas 18: 1035-1040. Mangifera from Central Sumatra has an unique ability to adapt to the high rainfall regions. This genus is therefore as a potential germplasm source in Sumatra. The aim of this study was to analyze and compare the nucleotide sequences of Mangifera in the central region of Sumatra based on gene loci of trnL-F intergenic spacer. The initial step of research was conducted by isolating DNA from leaves sample of Mangifera based on CTAB method. Sequences of gene loci of trnL-F were analyzed with Maximum Parsimony and Neighbour Joining methods through PAUP* Program version 4.0b10. From the results of sequences analysis with Maximum Parsimony method, it was obtained a monophyletic group of Mangifera consisted of two main clades which separated M. kemanga from five other species of Mangifera, i.e. M. foetida, M. odorata, M. laurina and Mangifera sp. Parsimony analysis also revealed that the common ancestor of M. kemanga is the first species appeared in the central region of Sumatra. The result of Neighbour Joining analysis showed M. laurina had the longest genetic distance among examined species and might be assumed as the most primitive species of Mangifera. Mangifera laurina and M. odorata were closely related as well as M. foetida and M. odorata. The results of research also revealed and supported the genus Mangifera as a monophyletic group.

Long term rainfall trend over meteorological sub divisions and districts of India

In this paper the long term trend of annual and seasonal rainfall over different districts, Meteorological (Met.) sub-divisions and whole India have been studied using the long term rainfall data for the period from 1901 to 2013. The changes in amount and pattern of rainfall have a significant impact on agriculture, water resources management and overall economy of the country. Mann-Kendall test is applied to check the significance of the trend. Linear Regression and Theil-Sen’s non parametric test has been applied to estimate the trend. The study is carried out for 632 districts and 34 sub divisions of India by utilizing the gridded rainfall data (0.25° × 0.25°) over the main land except Andaman & Nicobar and Lakshadweep islands. Many authors have studied that extreme events are increasing but there is no trend in Pan India’s rainfall. It is observed from the annual rainfall analysis 10% of the number of districts are showing significant increasing trend and 13% significant decreasing (mainly in Uttar Pradesh) trend whereas irrespective of high and low rainfall regions, 10% area of the country is showing significant increasing trend and 8% of the area of the country showing significant decreasing trend in annual rainfall. In Meteorological Sub divisions, east & west UP are showing significant negative trend and some of the coastal sub divisions are showing positive trend. It is also observed that the country’s rainfall is not showing any trend.

Limits to the applicability of the innovation platform approach for agricultural development in West Africa: Socio-economic factors constrain stakeholder engagement and confidence

Integrated Agricultural Research for Development (IAR4D) is a mode of participatory action research for development that aims to improve the well-being of smallholder farming households by facilitating networks between farmers and marketplace actors through groups called ‘innovation platforms’. In 2012, the Association for the Promotion of Livestock in the Sahel and Savannas (APESS, an NGO with rural membership) established nine innovation platforms in the Sahelian zone in Senegal, Burkina Faso, Cameroon and Chad, with the aim of engaging member livestock producers with meat and milk processors and traders. In late 2013 and early 2014, each innovation platform reviewed its perception of “performance” or “functionality”, using a consensus-based group assessment scored against nine criteria. The aim of this study is to test the extent to which perceived functionality was related to the activities of the innovation platform, as well as current farm productivity and profitability, household well-being, and regional context, using data gathered independently by APESS as part of its broader mandate to improve the lives of members.Across the nine innovation platforms, there were strong positive correlations between the responses to all self-assessment criteria i.e. members perceived that their innovation platform was performing strongly or weakly in all respects. The criterion scores were correlated positively with the number of meetings held, but not with numbers or gender of attendees, training opportunities, nor actions agreed at meetings. Innovation platforms self-assessed more positively in southern, higher rainfall regions than in the northern, lower rainfall regions. Performance was positively correlated with many measures of farm productivity and household well-being, including median area of farms, value of crop and hay production, sales of animals or animal products, expenditure on agricultural inputs, current engagement with markets, and estimated number of months per year that the family is able to feed itself.We conclude that the IAR4D approach is perceived to work well in high rainfall zones, for smallholders with a relatively high current level of well-being, who have larger and more productive farms, and who are already engaged with markets. The approach does not appear to work well in more arid regions for poorer smallholders, who are often not able to provide food for their families for 12months of every year. The IAR4D focus on social networking into markets appears to be relevant for producers who wish to strengthen or diversify existing market relationships, but is not perceived to be sufficiently relevant by smallholders for whom achieving reliable subsistence and averting starvation remains the priority.

Canopy Management to Improve Grape Yield and Wine Quality - Principles and Practices

This paper reviews the subject of canopy management with an attempt to develop principles. These principles provide guidelines for canopy surface area amount; spacing between canopies; within canopy shade, especially for the fruiting/ renewal zone; balance between fruit and shoot growth; and uniformity of location of fruit/renewal zones, shoot tips and cane bases. Field techniques of point quadrat analysis and canopy scoring are introduced as an aid to defining problem canopies. These techniques are cheap, quick and effective. A set of twenty-one numeric indices and descriptors to assess winegrape canopies is then presented as a winegrape canopy ideotype, which can be further used as management guidelines. Recent publications are reviewed from various aspects of canopy management. These include vigour control, shoot trimming, leaf removal in the fruit zone and training system responses. The paper concludes with presentation of the authors' unpublished data on the effects of canopy microclimate on yield and wine quality. The trial was conducted with the cultivar Cabernet franc on a deep, fertile soil in a cool, high rainfall region. Canopy division using the Ruakura Twin Two Tier doubled yield compared to dense, vertical shoot positioned canopies which are common in New Zealand. Shade caused reduction in all yield components, and also delayed fruit ripening and reduced wine quality. Similar results were obtained by comparing fruit production at different heights with the Te Kauwhata Three Tier trellis system, where lower tiers were shaded at the canopy exterior. The results confirm that grape yield and wine quaiity can be simultaneously increased by improved canopy management of shaded vineyards.

Genome-Wide Association Study for Pre-harvest Sprouting Resistance in a Large Germplasm Collection of Chinese Wheat Landraces.

Pre-harvest sprouting (PHS) is mainly caused by the breaking of seed dormancy in high rainfall regions, which leads to huge economic losses in wheat. In this study, we evaluated 717 Chinese wheat landraces for PHS resistance and carried out genome-wide association studies (GWAS) using to 9,740 DArT-seq and 178,803 SNP markers. Landraces were grown across six environments in China and germination testing of harvest-ripe grain was used to calculate the germination rate (GR) for each accession at each site. GR was highly correlated across all environments. A large number of landraces (194) displayed high levels of PHS resistance (i.e., mean GR < 0.20), which included nine white-grained accessions. Overall, white-grained accessions displayed a significantly higher mean GR (42.7–79.6%) compared to red-grained accessions (19.1–56.0%) across the six environments. Landraces from mesic growing zones in southern China showed higher levels of PHS resistance than those sourced from xeric areas in northern and north-western China. Three main quantitative trait loci (QTL) were detected by GWAS: one on 5D that appeared to be novel and two co-located with the grain color transcription factor Tamyb10 on 3A and 3D. An additional 32 grain color related QTL (GCR-QTL) were detected when the set of red-grained landraces were analyzed separately. GCR-QTL occurred at high frequencies in the red-grained accessions and a strong correlation was observed between the number of GCR-QTL and GR (R2 = 0.62). These additional factors could be critical for maintaining high levels of PHS resistance and represent targets for introgression into white-grained wheat cultivars. Further, investigation of the origin of haplotypes associated with the three main QTL revealed that favorable haplotypes for PHS resistance were more common in accessions from higher rainfall zones in China. Thus, a combination of natural and artificial selection likely resulted in landraces incorporating PHS resistance in China.

Adhesive Performance and Clinician Satisfaction of Two Novel Chlorhexidine Gluconate-impregnated Vascular Access Dressings in Comparison to a Commercial Reference

Design rainfall statistics are the primary inputs used to assess flood risk across river catchments. These statistics normally take the form of Intensity–Duration–Frequency (IDF) curves that are derived from extreme value probability distributions fitted to observed daily, and sub-daily, rainfall data. The design rainfall relationships are often required for catchments where there are limited rainfall records, particularly catchments in remote areas with high topographic relief and hence some form of interpolation is required to provide estimates in these areas. This paper assesses the topographic dependence of rainfall extremes by using elevation-dependent thin plate smoothing splines to interpolate the mean annual maximum rainfall, for periods from one to seven days, across Australia. The analyses confirm the important impact of topography in explaining the spatial patterns of these extreme rainfall statistics. Continent-wide residual and cross validation statistics are used to demonstrate the 100-fold impact of elevation in relation to horizontal coordinates in explaining the spatial patterns, consistent with previous rainfall scaling studies and observational evidence. The impact of the complexity of the fitted spline surfaces, as defined by the number of knots, and the impact of applying variance stabilising transformations to the data, were also assessed. It was found that a relatively large number of 3570 knots, suitably chosen from 8619 gauge locations, was required to minimise the summary error statistics. Square root and log data transformations were found to deliver marginally superior continent-wide cross validation statistics, in comparison to applying no data transformation, but detailed assessments of residuals in complex high rainfall regions with high topographic relief showed that no data transformation gave superior performance in these regions. These results are consistent with the understanding that in areas with modest topographic relief, as for most of the Australian continent, extreme rainfall is closely aligned with elevation, but in areas with high topographic relief the impacts of topography on rainfall extremes are more complex. The interpolated extreme rainfall statistics, using no data transformation, have been used by the Australian Bureau of Meteorology to produce new IDF data for the Australian continent. The comprehensive methods presented for the evaluation of gridded design rainfall statistics will be useful for similar studies, in particular the importance of balancing the need for a continentally-optimum solution that maintains sufficient definition at the local scale.

Tinospora fragosa (Menispermaceae) subsp. fragosa adaptation to its hostile African habitat.

Tinospora fragosa is a succulentstemmed winter deciduous twiner from the dry savannah region of southern Africa. As found in most other Tinospora species when the plant becomes detached from the soil, it has the ability to grow a survival root (life line) during the growing season, re-establishing the plant. One of three South African species, it is at once distinguished by distinctly succulent branches up to 3–5cm in diameter with shortened lateral branches from which the abbreviated inflorescences appears. The others, T. caffra (Miers) Troupin and T. tenera Miers have much thinner stems, knobbly in T. caffra and striate in T. tenera. Both these species are confined to higher rainfall regions in Mpumalanga and KwaZulu-Natal.

Genotype × environment interactions for phenological adaptation in narrow-leafed lupin: A simulation study with a parameter optimized model

An understanding of genotype×environment (G×E) interactions for phenological adaptation in crops can help identify traits that facilitate genetic improvement and cultivar selection. Such understanding is also necessary to identify environments that facilitate identification of cultivars with better environmental adaptation. Process-based crop simulation models including APSIM are valuable tools to investigate G×E interactions and traits conferring adaption to particular conditions. However cultivar parameters relating to crop phenology in crop model are difficult to determine directly through field experiments. Within this paper, we present a simulation study to explore the environmental and genotypic control of time to flowering and maturity in lupin and its grain yield, by using the APSIM model. In the model, lupin cultivar parameters were optimized by combining prior knowledge and PEST (Parameter ESTimation), a model-independent parameter optimiser. The parameterisation was for nine lupin cultivars with contrasting maturity (early vs late) and vernalization requirement (non-responsive vs responsive) across 13 sites×years across Australia. We showed that phenological differences among the cultivars were well explained by the optimized set of parameters, mainly reflected in vernalization response and photoperiodic sensitivity before flowering. Simulated flowering days and grain yield agreed well with the observations, with RMSEs (root mean squared error) of 4days and 0.34tha−1 for all cultivars together. The simulation results showed that lupin yield was significantly affected by temperature and water availability. An early-maturity cultivar would yield better than the late-maturity one at the warm and low rainfall region, while at high rainfall or long-season regions, cultivar types should be chosen tactically based on the climatic conditions for that season. Thus, lupin breeding in Australia should therefore focus on temperature regimes and rainfall gradients. These results indicate that the parameter-optimized APSIM model could be used to explore the adaptation of genotypes to a particular environment to provide guidance for a more efficient breeding program and develop optimal agronomic management practices.

Changes and variability of precipitation and temperature in the Ganges–Brahmaputra–Meghna River Basin based on global high‐resolution reanalyses

ABSTRACTPrevious studies suggest that climate change impacts significantly on the hydro‐climatic processes within the Ganges–Brahmaputra–Meghna (GBM) River Basin (RB). This study examines the observed climate characteristics and potential strengths and limitations of three global high‐resolution reanalyses and satellite remote‐sensing products over the GBM RB for period 1980–2013 by (1) estimating trends and interannual variations of precipitation and temperature, and (2) isolating precipitation variations likely associated with El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD). The surface temperature trends show widespread warming across the basin with a maximum increase of 0.6 °C decade−1 over western Nepal and southern Tibet from 1980 to 2013. Rainfall changes from 1980 to 2013 indicate pronounced decline over high rainfall regions of northeast India, Bhutan, Nepal, and Bangladesh, especially from 1998 to 2013. Basin‐wide averaged trends show rainfall decline of up to 39 mm decade−1 in June–August in the Brahmaputra–Meghna RB from 1998 to 2013. Temperature variability based on Principal Component Analysis indicates that the first mode is associated with sea surface temperature (SST) warming in the Arabian Sea and the western tropical Pacific Ocean, while the second mode appears to be significantly correlated to SST anomalies in the western (eastern) tropical Indian (Pacific) Ocean. ENSO and IOD events are found to significantly influence rainfall variability contributing to about 10–20% (ENSO) and 8–10% (IOD) of the annual rainfall, mainly over Bhutan, Nepal, Bangladesh, and north‐eastern India. Among the three reanalysis products: European Centre for Medium‐Range Weather Forecasts (ECMWF) retrospective analysis (ERA‐Interim), Modern‐Era Retrospective Analysis for Research and Applications (MERRA), and Climate Forecast System Reanalysis (CFSR), ERA‐Interim (and MERRA) agrees well with the observed precipitation (temperature) data sets while, CFSR shows the least skills in representing the spatio‐temporal variations of precipitation and temperature.

Water Management in the Urban Cultural Heritage of Myanmar

AbstractThis article assesses indigenous perceptions of water through a comparison of the water management strategies at three ancient sites located in different ecological zones of Myanmar. Two of our examples are in the high-rainfall regions of Lower Myanmar: Thagara in the Dawei River valley flanked by mountains on the east and west, and Kyaikkatha on delta lands at the egress of the Sittaung River. We contrast these adaptations with the micro-exploitation of the scarce water resources at Bagan (also spelled Pagan) in the arid zone of Upper Myanmar. In the southern wet regions, despite the different geographical setting of Thagara and Kyaikkatha, the focus was on drainage and control. Multiple ramparts and moats were used to conserve the scarce water in the dry months between December and April and control the heavy floods of the rainy months between May to November. At Bagan, sited directly on the broad Ayeyarwady River, water management of inland streams and seasonal lakes maximised the gentle slope of the plain while also coping with intermittent flash floods in the rainy months. The sites of Thagara, Kyaikkatha, and Bagan demanded specific adaptations but are alike in the absence of extensive transformation of the landscape. This balance of manmade and natural elements provides common ground despite their variable size and urbanised extent, ecological setting, and occupational sequence to highlight the shared significance of water management in their long-term urban success.

Synthesis and characterization of nanoamendment for effective remediation of soil acidity

Summary Industrialization and climate change had increased soil acidity which deteriorated the soil health and reduced crop productivity through release of toxic concentration hydrogen and aluminium, manganese and iron. Acid soils (pH < 5.5) are extensively found in region of high rainfall, temperature and hilly region. Liming of acid soils the changes (pH 5.5 to 6.5), rectifies adverse effects and also improves the soil fertility. But large quantity of lime used (7.2 tons per acre). In order to optimize the rate of lime nano technological approach was used. Naturally available micro-size conventional calcium carbonate particles were used for synthesis of nano crystals through physical method of top down approach, using high energy ball milling (HEBM) with different hours and encapsulated with non-ionic surfactant (1% chitosan). It produced uniform nano sized particles (nano-lime), which were characterised using particle size analyser (approximately 115 – 120 nm), zeta potential (-50 mV), powder X-ray diffraction (d spacing 3.13). It confirmed that presence of Ca and Mg with Raman Shifts (713, 1086 cm -1 ) and Fourier transform infrared spectroscopy (844.7 cm -1 ). Shape and structure was observed through scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Synthesized of calcium carbonate nano crystalline particles were environment friendly. Reduced particle size and increased surface area where offered an opportunity for reclamation of soil acidity as an amendment and can be scaled up for agricultural production.

Growth is impeded by gastrointestinal nematodes in weaned rather than suckling meat-breed lambs in a high summer rainfall region, on the Northern Tablelands, New South Wales

The hypothesis tested in this experiment was that the effects of gastrointestinal nematodes (GIN) on growth of meat-breed lambs would be absent during the suckling period and greatest after weaning. The experiment was a single factor design conducted on five farms over 2012–2014, using meat-breed lambs (Poll Dorset × Border Leicester/Merino), which were either GIN-suppressed (SUP) or not (NSUP). The experiment commenced at lamb marking and continued for 5 months. SUP lambs were serially treated with short- and long-acting anthelmintics. NSUP lambs were not treated before weaning and at weaning received a short-acting multi-active drench with subsequent treatments varying between farms. Worm egg count (WEC) of NSUP lambs were significantly higher (P &lt; 0.0001) than SUP lambs at weaning (1170 and 10 epg) and thereafter (P &lt; 0.0001) reaching 920 epg 2 months after weaning. Haemonchus contortus was the predominant species present in NSUP lambs with smaller contributions from Trichostrongylus spp. There was no effect of GIN control on lamb growth during the pre-weaning period (SUP 17.2 kg vs NSUP 17.0 kg, P = 0.093), whereas GIN reduced growth of lambs by 0.5 kg (SUP 7.1 kg vs NSUP 6.6 kg, P = 0.002) in the last month of observation. There was no effect of GIN control on lamb mortality. GIN did not affect growth of suckling meat-breed lambs despite high WEC at weaning indicating resilience to GIN infection in lambs growing at 200 g/day. In contrast, post-weaning growth was reduced by GIN infection, despite effective treatment at weaning and movement to GIN ‘safe’ pastures. The susceptibility of weaned lambs to the effects of GIN infection highlights the importance of effective control measures at this time.

Impact of climate changes on existing crop-livestock farming systems

The state of Western Australia is a major producer and exporter of crops and livestock. Mixed farming systems are typical agricultural enterprises in the Western Australian wheatbelt where climate drives the productivity and profitability of these farms and therefore the effects of likely climate change on their performance need to be understood. Here the effects of climate change projected at 2030 were evaluated compared to a baseline period (1980–1999) on mixed farming systems at paddock, enterprise and whole farm scales using the coupled APSIM and GRAZPLAN biophysical simulation models. The yield of different crops, livestock production and gross margins were assessed under current and projected climates using current farming technology and management practices. Representative mixed-farm systems were selected along a climate transect. Modelling analysis suggests that current production levels and gross margins of mixed farm systems in Western Australia will not be sustained in 2030 climate conditions except in areas of moderately high-rainfall. Whole farm gross margin declined at all site×potential climate scenarios between 1% and 22% except in moderately high rainfall where gross margin increased by up to 4% under a ‘hot and moderate change in rainfall’ climate. Projected crop yields declined for most of the crop×site×potential climate combinations, with greatest declines under a hot and dry climate (at driest margin of transect) in which wheat, barley, canola, and lupin yield declined up to 16%, 15%, 21%, and 27%, respectively. Increase in yield was predicted for wheat and barley at some of the site×potential climate s. Wheat yield increased only under moderately high rainfall region by 6% while barley increased by 1%. Simulated cropping gross margin was also shown to decline by between >1% and 23%, except for the moderately high-rainfall site where cropping gross margins were projected to increase by up to 3%. Changes in simulated livestock production were smaller and less variable than for crop production. The change in weight of livestock sold across sites×potential climate combinations ranged between −3% and +3%. Livestock gross margin varied between −11% and +6%. Modelling results indicated a greater fertilisation effect of the elevated CO2 on pasture production than on crop yield and biomass particularly in drier sites. But however, this could not offset negative impact of climate change under hot potential climates. The main negative environmental impacts from the projected climate change were declines in annual net primary production (ANPP), ground cover and water use efficiency mostly at drier sites. Whole farm N2O emission declined significantly for the majority of site×potential climate combinations, while smaller decreases in ruminant CH4 emission were predicted. In 2030, returns from livestock enterprises are predicted to be smaller, but less variable than from cropping and with increasing probability of success in drier regions. Reduced variability in financial return is important from the perspective of whole farm risk management. Shifts in enterprise mix in dryland mixed-farming systems towards increased livestock may be a helpful strategy in adapting to climate change and managing the associated financial risks.