The economics of precision land leveling: A case study from Pakistan

This paper identifies the economic and physical benefits attributable to precision land leveling. While the work is specific to Pakistan the implications are relevant for other arid areas of the world where irrigation is practiced.Two sets of fields were selected, one set that had been precision leveled and another set that had been leveled using traditional techniques. These fields were resurveyed and then the farmers were interviewed every month during the winter crop season. Cutting samples were taken on all the fields during harvest. The average yield of the precision leveled fields was 2274.7 kg/ha and the yield for traditional leveled was 1681.1 kg/ha. This difference is significant at the 0.001 level. In addition the mean time to irrigate a hectare field was 2.79 h for precision leveled and 5.24 h for traditional leveled. Again this is significantly different at the 0.001 level. The change yield attributable solely to precision land leveling was calculated by regression analysis at 246.1 kg/ha per 3 cm change in max—min range. The remaining difference in yields was attributable to increased use of nitrogen and phosphorus fertilizers on the precision leveled fields over the traditional leveled fields.The economic analysis of precision and leveling, assuming a life of 10 years, is positive but not above the two or three to one return that is usually required to persuade subsistent farmers to invest in a new technology. However, the precision land leveling acts as a catalyst and increases the efficiency of the other associated inputs and hence is a more valuable investment than is indicated by simple economic analysis.     

Assessing impacts of surge-flow irrigation on water saving and productivity of cotton

To improve water saving and conservation in irrigated agriculture, a range of field evaluation experiments was carried out with various furrow irrigation treatments in cotton fields to estimate the possibilities of improving furrow irrigation performances under conditions of Central Fergana Valley, Uzbekistan. The research consisted in comparing surge and continuous-flow in long furrows and adopting alternate-furrow irrigation. The best results were achieved with surge-flow irrigation applied to alternate furrows. Field data allowed the calibration of a surface irrigation model that was used to identify alternative management issues. Results identified the need to better adjust inflow rates to soil infiltration conditions, cut-off times to the soil water deficits and improving irrigation scheduling. The best irrigation water productivity (0.61 kg m⁻³) was achieved with surge-flow on alternate furrows, which reduced irrigation water use by 44% (390 mm) and led to high application efficiency, near 85%. Results demonstrated the possibility for applying deficit irrigation in this region.     

Water saving technology and saving water in China

Rapid expansion of irrigated agricultural and increasing urban demands for water have important implications for the economy of China, especially for the agricultural sector in the northern part of the nation. In response to the water crisis, China's government has begun in recent years to invest in research on techniques to save water in the agricultural sector, although there is a debate about the extent of success in adoption by farmers. Top policy makers have publicly stated they would allocate billions of dollars in funding if they knew it would succeed in saving water. Unfortunately, there has been relatively little research in China on the economics of water saving technology and there is almost no systematic information on the extent to which the technologies have been adopted, if they are appearing to save water, and the characteristics of the communities that have been adopting them. Our goal is to sketch a picture of the state of water saving technology in northern China to increase awareness of past trends and current status. In simplest terms, we seek to establish a set of first order facts about the role that water saving technology has been playing in China's agricultural sector. We pursue three specific objectives: (1) to illustrate progress in adoption over the past two decades, (2) to identify the characteristics of technologies that have been most successful and those that have not, and (3) to explain factors that might be promoting water saving technology and factors that might be holding back adoption. We find that, although water saving technologies have expanded rapidly in recent years—especially those that can be adopted by individual households (as opposed to those that require the collective action of an entire community), there is still considerable room for water saving technology to be expanded.     

The environmental impacts of the production of concentrated feed: the case of pig feed in Bretagne

Pig production systems often depend to a large extent on concentrated feed imported from outside the farm. This study used the Life Cycle Assessment (LCA) method to assess major environmental impacts associated with the production and on-farm delivery of concentrated feed for pigs. Feed composition was based on average data for Bretagne (France) in 1998 and on published data for wheat-based, maize-based and co-product based feeds. As crop and feed production practices in Bretagne are similar to those in most of western Europe, we conclude that the results of this study apply more largely for western Europe. Depending on feed composition and fertilisation practise for crop-based feed ingredients, the production and delivery of one kg of feed for finishing pigs will produce a eutrophication potential between 3.8 and 9.3 g PO₄-equivalents, a global warming potential between 472 and 792 g CO₂-equivalents, an acidification potential between 3.0 and 6.3 g SO₂-equivalents, a terrestrial ecotoxicity potential between 0.4 and 8.7 g 1,4-dichlorobenzene-equivalents, an energy use between 3.3 and 6.1 MJ, and land use between 1.44 and 2.07 m² year. These impacts are mainly due to the production of crop-based ingredients. The contribution of transport processes was substantial for climate change, acidification and energy use. A feed containing mainly co-products had higher energy use and lower terrestrial ecotoxicity than feeds consisting mainly of non-processed crop-based ingredients. Hypotheses with respect to the fertilisation practices for the feed's main ingredients have a major effect on its impact values. The effect of uncertainty concerning the emissions of N₂O, NH₃, and NO₃ was very large for climate change, and large for acidification and eutrophication. The environmental burdens associated with the production and delivery of pig feed can be decreased by: optimising the fertilisation of its crop based ingredients, using more locally produced feed ingredients, reducing concentrations of Cu and Zn in the feed, and using wheat-based rather than maize-based feeds.     

农田激光平地技术在湖南研究现状及发展趋势探讨

激光平地是提高农田灌溉效率与灌水均匀度,节水、增产、省工的一项重要措施.时近年来国内开展的主要研究工作及取得的成果进行综述,探讨激光控制农田土地平整技术在湖南研究现状及发展趋势.     

Lamb production: A case study of experimentation and simulation

Empirical relationships derived from field experiments were combined to form the basis of a model of a lamb production system. The model was then used to examine the effects of a management strategy which field results had indicated would benefit lamb production.This strategy reduced the area of pasture grazed until the end of mating with the aims of restricting ewe liveweights at mating and increasing pasture availability during pregnancy to ensure liveweight gains. The effects on gross margins were calculated for different combinations of environment, stocking rate and meat prices.This feeding restriction increased gross margins considerably if there was a marked trough in winter feed supplies, or if prices were low. In general, their effects were small relative to the influence of stocking rate.It is suggested that the contrast between large management effects found by experiment and relatively small effects predicted by the model is due to differences in constraints imposed by research workers and producers.     

Technical and economic considerations in the design of closed conduit irrigation systems: A case study

Closed conduit irrigation systems are designed to respond to moisture requirements and permit water application at different required rates. The formulation of these requirements allows the engineer to select one of the many possibilities of the water system layouts. However, the requirement that the cost of the system for a given set of operational conditions should be minimal is not always included in the design because of the difficulties in selecting the most economic layout among the many alternatives.The main parameters characterizing pipe irrigation systems are presented and discussed. A trade-off among the irrigation system components for various layouts is presented in a case study and discussed, emphasizing the complexity of the decision-making procedure.     

Technical and economic criteria in agricultural production: A case for a systems approach to farm decision-making in the Pakistan Punjab

This paper defines the criteria of ‘technical’ and ‘economic’ efficiencies. The relationship between these criteria is identified, and its implications are discussed. These two sets of criteria do diverge, with ramifications both at the farm and the national levels. An illustration of their relationship at the farm level is provided by examining the nature of water allocation to crops in the Punjab of Pakistan. The divergences that exist between ‘technical’ and ‘economic’ efficiencies at both farm and national levels are highlighted by considering the process of mechanisation in the Punjab in some detail. Finally, it is pointed out how a ‘systems approach’ can accomodate both the technical and economic criteria and their interaction.     

自流灌区节水灌溉及其对策

随着全球化水资源危机的出现,灌区发展中存在的问题明显暴露出来。一方面,灌区工程老化失修严重,灌水技术落后,管理粗放;另一方面,水资源不足,灌区引水量逐年下降,制约 了灌溉效益的发挥和灌区的发展。     

Assessing the groundwater dynamics and impacts of water saving in the Hetao Irrigation District, Yellow River basin

Water resources allocated to the agricultural sector in the Yellow River basin are being reduced due to severe water scarcity and increased demand by the non-agricultural sectors. In large-scale irrigation districts, the application of water-saving practices, e.g., improving the canal system, using water-saving irrigation technology and adjusting cropping patterns, is required for the sustainable agricultural development and the river basin environmental equilibrium. Adopting water-saving practices leads to lowering the groundwater table and to controlling salinity impacts related to excessive irrigation. However, assessing the effects of water-saving practices on the groundwater system requires further investigation. The Jiefangzha Irrigation Scheme of the Hetao Irrigation District is used as a case study for analyzing the temporal and spatial dynamics of the groundwater table. A lumped parameter groundwater balance model has been developed with this purpose and to assess impacts of various water-saving practices. The model was calibrated with monthly datasets relative to the non-frozen periods of 1997-1999 and validated with datasets from 2000 to 2002. Results indicate that canal seepage and deep percolation account for respectively 48% and 44% of the annual groundwater recharge. Groundwater discharge by direct evaporation and plant roots uptake represents 82% of the total annual groundwater discharge. After validation, the model was applied to assess the impacts of various canal and farm irrigation water-saving practices. It was observed that improvements in the canal system (e.g., canal lining, upgrading the hydraulic regulation and control structures, improving delivery schedules) might lower the groundwater table by 0.28-0.48 m, depending upon the level of implementation of these measures. Higher declines of the groundwater table are predicted when water-saving technologies are applied at both the canal and the farm systems. That decline of the water table favours salinity control and reduces capillary rise, thus reducing the groundwater evaporation and uptake by plant roots; that reduction may attain 128 mm. However, predictions may change depending on the way how water-saving measures are applied, which may be different of assumptions made; therefore, there is the need to perform a follow-up of the interventions in order to update predictions. Results indicate the need for appropriate research leading to improved irrigation management when the decline of the groundwater level will reduce groundwater contribution to vegetation growth.     

Productivity impacts of the system of rice intensification (SRI): A case study in West Bengal,India

The system of rice intensification (SRI) has generated considerable debate globally, particularly with regard to its potential to raise rice yields. Proponents of SRI have reported that the average rice yield with SRI is double the current average yield and can be increased to the level of three to four times. Opponents say the reported high yields are due to measurement error and that usual information expected in support of these fantastic yields is missing. The number of SRI adopters has increased in India in recent years. We evaluate the impact of adoption of SRI practices on rice yields, the economics of paddy cultivation and labour inputs based on field research conducted in Purulia, West Bengal, India. Paddy yields with SRI were higher than those under conventional paddy cultivation by 32% and net returns were higher by 67%. Labour input was reduced by 8%. SRI adoption enabled farmers consistently to enhance paddy yields, increase returns and save labour; and enhance productivity with respect to the key inputs in terms of paddy output per unit of seed, fertilizer and labour-day. SRI promises to be a significant alternative for not only raising paddy yields, but also for managing paddy based farming in resource-starved regions.     

Hydrological impact of biofuel production: A case study of the Khlong Phlo Watershed in Thailand

This study evaluates the potential impact of increased biofuel production on the hydrology of a small watershed, Khlong Phlo, in the eastern part of Thailand. The water footprint of biofuel energy was estimated for three crops in order to identify the most water-efficient crop. The Soil and Water Assessment Tool (SWAT) model was used to evaluate the impact of land use change (LUC) caused by the expansion of biofuel crops on the components of water balance and water quality in the studied watershed. Several LUC scenarios consisting of oil palm (biodiesel), cassava and sugarcane (bio-ethanol) expansion were evaluated. The water footprint results indicated that cassava is more water-efficient than the other two crops considered. Simulation results revealed that although oil palm expansion would have negligible alteration in evapotranspiration (0.5 to 1.6%) and water yield (−0.5 to −1.1%), there would be an increased nitrate loading (1.3 to 51.7%) to the surface water. On the contrary, expansion of cassava and sugarcane would decrease evapotranspiration (0.8 to 11.8%) and increase water yield (1.6 to 18.0%), which would lead to increased sediment (10.9 to 91.5%), nitrate (1.9 to 44.5%) and total phosphorus (15.0 to 165.0%) loading to surface water. Based on the results, it can be concluded that land use change for biodiesel production would affect water quality, while both the water balance components and water quality would be affected by the expansion of bio-ethanol crops. Overall, the study indicates that biofuel production would have a negative impact on the water quality of the studied watershed. Further research at large scale (e.g. basin level) and on the economic aspect is recommended, in order to contribute to developing suitable land use and energy policies.     

Hydrological impacts of rainwater harvesting (RWH) in a case study catchment: The Arvari River, Rajasthan, India. Part 1: Field-scale impacts

Rainwater harvesting (RWH), the small-scale collection and storage of runoff to augment groundwater stores, has been seen as a solution to the deepening groundwater crisis in India. However, hydrological impacts of RWH in India are not well understood, particularly at the larger catchment-scale. A key element to grasping RWH impact involves understanding the generated recharge variability in time and space, which is the result of variability in rainfall-runoff and efficiency of RWH structures. Yet there are very few reported empirical studies of the impact of RWH. Catchment-scale impacts are best studied using a water balance model, which would require a basic level of field data and understanding of the variability. This study reports the results of a 2-year field study in the 476 km² semi-arid Arvari River catchment, where over 366 RWH structures have been built since 1985. Difficulties associated with working in semi-arid regions include data scarcity. Potential recharge estimates from seven RWH storages, across three different types and in six landscape positions, were calculated using the water balance method. These estimates were compared with recharge estimates from monitored water levels in 29 dug wells using the water table fluctuation method. The average daily potential recharge from RWH structures varied between 12 and 52 mm/day, while estimated actual recharge reaching the groundwater ranged from 3 to 7 mm/day. The large difference between recharge estimates could be explained through soil storage, local groundwater mounding beneath structures and a large lateral transmissivity in the aquifer. Overall, approximately 7% of rainfall is recharged by RWH in the catchment, which was similar in the comparatively wet and dry years of the field analysis. There were key differences between RWH structures, due to engineering design and location. These results indicate that recharge from RWH affects the local groundwater table, but also has potential to move laterally and impact surrounding areas. However, the greatest weakness in such analysis is the lack of information available on aquifer characteristics, in addition to geology and soil type.     

寒地水稻节水灌溉研究

根据水稻发育过程中对水分反应的遗传性理论,经过试验研究,提出在寒冷地区气候条件下,以浅水层淹灌为主,晒田（中干）湿润相结合的浅湿型节水灌溉基本模式。在高产和维持相同产量前提下,直播水稻生育期灌水量６６７６．９５ｍ３／ｈｍ２,节水１９．６％,水的生产效率为０．９７ｋｇ／ｍ３;“旱育稀植”水稻：厚土层本田灌水量２２９９．５０ｍ３／ｈｍ２,节水５９．２％,水的生产效率为３．３７ｋｇ／ｍ３;薄土层本田灌水量４７８２．００ｍ３／ｈｍ２,节水４６．６％,水的生产效率为１．５４ｋｇ／ｍ３,在节水灌溉方面,达到北方寒冷稻区先进水平。     

Environmental and economic impacts of reducing total phosphorous runoff in an agricultural watershed

The economy of northwest Arkansas relies greatly upon livestock and poultry production. The supply of production by-products is increasingly coming under scrutiny as an important source of water pollution in the region. This study uses stochastic dominance techniques to evaluate, environmentally and economically, a range of ten best management practice scenarios to lessen water pollution in the Lincoln Lake watershed. The goal is to generate rankings that could be useful for supporting producers’ and watershed managers’ selection of management practices to reduce total phosphorous losses in runoff. Specifically, this study compares scenarios in terms of net return risk reduction for bermudagrass hay producers.The results showed that environmental and economic rankings differ from each other. Although all scenarios analyzed were effective in reducing total phosphorous losses when compared to a baseline, six of them also decreased net returns. This suggests that including some best management practices may lead to increased net return risk. However, some scenarios were identified that may increase net returns, reduce total phosphorous losses and do not differ considerably from producers’ current management practices.The previous results suggested that the joint environmental-economic impact was important when considering scenarios and that producers’ risk attitudes and best management practices’ economic impacts should be accounted for when selecting scenarios. Producers and watershed managers can weigh trade-offs between total phosphorous losses reduction and net returns variability when making water conservation decisions.     

干化土壤中节水型修剪枣树生长与水分利用效率研究

在野外山地设置4种不同土壤含水率水平的定位试验小区,试验枣树采用相同的节水型修剪标准使其保持一致的规格,在自然降水情况下连续2年观测土壤含水率、枣树生长、产量等。不同初始含水率的土壤在自然降水条件下,土壤含水率趋向某一个值,该值受年降水量的影响而异,2014平水年该值为(13.83±0.22)%,2015偏旱年为(9.46±0.32)%。初始土壤干化程度不同会显著抑制枣树枣吊生长和果实个数,在相同干化土壤中枣树的生长取决于当年的降水量,但节水型修剪下的产量比常规矮化修剪提高36%~41%,产量水分利用效率提高3.6倍以上。节水型修剪技术有利于提高枣树的产量水分利用效率。     

Ammonia abatement strategies in livestock production: A case study of a poultry installation

This study uses a linear programming approach to compare the potential effectiveness of uniform rules (under the Integrated Pollution Prevention and Control Directive) and a landscape-scale (a scale that includes different land-uses) based policy for reducing ammonia (NH₃) emissions and their related impacts from an operating case-study poultry installation. The model incorporates a variety of potential NH₃ abatement techniques. It also incorporates the first application of a spatial model of the diffusion of environmental impacts from NH₃ emissions. This models N deposition at a nearby nature reserve.     

Exploratory study on the land area required for global food supply and the potential global production of bioenergy

The areas of agricultural land on this globe that in the future possibly are available for biomass production for energy use and the potential global production of biomass were calculated. These available land areas increased when the global potential for food production (dependent on agricultural system and available land areas for agriculture) became higher in comparison to the global food requirement (dependent on population growth and mean consumption pattern). This study shows that 55% of the present agricultural land area at the global scale is needed for food production in the future (i.e. year 2050), if a high external input system of agriculture is applied. The remaining 45% can be used for other purposes, such as biomass production. If all potentially suitable land areas would be cultivated, the global potential for biomass production becomes about two times as large. If a low external input system is applied at the global scale for food production, however, no land area is available for biomass production.     

Accounting for water use: Terminology and implications for saving water and increasing production

Scarcity and competition for water are matters of increasing concern, as are potential shortages of food. These issues intersect both within the agricultural sector and across all water using sectors. Irrigation is by far the largest user of water in most water-scarce countries, and is under pressure to reduce utilisation (to release water to other sectors, including the environment) and use water more productively to meet demands for food and fibre.The terminology for such intra- and inter-sectoral analysis must be unambiguous across sectors so that interventions and their impacts are properly understood. Such terminology, based on previous work and debate, is set out. Implications for a better understanding of the scope for improved productivity of water in agriculture are traced, and some examples are given using data from recent research submissions, demonstrating the benefits of precise water accounting.