塔里木灌区棉花滴灌发展与效益分析

棉花是塔里木灌区主要种植作物.通过对该灌区历年滴灌面积、常规灌溉与滴灌棉花灌溉定额、单产及单方水效益等具体数据进行分析表明,棉花实施滴灌后每公顷可节水1 200 m3,计144元;到"十一五"末,滴灌比常规灌溉可节水约1亿m3;每公顷可使籽棉增产215 kg,计1 182.5元.     

灌水对冬小麦耗水量和产量影响的试验研究

2006年10月~2008年5月在山西省运城灌溉试验站进行了两年的冬小麦需水量和灌溉制度试验研究。结果表明,冬小麦的耗水规律为播种~越冬阶段0.48~1.11 mm/d;越冬~返青阶段0.14~1.07 mm/d;返青~拔节阶段0.69~2.10 mm/d;拔节~抽穗阶段2.02~4.27 mm/d;抽穗~灌浆阶段达到最大值3.57~8.62 mm/d;灌浆~收获阶段1.63~3.85 mm/d。冬小麦耗水量与产量呈抛物线关系,为了取得高产和较高的水分利用率,全生育期的耗水量应在380~440 mm之间。在当地气候、土壤及栽培模式下,冬小麦的灌溉制度为全生育期灌水3次,灌水定额60~80 mm,灌溉定额180~240 mm。     

水稻不同需水关键期适宜灌水下限指标研究

在5 m2有底测坑内研究水稻拔节孕穗期和抽穗开花期70%～90%土壤饱和含水率灌水下限对灌溉制度、渗漏量和产量等的影响。结果表明,不同灌水条件下,灌水次数、灌水模数、灌溉定额发生较大变化,灌水次数在本田期为28～37次,灌溉定额为8 190～9 450 m3/hm2,各处理渗漏量随着灌水量的降低而降低,渗漏量为灌水量的54.22%～64.25%,拔节孕穗期较抽穗开花期需水更敏感,拔节孕穗期应保持湿润状态,抽穗开花期适宜灌水下限为90%。     

对确立黑龙江省森工林区生态地位的讨论

分析了黑龙江省生态建设的实际状况及整体生态背景和生态作用,提出建设中存在的问题,并借鉴国外生态建设和我国国际合作生态建设的经验,就如何确立黑龙江省森工林区生态地位这一课题,阐述了在生态建设中应采取的相应措施。     

基于模糊聚类分析的游客景区选择研究

运用模糊聚类分析法建立游客景区选择的数学模型,对被选景区进行模糊聚类分析,得出游客景区选择的备选方案,方便游客进行景区决策,同时也为旅游景区经营管理者提供一种新的管理理念与管理方法。     

Wandering off the paths of planned innovation: The role of formal and informal intermediaries in a large-scale irrigation scheme in Morocco

For many years, large-scale irrigation around the world was based on state-driven water management and on a planned innovation process and diffusionist extension services. The purpose of this study is to show that formal extension services are not the only intermediaries of innovation and that local innovations take place at the initiative of farmers even in state-driven irrigation schemes. The study addressed changes in farming systems in a large-scale irrigation scheme in Morocco from two angles: a review of planned innovations and analysis of the actual innovation process at the village level. We show that the implementation of the large-scale irrigation scheme contributed to agricultural development, but often indirectly, and that it was not the only source of innovation. We also show how these results support recent thinking on innovation systems. Today, informal labour, neighbour and marketing networks are the main innovation intermediaries. New practices in agricultural extension are required to facilitate local innovations and to link farmers to more global innovation networks.     

Canopy temperature based system effectively schedules and controls center pivot irrigation of cotton

Cotton is a perennial plant with an indeterminate growth pattern that is typically produced like an annual, but requires proper management to effectively produce high yields and good fiber quality in a thermally limited environment like the northern Texas High Plains. In 2007 and 2008, we investigated the effect of irrigation scheduling/control method and amount on cotton (Gossypium hirsutum L.) yield and water use efficiency. Methods were automatic irrigation scheduling and control of a center pivot system, and manually scheduled irrigation to replenish soil-water to field capacity. Cotton was irrigated with LEPA (low energy, precision application) drag socks in furrow dikes; three blocks were irrigated manually and three were irrigated automatically. Six replicates of the manual and automatic irrigation treatments were included in the randomized block design. Manual irrigations were based on the weekly replenishment of soil-water to field capacity in the top 1.5 m of the soil profile and included a fully irrigated treatment (I₁₀₀), and treatments receiving 67% (I₆₇) and 33% (I₃₃) of the I₁₀₀ amount, plus a non-irrigated treatment (I₀). Automatic irrigations were triggered using a time temperature threshold (TTT) algorithm, which was designated as the I₁₀₀ treatment, and treatments receiving 67%, 33%, and 0% of that amount (I₆₇, I₃₃ and I₀, respectively). In 2007, overall mean lint yields (102.3 and 101.6 g m⁻², manual and automatic, respectively) were not significantly different. Similarly, yields were not significantly different across automatic and manual treatments in the same treatment level, with the exception of the I₆₇ treatment where the manual treatment yields were 11% greater. In 2008, the mean yields were 70% less than those in 2007 for both methods of irrigation (30.3 and 30.9 g m⁻², manual and automatic, respectively) due to harsh climatic conditions at emergence and heavy rainfall and cooler temperatures in the month of August. Yields from the automatically irrigated plots in the I₁₀₀ and I₆₇ treatments, however, were significantly greater than yields from the corresponding manually irrigated plots; though there was no significant difference between yields in the drier treatments (I₃₃ and I₀) plots. These results indicate that the TTT algorithm is a promising method for auto-irrigation scheduling of short season cotton in an arid region. However, further studies are essential to demonstrate consistent positive outcomes.     

基于单片机的光电式叶片面积测量系统

在农业生产中,叶片面积及其参数是衡量农作物产量的重要因素。传统叶片面积检测方法过程复杂,不能实现自动测量。为此,针对农业中田间叶片面积的实时测量需要,设计了基于单片机的光电式叶片面积测量系统;阐述了系统的整体设计思路、结构、测量原理、系统误差的计算及外部电路的设计。     

北方干寒地区日光温室CO2预测模型建立与冬季试验

根据质量平衡原理，构建了适用于北方干旱、寒冷地区典型日光温室CO2动态预测模型。模型定量描述了作物光合和呼吸作用、土壤呼吸作用、CO2施肥、自然通风及闭膜后的冷风渗透对室内空气中CO2的动态影响过程。利用内蒙古农牧业科技园区的日光温室对模型进行了冬季验证。结果表明，模型能较好地预测北方干旱、寒冷地区冬季晴天、多云天气的日光温室室内空气CO2浓度的动态变化过程，且预测值和实测值之间的相对误差小于10%。     

基于环路和改进遗传算法的树状灌溉管网优化

以投资最小为目标函数,建立了树状灌溉管网优化数学模型,用外部惩罚函数法将问题转化为无约束优化问题,并采用改进遗传算法进行求解。根据树状管网优化的特点,遗传算法采用二进制编码和整数编码相结合的双重编码,以同时对管网布置形式和管径进行优化。在遗传算法产生初始解及交叉、变异操作时,采用基于环路的方法,减少了不可行解的产生,提高了算法的计算效率,算例说明该优化方法有效、实用。