Effects of fertilizer,variety and location on barley production under rainfed conditions in Northern Syria 2. Soil water dynamics and crop water use

The effects of fertilizer and location on the water use of two contrasting varieties of barley were studied in Northern Syria using a neutron probe. The observed patterns of soil moisture dynamics and crop water use were typical of those previously observed in Mediterranean-type environments. Moisture supply, as reflected by rainfall, was the principal factor affecting total water use, but both the application of fertilizer (N and P) and varietal differences also resulted in increased water use, particularly at the wetter location. There were no differences in the water-use efficiency between the two varieties, but the application of fertilizer resulted in large increases of water-use efficiency at both locations. Separation of crop evapotranspiration into crop transpiration and soil evaporation indicated that increased water-use efficiency was partially due to increased transpiration efficiency but was largely due to a reduction in soil evaporative loss, through greater soil shading by the crop canopy, and increased crop transpiration. Examination of this dataset together with the patterns of root and shoot growth suggest that fertilizer and varietal effects on root growth are linked to patterns of water use, growth and yield formation in barley.     

Feeding behavior of a potential insect pest, Lygus hesperus, on four new industrial crops for the arid southwestern USA

Camelina (Camelina sativa), guayule (Parthenium argentatum), lesquerella (Physaria fendleri), and vernonia (Centrapalus pauciflorus [formerly Vernonia galamensis]) are either under limited commercial production or being developed for production in the southwestern USA. Insect pests are a potential economic threat to all these new crops, with Lygus hesperus, the western tarnished plant bug, among the most prominent due to its regional abundance and propensity to feed on reproductive plant tissue. The objectives of this study were to establish baseline data on the feeding behavior and potential impact of L. hesperus on camelina, guayule, lesquerella and vernonia. Behavioral observations of adult females and males, and nymphs of this insect were made in the laboratory. Insects spent ≈35% of their time either probing (=tasting) or feeding on various reproductive and vegetative tissues of guayule, lesquerella or vernonia, but only 20% on camelina. When insects did probe and feed they preferred reproductive tissues, primarily flowers and siliques/achenes, and there were differences in these behaviors relative to crop but not generally to insect stage or sex. Insects probed and fed more on flower tissue of guayule and vernonia compared with camelina and lesquerella, and more on siliques of lesquerella compared with achenes of vernonia. When probing and feeding on vegetative tissue, there was generally a preference for stems compared with leaves in all crops except guayule. Results show that L. hesperus will readily feed on the economically important tissues of all crops, and although research has shown that this feeding did not consistently affect lesquerella yield, further work will be needed to determine if such feeding poses a risk to commercial production of camelina, guayule or vernonia.     

The influence of mist irrigation on the potato: II. Growth and development

The influence of irrigation method on potato growth and development was assessed during three years. Low volume “mist” irrigation (M), furrow irrigation (F), mist plus furrow (MF) and no irrigation (NI) were compared. During a high and moderate stress season misting maintained the haulm later into the season and increased the proportion of small and medium size tubers. Further during the high stress season misted plots (M and MF) yielded more than NI plots.     

Intercropping potatoes in early spring in a temperate climate. 3. The influence of planting date, row width and temperature change on the potential for intercropping

Summary The effects of planting date and row width on canopy development, intercepted radiation and yield were studied in two experiments, with the variety Wilja in 1988 and Cara in 1989. Planting dates were between mid March and early May and were combined with row widths of 0.75 and 1.25 m. Increasing the row width decreased intercepted radiation and yields in both years. Delayed planting reduced the yield of Cara, but not of Wilja. Early planting increased radiation use efficiency of Cara. It is argued that intercropping in spring without potentially reducing tuber yield might be favoured by delaying the planting of a determinate variety such as Wilja but by increasing the row width for an indeterminate variety such as Cara. Trends in mean monthly and soil 10 cm temperatures however suggest that opportunities for intercropping potatoes in the spring in a temperate climate may become more restricted.     

The influence of mist irrigation on the potato I. Micro-environment and leaf water relations

The influence of low gallonage “mist” irrigation on the following parameters were measured: leaf, air and soil temperature; and soil moisture, relative turgor and stomatal aperature. Misted canopies had lower leaf, air and soil temperature and higher soil moisture than the non-irrigated plants. Stomata of misted plants did not close as rapidly as those of non-irrigated plants.     

Effects of cabergoline on the fertility of female mice during early and late pregnancy,and potential for its use in mouse control

To evaluate the dose effects of cabergoline on the fertility of female mice during early or late pregnancy, cabergoline was continuously administered by gastrogavage for three days within 1 day to 3 day or 15 day to 17 day of gestation. The body mass, reproductive rate, litter size at birth and weaning of females, as well as the body mass, survival rate of pups, were recorded. During early pregnancy, cabergoline treatment effectively terminated the pregnancy of mice. Cabergoline (100 μg/kg) was half effective in terminating pregnancy and significantly reduced the average litter size and survival rate of pups compared with those of the controls. Cabergoline treatment of 200 and 400 μg/kg completely terminated pregnancy of mice and induced incomplete restoration of fertility (40% and 44%, respectively) even at the second cycle of reproduction. During late pregnancy, cabergoline did not change the litter size at birth but significantly reduced the litter size at weaning and the survival rate of pups, 400 μg/kg cabergoline markedly reduced the survival rate to 77% compared with the controls. The death of pups mainly occurred during seven days after parturition. Cabergoline had no significant difference on the average body mass of surviving pups in treated groups compared with controls during lactation. In conclusion, cabergoline may inhibit or reduce the reproduction of female mice, and demonstrate different dose effects on the fertility during early or late pregnancy. Together with infertility efficacy in phase prior to mating and lactation, cabergoline is a potential fertility control agent for pest rodent control.     

Improving sink regulation,and searching for promising traits associated with hybrids,as a key avenue to increase yield potential of the rice crop in the tropics

Yield advantage of hybrid rice in the tropics has been reported recently as the result of higher biomass accumulation and better biomass partitioning over the whole crop growth. Considering that increasing biomass accumulation is the main target for higher yield potential in sub-tropical and temperate conditions, it is relevant to investigate in a wide range of growing conditions in the tropics if improved biomass partitioning plays a significant and consistent role in higher yield of hybrids. The growth pattern of two high-yielding and popular hybrid (H1) and inbred (I1) of the same maturity group was compared under six contrasted growing conditions to evaluate traits related to sink regulation. Grain yield of H1 was consistently higher than that of I1 by 16–32% with respect to the situation. Higher partitioning coefficients of the hybrid to key organs were confirmed over the whole crop growth for this set of environments whereas crop growth rates of hybrid were not consistently higher than that of inbreds. Sink strength index, as a way to express sink regulation at maturity more efficiently than harvest index, was higher with hybrids in five out of six environments. In search for promising traits related to sink regulation, higher specific leaf area of hybrids at very early stage was associated with higher leaf area, and earlier cessation of tiller production with hybrids coincided with higher partitioning of biomass to early culm growth: yet, maximum tiller number ranged from 548 to 962 tiller m⁻² with H1 and from 629 to 1427 tiller m⁻² with I1 while culm dry weight at 55 days after sowing ranged from 65 to 81 g m⁻² with H1 and from 46 to 53 g m⁻² with I1. This analysis strongly reinforced the pertinence of improving sink regulation for increasing yield potential in the tropics.     

Effect of maturity stage at harvest on the ensilability of maize hybrids in the early and late FAO classes,grown in areas differing in yield potential

The aim of this study was to assess the effects of earliness (according to FAO class), maturity stage at harvest and environmental conditions on the ensilability of maize hybrids described by their fermentation products and by a fermentation quality index (FQI). Maize hybrids belonging to early (n = 14) and late (n = 15) FAO classes were grown in low, medium and high potential yield areas and harvested at an early (EH), medium (MH) and late maturity stage (LH), that is, at 1/3, 2/3 and 5 d after the 2/3 milk line stage, respectively, according to a split‐plot design. Upon harvest, each sample (n = 522) was analysed for dry matter (DM) and water‐soluble carbohydrates (WSC) before being ensiled in vacuum‐packed bags (n = 1,044). After 60 days of conservation, samples were analysed for DM and fermentation products. In the pre‐ensiling phase, DM was higher in early hybrids (p = .001), low yield areas (p < .001) and at LH maturity (p < .001), whereas WSC contents were higher in early hybrids (p < .001), medium yield areas (p < .001) and at EH maturity (p < .001). With regard to silages, early hybrids had a higher FQI (p < .001), which was highest in areas with a high yield potential (p < .01) and at EH maturity (p < .01). Late hybrids proved to be better suited for low yield areas compared with early hybrids (p < .01) and had a higher FQI at EH and MH than at LH maturity (p < .01).     

The influence of ethofumesate on the growth and development, chlorophyll and nitrogen content of Lolium perenne L.

Pot experiments and a hand-weeded field trial were carried out to investigate the direct effect of ethofumesate on the growth and development of Lolium perenne cv. S24.
In the field trial, ethofumesate was applied in autumn as Nortron 20% ec formulation in a volume of 2001 ha^-1 at rates of 0, 1 or 2 kg a.i. ha^-1. Treatments had no direct effect on yield in the following summer. In both the field trial and pot experiments there was initial growth suppression in the form of a reduction in shoot dry weight, lamina dry weight, tiller number per plant and plant height. However, ethofumesate increased the chlorophyll and nitrogen contents of L. perenne laminae, but only when available soil nitrogen was not limited.
It is concluded that ethofumesate can increase the yield of L. perenne by suppressing weed competition, but there is no evidence of the herbicide directly increasing the growth or yield of cv. S24.     

大麦高赖氨酸的遗传选择与研究Ⅱ．大麦的赖氨酸含量与胚比及千粒重的相关

测定了14个皮、裸大麦品种籽粒的赖氨酸含量、胚比（胚干重与籽粒干重的百分比值）和千粒重,并估算了这些性状间的相关性。结果表明,各性状在品种间均存在显著的差异。赖氨酸含量与胚比在皮大麦中存在正相关,胚比大的材料在一定程度上可以作为选择高赖氨酸含量的形态指标,而裸大麦赖氨酸含量与胚比无相关;胚比与千粒重在皮、裸大麦中均呈负相关,低千粒重可作为选择高赖氨酸品种（系）的参考。     

The influence of seepage from canals and paddy fields on the groundwater level of neighboring rotation cropping fields: a case study from the lower Ili River Basin,Kazakhstan

In the large-scale irrigation schemes of the lower Ili River Basin of Kazakhstan, crop rotation combines paddy rice and non-rice crops. Continuous irrigation is practiced in paddy fields, whereas other crops are sustained from groundwater after only limited early irrigation. The water table in non-rice crops is raised by seepage from canals and the flooded paddy fields. We investigated the areal extent to which the groundwater level of non-irrigated fields is influenced by seepage from canals and paddy fields by examining the relationship between distance (from canal and paddy field) and groundwater level in upland fields. The groundwater level was influenced for up to 300 and 400 m from the canals and paddy fields, respectively. Geographic information system analysis of crop and canal patterns in the 11 selected years showed that if the zone of influence is 300 and 400 m from the canals and paddy fields, respectively, the groundwater level of most of the area of upland fields was raised by seepage. We conclude that the water supply to cropping fields by seepage from irrigation canals and paddy fields is adequate, but the spatial distribution of the paddy fields may be an important factor that needs more attention to help improve water use efficiency in this irrigation district.     

The conservation management of mesotrophic (meadow) grassland in northern England. 1. Effects of grazing, cutting date and fertilizer on the vegetation of a traditionally managed sward

The results are reported from an experiment on the effects of cutting date (14 June, 21 July and I September), fertilizer application (none or 80 kg ha^?1 N plus 40 kg ha^?1 P and K) and grazing treatments (none, autumn or autumn plus spring) on the vegetation of an upland mesotrophic grassland in Upper Teesdale. northern England, UK. Effects on plant species number and cover are reported for 4 years (1989–93) of treatment. Effects on ‘species -attributes’ are given for the fourth year. The cessation of grazing combined with the use of fertilizer progressively reduced species number by about 25%. Under traditional management (no fertilizer, cutting date on 21 July, autumn and spring grazing) the species number and cover remained relatively static over the 4 years. Comparison between treatments in the fourth year showed a reduction in species number under the fertilizer application, cutting date on 1 September and no-grazing treatments. Fertilizer use together with cutting date on 1 September particularly lowered species number and cover. Analysis of variance was used to assess the effect of treatment on species that occurred frequently in the sward. A cutting date of 1 September favoured Agrostis capillaris. Alopecurus pratensis, Poa trivialis, Phleum pratense and Trisetum flavescens, The absence of grazing favoured Dactylis glomerata and Holcus lanatus. The use of fertilizer particularly favoured A. pratensis and H. lanatus. Ordination methods were used to assess the effect of treatment on the less frequent species. These were primarily associated with the treatment combination that matched ‘traditional’ management. Deviations from this ‘traditional’ regime acted separately, rather than in combination, and favoured different grass species. Traditional management was associated with ruderal, stress-tolerant ruderal and competitive ruderal strategists and with longer seed germination times, heavier seeds, some of which needed scarifying or chilling to break dormancy, and transient seed banks that germinated in the autumn. The original sward was an Anthoxanthum odora-turn-Geranium sylvatirum grassland, Briza media subcommunity (MG3b). After 4 years, Festuca ovina-Agrostis capillaris-Galium saxatile grassland, Holcus lanatus-Trifolium repens subcom-munity (U4b) and Lolium perenne-Alopecurus pratensis-Festuca pratensis grassland (MG7c) were found in many of the fertilized and late-cutting treatments.