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52.
M. Santalla M. Lema A. P. Rodiño A. M. González A. B. Monteagudo A. M. De Ron 《Euphytica》2005,142(1-2):85-95
Approaches are needed to broaden the genetic base and improve earliness and yield potential of large-seeded beans under sustainable cropping systems. The objective of this research was to develop adapted dwarf bean populations having a commercial seed quality and yield suitable for the production in the South of Europe. The original base populations were produced from crosses between genotypes within each Mesoamerica, Nueva Granada and Peru races, and between Peru and Nueva Granada, and Mesoamerica and Nueva Granada races. Visual mass selection for plant performance was practised in the F2 and F3 generations. In the F4 and F5, single plants were harvested under two cropping systems (sole cropping and intercropping with maize). From F4, selection was based on precocity, combined with seed yield and seed commercial type. The F4:7 selected lines from each original population were compared with their parents and five checks at four environments and two cropping systems. Differences among environments, populations, parents and checks were observed for all traits. Under intercropping with maize, there was a 50% reduction in seed yield. Yield of parents and checks belonging to Andean South American races, intraracial (Nueva Granada × Nueva Granada) and interracial (Nueva Granada × Peru) populations, was higher than that of those of Middle American origin. Intraracial crosses within large-seeded Andean South American (Peru race) and Middle American gene pools (Mesoamerica race) did not produce lines yielding more than the highest yielding parent. Only two large-seeded lines selected from crosses between small- and large-seeded gene pools out-yielded the best parent and check cultivar. 相似文献
53.
Xinwei Guo;Linlin Zhao;Zhixiang Wu;Rui Sun;Chuan Yang;Qingmao Fu;Zhenghong Tan; 《Land Degradation u0026amp; Development》2024,35(9):3136-3145
Understanding the dynamic relationships between soil organic carbon (SOC) and stand age are essential to quantify and predict the terrestrial carbon sequestration potential. However, the spatial patterns in the response of rubber plantation SOC to stand age and their driving factors remain unclear. Based on SOC and its components measurement at different soil depths (0–40 cm) in rubber plantations under five different age classes (0–5, 5–10, 10–20, 20–30, and >30 years) in three major rubber cultivation regions in China, distribution pattern and controlling factors of SOC were investigated. We found that SOC and its components showed significant spatial variability vertically with soil depth and laterally across sampling sites. SOC contents in three major rubber cultivation regions range from 4.48 to 20.13 g kg−1 at a depth of 0–40 cm. Among the sampling sites, Jinghong had the highest SOC content at a depth of 0–10 cm (20.13 g kg−1). On a large-scale, the relationship between SOC and stand age in rubber plantations did not show a consistent pattern among different sampling sites. Additionally, annual rainfall, soil moisture content, and soil pH had a stronger impact on SOC in rubber plantations compared to stand age. The results indicated that the spatial variability of SOC in rubber plantations with stand age could be influenced by specific soil properties and climate-related variables at each sampling site. This study emphasized the significance of conducting multi-site, multi-scale studies to enhance our understanding of SOC dynamics and its influencing factors, and help to more accurately predict the dynamic changes of soil carbon storage in rubber plantations. 相似文献
54.
通过对山西省偏关县退耕还林、加快后续产业发展主要做法的调查。认为柠条先行、灌草结合、兴林促牧是一条改善生态、发展经济、农民增益、实现“三嬴”之路。推进灌草结合造林模式,不仅缓解了林牧矛盾,巩固了退耕还林成果,也为加快农村产业结构调整、推动农民在退耕还林后发展商品型畜牧业创造了有利条件。 相似文献
55.
Jens Blomquist Magnus Simonsson Ararso Etana Kerstin Berglund 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2018,68(4):311-322
It has been suggested that liming can improve soil structure and thereby decrease losses of particles and associated nutrients. In this study, two types of structure lime, slaked lime (Ca(OH)2) and a mixed product of calcium carbonate (CaCO3) and slaked lime (Ca(OH)2), were applied at three different rates in field trials on clayey soils (23%–40% clay). A combination of primary tillage and structure liming was also studied, in a split-plot trial on a clayey soil (25% clay). Aggregate (2–5?mm) stability, measured as reduction in turbidity (which is strongly correlated with losses of particulate phosphorus), was significantly increased with the highest application rates of both structure lime products. Aggregate size distribution was also improved with structure lime, creating a finer tilth in the seedbed. Yield response to structure lime was not consistent, with both negative and positive responses over the four-year study period. Positive yield responses can possibly be attributed to the finer tilth preventing evaporation in two dry growing seasons. Negative yield responses were probably an effect of impaired phosphorus availability associated with limited precipitation in May-July in 2011 and 2013. Two years after liming, soil pH levels were significantly elevated in plots with the highest application rate of structure lime, whereas no significant increases were found three years after liming. However, a lingering effect of liming was still detectable, as manganese concentration in barley grain was significantly lower in plots with the highest application rates of both structure lime products in the fourth study year. These results indicate that structure liming can be used as a measure to mitigate phosphorus losses from clayey soils, thereby preventing eutrophication of nearby waters. However, the yield response was varying and unpredictable and thus further investigations are needed to determine the circumstances in which field liming can act efficiently not only to prevent phosphorus losses, but also to ensure consistent yield increases. 相似文献
56.
The extent and persistence of the effect of soil compaction in a system with annual ploughing were investigated in 21 long-term field experiments in Sweden with a total of 259 location-years. Crop yield, soil physical properties and plant establishment were determined. All experiments had two common treatments: control (no extra traffic) and compacted (350 Mg km ha−1 of experimental traffic in the autumn prior to ploughing), using a tractor and trailer with traditional wheel equipment and an axle load restricted to 4 Mg. During the rest of the year, both treatments were conventionally and equally tilled. The compaction was repeated each autumn for at least 7 years, and the yield was determined each year until 5 years after the termination of the compaction treatment.
Compaction decreased the porosity and the proportion of large pores and increased the tensile strength of dry aggregates. On clay and loam soils, it decreased the proportion of fine aggregates in the seedbed and the gravimetric soil water content in the seedbed.
The yield in the compacted treatment declined compared with the control during the first 4 years, after which it reached steady state. During this steady state, the compaction treatment caused a yield loss of 11.4%, averaged over 107 location-years. Within 4–5 years after the termination of the compaction treatment, the yield returned to the control level. The average yield loss at individual sites increased with increasing clay content.
Results from additional treatments indicated that yield loss was linearly correlated with the amount of traffic up to 300–400 Mg km ha−1. With greater ground contact pressure or a greater soil water content at time of traffic, there was a greater yield loss.
Soil compaction effects on yield were similar for all spring-sown crops, and the percentage yield loss seemed to be independent of the yield. In a few location-years with winter wheat there was on average no yield decrease.
There were 5.1% less plants in the compacted treatment than in the control. The yield decrease was significantly correlated with the number of plants.
Between years results were highly variable, and no consistent correlations between yield loss and soil water content at the time of traffic or the weather conditions during the growing period were found. Soil compaction affected yield during years with good as well as poor conditions for crop growth. 相似文献
57.
N. K. Fageria V. C. Baligar A. Moreira T. A. Portes 《Journal of plant nutrition》2013,36(14):2167-2181
Dry bean along with rice is a staple food for the population of South America. In this tropical region beans are grown on Oxisols and phosphorus (P) is one of the most yield limiting factors for dry bean production on these soils. A greenhouse experiment was conducted to evaluate P use efficiency in 20 elite dry bean genotypes grown at deficient (25 mg P kg?1 soil) and sufficient (200 mg P kg?1) levels of soil P. Grain yields and yield components were significantly increased with P fertilization and, interspecific genotype differences were observed for yield and yield components. The grain yield efficiency index (GYEI) was having highly significant quadratic association with grain yield. Based on GYEI most P use efficient genotypes were CNFP 8000, CNFP 10035, CNFP10104, CNFC 10410, CNFC 9461, CNFC 10467, CNFP 10109 and CNFP 10076 and most inefficient genotypes were CNFC 10438, CNFP 10120, CNFP 10103, and CNFC 10444. Shoot dry weight, number of pods per plant, 100-grain weights and number of seeds per pod was having significant positive association with grain yield. Hence, grain yield of dry bean can be improved with the improvement of these plant traits by adopting appropriate management practices. Soil pH, extractable P and calcium (Ca) saturation were significantly influenced by P treatments. Based on regression equation, optimum pH value in water was 6.6, optimum P in Mehlich 1 extraction solution was 36 mg kg?1 and optimum Ca saturation value was 37% for dry maximum bean yield. 相似文献
58.
Ragab Ragab 《Irrigation and Drainage》2015,64(1):1-12
Good management will be required to double food production by 2050. Testing management strategies is commonly carried out in the field. Such trials are costly and require quite a long time to produce consistent and reliable results. An alternative option to field trials would be the use of tested models. Models can run with ‘what‐if’ scenarios depicting different types of field management. They are a less costly and faster alternative to field trials. In contrast to some existing models, the SALTMED 2013 model is designed for general applications that include various irrigation systems and water application strategies, water of different qualities, variety of crops and trees, different nitrogen‐based fertilizers and different soil types. The model can simulate up to 20 fields with different treatments, different crops, different irrigation systems and management as well as different N‐fertilizer applications. The SALTMED model has been tested using field experiment data from Portugal, Italy, Denmark, Morocco, Egypt, Syria, Brazil and Iran. It successfully simulated soil moisture, salinity, nitrogen content, grain yield and total dry matter. The model provides academics, professionals and extension services with a management tool for crops, soil, water and nitrogen fertilizers. This paper describes the processes, the equations of the model and summarizes the different applications and results obtained. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
59.
广东省桉树人工林发展现状与可持续发展对策 总被引：1，自引：0，他引：1
文章介绍了广东省桉树人工林发展现状,阐述了发展的优势及潜力,分析了发展中存在的问题,并提出了今后桉树人工林可持续发展对策。 相似文献
60.
从种植区域、播种技术及收获与贮藏等方面简要介绍了青海山旱地菊芋丰产栽培技术,采用该技术菊芋的产量可达30-45 t.hm-2。 相似文献