Effects of silvopastoral areas on milk production at dual-purpose cattle farms at the semi-humid old agricultural frontier in central Nicaragua

In extensive cattle production systems, the composition of grazing areas may significantly influence productivity. In dual-purpose cattle production systems in the lowland tropics, pasture lands with trees, so-called silvopastoral areas, are considered as being important, particularly to facilitate the management of crossbred European native cattle. The aim of the study was to quantify the effects of silvopastoral areas on production at dual-purpose cattle farms in the semi-humid lowlands of central Nicaragua. The relationships between seasonal milk production and herd data, and the proportions of land use types were examined for 74 farms by stepwise regression analysis.     

Past, present and future criteria to breed crops for water-limited environments in West Africa

Asia's Green Revolution of the 1960s and 1970s has largely bypassed West Africa, and “modern” (high-yielding, input responsive) germplasm for staple crops has found comparatively little adoption, except for systems that are have good access to markets and sufficient water resources. It is unlikely, however, that breeding objectives conserving traditional crop characteristics as found in extensive systems would have been more successful. The authors identify systems caught in the agricultural transition from subsistence to intensified, market-oriented production as the most important target for crop improvement, and provide examples of new breeding objectives for cowpea, sorghum and upland rice. In each of these cases, breeders, with the help of physiologists, have developed innovative plant-type concepts that combine improved yield potential and input responsiveness with specific traditional crop characteristics that remain essential during the agricultural transition. In the case of cowpea, dual-purpose varieties were developed that produce a good grain yield due to an erect plant habit, then produce new leaves enabling a second harvest of green foliage. For upland rice systems that are limited by labour (mainly needed to control weeds that abound due to shortened fallow periods), a weed competitive plant type was developed from Oryza sativa × Oryza glaberrima crosses. Lastly, sorghum breeders who had previously deselected photoperiod sensitivity are now re-inserting sensitivity into plants having “modern” architecture, in order to allow for flexible sowing dates while maintaining an agro-ecologically optimal time of flowering near the end of the wet season. The ecophysiological basis of these plant types, their place in current and future cropping systems, as well as the problem of under-funding for their realisation, are discussed.     

两系稻在江西不同地区的生育特性及其育性转换初探

本研究通过不同地区的分期播种试验,观察了W6154S、5460S的生育特性和育性转换特性,指出了两个核雄性不育系的播种至始穗历期随纬度和海拔升高而增加,随栽培季节温度的升高而缩短。温度是诱导两个核雄性不育系育性转换的主导因素。同时提出了其制种与繁殖的适宜季节。     

粮饲兼用型小麦种质资源筛选与评价

为筛选出适宜在陕西关中地区种植的粮饲兼用型小麦(Triticum aestivum L.)种质资源,本研究采用盆栽种植方式,在大田气候条件下,以春化发育特性、田间农艺性状、饲草产量、再生能力以及籽粒产量等为指标,对300份小麦种质资源的粮饲兼用特性进行筛选与评价。结果表明,'大地532’、'隆麦855’、'黎丰6号’、'WM353’、'普冰326’、'永顺188’、'XN719’、'XN911’共8个小麦种质资源的冬季饲草产量和籽粒产量较高、再生能力较强及综合表现较好,适宜作为粮饲兼用型小麦种质资源进行育种和生产利用。本研究可为陕西关中地区及类似生态区的粮饲兼用型小麦育种和生产应用提供物质基础。     

谷秆两用稻201对硒的生物富集作用研究

硒（Se）是人体必须的微量元素，采用40 mg/kg的亚硒酸钠在齐穗期开始喷施谷秆两用稻201，使大米有机硒含量达0.27 mg/kg左右（P<0.05）；同时米糠和高蛋白稻草的有机硒富集水平分别提高3到4倍（P<0.05）；为生产富硒优质米提供依据，为生产富硒食用菌提供了优质原料。     

Productivity of different cow genetic groups in dual-purpose cattle production systems in south-eastern Mexico

The objective was to evaluate the effect of cow genetic group, nutritional level and their interaction on some economically important traits of dual-purpose herds managed under field conditions. Nine herds were monitored during a production cycle in Yucatan, Mexico. Herds were grouped into four nutritional levels (NL) based on the metabolizable energy (ME) apparently available on pasture, nutritional management, and milk production. Cows were classified into three genetic groups (GG): low (≤25%), middle (25–75%) and high (≥75%) graded for Bos taurus inheritance. Total milk sold (TMS), days in milk (DIM), TMS adjusted to DIM within each NL (TMSA), body condition score (BCS) at calving, changes of BCS during lactation (CBCS), calf weaning weight (WW), age at weaning (AW), kg of calf weaned per cow (KWC) and calf mortality were studied. The statistical model included the fixed effects of NL, GG, month of calving (MC), parity number (PN) and BCS at calving and GG × NL interaction. The effects of NL, GG, MC, PN and GG × NL were significant (p < 0.05) for TMS, KWC. As expected, TMS increased with NL from 562.4 ± 106 kg for NL1 to 2366.3 ± 100.1 kg for NL4. KWC was greatest for NL2 (138.6 kg) followed by NL1 (135 kg); the lowest KWC corresponded to NL4 (96.0 kg) (p < 0.05). TMS values for the middle (1727 ± 94.7 kg) and the high graded GG (1603.5 ± 83.5 kg) were twice those for the low graded GG cows (828.5 ± 95 kg) (p < 0.05). KWC was also higher for the middle graded group (152.8 kg) than for the low or (104 kg) or the high graded GG (118 kg) (p < 0.05). With better nutrition cows of all GG improved their milk performance but not the calf traits. CBCS was negative for all GG. The highest BCS lost was for cows in NL1 and NL2 and for cows in the high graded GG (p < 0.05).     

优质光温敏核不育系虔S的选育与应用

虔S是赣州市农业科学研究所用具有安农S-1亲缘的田丰S-1与Ⅱ-32B杂交,从其后代中定向选育的两用核不育系。该不育系具有配合力好、稻米品质优、育性稳定、株型好、熟期适宜特点。介绍了虔S的选育经过、特征特性及所配组合表现。     

高产优质多抗蔬饲兼用型糯玉米单交种苏玉糯9号的选育

苏玉糯9号是以自选系W15为母本、W35为父本组配成的糯玉米单交种,历年试验示范结果表明：苏玉糯9号高产、优质、多抗,同时还具有较高产的优质青贮用茎秆,可作为蔬饲兼用型玉米品种应用。     

Exante assessment of dual-purpose sweet potato in the crop–livestock system of western Kenya: A minimum-data approach

Mixed crop–livestock systems have a crucial role to play in meeting the agricultural production challenges of smallholder farmers in sub-Saharan Africa. Sweet potato is seen as a potential remedial crop for these farmers because of its high productivity and low input requirements, while its usefulness for both food and feed (dual-purpose) make it attractive in areas where land availability is declining. In this paper, we develop and apply a ‘minimum-data’ methodology to assess exante the economic viability of adopting dual-purpose sweet potato in Vihiga district, western Kenya. The methodology uses and integrates available socio-economic and bio-physical data on farmers’ land use allocation, production, and input and output use. Spatially heterogeneous characteristics of the current system regarding resources and productivity are analyzed to assess the profitability of substituting dual-purpose sweet potato for other crops currently grown for food and feed. Results indicate that a substantial number of farmers in the study area could benefit economically from adopting dual-purpose sweet potato. Depending on assumptions made, the adoption rate, expressed as the percentage of the total land under adopting farms, is between 55% and 80%. The analysis shows that the adoption rate is likely to vary positively with the average total yield of dual-purpose sweet potato, the harvest index (the ratio between tuber and fodder yields), the price of milk, and the nutritional value of available fodder. This study demonstrates the usefulness of the minimum-data methodology and provides evidence to support the hypothesis that dissemination of the dual-purpose sweet potato could help improve the livelihoods of smallholder farmers operating in mixed crop–livestock systems in east Africa.     

Exploring integrated crop–livestock systems in different ecoregions of the United States

Large-scale, energy-intensive, specialized production systems have dominated agricultural production in the United States for the past half-century. Although highly productive and economically successful, there is increasing concern with unintended negative environmental impacts of current agricultural systems. Production systems integrating crops and livestock have potential for providing additional ecosystem services from agriculture by capturing positive ecological interactions and avoiding negative environmental outcomes, while sustaining profitability. A diversity of ecologically sound integrated crop-livestock systems have been and can be employed in different ecoregions: sod-based crop rotations, grazing cover crops in cash-crop rotations, crop residue grazing, sod intercropping, dual-purpose cereal crops, and agroforestry/silvopasture. Improved technologies in conservation tillage, weed control, fertilization, fencing, and planting, as well as improved plant genetics offer opportunities to facilitate successful adoption of integrated systems. This paper explores the use and potential of integrated crop-livestock systems in achieving environmental stewardship and maintaining profitability under a diversity of ecological conditions in the United States.