EFFICIENCY OF PRE-PLANT,TOPDRESS, AND VARIABLE RATE APPLICATION OF NITROGEN IN WINTER WHEAT

Past research about the efficiency of nitrogen application in winter wheat (Triticum aestivum L.) based on source and timing has produced inconsistent results. The majority of the literature used data from few locations over short time periods. This study used a unique data set of yields and nitrogen quantities from 2002–2009 at ten different locations in Oklahoma, USA. The objective of this research was to determine wheat yield response for granular pre-plant, uniform foliar topdress, and variable rate foliar topdress. Topdress liquid nitrogen had a 19% higher NUE than pre-plant urea, and was the most profitable source of nitrogen.     

东北玉米播种面积变化与相关成本效益比较研究:基于替代种植视角

本文从东北地区玉米与其生产替代作物播种面积变化入手,比较分析了1978-2014年东北三省相关作物成本收益数据,进一步采用联立方程模型研究相关成本收益变动和劳动力用工约束对玉米相对播种面积的影响。结果表明,玉米单位产量上的低成本造就了其较强的生产竞争力;玉米相对播种面积具有很强的延续性,且受价格和资本投入因素影响显著,而各作物间的用工差距对玉米相对播种面积影响并不显著;玉米单产的连续提高及单产差距的拉大,对玉米相对播种面积影响在不同作物间的表现不同。为确保国内玉米稳定生产、科学调整农业结构,我国应在保障玉米最低收购价和稳定农资产品价格的基础上稳步推进玉米价格市场化改革,依托玉米育种技术提高玉米单产水平,拓展农村社会化服务内容,重塑玉米竞争优势。     

Effects of Various Doses of Mineral Fertilizers (NPKS and Urea) on Yield and Economic Profitability of New Varieties ofZea mays L. in Faranah,Guinea

In Faranah Province(Guinea), the ratio of supply and demand of corn is approximately 1 : 2. The production is low and the deficit is covered by maize importation. This study was initiated in order to improve corn production by evaluating the effects of increasing doses of mineral fertilizers on the yield and economic profitability of corn. The experiment was conducted on a farm in Kamedankoude in a split plot with three replicates. Treatments included two varieties of maize(Perta and Kilissi113) and five doses of chemical fertilizers(D0=unfertilized control, D1=300 kg NPKS+200 kg urea · hm~(-2); D2=400 kg NPKS+800 kg urea · hm~(-2); D3=200 kg NPKS+400 kg urea-· hm~(-2) and D4=500 kg NPKS+600 kg urea · hm2). The results showed that all the agronomic parameters increased with increasing dose of fertilizers, except for the number of ears per plant. The two varieties of corn tested produced similar yields. However, the profitability of mineral fertilizers decreased with increased doses and with value/cost ratio of 3. We recommended a mineral fertilizer dose of 300 kg NPKS + 200 kg urea. The high prices of mineral fertilizers were often barriers to intensive maize cultivation, especially for low-income farmers. This study was a contribution to rational fertilization and adapted the socio-economic conditions of the region, with the background knowledge that most farmers in the regions earned low incomes.     

Using scenarios to project the changing profitability of fisheries under climate change

Over‐exploitation and economic underperformance are widespread in the world's fisheries. Global climate change is further affecting the distribution of marine species, raising concern for the persistence of biodiversity and presenting additional challenges to fisheries management. However, few studies have attempted to extend bioclimatic projections to assess the socio‐economic impacts of climate‐induced range shifts. This study investigates the potential implications of changes in relative environmental suitability and fisheries catch potential on UK fisheries by linking species distribution modelling with cost‐benefit analyses. We develop scenarios and apply a multimodel approach to explore the economic sensitivity of UK fisheries and key sources of uncertainty in the modelling procedure. We projected changes in maximum potential catch of key species and the resulting responses in terms of net present value (NPV) over a 45‐year period under scenarios of change in fuel price, discount rate and government subsidies. Results suggest that total maximum potential catch will decrease within the UK EEZ by 2050, resulting in a median decrease in NPV of 10%. This value decreases further when trends of fuel price change are extrapolated into the future, becoming negative when capacity‐enhancing subsidies are removed. Despite the variation in predictions from alternative models and data input, the direction of change in NPV is robust. This study highlights key factors influencing future profitability of UK fisheries and the importance of enhancing adaptive capacity in UK fisheries.     

Conservation agriculture based sustainable intensification of basmati rice-wheat system in North-West India

Continuous mono-cropping of rice-wheat (RW) system with conventional tillage (CT) based management practices have led to decline in soil health, groundwater table and farmers profit in north-west India. A medium-term (4 years) farmer’s participatory strategic research trial of basmati RW system was conducted to evaluate the effects of conservation agriculture (CA) based management practices on crop yields, water productivity, profitability and soil quality. Six treatments were compared varied in the cropping system, tillage, crop establishment and residue management. CA-based management under zero-till direct seeded rice-wheat-mungbean recorded 36% higher system yield than conventional till rice-wheat system (14.91 Mg ha^?1). CA-based rice-wheat system and rice-wheat-mungbean system saved ~35% irrigation water compared to conventional RW system (2168 mm ha^?1). Total water productivity (WP_I+R) was improved by 67% with CA-based rice-wheat-mungbean system (0.90 kg grain m^?3) over the conventional system. On system basis, 42% higher net return was recorded with CA-based rice-wheat-mungbean system compared to conventional system (USD 2570 ha^?1). Mungbean integration in basmati RW system contributed 29% share in system net returns across the treatments. Soil chemical and biological properties were improved by ~40% and 150%, respectively, with CA-based management system.     

No room for dessert: A mechanistic model of prey selection in gut‐limited predatory fish

Predatory fish structure communities through prey pursuit and consumption and, in many marine systems, the gadoids are particularly important. These predators have flexible feeding behaviours and often feed on large prey items. Digestion times of large prey are usually longer than handling times, and gut processing limits feeding rate at high prey density. Optimizing the gut content mix can therefore be an important behavioural strategy. Here, we develop a foraging model that incorporates gut processing and use the model to disentangle internal and external limitations on feeding in the omnivorous cod (Gadus morhua, Gadidae). We extend the traditional definition of prey profitability to consider prey digestive quality, which we quantify for prey of Northeast Atlantic cod populations. We find an important role for gut limitation; within a range of ecologically relevant temperatures and prey densities, predicted feeding rates were strongly reduced compared to feeding constrained by external factors only, and the optimal diet composition under gut limitation differed from predictions from traditional foraging theory. Capelin, a main prey of Northeast Arctic cod, had the highest digestive quality of all prey across ecosystems, but the cold temperatures in the Barents Sea strongly limited feeding rate by slowing down digestion. Baltic cod fed on a higher proportion of poor‐quality prey compared to the other populations, contributing to its slow growth in relation to water temperature. Gut limitation is particularly important to consider in foraging models for fish with many alternative prey species or fish occupying cold waters where digestion is slow.     

Plastic mulch and indigenous microorganism effects on yield and yield components of cauliflower and tomato in inland and coastal regions of Bangladesh

Production gaps exist in vegetable crops at the farm level in inland and coastal regions of Bangladesh and these gaps could be minimized using different innovative/new agricultural technologies and improved crop management practices. The present study was conducted to compare yield, yield components of cauliflower (Brassica oleracea var. botrytis) and tomato (Solanum lycopersicum L.), and income of smallholder vegetable farmers within different innovative technology practices (with plastic mulch and indigenous microorganism (IMO) vs. without plastic mulch and IMO) at Baliakandi, Rajbari (inland region); and Dashmina, Patuakhali; and Charfession, Bhola (coastal region) in Bangladesh. Yield and gross margins of cauliflower and tomato with plastic mulch and IMO were higher compared with no plastic mulch and no IMO, regardless of location. At Baliakandi, Rajbari, cauliflower yield with plastic mulch was 42.5 t ha^–1, which was a 24.3% improvement over cauliflower yield obtained without plastic mulch (34.2 t ha^–1). At Charfession, Bhola, the highest yield of tomato (57.6 t ha^–1) was obtained with IMO compared with tomato yield (49.2 t ha^–1) without IMO, indicating a 17.1% improvement in yield. Similar trends were obtained at Dashmina, Patuakhali. The difference in gross margin between tomato with and without plastic mulch was US$ 1146 ha^–1 at Dashmina, Patuakhali. Similar trends were obtained in other locations. Innovative agricultural technologies have the potential to increase yield and income of smallholder vegetable farmers in inland and coastal regions of Bangladesh.     

Influence of Sesbania Brown Manuring and Rice Residue Mulch on Soil Health,Weeds and System Productivity of Conservation Rice–Wheat Systems

The sustainability of rice–wheat cropping system (RWCS) is threatened by increasing labor, water, and energy crises in the region. Conservation RWCSs offers an ecofriendly alternate option. This study was aimed to evaluate the impact of sesbania brown manuring in direct‐seeded aerobic rice (DSAR) and of rice residue mulch in no‐tilled wheat (NTW) on soil health, weed dynamics and system productivity. The experiment was composed of five RWCS systems: (i) DSAR‐NTW; (ii) DSAR + sesbania brown manuring‐NTW; (iii) DSAR‐NTW + rice residue mulch; (iv) puddled transplanted flooded rice (PudTR)‐NTW; and (v) PudTR‐plow‐tilled wheat. Sesbania brown manuring in direct‐seeded rice decreased the weed density and dry biomass 41–56% and 62–75%, respectively, than the sole direct‐seeded rice crop. At rice harvest, better soil health, in terms of total nitrogen (N), soil organic carbon, soil microbial biomass carbon, and soil microbial biomass nitrogen, was noted with DSAR + sesbania brown manuring‐NTW. Rice residue mulch retention in NTW decreased weed density and dry weight by 60 and 69%, respectively, than those under NTW with no mulch. At wheat harvest, highest total N, soil organic carbon, and soil microbial biomass carbon were recorded with DSAR‐NTW + rice residue mulch, followed by DSAR + sesbania brown manuring‐NTW. Overall, NTW grown after DSAR + sesbania brown manuring produced more grain yield than PudTR‐NTW and PudTR‐plow‐tilled wheat systems. In conclusion, sesbania brown manuring in DSAR and residue mulch retention in NTW may be opted to improve soil properties, suppress weeds, and to harvest better grain yield and achieve higher system productivity in conservation RWCSs. Copyright © 2016 John Wiley & Sons, Ltd.     

巧记盈利能力指标研究

在不同的教材中盈利能力的计算公式有很多种类,在计算的过程中,指标的名称、具体计算公式都不尽相同。笔者从三个角度对盈利能力指标进行分类,然后根据这些指标的通用计算公式,利用指标名称推导出计算公式,帮助大家去理解记忆相关指标。     

On-Farm Participatory Technology Development Effects on Resource Conservation Technologies in Rainfed Upland Paddy in Himachal Pradesh,India

Rice is a major cereal crop in Himachal Pradesh, a Himalayan state of India, where paddy acreage is about 78,000 ha with a low average yield of 19.62 q ha^?1 due to rainfed upland farming. High seeding rates and poor resource-use efficiency of conventional fertilizer nitrogen (N) management practices in rainfed upland paddy have also been major production constraints in rainfed upland ecosystems. To validate and refine the production technology on seed rate and fertilizer N management, the Farm Science Centre, Sundernagar, India, conducted numerous on-farm trials (OFTs) during 2006–2010 under an on-farm participatory technology development approach to enhance resource use efficiency through these resource conservation technologies and boost the paddy productivity in the region. Results of two OFTs conducted during Kharif 2006 in the Mandi District of Himachal Pradesh on different seed rates under different sowing methods on VL Dhan-221 and Sukaradhan-1 (HPR-1156) cultivars suitable for rainfed upland conditions revealed that the seed rate at 80 kg ha^?1 sown in rows 20 cm apart resulted in the greatest average paddy productivity to the tune of 25.6 q ha^?1 besides greater profitability, followed by a seed rate at 60 kg ha^?1 sown in rows 20 cm apart (25.2 q ha^?1), over the earlier State Agricultural University (SAU)–recommended practice, that is, seed rate at 100 kg ha^?1 in rows 20 cm apart. This refinement in the seed rate was accepted by the participating farmers of the region. The greatest average benefit/cost (B/C) ratio was observed in plots with seed rate at 60 kg ha^?1 sown in rows 20 cm apart. Based on these results and data compilation from other locations of the state, now the SAU has refined the seed rate from earlier recommendation of 100 kg ha^?1 to 60 kg ha^?1 in rows 20 cm apart as well as 80 kg ha^?1 through broadcast method under rainfed upland paddy in Himachal Pradesh. Results of two OFTs conducted during Kharif 2009 on integrated nutrient management in rainfed upland paddy revealed that farmyard manure (FYM) at 10 t ha^?1 + nitrogen, phosphorus, and potassium (N, P, K) at 15:30:30 kg ha^?1 at sowing followed by 15 kg N ha^?1 15 days after sowing (DAS) and remaining the N [i.e., 30 kg N ha^?1] at tillering (45–50 DAS) resulted in the greatest grain yield of 29.85 and 31.67 q ha^?1 in VL Dhan-221 and HPR-1156, respectively, with respective greater yields of 35.99 and 36.51% over farmers’ practice, besides better profitability. To further standardize fertilizer N split doses and assess their effect on paddy productivity, another OFT was conducted during Kharif 2010 under rainfed upland paddy conditions in HPR-1156. The results revealed that NPK at 60:30:30 kg ha^?1 (whole of P and K as basal, 50% N at 15 DAS, 25% N each at 45–50 DAS and 70–75 DAS splits) resulted in better grain yield (34.3 q ha^?1) and net profitability (?29,786 ha^?1) over other treatments. Overall, it is concluded that these resource conservation technologies developed under the OFT participatory approach can enhance the rainfed upland paddy productivity and strongly show that there is dire need to split the N requirement of rainfed upland paddy in 2–3 splits to reduce the fertilizer N losses, enhance resource-use efficiency, and increase productivity and profitability in Himachal Pradesh, India.