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1.
This paper applies linear mixed model analysis to 122 on-farm trials of commercial and near-commercial sunflower (Helianthus annuus L.) hybrids grown over 15 years in 32 locations of central Argentina to quantify increases in oil yield and to determine the contributions of change in both biotic stress resistance and yielding ability in favourable environments. The best linear unbiased predictors (BLUPs) from this analysis can be regarded as measures of ‘relative peak performance’ of hybrids in environments for which they were selected, and are a better measure of their adaptation compared to small trial sets of ‘historical’ hybrids. The BLUPs of 49 commercial hybrids released between 1983 and 2005 showed a genetic gain for oil yield of 11.9 kg ha−1 yr−1. Special purpose hybrids that were converted for single traits or that were developed for low-technology markets lagged by 5–15 years in terms of genetic gain. Genetic gains came about due to both an increase in the number of hybrids with resistance to the major biotic stress (Verticillium dahliae Klebahn) and a genetic gain in oil yield of 14.4 kg ha−1 yr−1 within these hybrids. Based on the data and the estimated time lag between commercial release and peak use, the improvement in oil and grain yield of conventional hybrids in central Argentina will be sustained until at least 2010, with evidence that the new germplasm pools still have substantial genetic variance to be exploited. 相似文献
2.
The paper investigates management and cultivar type effects on pearl millet stover yield and fodder quality. Sixteen pearl millet cultivars available to farmers in India were selected to represent three cultivar types: (1) traditional landrace germplasm from the arid/semi-arid millet production zones, (2) improved dual-purpose (grain and stover) open-pollinated varieties incorporating differing amounts of traditional landrace germplasm and (3) commercial, grain-type F1 hybrids, bred for use in the arid/semi-arid zone. The cultivars were grown for 2 years (2000 and 2001) at high fertility (HF: 65 kg N ha−1 and 18 kg P ha−1) and low fertility (LF: 21 kg N ha−1 and 9 kg P ha−1). Within each fertility level high (HP) and low (LP) plant population densities were established by varying sowing rate and then thinning to the target populations (HP: 11 plants m−2 and LP: 5 plants m−2). Stover fodder quality traits (nitrogen concentration, sugar content, in vitro digestibility and metabolizable energy content) were analyzed using a combination of conventional laboratory analysis and near infrared spectroscopy. In general, fertility level and cultivar type had strong effects on grain and stover yields, and on a range of stover nutritional quality traits, but with significant year interactions. In contrast, the effect of population density on these variables was largely insignificant. Higher fertilizer application significantly increased grain and stover yields and stover nitrogen concentration, in vitro digestibility and metabolizable energy content. As a result, fertilization resulted in significant increases in the yields of both digestible and metabolizable stover. Landrace cultivars as a group produced higher quality fodder than modern hybrids, but at a significant cost in grain yield. Dual-purpose, open-pollinated cultivars were generally intermediate between the landraces and hybrids, in terms of both stover quality and grain yield, but produced the highest yields of both digestible and metabolizable stover. The paper discusses the implications of these findings for Indian pearl millet farmers with various resource levels and farming objectives. 相似文献
3.
Valtcho D. Zheljazkov Brady VickM. Wayne Ebelhar Normie BuehringTess Astatkie 《Industrial Crops and Products》2012,36(1):28-32
Winter mustard (Brassica juncea L.) is not a common crop in the Southeastern United States. With increased interest in biodiesel production, there has been corresponding interest in mustard in this region. The objective of this study was to evaluate the effect of N fertilization (0, 50, 100, 150 kg N ha−1) on productivity, oil content, and oil composition of winter mustard ‘Pacific Gold’ grown at three locations in Mississippi (Stoneville, and two locations at Verona, namely Verona silt loam (Verona-SL) and Verona clay (Verona-C)). Nitrogen did not affect oil content (percent oil). Seed and oil yields (kg ha−1) increased with N application relative to the unfertilized control. At the Verona-C location, the concentration of oleic acid was higher in the 50 kg N ha−1 treatment. At Stoneville, linolenic acid concentration was higher in the 150 kg N ha−1 and lower in the 100 kg/N ha−1 treatment, while it was not different in the other treatments. Overall, the yield of the fatty acids (FA) palmitic, palmitoleic, stearic, oleic, linoleic, linolenic, arachidic, eicosanoic, behenic, erucic, lignoceric, and nervonic acid increased with higher N rates (100 or 150 kg N/h). The highest yield of FA in the two Verona locations were achieved in the 100 kg N ha−1, while greatest yield of FA at Stoneville was achieved in the highest N rate (150 kg N ha−1). Means of mustard oil yields in our study in the higher fertility treatment ranged from 737 to 1094 kg ha−1. This study demonstrated winter mustard production in Mississippi and possibly other areas in the Southeastern United States can be successful and could provide seed and oil yields comparable to yields from other production areas. 相似文献
4.
The present investigation was conducted at Vittal, Karnataka, India during 2004-2007 to study the feasibility of intercropping of medicinal and aromatic plants (MAPs) in arecanut plantation. The results revealed that MAPs can be successfully grown as intercrops in arecanut plantation with increased productivity and net income per unit area. Kernel equivalent yield of MAPs varied between 272 kg ha−1 in case of Piper longum to 1218 kg ha−1 in Cymbopogon flexuosus. Pooled data indicated that Asparagus racemosus produced fresh root yield of 10,666 kg ha−1 of arecanut plantation and contributed to maximum kernel equivalent yield of 1524 kg ha−1 among all medicinal and aromatic plants. Intercropping of MAPs in arecanut was found economical. The net return per rupee investment was highest in C. flexuosus (4.25) followed by Bacopa monnieri (3.64), Ocimum basilicum (3.46) and Artemisia pallens (3.12). The total system productivity of arecanut + MAPs intercropping system varied from 2990 to 4144 kg ha−1. Arecanut + O. basilicum intercropping system registered significantly higher production efficiency 8.2 kg ha−1 day−1 than other systems. Intercropping of MAPs had more positive effect on soil pH in arecanut based cropping system. The soil pH was 5.6 in 2004 and it was 0.3-0.9 units higher in 2007. Soil organic carbon (SOC) content varied significantly due to intercropping of MAPs at the end of experiment. The SOC content increased in Aloe vera, A. pallens, P. longum and B. monnieri, while it depleted in grasses and rhizomatic MAPs. Based on demand and marketing opportunities for MAPs, farmers are advised to grow aromatic plants in large areas on a community basis to meet huge industrial demand and variety of medicinal crops in small areas to meet the requirement of traditional systems of medicine. 相似文献
5.
The increases in crop yield that played an important role in maintaining adequate food supplies in the past may not continue in the future. Soybean (Glycine max L. Merrill) county yield trends (1972–2003) were examined for evidence of plateaus using data (National Agricultural Statistics Service) for 162 counties (215 data sets) in six production systems [Iowa, Nebraska (irrigated and non-irrigated), Kentucky and Arkansas (irrigated and non-irrigated)] representing a range in yield potential. Average yield (1999–2003) was highest in irrigated production in Nebraska (3403 kg ha−1) and lowest in non-irrigated areas in Arkansas (1482 kg ha−1). Average yield in the highest yielding county in each system was 31–88% higher than the lowest. Linear regression of yield versus time was significant (P = 0.05) in 169 data sets and a linear-plateau model reached convergence (with the intersection point in the mid-1990s) in 35 of these data sets, but it was significantly (P = 0.10) better in only three data sets (<2% of the total). Absolute (kg ha−1 year−1) growth rates were associated with productivity, but relative rates were not with the mean relative rates ranging from 1.0 to 1.3% over the six systems. There was, however, a two- to threefold range in relative rate among counties within systems in Nebraska, Iowa, Kentucky and Arkansas (irrigated). Yield did not change (linear regression not significant, P = 0.05) between 1972 and 2003 in 41 counties in non-irrigated areas of Arkansas and Nebraska and in six Kentucky counties of which four had high levels of double-cropping soybean after wheat (Triticum aestivum L.). I found no convincing evidence that soybean yields are reaching plateaus but the technology responsible for this yield growth was apparently completely ineffective in low-yield, high-stress environments. 相似文献
6.
Nitrogen rates and plant genotypes effects yield and quality of medicinal plants therefore, this experiment was conducted in order to determine the effects of nitrogen rates on fennel accessions quality and quantity. The experimental design was a split plot with nitrogen rate (0, 40, 80, 120 and 160 Kg N ha−1) as main and accession (Isfahan, Tehran, Yazd and EU11486) as sub plots and replicated four times. The experiment was conducted at the Isfahan University of Technology Experimental Station, Isfahan, Iran during 2008-2009. Plant height, number of umbel per plant, 1000seed weight, number of seeds per umbel, seed yield, seed essential oil yield, seed and foliage essential oil contents and seed ash, protein and fiber contents were measured. Nitrogen fertilization increased all measured traits, but reduced ash content. On average, the highest seed and foliage essential contents and seed essential yield were produced at 160 kg per N ha−1 and EU11486 was a superior cultivar for these traits. However, there was an interaction between N rate and accession on all traits. Isfahan (11.65 kg ha−1), EU11486 (38.26 kg ha−1), Tehran (15.32 kg ha−1) and Yazd (22.06 kg ha−1) produced the highest seed essential oil yield under application of 160, 80, 160 and 120 kg N ha−1, respectively. Foliage of the accessions contained 0.45-0.91% essential oil and seeds of accessions contained 17.6-18.2% protein and 8.9-9.4% ash suggesting that foliage of fennel also is a good source of essential oil and seeds of fennel are good sources of protein and minerals. The results showed that N fertilization and accession can affect yield and quality of fennel and accessions responded differently to N fertilization rates, thus selection among the accessions and N rates for better fennel production is possible. 相似文献
7.
In the low-input rice–wheat production systems of Nepal, the N nutrition of both crops is largely based on the supply from soil pools. Declining yield trends call for management interventions aiming at the avoidance of native soil N losses. A field study was conducted at two sites in the lowland and the upper mid-hills of Nepal with contrasting temperature regimes and durations of the dry-to-wet season transition period between the harvest of wheat and the transplanting of lowland rice. Technical options included the return of the straw of the preceding wheat crop, the cultivation of short-cycled crops during the transition season, and combinations of both. Dynamics of soil Nmin, nitrate leaching, nitrous oxide emissions, and crop N uptake were studied throughout the year between 2004 and 2005 and partial N balances of the cropping systems were established. In the traditional system (bare fallow between wheat and rice) a large accumulation of soil nitrate N and its subsequent disappearance upon soil saturation occurred during the transition season. This nitrate loss was associated with nitrate leaching (6.3 and 12.8 kg ha−1 at the low and high altitude sites, respectively) and peaks of nitrous oxide emissions (120 and 480 mg m−2 h−1 at the low and high altitude sites, respectively). Incorporation of wheat straw at 3 Mg ha−1 and/or cultivation of a nitrate catch crop during the transition season significantly reduced the build up of soil nitrate and subsequent N losses at the low altitude site. At the high altitude site, cumulative grain yields increased from 2.35 Mg ha−1 with bare fallow during the transition season to 3.44 Mg ha−1 when wheat straw was incorporated. At the low altitude site, the cumulative yield significantly increased from 2.85 Mg ha−1 (bare fallow) to between 3.63 and 6.63 Mg ha−1, depending on the transition season option applied. Irrespective of the site and the land use option applied during the transition season, systems N balances remained largely negative, ranging from −37 to −84 kg N ha−1. We conclude that despite reduced N losses and increased grain yields the proposed options need to be complemented with additional N inputs to sustain long-term productivity. 相似文献
8.
Improving crop yield and N uptake with long-term straw retention in two contrasting soil types 总被引：4，自引：0，他引：4
Retention and/or reincorporation of plant residues increases soil organic nitrogen (N) levels over the long-term is associated with increased crop yields. There is still uncertainty, however, about the interaction between crop residue (straw) retention and N fertilizer rates and sources. The objective of the study was to assess the influence of straw management (straw removed [SRem] and straw retained [SRet]), N fertilizer rate (0, 25, 50 and 75 kg N ha−1) and N source (urea and polymer-coated urea [called ESN]) under conventional tillage on seed yield, straw yield, total N uptake in seed + straw and N balance sheet. Field experiments with barley monoculture (1983-1996), and wheat/barley-canola-triticale-pea rotation (1997-2009) were conducted on two contrasting soil types (Gray Luvisol [Typic Haplocryalf] loam soil at Breton; Black Chernozem [Albic Argicryoll] silty clay loam at Ellerslie) in north-central Alberta, Canada. On the average, SRet produced greater seed yield (by 205-220 kg ha−1), straw yield (by 154-160 kg ha−1) and total N uptake in seed + straw (by 5.2 kg N ha−1) than SRem in almost all cases in both periods at Ellerslie, and only in the 1997-2009 period at Breton (by 102 kg seed ha−1, 196 kg straw ha−1 and by 3.7 kg N ha−1) for both N sources. There was generally a considerable increase in seed yield, straw yield and total N uptake in seed + straw from applied N up to 75 kg N ha−1 rate for both N sources at both sites and more so at Breton, but the response to applied N decreased with increasing N rate. The ESN was superior to urea in increasing seed yield (by 109 kg ha−1), straw yield (by 80 kg ha−1) and total N uptake in seed + straw (by 2.4 kg N ha−1) in the 1983-1996 period at Breton (mainly at the 25 and 50 kg N ha−1 rates). But, urea produced greater straw yield (by 95 kg ha−1) and total N uptake in seed + straw (by 3.3 kg N ha−1) than ESN in the 1983-1996 period at Ellerslie. The N balance sheets over the 1983-2009 study duration indicated large amounts of applied N unaccounted for (ranged from 740 to 1518 kg N ha−1 at Breton and from 696 to 1334 kg N ha−1 at Ellerslie), suggesting a great potential for N loss from the soil-plant system through denitrification and/or nitrate leaching, and from the soil mineral N pool by N immobilization. In conclusion, the findings suggest that long-term retention of crop residue may gradually improve soil productivity. The effectiveness of N source varied with soil type. 相似文献
9.
Abiotic constraints override biotic constraints in East African highland banana systems 总被引：1，自引：0，他引：1
Lydia W.I. Wairegi Piet J.A. van Asten Moses M. Tenywa Mateete A. Bekunda 《Field Crops Research》2010
Banana is the primary food crop in Uganda, but yields are low due to a complex of abiotic and biotic constraints. However, quantitative information on the importance, interactions, and geographic distribution of yields and constraints is scanty. We monitored yields, biotic and abiotic constraints in 159 plots in Central, South and Southwest Uganda in 2006–2007. About half the plots were on-farm demonstrations that received fertilizer (average 71N, 8P, 32 K kg ha−1 year−1) through a development project, the rest were ordinary farmer fields (i.e. controls). Fresh banana yields in controls were significantly (P ≤ 0.05) higher in Southwest (20 t ha−1 year−1) compared with Central (12 t ha−1 year−1) and South (10 t ha−1 year−1). Demonstrations yielded 3–10 t ha−1 year−1 more than controls. Yield losses were calculated using the boundary line approach. In Central, yield losses, expressed as percentage of attainable yield, were mainly attributed to pests (nematodes 10% loss, weevils – 6%) and suboptimal crop management (mulch 25%). In South, poor soil quality (pH – 21%, SOM – 13%, N-total – 13%, and Clay – 11%) and suboptimal crop management (weeds – 20%) were the main constraints. In Southwest, suboptimal crop management (mulch 16%), poor soil quality (K/(Ca + Mg) − 11%) and low rainfall (5%) were the primary constraints. The study revealed that biotic stresses (i.e. pests, weeds) are particularly important in Central, whereas abiotic stresses (i.e. nutrient deficiencies, drought) dominate in South and Southwest. This study concludes that (i) technologies currently available allow farmers to double yields and (ii) past research efforts have mistakenly neglected abiotic constraints. 相似文献
10.
Valdinei SofiattiLiv S. Severino Franklin M.O. SilvaVivianny N.B. Silva Giovani G. Brito 《Industrial Crops and Products》2012,37(1):235-237
Weed management is among the main factors limiting cultivation of castor (Ricinus communis) in extensive fields, particularly when labor is scarce or expensive. This experiment evaluated the efficiency of weed management programs using preemergence (clomazone, pendimethalin, and trifluralin) and a postemergence herbicide (chlorimuron-ethyl) applied at 20 days after emergence in castor plants cv. BRS Energia under rainfed conditions in Apodi, Brazil. No phytotoxicity was observed on the castor plants, and the postemergence herbicide significantly increased castor seed yield to 1466 kg ha−1 complementing the weed control of preemergence herbicides treatments in which seed yield was 1207 kg ha−1. Seed yield on weedy and weed-free treatments was 760 and 1971 kg ha−1, respectively. Weeds were kept under a satisfactory control up to 40 days after emergence. This program resulted in reasonable weed control because the preemergence herbicides controled monocotyledon weeds, while the postemergence herbicide controlled broad leafed species being selective to castor plants. 相似文献
11.
Artemisia annua L. is an annual aromatic antibacterial herb, with effective antimalarial properties due to the presence of artemisinin. The intention of the present study was to establish plant survival, growth attributes, yield attributes and artemisinin yield of A. annua cv CIM - Arogya with different transplanting months in two cropping seasons (March 2005-February 2006 and March 2006-February 2007) under temperate climatic conditions of Himalaya, India. Artemisinin yield in the dried leaves was found maximum amongst the plants that were transplanted in March (24.39 kg ha−1) and minimum in those transplanted in November (3.39 kg ha−1). 相似文献
12.
Long-term (over 15 years) winter wheat (Triticum aestivum L.)–maize (Zea mays L.) crop rotation experiments were conducted to investigate phosphorus (P) fertilizer utilization efficiency, including the physiological efficiency, recovery efficiency and the mass (the input–output) balance, at five sites across different soil types and climate zones in China. The five treatments used were control, N, NP, NK and NPK, representing various combinations of N, P and K fertilizer applications. Phosphorus fertilization increased average crop yield over 15 years and the increases were greater with wheat (206%) than maize (85%) across all five sites. The wheat yield also significantly increased over time for the NPK treatments at two sites (Xinjiang and Shanxi), but decreased at one site (Hunan). The P content in wheat was less than 3.00 g kg−1 (and 2.10 g kg−1 for maize) for the N and NK treatments with higher values for the Control, NP and NPK treatments. To produce 1 t of grain, crops require 4.2 kg P for wheat and 3.1 kg P for maize. The P physiological use efficiency was 214 kg grain kg−1 P for wheat and 240 kg grain kg−1 P for maize with over 62% of the P from P fertilizer. Applying P fertilizer at 60–80 kg P ha−1 year−1 could maintain 3–4 t ha−1 yields for wheat and 5–6 t ha−1 yields for maize for the five study sites across China. The P recovery efficiency and fertilizer use efficiency averaged 47% and 29%, respectively. For every 100 kg P ha−1 year−1 P surplus (amount of fertilizer applied in excess of crop removal), Olsen-P in soil was increased by 3.4 mg P kg−1. Our study suggests that in order to achieve higher crop yields, the long-term P input–output balance, soil P supplying capacity and yield targets should be considered when making P fertilizer recommendations and developing strategies for intensively managed wheat–maize cropping systems. 相似文献
13.
Valtcho D. Zheljazkov Brady A. VickBrian S. Baldwin Normie BuehringChristine Coker Tess AstatkieBilly Johnson 《Industrial Crops and Products》2011,33(2):537-543
Sunflower (Helianthus annuus L.) is a potential cash crop for the southeastern United States for production of cooking oil or biodiesel. Two years (2006 and 2007) of experiments were conducted at each of five locations in Mississippi to evaluate the effect of planting date (April 20, May 20, and June 20), and hybrid (DKF3875, DKF2990, DKF3510, DKF3901, PR63M80, PR62A91, PR63A21, PR63M91, and PR64H41) on seed yield, oil content, and oil composition of sunflower. Seed oil concentration varied from 25 to 47%. The oleic acid concentration in the oil was greater than 85% for DKF3510 and PR64H41, above 65% for PR63M80 and PR63M91, and intermediate for the other hybrids. Total saturated fatty acids (TSFA) concentration in the oil (the sum of palmitic, stearic, arachidic, behenic, and lignoceric acids) ranged from 6.3 to 13.0%, with DKF3510, PR63M91, and PR64H41 having lower concentration of TSFA than the other hybrids. Mean seed yields ranged from 997 to 2096 kg ha−1 depending on location. Mean oil yields at the five locations ranged from 380 to 687 kg ha−1, and calculated biodiesel production ranged from 304 to 550 kg ha−1. Seed and oil yields in this study suggest sunflower in Mississippi should be planted by the last week of May. Later planting (20 June) may significantly decrease both seed and oil yields in the non-irrigated system in Mississippi and in other areas of the southeastern United States with similar environmental conditions. 相似文献
14.
Wei-li Liang Peter CarberryGui-yan Wang Run-hai LüHong-zhan Lü Ai-ping Xia 《Field Crops Research》2011,124(2):180-185
Wheat-maize double cropping is the most important cropping system on the Hebei Plain and is one of the most important cropping systems in China. In a scenario of greater food demand, and increasing water and rural labour scarcity, it is critical that the annual productivity of the system is improved in water-energy-cost efficient and low carbon ways. Based on farm surveys, this paper benchmarked the performance of wheat-maize double crops on the Hebei Plain during the 2004-2005 season. These farm yields were assessed both against experimental yields collected from on-farm maximum yield trials conducted during the same 2004-2005 season and relative to simulated estimates of the climate-driven potential productivity of the region.The survey of 362 farms in six counties of the Hebei Plain during the 2004-2005 season found wheat yields ranging from 3375 kg ha−1 to 9000 kg ha−1 with an overall average yield of 6556 kg ha−1. Maize yields averaged 7549 kg ha−1 and ranged from 3375 kg ha−1 to 11,250 kg ha−1. The aggregate production for the wheat-maize double crops grown in the 2004-2005 season averaged 14,105 kg ha−1 across the six counties. This was 72% of the average production (19,586 kg ha−1) recorded from on-farm trials conducted in each of the six counties and 60% of the simulated average production potential (24,147 kg ha−1) for the Hebei Plain in the 2004-2005 season. Thus, the annual productivity of the current cropping system could be increased with currently available technologies by 28%, while a yield increase of 42% is possible if farm yields approach the simulated yield potential.Based on farmer interviews and field observations, a number of real and perceived reasons for the current yield gaps in farmers’ fields were recognised. For instance, irrigation at stem-elongation of wheat is a current recommendation, yet only a proportion of the surveyed farmers were able to follow this strategy due to lack of access to shared irrigation facilities. Improving the region's infrastructure to enable more timely irrigation of crops will be a necessary prerequisite to improved productivity.The results from the farm surveys and on-farm trials indicate that, with current recommended practices, farmers can improve their annual farm productivity and close the current yield gaps. However, the survey identified that increasing system performance and efficiency will require a focus on both agronomic and socio-economic issues. 相似文献
15.
The CERES-sorghum module of the Decision Support System for Agro-Technological Transfer (DSSAT) model was calibrated for sorghum (Sorghum bicolor (L.) Moench) using data from sorghum grown with adequate water and nitrogen and evaluated with data from several N rates trials in Navrongo, Ghana with an overall modified internal efficiency of 0.63. The use of mineral N fertilizer was found to be profitable with economically optimal rates of 40 and 80 kg N ha−1 for more intensively managed homestead fields and less intensively managed bush fields respectively. Agronomic N use efficiency varied from 21 to 37 kg grain kg−1 N for the homestead fields and from 15 to 49 kg grain kg−1 N in the bush fields. Simulated grain yield for homestead fields at 40 kg N ha−1 application was equal to yield for bush fields at 80 kg N ha−1. Water use efficiency generally increased with increased mineral N rate and was greater for the homestead fields compared with the bush fields. Grain yield per unit of cumulative evapo-transpiration (simulated) was consistently higher compared with yield per unit of cumulative precipitation for the season, probably because of runoff and deep percolation. In the simulation experiment, grain yield variability was less with mineral N application and under higher soil fertility (organic matter) condition. Application of mineral N reduced variability in yield from a CV of 37 to 11% in the bush farm and from 17 to 7% in the homestead fields. The use of mineral fertilizer and encouraging practices that retain organic matter to the soil provide a more sustainable system for ensuring crop production and hence food security. 相似文献
16.
Prabhakar JhaMauji Ram M.A. KhanUsha Kiran Mahmooduzzafar M.Z. Abdin 《Industrial Crops and Products》2011,33(2):296-301
Artemisinin isolated from the aerial parts of Artemisia annua L. is a promising and potent antimalarial drug. It posses remarkable activity against both chloroquinine resistant as well as chloroquinine sensitive strains of Plasmodium falciparum. It is also useful in the treatment of cerebral malaria. The relatively low content of artemisinin in A. annua and unavailability of cost effective and viable synthetic protocol however, are major obstacles to the commercial production of the drug. The enhanced production of artemisinin is hence, highly desirable, which can be achieved by adequate and judicious supply of plant nutrients. The present experiment was therefore, designed to study the effect of organic manure (15 tonnes ha−1) and chemical fertilizers (N40+40, P40, K40, S15+15 kg ha−1; nitrogen, phosphorus, potassium and sulphur) on the accumulation of artemisinin and biomass in various plant parts through the developmental stages of A. annua L. Artemisinin yield (kg ha−1) was also determined through the developmental stages of A. annua L. Artemisinin content and artemisinin yield of dried leaves were increased significantly at pre-flowering stage in the plants treated with NPKS (27.3% and 53.6%) and NPK (18.2% and 33.5%), respectively, when compared with control. Maximum dry yield of leaf ranging from 2596 to 3141 kg ha−1 was observed at pre-flowering stage with various treatments. 相似文献
17.
Jadwiga Andrzejewska Katarzyna SadowskaSebastian Mielcarek 《Industrial Crops and Products》2011,33(2):462-468
In the moderate climate of Poland it is recommended that milk thistle (Silybum marianum L. Gaertn.) be grown on fertile soils. The plant, however, develops a strong root system, so a working hypothesis has developed that cultivation can be extended to light soils with periodic water deficits. The aim of the present research was to determine the effects of sowing milk thistle on light soil at different dates and rates on the achene yield and flavonolignan content. This experiment was carried out during 2004-2006 at the Mochelek Experiment Station of the University of Technology and Life Sciences in Bydgoszcz (53°13′ N; 17°51′ E). The average fruit yields were 1.23 t ha−1; those of silymarin were 26.5 kg ha−1. The moisture and thermal conditions during the research years caused the fruit yields to range from 0.55 to 1.68 t ha−1 and silymarin yields from 13.3 to 35.4 kg ha−1. Delaying sowing from early to mid-April increased the plant density and decreased numbers of inflorescences and fruits per inflorescence; as a result, no effect of sowing date on fruit yield was found. Delaying the sowing date increased silymarin content by about 0.4% and its yield by 5.3 kg ha−1. Increasing the sowing rate from 12 to 24 kg ha−1 resulted in a slight (40 kg ha−1) but significant increase in achene yield; however, it did not affect the silymarin content. The average silymarin content in fruits was 2.18%. The ratio of silydianin to silychristin was 1:2.2, and the ratio of silydianin to the sum of silybinin and isosilybinin was 1:3.3. 相似文献
18.
Radiation use efficiency,N accumulation and biomass production of high-yielding rice in aerobic culture 总被引：1，自引：0，他引：1
The concept of aerobic culture is to save water resource while maintaining high productivity in irrigated rice ecosystem. This study compared nitrogen (N) accumulation and radiation use efficiency (RUE) in the biomass production of rice crops in aerobic and flooded cultures. The total water input was 800–1300 mm and 1500–3500 mm in aerobic culture and flooded culture, respectively, and four high-yielding rice cultivars were grown with a high rate of N application (180 kg N ha−1) at two sites (Tokyo and Osaka) in Japan in 2007 and 2008. The aboveground biomass and N accumulation at maturity were significantly higher in aerobic culture (17.2–18.5 t ha−1 and 194–233 kg N ha−1, respectively) than in flooded culture (14.7–15.8 t ha−1 and 142–173 kg N ha−1) except in Tokyo in 2007, where the surface soil moisture content frequently declined. The crop maintained higher N uptake in aerobic culture than in flooded culture, because in aerobic culture there was a higher N accumulation rate in the reproductive stage. RUE in aerobic culture was comparable to, or higher than, that in flooded culture (1.27–1.50 g MJ−1 vs. 1.20–1.37 g MJ−1), except in Tokyo in 2007 (1.30 g MJ−1 vs. 1.37 g MJ−1). These results suggest that higher biomass production in aerobic culture was attributable to greater N accumulation, leading to higher N concentration (N%) than in flooded culture. Cultivar differences in response to water regimes were thought to reflect differences in mainly (1) early vigor and RUE under temporary declines in soil moisture in aerobic culture and (2) the ability to maintain high N% in flooded culture. 相似文献
19.
Soil fertility varies markedly within and between African smallholder farms, both as a consequence of inherent factors and differential management. Fields closest to homesteads (homefields) typically receive most nutrients and are more fertile than outlying fields (outfields), with implications for crop production and nutrient use efficiencies. Maize yields following application of 100 kg N ha−1 and different rates and sources of P were assessed on homefields and outfields of smallholder farms in Zimbabwe. Soil organic carbon, available P and exchangeable bases were greater on the homefields than outfields. In each of three experimental seasons, maize yields in homefield control plots were greater than in the outfields of farms on a granitic sandy and a red-clay soil. Application of mineral N significantly increased maize yields on homefields in the first season (2.1–3.0 t ha−1 on the clay soil and 1.0–1.5 t ha−1 on the sandy soil) but the effects of N alone were not significant on the outfields due to other yield-limiting factors. Greatest yields of about 6 t ha−1 were achieved on the clayey homefield with 100 kg N ha−1 and 30 kg P ha−1 applied as single super phosphate (SSP). Manure application gave greater yields (3–4 t ha−1) than SSP (2–3 t ha−1) in the sandy homefield and in the clayey outfield. Maize did not respond significantly to N, dolomitic lime, manure and P on the sandy outfield in the first and second seasons. In the third season, manure application (∼17 t manure ha−1 year−1) on the sandy outfield did result in a significant response in grain yields. Apparent P recovery in the first season was 55–65% when P was applied at 10 kg ha−1 on the clayey homefield (SSP), clayey outfield (SSP and manure) and sandy homefield (manure) with apparent P recovery less than 40% when P was applied at 30 kg ha−1. On the sandy outfield, P recovery was initially poor (<20%), but increased in the successive seasons with manure application. In a second experiment, less than 60 kg N ha−1 was required to attain at least 90% of the maximum yields of 2–3 t ha−1 on the sandy homefield and clayey outfield. N use efficiency varied from >50 kg grain kg−1 N on the infields, to less than 5 kg grain kg−1 N on the sandy outfields. Apparent N recovery efficiency by maize was greatest at small N application rates with P applied. We conclude that blanket fertilizer recommendations are of limited relevance for heterogeneous smallholder farms. Targeted application of mineral fertilizers and manure according to soil type and past management of fields is imperative for improving crop yields and nutrient use efficiencies. 相似文献
20.
David C. Nielsen 《Field Crops Research》2011,124(3):400-407
Forages could be used to diversify reduced and no-till dryland cropping systems from the traditional wheat (Triticum aestivum L.)-fallow system in the semiarid central Great Plains. Forages present an attractive alternative to grain and seed crops because of greater water use efficiency and less susceptibility to potentially devastating yield reductions due to severe water stress during critical growth stages. However, farmers need a simple tool to evaluate forage productivity under widely varying precipitation conditions. The objectives of this study were to (1) quantify the relationship between crop water use and dry matter (DM) yield for soybean (Glycine max L. Merrill), (2) evaluate changes in forage quality that occur as harvest date is delayed, and (3) determine the range and distribution of expected DM yields in the central Great Plains based on historical precipitation records. Forage soybean was grown under a line-source gradient irrigation system to impose a range of water availability conditions at Akron, CO. Dry matter production was linearly correlated with water use resulting in a production function slope of 21.2 kg ha−1 mm−1. The slope was much lower than previously reported for forage production functions for triticale (X Triticosecale Wittmack) and millet (Setaria italic L. Beauv.), and only slightly lower than slopes previously reported for corn (Zea mays L.) and pea (Pisum sativa L.) forage. Forage quality was relatively stable during the last four weeks of growth, with small declines in crude protein (CP) concentration. Values of CP concentration and relative feed value indicated that forage soybean was of sufficient quality to be used for dairy feed. A standard seed variety of maturity group VII was found to be similar (in both productivity and quality) to a variety designated as a forage type. The probability of obtaining a break-even yield of at least 4256 kg ha−1 was 90% as determined from long-term precipitation records used with the production function. The average estimated DM yield was 5890 kg ha−1 and ranged from 2437 to 9432 kg ha−1. Regional estimates of mean forage soybean DM yield ranged from 4770 kg ha−1 at Fort Morgan, CO to 6911 kg ha−1 at Colby, KS. Forage soybean should be considered a viable alternative crop for dryland cropping systems in the central Great Plains. 相似文献