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1.
In recent years, there has been a growing interest in brown midrib (BMR) sorghum (Sorghum bicolor (L.) Moench.) × sudangrass (Sorghum sudanense Piper) hybrids (SxS) as a replacement for silage corn (Zea mays L.) in the north‐eastern USA. Recent studies suggest it is suitable for both rotational grazing and as a hay crop and could compete with corn harvested for silage in years when wet spring conditions prevent the timely planting of corn. However, little is known about its suitability as forage for non‐lactating cows that require low potassium (K) forages to prevent health problems. Our objective was to evaluate the impact of K fertilizer management (0, 112 or 224 kg K2O ha?1 cut?1) under optimum N management (112–168 kg N ha?1 cut?1) on yield, quality and K concentrations of BMR SxS over a 2‐year period. Field trials were established on a fine loamy, mixed, active, mesic Aeric Fragiaquepts with medium K‐supplying capacity and characteristic of a large region in New York. Potassium application did not affect dry matter yields in either of the 2 years. Averaged over 2 years, neutral detergent fibre (NDF) significantly increased with K addition with similar but non‐significant trends observed in each of the years individually. The digestibility of NDF was unaffected by K application. Crude protein (CP) concentrations showed a significant decrease with K application in 2002 and similar trends were observed in 2003, although differences were not significant at P ≤ 0.05. The changes in NDF and CP did not significantly impact forage quality expressed as milk production per megagram of silage. Potassium application increased forage K concentration up to 13 mg K kg?1 dry matter (in the first cut in 2003). Forage Ca and Mg concentrations decreased with K addition except for the first cut in 2002 where differences between 112 and 224 kg K2O ha?1 treatments were not significant. Without K addition in the 2‐year period, K concentrations in the forage decreased from 23 g kg?1 for the first cutting in 2002 to 15 g kg?1 for the second cut in 2003. Low K forage was obtained for all second‐cut forage unless 224 kg K2O ha?1 cut?1 had been added. First‐cut forage was suitable only when no additional K had been applied. These results suggest low K BMR SxS forage can be harvested from initially high K soils without loss in dry matter yield as long as no additional K is added.  相似文献   

2.
Research was undertaken to determine the response of newly planted saffron to the application of different levels of nitrogen (0, 50 and 100 kg N · ha?1 · year?1), phosphorus (0, 25, and 50 kg P2O5 · ha?1 · year?1), and composted cow manure (0, 20, and 40 tons · ha?1 · year?1) in terms of fresh flower weight (FFW), saffron yield (SY) and leaf biomass. The experiments were conducted in Birjand, and Ghaen, Khorasan province, Iran, from 1991 to 1993. Significant differences were found between the two locations and among the years within each location for FFW and SY. Averaged over all treatments and years, mean values for FFW and SY were 644.3 and 9.1 kg · ha?1, respectively, at Birjand, and 296.0 and 3.7 kg · ha?1, respectively, at Ghaen. At Birjand, mean FFW in the three consecutive years was 229.0, 796.2, and 907.8 kg · ha?1 and mean SY was 3.4, 10.6, and 13.4 kg · ha?1. The corresponding means at Ghaen were 87.5, 225.9, and 574.7 kg · ha?1 for FFW and 1.3, 3.2, and 6.7 kg · ha?1 for SY. Simple correlation coefficients between FFW and SY were positive and highly significant. At both locations, FFW and SY increased significantly from year to year. The rate of increase, however, decreased with the age of the saffron field because of overcrowding of new corms. Different combinations of fertilizers had either a negative or nonsignificant effect on FFW and SY. The application of phosphorus fertilizer did not result in increased FFW and SY. The application of 40 tons · ha?1 of cow manure in the first year followed by no fertilizer in the second year and by 20 tons · ha?1 in the third year increased FFW and SY at Birjand. The use of 100 kg · ha?1 nitrogen only in the third year also increased FFW and SY at Birjand. At Ghaen, only the application of 50 kg · ha?1 nitrogen in the third year resulted in increased FFW and SY.  相似文献   

3.
The faba bean is among the major grain legumes cultivated in Ethiopia and is used extensively as a break crop in the highlands. Although a blanket application of DAP (diammonium phosphate) at the rate of 100 kg · ha?1 has been practised in faba bean production in the country, this was not based on research results. In addition, little information is available on the response of the crop to N and P fertilizers under diverse environmental conditions. Hence, field experiments were carried out at three locations in 1991, seven locations during 1992 and 1993 and at one location in both 1993 and 1995 to determine faba bean response to N and P fertilization. Five levels of N (0, 9, 18, 27 and 36 kg N · ha?1 as urea) in factorial combinations with four levels of P (0, 23, 46 and 69 kg P2O5 · ha?1 as TSP [triple super phosphate]) were studied in a randomized complete block design with four replications in the first year. In the remaining years four levels of N (0, 18, 27 and 36 kg N · ha?1 as urea) in factorial combinations with four levels of P (0, 23, 46 and 92 kg P2O5 · ha?1 as TSP) were used in a randomized complete block design with three and four replications at one and seven locations, respectively. Results indicated that a positive linear response of faba bean seed yield was noted at all locations (except Debre Zeit and Burkitu) to P fertilization, while a significant quadratic response was also found at Holetta. In addition, plant height, above ground biomass and number of pods per plant were positively influenced by P application while the effect of N on these was mostly nonsignificant. Faba bean seed yield response to N was noted at only two out of eight locations; in most cases, nonsignificant and inconsistent seed yield responses to N fertilization were obtained. There was nonsignificant N × P rate interaction. In conclusion, we do not recommend supplemental N application to faba bean at six out of eight locations but we recommend the application of P fertilizer to faba bean at almost all locations (with the exception of Debre Zeit) and for other soils deficient in available P. Further work is recommended on the determination of critical levels for soil-available P, below which P fertilization should be practised for optimum faba bean seed yield.  相似文献   

4.
Four crops, corn (Zea mays L.), sweet sorghum (Sorghum bicolor L.), fodder beet (Beta vulgaris L.) and sugarbeet (Beta vulgaris L.) were grown in irrigated plots at the experimental farm of the University of California, Davis, in 1980 and 1981. Six fertilizer N levels ranging from 0 to 280 kg ha?1 were used to estimate the most efficient N input for each of the tested crop in terms of energy input and output analysis. Calculations of cultural energy input costs in relation to potential ethanol yield showed production requirements of: corn 30.9 GJ ha?1, sweet sorghum 30.4 GJ ha?1, fodder beet 49.4 GJ ha?1 and sugarbeet 41.0 GJ ha?1. Highest average energy inputs were for liquid fuels for operations 35%, irrigation 23% and fertilizer nitrogen 19%. Fodder beet had the highest fermentable carbohydrate yield at 13.05 Mg ha?1 followed by sugarbeet at 11.5 Mg ha?1. Sweet sorghum and corn yields were lower at 9.71 and 8.09 Mg ha?1, respectively. Crop production inputs of energy per liter of potential ethanol were: corn 6.42 MJL?1 sweet sorghum 5.25 MJL?1, fodder beet 6.35 MJL?1 and sugarbeet 5.95 MJL?1.  相似文献   

5.
In this study, conducted from 1979 to 1986 in southern Spain, the objective was to analyze the effects of a possible interaction between soil-applied N and foliar S applied to barley (Hordeum vulgare L.) during tillering on grain yield and to identify the mechanism involved. From 1979 to 1982, we used rates of 20, 40, 60 and 80 kg a.i. N ha?1, together with 12.5 or 25 kg foliar a.i. S ha?1 during tillering. The results demonstrated that foliar S at both dosages acted as a partial (but not total) substitute for N, when the latter was applied at levels of 40 to 60 kg ha?1. These effects of S did not appear to result only from a nutritive mechanism, but rather from a hormonal mechanism through the increase in ethylene biosynthesis. Therefore, during 1983 to 1986, we used 40, 60 and 80 kg a. i. N ha?1, together with 12.5 a. i. S ha?1 and 0.55 kg a.i. ethrel (2-chloroethyl-phosphonic acid) ha?1. The results showed that the effects of S and ethrel on yield were practically the same. Assayed with 40 and 60 kg N ha?1, S and ethrel acted as partial (but not total) substitutes for N, exceeding the yield of the control without S or ethrel, and equalling the yield obtained with 20 kg more of N ha?1. The S or ethrel applied with 80 kg N ha?1 presented an additive effect with the N. The increases in yield using S or ethrel were in all cases due to the increased final number of spikes m?2, which was principally a consequence of the higher number of tillers formed but also a result of increased survival of tillers to form a viable spike. In addition, the positive effects of S on yield were greater the smaller the N dosage and the lower the annual yield. Finally, we present a possible mechanism of hormonal action, to explain how foliar S applied during tillering affects grain yield in barley.  相似文献   

6.
Effects of tillage on the appropriate fertilizer N applications needed to achieve maximal grain yield are poorly denned. The study objective was determination of relative corn grain yield response to N application rate for four tillage practices: no-tillage (NT), ridge tillage (RT), fall chisel plowing (CP) and fall moldboard plowing (MP). Maize (Zea mays L.) grain yield and N accumulation were monitored over a 6 year period with the same tillage treatment and the same fertilizer N rate applied each year to each plot. Two hybrids, differing in relative maturity rating, were planted each year. Fertilizer N rates ranged from 10 to 190 kg ha?1 and consisted of 10 kg ha?1 of liquid starter N applied at planting with varying amounts of fall applied anhydrous ammonia. With only starter fertilizer, grain yields increased with tillage intensity in the order NT ≤ RT ≤ CP ≤ MP. With ≥ 55 kg total applied Nha?1, 6 year average grain yields were unaffected by tillage. Total N removed in grain annually with only starter fertilizer ranged from 25–85 kg ha?1 Maximal amounts of N removed, about 145 kg N ha?1, occurred with 100–145 kg applied N ha?1 for all tillage treatments under the more favorable climatic conditions. Several interactions affecting grain yield appear climatically sensitive with exception of tillage by fertilizer N interactions. Because of variability in climate, planting dates varied by almost 4 weeks. Relative yield loss due to planting delay were Fertilizer N (mean change ??124 –?275 kg ha?1 day?1) > Starter N only and MP (mean ?? 259 kg ha?1 day?1) > other tillages in general. Yield loss due to delayed planting ranged from 0.0–275 kg ha?1 day?1. Grain yield gains due to early spring soil temperatures were 16.0–21.8 kg ha?1 index-degree?1 with MP tillage and averaged 2.7– 16.7 kg ha?1 index-degree?1 more than those of other tillage-hybrid combinations.  相似文献   

7.
Field trials were replicated at four sites in the moist savanna ecological zone of West Africa to study the effect of maturity class and phosphorus (P) rate on grain yield and total protein yield (TPY) of some new soya bean varieties. Grain yield and TPY averaged 1.43 Mg ha?1 and 587 kg ha?1, respectively. Without P application grain yield and TPY were not significantly different among the varieties. In addition, at zero P treatment, grain yield and TPY were not significantly different among three sites where available P was 6.2 mg kg?1 or less. P application depressed grain yield and TPY at a site where the available soil P was high (16.2 mg kg?1). With P application grain yield and TPY were in the range of 1.2–2.28 Mg ha?1 and 505–948 kg ha?1, respectively, for the varieties compared with 0.99–1.12 Mg ha?1 and 454–462 kg ha?1 when P was not applied. The response of grain yield to 30 kg P ha?1 was substantial at Gidan Waya (113 %), Kasuwan Magani (63 %) and Fashola (60 %), three sites where available soil P was low. The application of 30 kg P ha?1 increased grain yield by 21 % in early, 26 % in medium and 58–70 % in the late varieties. Significant variety by P rate interaction effects were observed on grain yield and TPY but not on grain protein concentration (GPC). TPY showed greater response to P in the late varieties than in the early or medium. While seed size correlated significantly and positively with GPC, P application had no significant effect on GPC.  相似文献   

8.
The effects of four row spacings (17.5, 35.0, 52.5 and 70.0 cm) and five seeding rates (50, 100, 200, 400 and 800 viable seeds m?2) on seed yield and some yield components of forage turnip (Brassica rapa L.) were evaluated under rainfed conditions in Bursa, Turkey in the 1998–1999 and 1999–2000 growing seasons. Plant height, stem diameter, pods/terminal raceme, total pods/plant, seeds/pod and primary branches/plant were measured individually. The number of plants per unit area was counted and the lodging rate of the plots was scored. The seed yield and 1000‐seed weight were also determined. Row spacing and seeding rate significantly affected most yield components measured. The number of plants per unit area increased with increasing seeding rate and decreasing row spacing. Plant height was not greatly influenced by row spacing and seeding rate, but higher seeding rates reduced the number of primary branches and the stem diameter. The number of pods/main stem was affected by row spacing and but not by the seeding rate. Also, the number of seeds per pod was not affected by either the row spacing or the seeding rate. In contrast, the number of pods per plant clearly increased with increasing row spacing, but decreased with increasing seeding rate. The plots seeded at narrow row spacings and at high seeding rates were more sensitive to lodging. Seeding rate had no significant effect on seed yield in both years. Seed yield was similar at all seeding rates, averaging 1151 kg ha?1. However, row spacing was associated with seed yield. The highest seed yield (1409 kg ha?1) was obtained for the 35.0‐cm row spacing and 200 seeds m?2 seeding rate combination without serious lodging problems.  相似文献   

9.
Field experiments were conducted at Indian Agricultural Research Institute, New Delhi, during 2001–2002 and 2002–2003, to study the effect of inorganic, organic and Azotobacter combined sources of N on cotton (Gossypium hirsutum L.) and their residual effect on succeeding wheat (Triticum aestivum L.) crop. The results indicated considerable increase in yield attributes and mean seed cotton yield (2.33 Mg ha?1) with the combined application of 30 kg N and farmyard manure (FYM) at 12 Mg ha?1 along with Azotobacter (M4). The treatment in cotton that included FYM, especially when fertilizer N was also applied could either improve or maintain the soil fertility status in terms of available N, P and K. Distinct increase in yield attributes and grain yield of wheat was observed with the residual effect of integrated application of 30 kg N ha?1 + FYM at 12 Mg ha?1 + Azotobacter. Direct application of 120 kg N ha?1 resulted 67.4 and 17.7 % increase in mean grain yield of wheat over no N and 60 kg N ha?1, respectively. Integrated application of organic and inorganic fertilizer is therefore, recommended for higher productivity and sustainability of the cotton–wheat system.  相似文献   

10.
To assess the scope for enhancing productivity of groundnut (Arachis hypogaea L.) in India, well‐calibrated and validated CROPGRO‐Peanut model was used to assess potential yields (water non‐limiting and water limiting) and yield gaps of groundnut for 18 locations representing major groundnut growing regions of India. The average simulated water non‐limiting pod yield of groundnut for the locations was 5440 kg ha?1, whereas the water limiting yield was 2750 kg ha?1 indicating a 49 % reduction in yield because of deficit soil moisture conditions. As against this, the actual pod yields of the locations averaged 1020 kg ha?1, which was 4420 and 1730 kg ha?1 less than the simulated water non‐limiting and water limiting yields, respectively. Across locations, the simulated water non‐limiting yields were less variable than water limited and actual yields, and strongly correlated with solar radiation during the crop season (R2 = 0.62, P ≤ 0.01). Simulated water limiting yield showed a significant positive, but curvilinear relationship (R2 = 0.73, P ≤ 0.01) with mean crop season rainfall across locations. The relationship between actual yield and the mean crop season rainfall across locations was not significant, whereas across seasons for some of the locations, the association was found to be significant. Total yield gap (water non‐limiting minus actual yields) ranged from 3100 to 5570 kg ha?1, and remained more or less unaffected by the quantity of rainfall received across locations. The gap between simulated water non‐limiting and water limiting yields, which ranged from 710 to 5430 kg ha?1, was large at locations with low crop season rainfall, and narrowed down at locations with increasing quantum of crop season rainfall. On the other hand, the gap between simulated water limiting yield and actual farmers yield ranged from 0 to 3150 kg ha?1. It was narrow at locations with low crop season rainfall and increased considerably at locations with increasing amounts of rainfall indicating that type of interventions to abridge the yield gap will vary with the rainfall regimes. It is suggested that improved agronomic management (such as high yielding cultivars, balance crop nutrition and control of pest and diseases) in high rainfall regimes and rainfall conservation and supplemental irrigations in low rainfall regimes will be essential components of the improved technologies aimed at abridging the yield gaps of groundnut.  相似文献   

11.
Cool‐season food legumes (CSFLs) are important supplementary protein sources and soil fertility restorers for subsistence farmers in Ethiopia. Yields of CSFLs, however, are limited by low soil fertility, as they are grown in poor soils, often without fertilizer. Dekoko (Pisum sativum var. abyssinicum) is one of the CSFLs cultivated in Tigray, Northern Ethiopia. It is highly appreciated by the local people for its taste. This paper reports on the effect of phosphorus (P) on the yield and nutrition value of Dekoko under field conditions, and compares the results with those obtained for Ater (Pisum sativum var. sativum). The experiment was conducted in the 1998 and 1999 growing seasons. Three rates of P equivalent to zero, 30, and 60 kg ha?1 P2O5 were tested. Biomass, leaf area index, branches/plant, pods/m2 and yield responded positively while seeds/pod and seed weight were not significantly affected by P. Tissue P contents in shoots and roots increased with an increase in P application rate, while P in the nodules was not affected. Crude protein (CP) content increased from 24.9 % of dry matter (DM) at P0 to 26.2 % at P2, and from 24.3 % at P0 to 25.2 % at P2, in Dekoko and Ater seeds, respectively, while total sugars decreased with an increase in P application rate. Cysteine in Dekoko and asparagine and threonine in both varieties decreased, while lysine and other amino acids were not significantly affected by P. P improved seed yield and CP content without greatly affecting the amino acid profile of Dekoko, when compared with that of the FAO/WHO (1991, Protein Quality Evaluation. Food and Nutrition, Paper 51. FAO/WHO, Rome) standard pattern of amino acid for children 2–5 years of age. Thus, improving yield through fertilization may help to improve nutritional quality and household food security for subsistence farmers.  相似文献   

12.
Little is known about the effect of combined phosphorus and nitrogen (P‐N) fertilization on the N requirement of sunflower (Helianthus annus L.). This study was carried out to evaluate the effects of varying levels of P and N, as well as the interaction P × N, on the N uptake, yield and N apparent utilization efficiency under field conditions. Split‐plot design experiments were conducted in the mid‐western Pampas in Argentina. Four levels of N (0, 46, 92 and 138 kg N ha?1) and three levels of P (0, 12 and 40 kg P ha?1) were applied to two Typic Hapludolls over two growing seasons (1997–98 and 1998–99). N uptake and soil N‐NO3 contents were determined at the V7, R5 and R9 growth stages. The sunflower yield ranged from 2.5 to 5.0 Mg ha?1. The total N requirement was around 45 kg N Mg?1 grain, and this result suggests that it is not necessary to use different N requirements (parameter b) for fertilized crops when a yield response is expected. To achieve a 100 % yield maximum a N supply (soil plus fertilizer) of 181 kg N ha?1 at P40 was needed. However, at P0, the highest yield was about 80 % of the maximum yield with a N supply (soil plus fertilizer) of 164 kg N ha?1. P application increased the apparent use efficiency of the supplied N.  相似文献   

13.
A field experiment was conducted on sandy loam acidic soil to study the effect of nutrient managements on light interception, photosynthesis, growth, biomass production and yield of Indian mustard [Brassica juncea (L.) Czern & Coss.]. Plant height, number of branches per plant, number of siliqua per plant, number of seeds per siliquae, 1000‐seed weight, seed and oil yield of Indian mustard improved at 100 % recommended rates of NPK (N‐P‐K at 80‐17.2‐33.2 kg ha?1) + 10 t ha?1 farmyard manure (FYM) (T3) compared with 100 % NPK rate (T2). It was also at par with 100 % NPK + 10 kg ha?1 borax + 20 kg ha?1 ZnSO4 (T6) and 50 % NPK + 10 t ha?1 FYM +10 kg ha?1 borax + 20 kg ha?1 ZnSO4 (T10). The rate of photosynthesis increased due to appropriate nutrient management treatments (T3, T6 or T10) with concomitant increase in photosynthetically active radiation, internal CO2 concentration and rate of transpiration and decrease in stomatal resistance. Consequent upon the higher rate of photosynthesis, dry‐matter accumulation increased. The crop receiving nutrient treatment T3 or T6 maintained higher light interception ratio (LIR), leaf area index (LAI), biomass production, crop growth rate (CGR) and net assimilation rate (NAR) that resulted in greater rate of photosynthesis, harvest index and seed yield. Similarly, T10 was equally efficient in registering greater LIR, LAI, CGR, NAR and seed yield of mustard. The average seed yields were 1692, 1683 and 1668 kg ha?1 in T3, T6 and T10, respectively, and these three treatments were significantly superior to T2 (1332 kg ha?1), control (723 kg ha?1) and other treatments. Significantly greater seed oil contents of 41.30, 40.60 and 41.07 % were recorded in T3, T6 and T10, respectively. Thus, significant improvement due to appropriate combination of NPK, FYM, borax and ZnSO4 was observed for uptake of nutrients.  相似文献   

14.
In a two year factorial field trial the influence of slight shading (daylight reduced by 27 %), row spacing (15 and 30 cm respectively) and N fertilization (60 and 120 kg* ha?1*cut?1 respectively) on yield and nutritive value of Lolium multiflorum (Lam.) was investigated. Three cuts were taken in the seeding year and four in the full harvest year. Shading reduced DM yield by 4 % at low and 16 % at high level of N fertilization. Higher amount of N fertilizer increased yield by 28 % without and 12 % with shading. Row spacing was of minor importance; on average wider spacing decreased yield by 9 %. Increasing N fertilization and shading had the same effects on nutritive value: crude protein (CP), nitrate content and protein/energy ratio (P/E) went up, whereas energy value (NEL) went down. Compared to the effects of shading or N fertilization, the influence of sward density on nutritive value was small. The effect of shading and high fertilization on nutritive value was similar in both years. However for vegetatively grown forage in the seeding year shading caused P/E values and nitrate contents too high for an adequate ruminant feeding which was already evident at low level of N fertilization; also increased supply of N fertilizer without shading deteriorated the nutritive value. On the other hand forage of the full harvest year (at reproductive stages) showed too high P/E values only in shaded and highly fertilized plots. Therefore N fertilization ought to be limited at periods when the grass only grows vegetatively and/or light intensity is low, like e.g. in autumn. None of the experimental treatments had any marked effect on the fibre content of the forage (ADF) in the seeding year; in the full harvest year, however, when plants grew reproductively, shading as well as higher N fertilization increased ADF content. There was no significant correlation between ADF and NEL for vegetatively grown plants but a close relation for plants which were at reproductive stages.  相似文献   

15.
We determined the effect of N fertilization on dry matter (DM) yield, predicted milk yield, and forage quality of fresh (green chopped) and ensiled forage of two brown midrib (BMR) hybrids, a leafy hybrid, and a conventional silage hybrid. Increasing N rates from 0 to 200 kg ha?1 increased corn grain, stover and whole plant DM yield and milk yield. The forage yield and quality response to N was similar for all hybrids. Nitrogen fertilization increased forage crude protein (CP) concentration but had little effect on other forage quality components. BMR hybrids, F377 and F657, had the lowest grain, stover and whole plant yield but had the highest digestibility and predicted milk yield Mg?1 of forage. Predicted milk yield ha?1 was similar for the BMR, leafy and conventional hybrids. Ensiling reduced starch concentration compared with green chopped forage, but effects on other forage quality variables were less consistent. Hybrid and N fertilization affects were similar for green chopped and ensiled corn forage.  相似文献   

16.
A field study was conducted to investigate the influence of variable rates of application of N and P fertilizers in splits at various times on the growth and the seed and oil yields of canola (Brassica napus L.) during 1995–97. Rates of fertilizer application were 0 and 0 (F0), 60 and 0 (F1), 0 and 30 (F2), 60 and 30 (F3), 90 and 60 (F4) and 120 and 90 (F5) kg N ha?1 and kg P2O5 ha?1. All the P was applied at sowing while N was applied in splits, i.e. all at sowing, half at sowing and half with first irrigation, or half at sowing and half at flowering. The responses of growth, seed yield and components of yield were consistent in both years. Increasing the rate of fertilizer application from F4 (90/60 kg N/P2O5 ha?1) to F5 (120/90 kg N/P2O5 ha?1) increased the leaf area index (LAI) relative to the control and to lower rates of fertilizer application. For both crops, application of 90/60 kg N/P2O5 ha?1 significantly enhanced total dry matter (TDM) and seed yield. Seed yield increased mainly due to a greater number of pods per plant and seeds per seed‐pod. The time of fertilizer application did not significantly affect seed yield or components of yield in either season. Oil yield generally followed seed yield, increasing with increasing rate of fertilizer application up to 90/60 kg N/P2O5 ha?1. The maximum oil contents were obtained from the control. The results show that seed and oil yields of canola were maximized at the F4 (90/60 kg N/P2O5 ha?1) rate of application under the agro‐ecological conditions of Faisalabad, Pakistan.  相似文献   

17.
Studies were conducted at Adana, in the Çukurova region of southern Turkey, to evaluate the effects of the rate and timing of application of soil‐applied potassium (K) on cotton (Gossypium hirsutum L.) in 1999 and 2000. Potassium rates of 0, 80, 160 and 240 kg K2O ha?1 were soil‐applied in single treatments (all at early boll development) or in split treatments (1/2 at first square and 1/2 at first white flower; 1/4 at first square, 1/4 at first white flower and 1/2 at early boll development). Data collected in the two years indicated that application of 160 kg K2O ha?1 produced significant differences in seed‐cotton yield, lint yield and boll weight compared with the untreated control. The best combination producing the greatest yield was application of 160 kg K2O ha?1 with all of the K soil‐applied at early boll development. Cotton yields did not respond to K fertilization above the rate of 160 kg K2O ha?1 under the production practices typically found in the region. For application of K at a rate of 240 kg K2O ha?1 there was a marked difference in fibre strength between years in this study, but micronaire and uniformity ratio were not different amongst K rates within each year. When the total amount of K was applied at early boll development, higher yields, boll weights and lint turnouts were obtained compared with split applications, but the single application did not have a large impact on fibre properties.  相似文献   

18.
A better understanding of the agronomic importance of planting date and the influence of cold temperatures and photoperiod during germination and plant growth may lead to better management strategies for cultivation of the sweet white lupin (Lupinus albus). The effects of planting date (temperature and photoperiod) were determined on the number of days to flowering, yield and yield components of four early to medium and one late sweet white lupin genotype in a field trial at Potchefstroom, South Africa, planted during February 1996 to January 1997. Moisture stress was avoided through regular irrigation. Duration of the developmental phases planting date to emergence, emergence to floral initiation, initiation to first flower, duration of flower and days to physiological and harvest maturity was related to field measurements of temperature and photoperiod. Differences in the main determinants of yield, i.e. seeds per pod, pods per plant, single seed mass (SSM), plant and pod height and yield, were measured. Results showed that both temperature and photoperiod influence the growth and development of the Lupinus albus genotypes ‘Esta’, ‘Hantie’, ‘Tifwhite’, ‘Kiev’ and ‘LAL 186’. Temperature influences include the effect of vernalization at seedling emergence. Minimum grass temperatures under 5 °C at emergence are effective for vernalization. However, after grass temperatures at emergence increased again from June to December, to gether with an increase in the photoperiod length, ‘Tifwhite’ as well as the other genotypes still flowered earlier, confirming that these cultivars are long‐day plants, which is in accordance with controlled‐environment data. Cool vernalizing temperatures thus not only influence obligate vernalization requiring genotypes such as ‘Tifwhite’, but also influence the non‐obligate genotypes studied. Plan‐ting date had a significant influence on pods per plant, single seed mass (SSM) and seed yield. In all trials laterplanting, from June to November, decreased SSM and seed yield. The highest seed yield of 1.5 t ha?1 was obtained for the 10 June planting date and the lowest average yield of 0.450 t ha?1 for the 5 November planting date.  相似文献   

19.
For three successive growing seasons (1999–2001), a completely randomized block design experiment was established at the surrounding area of each of four sugar beet processing plants of Hellenic Sugar Industry SA, Greece (a total of 12 experiments). Nitrogen was applied at five rates (0, 60, 120, 180 and 240 kg N ha−1) and six replications per rate. Nitrogen fertilization had site-specific effects on quantitative (fresh root and sugar yields) and qualitative (sucrose content, K, Na, α-amino N) traits. When data were combined over years and sites, fresh root and sugar yields were maximized at high N rates (330.75 and 295 kg N ha−1 respectively), as derived from quadratic functions fitted to data. In three trials, increased N rates had negative effects on root and sugar yield. These sites were characterized by high yield in control plots, light soil texture (sand > 50 %) and low CEC values. When data were converted into relative values (the ratio of the trait values to the control mean of each experiment), root and sugar yield was found to be maximized at higher N rates (350 and 316 kg N ha−1, respectively). Sucrose content was strongly and linearly reduced by the increased N rates when data were combined but a significant reduction with increasing N rates was found in only two sites. Non-sugar impurities (K, Na, α-amino N) were positively related to the increased N rates when data were combined. Sodium and α-amino N showed to be most affected by N fertilization as positive relationships were found in six and eight of 12 locations, respectively. Increased N supply resulted in higher soil NO3-N concentrations (0–90 cm depth) at harvest which were related with amino N contents in sugar beet roots (in 1999 and 2001).  相似文献   

20.
The field experiments conducted on the grey‐brown podzolic soil in the four growing seasons (1998–2001) at Krzeslice Farm, central‐western Poland comprised seven fertilization variants: 80NF + 80CAN; 80CAN + 80CAN; 80AN + 80AN; 80NF + 50CAN + 30CN; 80CAN + 50CAN +30CN; 80AN + 50AN + 30CN (where NF – nitrofos NPK; CAN – calcium‐ammonium nitrate; AN – ammonium nitrate; CN – calcium nitrate) and control (without N) applied in split rates at the beginning of spring regrowth (80 kg N ha?1), stem elongation (80 or 50) and flower buds visible stages (30). The yielding effect of tested fertilization variants was significant in comparison with the control (2.24 t ha?1). The highest mean seed yield (3.64 t ha?1) was collected from 80AN + 80AN and 80CAN + 80CAN variants. Mean values of 4 years indicate that the second N rate division (80 + 50 + 30) decreased yield, although not significantly in comparison with these two N treatments. Plants grown on these treatments have developed different patterns of growth to yield the seeds. These patterns were characterized by very high crop growth rate during flowering (above 21 g m?2 day?1) and negative at maturation (down to ?2.5 g m?2 day?1). Plants fertilized with ammonium nitrate (80AN + 80AN) reached maximum growth rate earlier (65 days), which lasted longer (20 days) than plants fertilized with calcium‐ammonium nitrate (71 days lasting 17.5 days). Plants grown on the control treatment reached the highest crop growth rate within 79 days (14.8 g m?2 day?1), which lasted 15 days.  相似文献   

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