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1.
Valorization of three varieties of grape   总被引：2，自引：0，他引：2  
In the present investigation, seed methanolic extracts of three Vitis vinifera (Muscat d’Italie, Syrah and Carignan) were assayed for their antioxidant activities. Results showed that there are strong variations in the contents of total phenols (440.97–121.94 mg GAE g−1 DW), flavonoids (48.07–16.81 mg EC g−1 DW) and tanins (37.15–14.9 mg EC g−1 DW) from the studied seeds. The phenolic composition of these extracts was determined by RP–HPLC after acid hydrolysis. The main phenolic compound was quercetin with 27.2% in Muscat d’Italie, 48.8% in Syrah and 28.4% in Carignan. Besides, all seed extracts showed remarkable DPPH radical scavenging activity with IC50 values ranged from 1.8 to 30 μg ml−1. EC50 values of reducing power activity ranged from 100 to 120 μg ml−1. The high phenolic content and the considerable antioxidant activities of vitis seed extracts could potentially be considered as an expensive source of natural antioxidants.  相似文献   

2.
Between 2006 and 2008, 120 isolates of Sclerotinia sclerotiorum from the Jiangsu Province of China were characterized for the baseline sensitivity to boscalid, a new active ingredient that interferes with succinate ubiquinone reductase in the electron transport chain of fungi. The isolates collected between 2006 and 2008 all showed similar sensitivity to boscalid. Baseline sensitivities were distributed as unimodal curves with mean EC50 values of 0.17 ± 0.09 μg ml−1 for inhibition of mycelial growth. Inhibition of mycelial growth of isolates whether they had resistance to carbendazim or, dimethachlon or dual resistance to both carbendazim and dimethachlon was similar, suggesting that there was no cross-resistance between boscalid and MBC/dimethachlon already in commercial use. In field trials, the treatments boscalid (50% WG), at 125, 187.5 and 250 g ai ha−1 provided higher control efficacies of 65.2, 69.0 and 75.1%, respectively, than the treatments carbendazim (50% WP), at 750 g ai ha−1 and dimethachlon (46% WP), at 690 g ai ha−1 with control efficacies of 18.9 and 44.6%, respectively.  相似文献   

3.
Rheum officinale liquid formulation, the ethanol extract from roots of R. officinale Baill., formulated as physcion 5 g l−1 aqueous solution (AS), has been commercialized in China for controlling cucumber powdery mildew (Podosphaera xanthii (Castagne) U. Braun & Shishkoff). The efficacy of the product was evaluated in pot tests under controlled conditions and in open and protected fields in China over 2 years. In most trials, the efficacy reached above 80% at the rates of 10–50 mg a.i l−1 water after three applications and at the rates of 20–50 mg a.i l−1 water after two applications. The cucumber fruit yield in the product treatment was as many or more as triadimefon treatment, and over 53.1% compared to the untreated control. These results showed that Chinese rhubarb extract could be an effective alternative plant protecting agent in the integrated and biological management of cucumber powdery mildew.  相似文献   

4.
Miscanthus × giganteus, a perennial rhizomatous grass commercially used as a biofuel crop was grown in a field experiment on a silty clay loam soil for 14 years. There were 3 rates of fertilizer nitrogen (N), none (control), 60 kg N ha−1 yr−1 and 120 kg N ha−1 yr−1 as cumulative applications. The crop was harvested in winter and dry matter yield measured. N did not influence yield. Yield, which increased for the first 6 years, decreased in years 7 and 8, but then increased again and was highest in the 10th year averaging 17.7 t ha−1 across all treatments. Differences in total production over the14 years were only 5% between the highest and lowest yielding treatments and averaged 178.9 t ha−1 equivalent to 12.8 t ha−1 yr−1. In the first 10 harvests, 92% of dry matter was stem. Although the study showed N fertilizer was not required, it is considered that an application of 7 kg P ha−1 yr−1 and 100 kg K ha−1 yr−1 would avoid soil reserve depletion. Pesticides were not required every year and the crop can be considered as low input with a high level of sustainability for at least 14 years.  相似文献   

5.
Physical properties of Salvia hispanica L. seeds were investigated and their application was also discussed. Physical properties were assessed for white and dark seed separately, except for the angle of repose and static coefficient of friction, which were determined for the seed mixture. The mean moisture content was 7.0% (dry basis). The average for the three characteristic dimensions, length, width and thickness was 2.11, 1.32 and 0.81 mm for dark seeds and 2.15, 1.40 and 0.83 mm for white seeds, respectively. The bulk density, true density and the porosity were between 0.667 and 0.722 g cm−3, 0.931 and 1.075 g cm−3, and 22.9 and 35.9%, respectively. The equivalent diameter ranged from 1.32 to 1.39 mm. The volume of single grain and sphericity ranged between 1.19 and 1.42 mm3, and 62.2 and 66.0%, respectively. The geometric mean diameter ranged between 1.31 and 1.36 mm for dark and white chia seeds, respectively. This parameter could be used for the theoretical determination of seed volume and sphericity. One thousand seed mass averaged 1.323 g for dark seeds, and 1.301 g for white seed. The angle of repose varied between 16° and 18° whereas the value of static coefficient of friction was 0.28 on galvanized sheet and 0.31 on mild steel sheet.  相似文献   

6.
A method for the eradication of Clavibacter michiganensis subsp. michiganensis was tested for its efficacy in three experiments carried out in the laboratory and greenhouse. In the first experiment, peat moss and sand mix in pots was amended with fresh tomato debris which was either artificially infected with the pathogen, or was not amended. Pots were enclosed in plastic bags or left open. Two temperatures (25 °C and 45 °C) were tested over a 6-week period. The pathogen was not detected in the amended soil after 4 weeks treatment at 45 °C, but was not eradicated after treatments in open pots at 25 °C.In the second experiment, the survival of C.m. michiganensis in either artificially infested soil or in artificially infected tomato plants was studied to determine the behaviour of the pathogen under these conditions. Strains of saprophytic bacteria in the genera Bacillus, Paenibacillus and Brevibacillus were identified under the experimental conditions. In vitro antagonism between Bacillus subtilis and C.m. michiganensis was observed. Finally, the recovery of C.m. michiganensis introduced into disinfected substrate was determined. Survival of C.m. michiganensis in plates artificially inoculated with substrate was greatly reduced after a 4-week treatment at 25 °C, or after 1 week at 45 °C.C.m. michiganensis remained pathogenic on plant tissue after 4 weeks of either thermal treatment.It is important to take these results into account with regard the effect of different soil disinfection techniques or ecological alternatives such as biofumigation, solarization, and the addition of organic matter, as well as for integrated pest management systems.  相似文献   

7.
Preliminary chemical studies were undertaken during one year on plant materials collected in a 40 ha field located in Henderson, Province of Buenos Aires, in order to determine the technical viability of the industrial production of essential oil from bay leaves (Laurus nobilis L., Lauraceae) growing in Argentina. The oils were extracted at a pilot scale plant and analyzed by GC–FID-MS. The apparent density of the plant material used for the distillation ranged from 90 g L−1 to 170 g L−1, depending on the type of material. The quality of the volatile oils obtained complied with market requirements and were in agreement with values reported from other countries. No considerable variations were observed in the chemical composition of the oils throughout the year. Taking in account the composition of the sub-fractions obtained during the distillation process, the quality of the final essential oil can be adjusted by fractional distillation. The occurrence of alcohol terpenes and phenols in the condensed waters (hydrolate) makes them a possible alternative to be used in industry. Moreover, and due to the good energetic and digestibility values obtained, our results showed that the exhausted plant material obtained after distillation could be a putative fibrous feed for ruminants. Both, hydrolate and exhausted plant materials are resources that can enhance added values in new endeavours. This is the first report on bay leaves essential oil production at industrial scale in Argentina.  相似文献   

8.
During 2002–2006, nymph bands of Locusta migratoria manilensis (Meyen) were treated by ground and aerial applications in 6000 ha of grasslands and the nearby beach of Yellow river using a soybean oil miscible suspension ULV formulation of Metarhizium anisopliae var. acridum isolate CQMa102. The formulation was also applied in Tianjin, Henan, Hebei, Shandong and Shanxi provinces of Northern China by ground and aerial applications. During field studies, cage tests were carried out in corresponding field plots in order to estimate the mortality accurately. Doses of 3.3×1012 and 5.0×1012 conidia ha−1 were equally effective and caused 90% mortality 9–13 days after treatment. In the ground spray trial, 3.3×1012 conidia ha−1 killed >90% of L. migratoria manilensis 11–15 days after treatment in a wide variety of vegetation and weather conditions. The decline of locust populations was slower where vegetation was taller and denser. In the aerial spray treatment, the final percent survival of locusts was lowered to 10% at 11 and 14 days in the field cage and open field locusts, respectively. Furthermore, the M. anisopliae oil miscible suspension formulation did not appear to harm natural enemies of locusts in the field.  相似文献   

9.
The efficacy of a new fungicide fluopicolide in suppression of Phytophthora blight caused by Phytophthora capsici was evaluated under laboratory and field conditions. Studies with 51 P. capsici isolates from vegetable crops in Georgia, USA, indicated that 5.9% of the isolates were resistant, 19.6% were intermediately sensitive, and 74.5% were sensitive to 100 μg ml−1 of mefenoxam based on in vitro mycelial growth. EC50 values of fluopicolide in inhibiting mycelial growth of 25 isolates, representing resistant, intermediately sensitive, and sensitive to mefenoxam, ranged from 0.05 to 0.35 μg ml−1 with an average of 0.2 μg ml−1 EC50 values of fluopicolide in suppressing zoospore germination and sporangium production of the 25 isolates ranged from 1.1 to 4.5 μg ml−1 and 0.3–9.0 μg ml−1, respectively. Evaluation of a collection of 150 P. capsici isolates from vegetables and irrigation ponds found none of the isolates were resistant to 10 μg ml−1 of fluopicolide. Field experiments were conducted to determine the efficacy and application methods of fluopicolide for control of P. capsici on squash in spring 2007 and 2009. Fluopicolide applied through drip irrigation or as a foliar spray at 86.6 or 115.4 g ha−1 consistently provided significant disease reduction and increased squash yield. Results with fluopicolide were similar or slightly superior to mefenoxam applied at recommended rate. Fluopicolide applied at 57.7 g ha−1 did not provide consistent satisfactory disease suppression. The results indicated that fluopicolide was effective in suppression of different stages of the life cycle of P. capsici and could be a viable alternative to mefenoxam for managing Phytophthora blight in squash production.  相似文献   

10.
To reduce the time period for in vitro regeneration in annatto (Bixa orellana L.), a highly efficient two-stage plant regeneration protocol had been developed that can be used commercially. Different types of explants: nodal shoot tips, shoot tips and single nodes from in vitro grown seedlings were inoculated onto the Murashige and Skoog (MS) medium supplemented with different concentrations and combinations of plant growth regulators. Highest number of shoot buds was obtained when nodal shoot tip explants were inoculated onto MS medium supplemented with 31.1 μM N6-benzyladenine (BA) and 14.7 μM phenylacetic acid (PAA). PAA in combination with BA exhibited a synergistic effect on shoot multiplication and elongation. Sub-culturing of the shoots onto the MS medium supplemented with BA (13.3 μM) and PAA (7.3 μM) produced elongated shoots. Elongated shoots when inoculated onto the MS medium supplemented with 4.9 μM indole-3-butyric acid (IBA) produced optimal rooting. The rooted plantlets were hardened and their field survival rate after 6 weeks time was 73%.  相似文献   

11.
Hybrid indica rice (Oryza sativa L.) cultivars play an important role in rice production system due to its heterosis, resistance to environmental stress, large panicle and high yield potential. However, no attention has been given to its yield responses to rising atmospheric [CO2] in conjunction with nitrogen (N) availability. Therefore we conducted a free air CO2 enrichment (FACE) experiment at Yangzhou, Jiangsu, China (119°42′0′′E, 32°35′5′′N), in 2004–2006. A three-line hybrid indica rice cv. Shanyou 63 was grown at ambient and elevated (ca. 570 μmol mol−1) [CO2] under two levels of supplemental N (12.5 g Nm−2 and 25 g Nm−2). Elevated [CO2] had no effect on phenology, but substantially enhanced grain yield (+34%). The magnitude of yield response to [CO2] was independent of N fertilization, but varied among different years. On average, elevated [CO2] increased the panicle number per square meter by 10%, due to an increase in maximum tiller number under enrich [CO2], while productive tiller ratio remained unaffected. Spikelet number per panicle also showed an average increase of 10% due to elevated [CO2], which was supported by increased plant height and stem dry weight per tiller. Meanwhile, elevated [CO2] caused a significant enhancement in both filled spikelet percentage (+5%) and individual grain weight (+4%). Compared with the two prior FACE studies on rice, hybrid indica rice cultivar appears to profit much more from elevated [CO2] than japonica rice cultivar (ca. +13%), not only due to its stronger sink generation, but also enhanced capacity to utilize the carbon sources in a high [CO2] environment. The above data has significant implication with respect to N strategies and cultivar selection under projected future [CO2] levels.  相似文献   

12.
Increasing interest in vegetable oils for use in green chemistry has stimulated research into high-erucic Brassicaceae species such as winter oilseed rape (Brassica napus L. var. oleifera) and Ethiopian mustard (Brassica carinata A. Braun). The objective of this study was to determine the yield response of recently released cultivars of these species under high and low production inputs. The varieties Maplus and Hearty of B. napus, and BRK1 of B. carinata were cultivated with autumn sowing in a large-scale field trial at the experimental farm of the University of Padova in Legnaro (NE Italy, 45°21′N). The genotypes were compared under high and low input management systems: high input was characterised by conventional soil tillage, chemical weed control, and high N–P–K fertilization, and low input by minimum tillage, mechanical weed control, and limited N–P–K fertilization.Oilseed rape varieties had greater seed yield than BRK1, and interactions with input level and cultivation year were significant. Maplus yielded most at high input (3.78 vs. 3.31 t ha−1 DM at low; average of two years), whereas Hearty showed no significant differences between inputs (3.49 t ha−1; average of years and inputs), indicating its better adaptability to extensive agricultural management. Yield performance of BRK1 B. carinata was very stable at varying agricultural managements, but not very high (2.73 t ha−1 on average) – a fact that may limit its competitiveness with oilseed rape in autumn sowing, especially at higher latitudes. B. carinata was also more variable across the years than oilseed rape in terms of seed yield, oil content, and percentage of erucic acid. This was mainly due to the particular climatic conditions of the second year of the experiment (mild winter; hot, dry spring) which led to considerable winter elongation and pre-flowering, and later to incomplete seed filling. In these conditions, BRK1 had both lower oil seed content (36.7% vs. 47.1%) and erucic acid (41.3% vs. 49.1%) than oilseed rapes.In general, with few exceptions, the reduction in inputs did not affect either seed oil content or the amount of erucic acid, regardless of variety and year, but seed crude proteins were reduced mainly because of N shortage.  相似文献   

13.
Tobacco black shank caused by Phytophthora parasitica is a devastating soil-borne disease of tobacco in China. Control of tobacco black shank relies on numerous fungicide applications. A new carboxylic acid amide (CAA) fungicide, mandipropamid, was examined for its effects on various asexual developmental stages of P. parasitica in vitro and in tobacco seedlings. Although mandipropamid did not affect discharge of zoospores from sporangia, it strongly inhibited mycelial growth (mean EC50 value of 0.0112 μg ml−1), sporangia production (mean EC50 value of 0.009 μg ml−1), germination of encysted zoospores (mean EC50 value of 0.014 μg ml−1), and germination of sporangia (mean EC50 value of 0.017 μg ml−1). For protective activity in tobacco seedlings, various applications of mandipropamid were superior in reducing black shank compared to that of metalaxyl and of azoxystrobin; while for curative activity assay, 100 μg ml−1 of mandipropamid exhibited the same efficacy as that of metalaxyl, and presented superior activity than that of azoxystrobin. In 2010 and 2011, 119 isolates of P. parasitica from Guizhou Province of China were characterized for the baseline sensitivity to mandipropamid by measuring mycelial growth. Values of effective concentrations for 50% mycelia growth inhibition varied from 0.0068 to 0.0285 μg ml−1 and averaged 0.013 (±0.0045) μg ml−1, with a unimodal distribution. This information will serve as a baseline for tracking future changes in sensitivities of P. parasitica populations to mandipropamid in China.  相似文献   

14.
Intensive rice farming in aerobic soil, referred to herein as aerobic rice, can greatly reduce the water input compared to that of flooded rice cultivation. The objective of this study was to compare the potential productivity of aerobic rice and flooded rice using high-yielding varieties at two locations in Japan in two successive years. In aerobic fields, the total amount of water supplied (irrigation plus rainfall) was 800–1300 mm. The soil water potential at 20-cm depth averaged between −15 and −30 kPa each growing season, but frequently reached −60 kPa. The average yield under aerobic conditions was similar to or even higher than that achieved with flooded conditions (7.9 t ha−1 in 2007 and 9.4 t ha−1 in 2008 for aerobic versus 8.2 t ha−1 for flooded). The average water productivity under aerobic conditions was 0.8–1.0 kg grain m−3 water, slightly higher than common values in the literature. The super-high-yielding cultivar Takanari achieved yields greater than 10 t ha−1 with no yield penalty under aerobic conditions in 3 out of 4 experiments. The favorable agronomic characteristic of Takanari was its ample sink capacity (grain number × grain weight). In conclusion, high-productivity rice cultivation in aerobic soil is a promising technology for water conservation. With continued breeding, future aerobic rice varieties will possess large numbers of spikelets and sufficient adaptation to aerobic conditions such that they will consistently achieve yields comparable to the potential yield of flooded rice.  相似文献   

15.
Atmospheric concentrations of Erysiphe necator conidia were monitored for 2 years in a vineyard planted with cultivars susceptible to powdery mildew in the vine production area of Quebec, Canada. The concentrations of airborne conidia were determined and compared using two types of samplers: a Burkard volumetric sampler and a rotating-arm sampler. The coefficients of correlation between the volumetric and rotating-arm sampler placed at 45 cm from the ground was r = 0.81 and 0.82 in 2000 and 2001, respectively. The relationship between incidence of powdery mildew on the leaves of three cultivars (Chancellor, Geisenheim, and Frontenac) and the cumulative concentration of airborne conidia (based on 3 d of sampling weekly) was then studied. This relationship was similar for the three cultivars, (R2 = 0.97, 0.95, 0.97, for cvs Chancellor, Geisenheim, and Frontenac respectively) and was well described using the cumulative form of the Weibull model. Based on this model, it was possible to establish the period of high risk (highest rate of increase in powdery mildew incidence) from 645 to 5614, 2437 to 2951, and 1052 to 3061 conidia m−3 of air for the cvs Chancellor, Geisenheim, and Frontenac, respectively. An action threshold, for timing interval between fungicide sprays, of 50 conidia m−3 d−1 was evaluated under field conditions with cv Chancellor and was as good as a calendar-based program with fewer fungicide sprays under unfavourable weather conditions. Monitoring airborne inoculum could be used as a component of a risk management system for grape powdery mildew to time intervals between fungicide sprays.  相似文献   

16.
Spring wheat (Triticum aestivum L. cv. Triso) was grown in a free-air CO2 enrichment (FACE) field experiment in order to gain information on CO2-induced effects on grain composition and quality at maturity. A proteome analysis was performed using two-dimensional gel electrophoresis (2-DE) and protein identification was done with mass spectrometry (MALDI-TOF MS). In elevated CO2 (526 μl l−1), an increase of 13.5% in grain yield was observed relative to 375 μl l−1 at a low level of significance (P = 0.528). Total grain protein concentration was decreased by 3.5% at a high level of statistical significance. Most importantly, a number of statistically significant changes within the grain proteome were observed, as the levels of 32 proteins were affected by elevated CO2: 16 proteins were up-regulated and 16 were down-regulated. Our experiment demonstrates that high-CO2 can markedly affect the proteome of mature wheat grain. The potential role of the proteins, changed in response to CO2 enrichment, is discussed as some may affect grain quality. For the task of selecting cultivars resistant to CO2-induced quality loss, we propose to consider the proteins affected by elevated CO2 identified in this work here.  相似文献   

17.
Cereals are widely consumed foodstuffs and it is therefore important to take them into account when estimating consumer exposure to packaging-related chemicals. The mass transport of three model migrants (diphenylbutadiene, triclosan and BHT) from low-density polyethylene (LDPE) within dry foodstuffs of different particle size (rice and wheat flour) was studied because of the relationship between consumer exposure and possible harmful effects on human health. The conditions that most affect the mass transport of substances within dry foods are evaluated and discussed. The diffusion coefficients (DF) for diphenylbutadiene (DPBD) and triclosan in the studied foodstuffs were estimated. The DF values for DPBD and triclosan in wheat flour at 25 °C were 7.1 × 10−8 cm2/s and 3.3 × 10−8 cm2/s, respectively. The DF values for DPBD and triclosan in rice at 25 °C were 4.7 × 10−8 and 4.3 × 10−8 cm2/s, respectively. BHT displayed different behaviour and other tests were therefore carried out to elucidate the associated mass transport process.  相似文献   

18.
Associations between RVA pasting properties and three single nucleotide polymorphism (SNP) sites in the Waxy gene intron 1, exon 6, and exon 10 were determined using rice genotypes of diverse geographic origin. A total of four SNP-haplotypes (combination of SNP alleles) were identified that explained high proportions of the variation in RVA pasting properties (R2 = 0.574–0.704). A haplotype containing DNA sequence variation in exon 10 (exon 10 cytosine nucleotide) was exclusively found in high-apparent amylose content (AAC) genotypes with a higher RVA viscosity profile compared to the high AAC genotypes with a different haplotype. The exon 10 SNP explained variances in coolpaste and setback (coolpaste–hotpaste) to 0.642 and 0.499, respectively. Across three haplotypes, which contained exon 10 adenine nucleotide, AAC was correlated with peak, hotpaste, breakdown and setback (coolpaste–hotpaste) at r = −0.85, −0.75, −0.79, and 0.49, respectively. Therefore, the exon 10 SNP differentiates high AAC types with a strong RVA profile and thus can be used by molecular breeding programs focused on quality improvement. Additionally, characterizing genotypes by their functional SNPs allowed us to better understand the relationship between the Waxy gene, its chemical product (i.e., AAC) and the functionality created by the product (i.e., pasting properties).  相似文献   

19.
Brewer's spent grain (BG), the most abundant brewing by-product, is used in the present study as a low-cost feedstock for the production of ethanol by the mesophilic fungus Fusarium oxysporum using a consolidated bioconversion process. The production of required cellulolytic and hemicellulolytic enzymes was optimized under solid-state cultivation (SSC) concerning carbon source and initial moisture. The optimal medium contains BG and corn cobs (CC) in a ratio 7:3 while the optimal initial moisture is 66% (w/w). SSC in a laboratory horizontal bioreactor using the optimized medium allowed the large-scale production of a multienzymic system including endoglucanase, cellobiohydrolase, β-d-glucosidase, xylanase, feruloyl esterase, acetyl esterase, β-d-xylosidase and α-l-arabinofuranosidase. Chromogenic (fluorogenic) 4-methylumbelliferyl substrates were used to partially characterize the extracellular proteome of the microbe after the separation by isolectric focusing (IEF) electrophoresis. Alkali pretreatment of brewer's spent grain and different aeration levels were studied for the optimization of the ethanol production by F. oxysporum in a consecutive submerged fermentation. A yield about 65 g ethanol kg−1 of dry BG was obtained with alkali pretreated BG under microaerobic conditions (0.01 vvm) corresponding to 30% of the theoretical yield based on total glucose and xylose composition of BG.  相似文献   

20.
Long-term (over 15 years) winter wheat (Triticum aestivum L.)–maize (Zea mays L.) crop rotation experiments were conducted to investigate the accumulation of phosphorus (P) at five sites differing geographically and climatically in China. The results showed that, in soils without P added, the concentration of soil P extracted by 0.5 mol L−1 NaHCO3 at pH 8.5 (Olsen-P) decreased with cultivation time until about 3 mg kg−1, afterwards it remained constant. The trend of decrease in Olsen-P in soils without P added could be described by an exponential function of time. The concentration of Olsen-P in soils with P fertilizers increased with cultivation time and the model of accumulation of Olsen-P in soils could be described using P application rate, crop yield and soil pH. The accumulation rate of Olsen-P in the long-term wheat–maize crop rotation experiments was 1.21 mg kg−1 year−1 on average. If the target yield of wheat and maize is 10 ton ha−1 in the soil with pH 8, the increasing rates of Olsen-P in soils as estimated by the model will be 0.06, 0.36, 0.66, 0.95, 1.25 and 1.55 mg kg−1 year−1 when P application rates are 30, 40, 50, 60, 70 and 80 kg P ha−1 year−1, respectively. The models of accumulation of Olsen-P in soils were validated independently and could be used for the accurate prediction of accumulation rate of Olsen-P in soils with wheat–maize rotation systems. Also the application of the model was discussed for best management of soil P in agricultural production and environment protection.  相似文献   

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