Performance consistency of reduced atrazine use in sweet corn

Atrazine is the most widely used herbicide in North American corn production; however, additional restrictions on its use in the near future are conceivable. Currently, a majority of commercial sweet corn fields suffer losses due to weeds, despite widespread use of atrazine. Field experiments were conducted in the primary North American production areas of sweet corn grown for processing to determine the implications of further reductions in atrazine use on weed control and crop yield. A range of atrazine doses (0-1120 g ha⁻¹) applied postemergence with tembotrione (31 g ha⁻¹) were tested in two hybrids differing in canopy architecture and competitive ability with weeds. Atrazine applied postemergence reduced risk (i.e. more variable outcomes) of poor herbicide performance. Atrazine doses up to 1120 g ha⁻¹ with tembotrione improved grass control and broadleaf weed control in five of eight and seven of eight environments, respectively. Of the three environments which had particularly low broadleaf weed control (<50%) with tembotrione alone, sweet corn yield was improved with atrazine. Hybrid ‘Code128’ produced a taller, denser canopy which was more efficient at capturing light and competing with weeds than ‘Quickie’. As a result, greater crop competitiveness decreased risk of incomplete weed control as atrazine dose was reduced. Atrazine's contribution to weed control and yield protection was greatest when other aspects of weed management resulted in poor weed control. Should atrazine use be further restricted or banned altogether, this research demonstrates the importance of improving other aspects of weed management systems such as herbicidal and non-chemical tactics.     

The impact of tillage system and herbicides on weed density,diversity and yield of cotton (Gossipium hirsutum L.) and maize (Zea mays L.) under the smallholder sector

The study was carried out to evaluate the impact of tillage system in combination with different herbicides on weed density, diversity, crop growth and yields on 18 farms in Kadoma, Zimbabwe. Experiments were set up as a split plot design with three replications on each farm. Tillage was the main plot (Conservation Tillage (CT), Conventional Tillage (CONV)) and weeding option (hand weeding, cyanazine, atrazine, glyphosate only and mixture of cyanazine + alachlor and atrazine + alachlor) as the sub-plots. Due to the heterogeneous nature of farmers' resource base, the farms were grouped into three farm types: high (Type 1), medium (Type 2) and poorly resourced farmers (Type 3). The hand hoe weeded treatments had 49 percent higher total weed densities in CT relative to CONV, and was statistically similar to the glyphosate treatment. The mixed pre-emergence herbicides reduced the diversity indices by 69 and 70 percent when compared to the hand hoe weeded treatment under CT in cotton and maize, respectively. The effectiveness of all pre-emergence herbicides were not influenced by tillage but were affected by farmers resource endowments with pronounced effect in Farm Type 1. Maximum plant heights of 85 and 238 cm were recorded for mixed pre-emergence herbicides under CT for cotton and maize, respectively. Minimum plant heights of 75 and 217 cm were recorded for the respective hand hoe weeded treatments. The hand hoe weeded treatments resulted in average cotton lint yield of 1497 and 2018 kg ha⁻¹ for maize. The mixed pre-emergence herbicides treatments gave yields of 2138 and 2356 kg ha⁻¹ of cotton and maize, respectively. The higher weed densities in CT under hand weeded treatments underscored the need for other weeding options. Similarly, a mixture of cyanazine + alachlor in cotton and atrazine + alachlor in maize is recommended for suppressing broad and grass weed populations and enhancing yields in CT systems.     

Effects of in situ freezing on soil net nitrogen mineralization and net nitrification in fertilized grassland of northern China

Effects of soil freezing on nitrogen (N) mineralization have been the subject of increased attention in the ecological literature, though fewer studies have examined N mineralization responses to successive mild freezing, severe freezing and cyclic freeze–thaw events. Even less is known about relationships of responses to soil N status. This study measured soil N mineralization and nitrification in the field along an experimental N gradient in a grassland of northern China during the dormant season (October 2005–April 2006), a period in which freezing naturally occurs. Net N mineralization exhibited great temporal variability, with nitrification being the predominant N transformation process. Soil microbial biomass C and N and extractable NH₄ ⁺ pools declined by 40, 52, and 56%, respectively, in April 2006, compared with their initial concentrations in October 2005; soil NO₃^– pools increased by 84%. Temporal patterns of N mineralization were correlated with soil microbial biomass C and N. N mineralization and nitrification increased linearly with added N. Microbial biomass C in treated soils increased by 10% relative to controls, whereas microbial N declined by 9%. Results further suggest that freezing events greatly alter soil N dynamics in the dormant season at this site, with considerable available N accumulating during this period.     

Weed emergence as affected by maize (Zea mays L.)-cover crop rotations in contrasting arable soils of Zimbabwe under conservation agriculture

Weed control in smallholder farming systems of sub-Saharan Africa is labour intensive or costly. Many researchers have therefore advocated for the use of cover crops in weed management as an affordable alternative for smallholders. Cover crops may be grown in rotations to suppress weeds and reduce the reliance on herbicides. The use of cover crops creates microenvironments that are either conducive or inhibitive to the emergence of certain weed species. A study, initiated in 2008 in contrasting soils at four different locations of Zimbabwe, investigated the effect of maize (Zea mays L.)-cover crop rotations on the emergence of weeds that showed dominance in those soils. Weed assessments were however, carried out from 2011 to 2014. The weed species Galinsoga parviflora Cav., Commelina benghalensis L., and Richardia scabra L. showed dominance in all four locations with weed densities as high as 500 plants m⁻² being recorded for R. scabra L. in a sandy soil. Maize-cover crop rotations resulted in higher densities of Bidens pilosa compared with maize monocropping (control treatment) due to its high nitrogen (N) requirement to produce more seeds. On the other hand, the integration of cover crops such as pigeon pea [Cajanus cajan (L.) Millsp.] that had poor shading qualities, due to large gaps or spaces and slower initial growth, had limited effects on competitive weeds such as Cyperus esculentus L. which tend to dominate exhausted soils. The density of C. esculentus was 38% greater in maize–pigeon pea rotations compared with the control treatment. Variability between seasons and sites affected emergence of all weeds in the present study, which masked long-term trends. The results suggest that there is need to identify the germination and emergence requirements of specific weeds and select cover crops best suitable for their control. The study provides useful information for farmers and advisors on the best cover crops for control of certain problematic weeds in different soil types of Zimbabwe.     

施钾对小麦/ 玉米产量及土壤钾素平衡的影响

为指导河南小麦/玉米生产中钾肥的合理施用,于2010-2012年在高、中和低三种土壤供钾水平的试验点,研究了施钾量及施钾技术对小麦/玉米轮作产量、钾肥利用效率及土壤钾素平衡的影响。结果表明,在高钾、中钾和低钾土壤上施用钾肥,玉米分别增产4.76%～12.49%、7.56%～16.08%和7.01%～22.61%;小麦分别增产6.87%～13.87%、11.19%～18.57%和18.71%～27.49%。在不同供钾水平土壤上小麦钾肥利用效率均高于玉米,钾肥偏生产力表现为高钾点>中钾点>低钾点,高钾点钾肥当季利用率较高,低钾点的农学效率较高;当施钾量为90、135 kg·hm^-2时,小麦和玉米均以钾肥分2次施用效果较好;施钾量为45 kg·hm^-2时,玉米以底施较好,小麦以追施较好。低钾和中钾点在施钾量大于45 kg·hm^-2时,基本就能维持土壤钾素平衡,而高钾点则在施钾量大于90 kg·hm^-2时土壤钾素才有盈余。综合来看,高、中和低钾点适宜的钾肥用量分别在45、90、135 kg·hm^-2左右,以钾肥分2次施用效果较好。     

Rice straw mulching and nitrogen response of no-till wheat following rice in Bangladesh

Wheat (Triticum aestivum L.) cultivation in no-till soil of a postrice harvest field utilizes residual soil moisture and reduces the time period from rice harvest to wheat seeding in intensive rice-wheat cropping systems. Some of the major constraints in no-till wheat production are high weed infestation, poor stand establishment due to rapid drying of topsoil and low nitrogen use efficiency (NUE). A field experiment was conducted at the research farm of the Wheat Research Centre, Dinajpur, Bangladesh, for two consecutive years to overcome those constraints, to evaluate rice straw as mulch, and to determine the optimum application rate of nitrogen (N) for no-till wheat. The treatments included 12 factorial combinations of three levels of mulching: no mulch (M₀), surface application of rice straw mulch at 4.0 Mg ha⁻¹ that was withdrawn at 20 days after sowing (M₁), the same level of mulch as M₁ but allowed to be retained on the soil surface (M₂), and four nitrogen levels (control 80, 120 and 160 kg ha⁻¹). Rice straw mulching had a significant effect on conserving initial soil moisture and reducing weed growth. Root length density and root weight density of wheat were positively influenced both by straw mulching and N levels. N uptake and apparent nitrogen recovery of applied N fertilizer were higher in mulch treatments M₁ and M₂ as compared to M₀. Also mulch treatment of M₁ and M₂ were equally effective at conserving soil moisture, suppressing growth of weed flora, promoting root development and thereby improved grain yield of no-till wheat. N application of 120 kg ha⁻¹ with straw mulch was found to be suitable for no-till wheat in experimental field condition.     

Phosphorus accumulation and depletion in soils in wheat–maize cropping systems: Modeling and validation

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.     

降解菌对大豆生长前期莠去津毒害作用的缓解

为明确降解菌(Enterobacter sp.)对大豆莠去津毒害作用的缓解能力,以辽豆15为试验材料,通过室内种子萌发和幼苗盆栽试验方法,对大豆生长前期的生长和生理指标进行测定。结果表明:与莠去津处理比较,降解菌能显著提高大豆种子的发芽率、发芽指数、种子活力指数和α-淀粉酶活性,减少电解质外渗和脯氨酸积累。同时,降解菌对大豆幼苗生长有一定的促进作用,大豆经菌液处理后,其根系相关发育指标、胚芽和子叶重量均显著高于莠去津处理。可见,试验菌株能有效缓解生长前期莠去津对大豆的毒害作用。     

Effect of the type of fertilizer and source of irrigation water on N use in a maize crop

An experiment in a maize crop evaluated the influence of several types of commercial nitrogenous fertilizers with different action mechanisms — urea (soluble), Floranid-32 (low water solubility) and Multicote 4 (coated fertilizer) — on maize grain and biomass yields, as well as on plant N use. The fertilizers were applied as a top-dressing of 294 kg N ha⁻¹. All treatments additionally received 64 kg N ha⁻¹ as 8.0 (N):6.5 (P):12.5 (K) compound prior to seedbed preparation. The influence of NO⁻₃ content in the irrigation water was also assessed, using water with either 2.5 or 35 mg l⁻¹ of NO⁻₃. Irrigation plus rainfall totalled 513 mm (1.20 potential ET). Nitrogen lost during the cultivation period was calculated from the N balance of the topsoil.Results obtained under these experimental conditions showed that the type of fertilizer did not alter maize grain and biomass yields. Yields for maize irrigated with the higher NO⁻₃ water were systematically greater than those obtained with irrigation water of low NO⁻₃ content.Nitrogen lost from the topsoil during the cultivation period varied between 240 and 280 kg N ha⁻¹ for all treatments, and was well correlated with NO⁻₃-N leached into the aquifer during the same period.     

Evaluation of some weed control treatments for long season weed control in maize (Zea mays L.) under zero and minimum tillage at Samaru, in Nigeria

The effect of weed control treatments for long season control of weeds in maize under zero and minimum tillage was evaluated at Samara in northern Nigeria. Among the weed control treatments evaluated, soil ridging plus application of either 2,4-D or atrazine at 1.5 kg a.i/ha performed well as they effectively controlled weeds and resulted in better growth and a grain yield that was comparable to the hand weed control. Maize production under minimum tillage was better than under zero tillage.     

Evaluation of combinations of paraquat plus photosystem II-inhibiting herbicides for controlling failed stands of maize (Zea mays)

Existing plants remaining in failed stands of maize must be removed prior to planting a subsequent crop, and glyphosate and glufosinate are generally ineffective because of the presence of herbicide-resistant genes in most US maize. Research was conducted at three locations in 2009 to evaluate maize control with paraquat as influenced by (1) the addition of three PSII-inhibiting herbicides, (2) maize growth stage at application with and without addition of atrazine, and (3) time of day of application with and without addition of atrazine. Delaying an application of paraquat beyond the V4 stage (four visible collars) of maize resulted in ineffective control of maize, and the addition of atrazine to paraquat improved control of older plants. A paraquat dose of at least 525 g/ha was often needed for acceptable control of maize. Of the three PSII-inhibiting herbicides evaluated, maize control was generally greater and more consistent with the addition of metribuzin or diuron to paraquat than with atrazine, even though atrazine did often improve control over paraquat alone. Applying paraquat at sunset did improve control over applications made near sunrise, but a PSII-inhibiting herbicide was still needed with paraquat to maximize control of maize. These findings demonstrate that undesirable maize plants can be effectively controlled with combinations of paraquat plus PSII-inhibiting herbicides when applied no later than the V4 stage of maize, and applications in close proximity to sunset can further improve control.     

Weed control and sweet maize (Zea mays L.) yield as affected by pyroxasulfone dose

Pyroxasulfone is a new herbicide being considered for registration in sweet maize in Canada; however, there is still little information on the doses required to provide 90% control of annual grass and broadleaved weeds found in southwestern Ontario. The objective of this study was to determine pyroxasulfone doses that would provide at least 90% control of several economically important weeds, without impacting final sweet maize yield by more than 5% in comparison to a weed-free control. Six field trials were conducted over a two-year period (2007 and 2008) at three Ontario locations to evaluate the effectiveness of pyroxasulfone at doses ranging from 31.25 to 1000 g a.i. ha⁻¹. The doses required to reduce weed biomass by at least 90% (I₉₀) varied by weed species. Doses of 93, 499, and 111 g a.i. ha⁻¹ were required to reduce the biomass by 90% of redroot pigweed, common lambsquarters and green foxtail, respectively. There was greater than 95% control of velvetleaf, large crabgrass and barnyardgrass with 31.25 g a.i. ha⁻¹, the lowest dose tested. Sweet maize yield could not be consistently maintained within 5% of the weed-free control. There are several factors that may have contributed to the reduced yield, including soil texture effects, competition as a result of poor common lambsquarters control, and hybrid sensitivity. These results show that biologically effective weed control with pyroxasulfone may be achieved at lower than proposed doses for several weed species; it remains unclear if this is economically sustainable due to the potential impacts on yield.     

Nitrogen efficiency in long-term wheat–maize cropping systems under diverse field sites in China

Efficiency of fertilizer N is becoming increasingly important in modern agricultural production owing to increasing food requirement and growing concern about environments. However, there is almost no study regarding its long-term efficiency in wheat and maize cropping systems. Long-term (15 years) experiments involving wheat (Triticum aestivum L.) and maize (Zea mays L.) rotations at five field sites with various soil and climate characteristics in China were used to determine the nitrogen (N) efficiency, including the physiological efficiency, recovery efficiency and N mass balance of soil–plant systems in response to different fertilization treatments. The present study consisted of nine treatments: unfertilized, N, phosphorus, potassium, straw and manure or their combinations. The contribution of N fertilizers to wheat yield was higher than to maize and suggested that wheat could be given priority over maize when determining N application rates. Uptake of 1 kg N produced 35.6 kg of wheat grain and 39.5 kg of maize grain. The deficit of N in soils without applied N ranged from 40 to 103 kg N ha⁻¹ year⁻¹, while N surpluses in soils with applied N fertilizers ranged from 35 to 350 kg N ha⁻¹ year⁻¹. The apparent accumulated N recovery efficiency (NRE_ac) varied widely from 4% to 90%: unbalanced fertilization and other soil limiting factors (such as aluminium toxicity) were associated with low NRE_ac. In the treatments of combination of N, phosphorus and potassium with normal application rates, the average of NRE_ac in four out of five sites reached 80%, which suggested that best management of N fertilizers could recover most of N fertilizers applied to soils. The results will be helpful to understand the long-term fate of N fertilizers and to optimize the N fertilization for agricultural practices and environment protection.     

Impact of different crop rotations and tillage systems on weed infestation and productivity of bread wheat

Crop rotation and tillage systems have important implications for weed infestation and crop productivity. In this study, five tillage systems viz. zero tillage (ZT), conventional tillage (CT), deep tillage (DT), bed sowing (60/30 cm with four rows; BS₁) and bed sowing (90/45 cm with six rows; BS₂) were evaluated in five different crop rotations viz. fallow-wheat (FW), rice-wheat (RW), cotton-wheat (CW), mungbean-wheat (MW) and sorghum-wheat (SW) for their effect on weed infestation and productivity of bread wheat. Interaction between different tillage practices and cropping systems had significant effect on density and dry biomass of total, broadleaved and grass weeds, agronomic and yield-related traits, and grain yield of bread wheat. The un-disturbed soils (ZT) under fallow-wheat or mungbean-wheat rotations favoured the weed prevalence (a total weed dry biomass of 72.4–109.6 and 105.6–112.1 g m⁻² in first and second year, respectively). Contrary to this, the disturbed soils (CT, DT, BS₁ and BS₂) had less weed infestation with either of the rotations (a total weed biomass of 0.4–7.1 and 1.1–5.4 g m⁻² in first and second year, respectively). Sorghum-wheat rotation had strong suppressive effect on weed infestation in all tillage systems. The impact of crop rotation was more visible during second year of experimentation. Bed sown wheat (BS₁ and BS₂) in mungbean-wheat rotation had the highest wheat grain yield (6.30–6.47 t ha⁻¹) compared to other tillage systems in different crop rotation combinations.     

柳叶刺蓼对玉米生长的影响及其经济阈值研究

柳叶刺蓼是吉林省春玉米田的恶性杂草,严重危害玉米生长发育,降低玉米产量。在大田条件下采用添加柳叶刺蓼密度系列试验和拟合函数关系模型方法,研究柳叶刺蓼与玉米的竞争关系。结果表明,在柳叶刺蓼的竞争干扰下,玉米株高、茎粗、穗长、单穗重、百粒重及产量均随柳叶刺蓼密度的增加而降低,空秆率增加。幂函数y=2.947x~(0.855)能较好地拟合玉米产量损失与柳叶刺蓼密度之间的关系(R~2=0.983;F=287.355;P=0.000 1)。玉米田柳叶刺蓼人工除草的经济阈值为3.97~5.02株/m~2,90%莠去津可分散粒剂或20%氯氟吡氧乙酸乳油化学防除柳叶刺蓼的经济阈值分别为0.45~0.58和0.53~0.67株/m~2。     

有机无机肥配施对土壤硝态氮、玉米产量和氮素利用率的影响

通过田间定位试验,等氮量条件下研究100%有机肥(T1)、30%有机肥+70%无机肥(T2)、20%有机肥+80%无机肥(T3)、100%无机肥(T4)和不施肥(CK)对玉米各生育期0~90 cm土层硝态氮含量、玉米产量和氮素利用率的影响。结果表明,施肥均可增加各土层硝态氮含量,随玉米生长发育,表层硝态氮有下移趋势,成熟期最明显,其中,T4处理31~90 cm土层分别比CK、T3、T1和T2处理高96.9%、39.1%、36.1%和17.8%。苗期和灌浆期0~90 cm土层硝态氮累积量与玉米产量相关系数分别为0.925~*和0.904~*,拔节期达0.997~(**),T2和T3处理供氮能力较强。T3、T2、T4和T1处理玉米增产率分别达138.76%、131.93%、117.28%和71.73%,其中,T3和T2处理高产并稳产,可最大限度提高氮肥利用率,明显降低环境污染风险。有机无机肥配施是较为合理的施肥模式,且配比以20%∶80%为最佳。     

东北部分春玉米地乙莠合剂防效下降的原因和对策

在我国的东北春玉米区,长时间使用乙草胺和莠去津,导致部分地区防效下降。在吉林省农安县通过定点试验、大面积试验和大范围调查发现,乙莠合剂防效下降的主要原因是因为杂草群落结构的变化引起的,同时降水的减少和药剂使用方法不当也起了一定的作用,未发现产生明显抗性的迹象。在未来,乙莠合剂仍是该地区玉米地除草剂的主要药剂,对于杂草群落尚未发生变化的地块仍然有很好的防效,而在杂草群落发生变化的地区,应适当更换除草剂或适当增加轮作;针对当地特点,适当推迟乙莠合剂的喷施时间,采用机械喷雾、加大用水量等措施来提高乙莠合剂的防效。     

Analyzing soil-available phosphorus by the Mehlich-3 extraction method to recommend a phosphorus fertilizer application rate for maize production in northern Mozambique

ABSTRACT

The available phosphorus (P) in soil is a major limiting factor for maize productivity in the Nacala corridor, Mozambique. In this study, soils were collected from three representative sites, Ribaue, Nampula, and Nacala, in the area, and each was used for maize pot experiment with five P fertilizer levels. The soil-available P content was determined by the Mehlich-3 method at 30 days after P fertilization. The shoot biomass and P concentration at the tasseling stage increased as the P fertilizer level increased and were significantly expressed as a function of soil-available P. Based on the function, the available P that attains 90% of the maximum shoot biomass was estimated as 79 mg P₂O₅ kg^?1. Consequently, the results in this study suggest a recommendation of 32–74 kg P₂O₅ ha^?1 fertilizer for maize production in the Nacala corridor although a field evaluation and economical evaluation are necessary.     

阿特拉津对不同种子大小品种大豆的危害

玉米和大豆轮作是我国东北地区应用广泛的种植方式,但玉米田除草剂阿特拉津常引起下茬大豆药害。选用东北地区推广应用的45个不同种子大小的大豆品种（粒重范围81～302 mg/seed）进行温室盆栽试验,探讨大豆地上冠部和地下根系对阿特拉津危害的响应。结果表明,阿特拉津在土壤中有效成分用量为500g/hm2的条件下,大豆地上部干物质生产随种子重量增加而增加,呈显著正相关（P＜0.05）,而根系干物质生产与种子大小未呈显著正相关（P＞0.05）。这说明大粒品种大豆对阿特拉津耐药性强,小粒品种则敏感,因此,种植大粒品种大豆或品种中大粒种子,可使阿特拉津对大豆危害降到最低。 

     

冀东地区春玉米田杂草群落特征及烟嘧·莠去津配比优选

采用倒置“W”取样法对唐山、秦皇岛主要春玉米产区的田间杂草进行调查，利用茎叶处理法对烟嘧磺隆+莠去津药剂组合进行最佳配比筛选。结果表明，冀东地区发生优势度较大的杂草有马唐、稗草、鸭跖草、虎尾草、藜、反枝苋、马齿苋、苘麻、苣荬菜、铁苋菜、小马泡、豚草、葎草、狗尾草共14种。秦皇岛地区以藜、反枝苋、马齿苋、马唐、稗、苘麻、鸭跖草、苣荬菜和虎尾草为主，Shannon''s指数H''为0.63，Shannon''s均匀度指数E为0.09，Margalef物种丰富度指数D_MG为0.98；唐山地区以藜、马唐、鸭跖草、反枝苋、铁苋菜、苘麻、小马泡、豚草、葎草为主，Shannon''s指数H''为0.51，Shannon''s均匀度指数E为0.11，Margalef物种丰富度指数D_MG为1.56。药剂筛选结果显示，与其他处理相比，烟嘧磺隆+莠去津(30 g/hm²+285 g/hm²)组合对玉米田主要杂草的防效最高，药后14 d的株防效为93.55%，药后28 d的株防效和鲜重防效分别为95.32%和93.24%。