Biofumigant Biomass,Nutrient Content,and Glucosinolate Response to Phosphorus

Information on biofumigant-green manure vegetative biomass, nutrient, and glucosinolate content sensitivity to phosphorus (P) is lacking for species used in potato and sugarbeet production. Therefore, available P effects on field-grown condiment yellow mustard (Sinapis alba, cv. IdaGold) and oilseed radish (Raphanus sativa, cv. Colonel) were evaluated (2001–03). Low soil P was generally more limiting to radish foliage P concentrations or uptake than to the mustard, suggesting inherent differences in their ability to access and accumulate P. While radish P and S concentrations increased with higher P, concentrations in mustard were either unaffected or reduced. Foliage P concentrations were more closely related to biomass of radish (r² = 0.46) than mustard (r² = 0.11). Mustard exceeded radish in biomass and S accumulation. Phosphorus effects on glucosinolates producing ionic or isothiocyanates were relatively insignificant. These biofumigants differ appreciably in their ability to access and accumulate P, but P effects on nutrient content or glucosinolates were minor.     

Cover cropping influences physico-chemical soil properties under direct drilling soybean

In seeking effective methods to prevent soil degradation, conservation tillage plays an important protective role. Apart from significantly reducing production costs, cover crops contributes to beneficial changes in the soil environment. A three-year field experiment included three cover crops (winter rye, winter oilseed rape, and white mustard) subjected to mulching or desiccation and to the action of a herbicide at three rates (100%, 75%, and 50%). The study evaluated soil moisture and the content of organic matter, phosphorus, potassium, and magnesium in two soil layers (0–15?cm and 15–30?cm). Cover cropping had a positive effect on soil organic matter content. More organic matter (by 4.7%) was recorded in the topsoil layer (0–15?cm). Among the cover crops most favorable effect on the content of organic matter in the soil had white mustard (an increase of 14.2%) compared to the control. Moreover, rye and white mustard mulch increased the soil content of phosphorus and magnesium, while oilseed rape mulch increased the potassium content. At the critical growth stages (the flowering/pod set) of soybean (Glycine max (L.) Merril), soil moisture was dependent on mulching treatment and soil layers.     

Biofumigation effects of brassicaceous cover crops on soil health in cucurbit agroecosystems in Hawaii, USA

Brassicaceous cover crops, such as brown mustard(Brassica juncea) and oil radish(Raphanus sativus), are commonly used for biofumigation, a process that utilizes isothiocyanates(ITCs) generated from the hydrolysis of glucosinolates in Brassica plants to suppress soil-borne pathogens, including plant-parasitic nematodes. Given the biocidal nature of ITCs, limited information is available on the non-target effects of biofumigation on free-living nematodes, which are reliable soil health indicators....     

Effects of cover crops sown in autumn on N and P leaching

A field experiment with separately tile-drained plots was used to study the ability of oilseed radish (Rhaphanus sativus L.), as a cover crop sown after harvest of a main crop of cereals or peas, to reduce nitrogen (N) and phosphorus (P) leaching losses from a clay loam in southern Sweden over 6 years. In addition to oilseed radish in pure stand, two cover crop mixtures (hairy vetch (Vicia villosa) and rye (Secale cereale) for 3 years and oilseed radish in mixture with buckwheat (Fagopyrum esculentum) for 2 years) were tested. The cover crop plots (three replicates per treatment) were compared with unplanted plots as a control. Plots cropped with oilseed radish during autumn (August–November) had significantly smaller yearly mean N concentration in drainage water over 5 of 6 years compared with unplanted controls. Mineral N content in the soil profile in autumn was significantly less in oilseed radish plots than for control plots in all years. The cover crop mixtures of hairy vetch and rye or buckwheat and oilseed radish also showed the potential to reduce soil mineral N in autumn and N concentration in drainage water, compared with unplanted controls. The cover crops had no impact on P leaching. In conclusion, oilseed radish has the ability to reduce leaching losses of N, without increasing the risk of P leaching.     

Effect of light conditions on the contents of glucosinolates in germinating seeds of white mustard, red radish, white radish, and rapeseed

The study was aimed at determining the effect of light conditions on contents of glucosinolates (GLS) in germinating seeds of white mustard, red radish, white radish, and rapeseed. The seeds were germinated in light and dark, at 25 degrees C, for up to 7 days. As compared to the nongerminated seeds, in seeds exposed to light and germinated for 4, 5, 6, and 7 days the content of total GLS was observed to decrease by 30 to 70% depending on the species. Germination in conducted the dark for the respective periods of time resulted in decreases of total GLS not exceeding 25%. The changes in the concentration of total GLS were attributed to aliphatic GLS predominating in seeds, yet in the case of white mustard to sinalbin belonging to aralkyl glucosinolates. Although seeds germinated in the dark, as compared to those exposed to light, were characterized by a higher total content of indole GLS, the percentage contribution of that group of compounds in white mustard, red radish, and white radish remained at a similar level, irrespective of germination time. Only in the case of rapeseed was the percentage of the sum of indole GLS observed to increase from 17 to up to 45% once the seeds were exposed to light and to 50% once they were germinated in the dark.     

绿肥腐解液中有机酸组成对铝磷和铁磷活化能力的影响

  【目的】  研究绿肥还田腐解过程中产生的有机酸阴离子对土壤中难溶性磷素的活化效果,以深化理解绿肥作物提高土壤养分供应能力的机理。  【方法】  供试6种绿肥作物为紫云英 (Astragalus sinicus L.)、肥田萝卜 (Raphanus sativus var. Longipinnatus)、二月兰 (Orychophragmus violaceus)、双低甘蓝型油菜 (Brassica napus L.)、双高甘蓝型油菜 (Brassica napus L.) 和芥菜型油菜 (Brassica juncea)。将绿肥植株切碎后,置于离心管中,加入土壤浸提液于室外背光处密闭腐解45天,采用离心法提取植株腐解液。测定腐解液中10种有机酸组分 (丙二酸、苹果酸、柠檬酸、草酸、乳酸、酒石酸、乙酸、琥珀酸、马来酸和富马酸阴离子) 含量。采用室内模拟方法,分别用6种绿肥腐解液溶解难溶性铝磷 (Al-P,AlPO₄) 和铁磷 (Fe-P,FePO₄·2H₂O),测定溶液中的无机磷含量。  【结果】  二月兰腐解液中10种有机酸组分总含量最高,其次为肥田萝卜、双低甘蓝型油菜和芥菜型油菜,双高甘蓝型油菜和紫云英腐解后腐解液中较低。所有绿肥作物腐解液中10种有机酸组分含量大小依次为酒石酸、丙二酸、柠檬酸、琥珀酸、乳酸、苹果酸、乙酸、草酸、马来酸和富马酸阴离子。其中酒石酸和丙二酸阴离子占上述10种主要有机酸总量的15%以上,马来酸和富马酸阴离子占比最低,不到总量的1%。不同绿肥腐解液对Al-P和Fe-P的活化能力有显著差异,肥田萝卜对两种难溶性磷素的活化能力最高,理论上1000 kg肥田萝卜绿肥可活化0.6～1.2 kg的Al-P和Fe-P,其次为紫云英和芥菜型油菜,对Al-P和Fe-P的活化量均约为0.6～1.0 kg,而二月兰的活化量最低,约为0.2～0.6 kg。对不同有机酸含量与难溶性磷活化量进行相关性分析发现,Al-P活化量与柠檬酸、苹果酸和草酸阴离子的含量呈现正相关关系,Fe-P的活化量与酒石酸的含量呈现正相关关系。  【结论】  与Al-P和Fe-P的活化密切相关的是有机酸中含有较高的柠檬酸、草酸、苹果酸和酒石酸。供试6种绿肥作物腐解液中的10种有机酸的总含量及各有机酸组分的占比差异很大。二月兰虽然有机酸总量高,但是柠檬酸、草酸和酒石酸比例均较低;而肥田萝卜腐解液中的酒石酸含量及其占比高于其他绿肥,且柠檬酸和琥珀酸占比较高,对Fe-P的活化能力强;芥菜型油菜和紫云英腐解液中草酸、柠檬酸和琥珀酸占比高于其他绿肥,对Al-P的活化能力强。供试6种绿肥中以肥田萝卜腐解液的活化能力最强,芥菜型油菜和紫云英腐解液的活化能力次之。     

陇东旱塬区复种马铃薯田蛴螬及金针虫防治药剂筛选试验

陇东旱塬区种植冬油菜和冬小麦后，土地闲置期可复种马铃薯，但蛴螬、金针虫等地下害虫对马铃薯为害严重，科学合理防治蛴螬、金针虫对保证马铃薯产量非常重要。为筛选出陇东旱塬区复种马铃薯田防治蛴螬、金针虫危害的低毒高效的适宜药剂，以马铃薯品种陇薯7号为指示品种，蛴螬、金针虫为防治对象，选用3种高效低毒杀虫剂对各药剂的拌种或喷沟处理进行田间防效试验，调查各处理蛴螬、金针虫虫口基数，出苗期的出苗率、受害率、安全性和成熟期的受害率、安全性。结果表明，35%噻虫嗪种衣剂、60%帮巧时种衣剂防效均达85%以上，且拌种处理和喷沟处理无显著差异。60%帮巧时悬浮种衣剂拌种和喷沟防效均好，分别为88.44%、90.36%；折合产量高，分别为16 407.41、17 066.14 kg/hm2，较空白对照分别增产16.71%、21.40%，较常规药剂对照分别增产12.07%、16.57%；保产效果好，分别为95.39%、96.20%。见于此，60%帮巧时悬浮种衣剂可作为陇东旱塬区复种马铃薯田蛴螬、金针虫防治的候选杀虫剂；并建议用48.00 mL的药量稀释10倍液后拌种薯100 kg，将525.00 mL的药量稀释250倍液，按225 L/hm2喷沟。     

Effect of Biofumigants on Soil Microbial Communities and Ecotoxicology of Earthworms (<Emphasis Type="Italic">Eisenia andrei</Emphasis>)

Biofumigation is considered a good alternative to chemical fumigation because it can control crop pathogens and diseases with lower health and environmental risks than chemical fumigants. Glucosinolates are volatile compounds found in most Brassica species, and when hydrolysed, it forms a range of natural toxins including isothiocyanates that act as biofumigants. However, the effect of glucosinolates and their breakdown products on non-target and beneficial soil organisms is not well documented. Three biofumigants, broccoli, mustard and oilseed radish, were evaluated for their effect on earthworms (Eisenia andrei) and the soil microbial community. Sub-lethal endpoints, including growth and reproductive success of the earthworms, were monitored. Genotoxicity of the biofumigants towards earthworms was evaluated by means of the comet assay. Broccoli reduced earthworm reproduction while mustard induced more DNA strand breaks in earthworm cells compared to the control. Soil microbial community function and structure were evaluated by means of community level physiological profiling and phospholipid fatty acid analyses. The effects exerted by the biofumigants on the microbial community were the most pronounced within the first 14 days after application. Carbon substrate utilisation was most affected by the oilseed radish treatment and microbial community structure by the mustard treatment.     

Optimizing the NPK application in white mustard (Sinapis alba L.) under an arid climate in Punjab,Pakistan

The production of oil from the conventional oilseed seed crops (viz. mustard, rapeseed) is not sufficient to meet the demands of Pakistani people. Due to this reason, a surplus quantity of oil is imported every year from different countries to fulfill the domestic demands of the cooking oil. This 2-year study was aimed to optimize the dose of NPK for profitable production of white mustard. Nitrogen (0, 60, 90?kg ha^?1), phosphorous (0, 30, 60?kg ha^?1) and potassium (0, 75, 100?kg ha^?1) were applied in various combinations. The results indicated that highest seed yield and profitability was recorded with NPK at 90–60–100?kg ha^?1, which was attributed to improvement in crop growth. In crux, application of NPK at pre-optimized rate might be a viable option to improve the growth, yield, oil quality, and economics of white mustard production under arid climates in Pakistan. According to the results, a balanced use of NPK fertilization is a key management strategy for white mustard growing farmers of arid region.     

Cover crops and their erosion-reducing effects during concentrated flow erosion

Cover crops are a very effective erosion control and environmental conservation technique. When cover crops freeze at the beginning of the winter period, the above-ground biomass becomes less effective in protecting the soil from water erosion, but roots can still play an important role in improving soil strength. However, information on root properties of common cover crops growing in temperate climates (e.g. Sinapis alba (white mustard), Phacelia tanacetifoli (phacelia), Lolium perenne (ryegrass), Avena sativa (oats), Secale cereale (rye), Raphanus sativus subsp. oleiferus (fodder radish)) is very scarce. Therefore, root density distribution with soil depth and the erosion-reducing effect of these cover crops during concentrated flow erosion were assessed by conducting root auger measurements and controlled concentrated flow experiments with 0.1 m topsoil samples. The results indicate that root density of the studied cover crops ranges between 1.02 for phacelia and 2.95 kg m^− 3 for ryegrass. Cover crops with thick roots (e.g. white mustard and fodder radish) are less effective than cover crops with fine-branched roots (e.g. ryegrass and rye) in preventing soil losses by concentrated flow erosion. Moreover, after frost, the erosion-reducing potential of phacelia and oats roots decreased. Amoeba diagrams, taking into account both below-ground and above-ground plant characteristics, identified ryegrass, rye, oats and white mustard as the most suitable species for controlling concentrated flow erosion.     

Diagnosing boron deficiency in rapeseed and mustard by plant analysis and soil testing

Abstract

Boron (B) deficiency is a widespread nutritional disorder in crop plants, including rapeseed and mustard. However, plant analysis and soil testing diagnostic criteria for B are inadequately reported in the literature. Therefore, greenhouse and incubation studies were carried out using a B‐deficient alkaline calcareous soil (hot water extractable B, 0.11 mg/kg) of Pakistan to determine the internal and soil test B requirement of rapeseed and mustard. Boron fertilization substantially enhanced the growth of both species; the maximum increase in grain yield was 43% for rapeseed and 36% for mustard over the yield of respective control plants. Fertilizer requirement for near‐maximum (95%) grain yield was 0.7 mg B/kg for rapeseed and 0.9 mg B/kg for mustard. Critical plant tissue B concentration in rapeseed was 32 mg/kg in whole shoots and 38 mg/kg in most recently matured leaves. However, internal B requirement of mustard was relatively greater: i.e. 41 mg/kg in whole shoots and 49 mg/kg in leaves. The three soil tests studied, hot water, hydrochloric acid (HCl), and mannitol, were almost equally effective in determining soil B status. Because of simplicity and low cost, however, the HCl method appears superior than the other two for routine B analysis. Critical soil B levels (mg/kg) for rapeseed were: hot water, 0.5; HCl, 0.45; and mannitol, 0.4. Similar to internal B requirements, soil test critical B levels (mg/kg) were also greater for mustard, i.e. hot water, 0.6; HCl, 0.55; and mannitol, 0.48.     

Increased pepper yields following incorporation of biofumigation cover crops and the effects on soilborne pathogen populations and pepper diseases

The use of brassica cover crops and their associated degradation compounds as biofumigants to manage soilborne pathogens could offer vegetable growers an alternative to the restricted broad-spectrum fumigant methyl bromide. Biofumigation was tested in two experiments to manage Rhizoctonia solani, Sclerotium rolfsii, and Pythium spp., and the diseases they cause on pepper. Field plots were seeded in fall 2010 and spring 2011 to oilseed radish (Raphanus sativus L.), ‘Pacific Gold’ mustard (Brassica juncea (L.) Czern), or ‘Dwarf Essex’ winter rapeseed (Brassica napus L.). Cover crops were disked into soil in spring 2011 and immediately covered with virtually impermeable film (VIF) to reduce the escape of volatile pesticidal compounds. Controls included fallow plots with (CVIF) and without (fallow) VIF. Green bell pepper was transplanted into all plots. Concentrations of isothiocyanates (ITCs), the brassica degradation compounds primarily responsible for pesticidal activity, were highest following incorporation of mustard. Rapeseed yielded the second highest ITC concentrations. Radish yielded very low ITC concentrations in experiment 1, and none during experiment 2. ITCs also were detected in low concentrations in CVIF treatments. All treatments that received VIF reduced populations of R. solani compared to fallow, with no differences between biofumigation treatments and CVIF. Biofumigation treatments did not reduce populations of Pythium spp. or S. rolfsii compared to CVIF. Pepper stunting was significantly lower in treatments that received VIF compared to fallow, with no consistently significant differences between biofumigation treatments and CVIF. Pythium isolated from roots of stunted peppers was identified as Pythium aphanidermatum. Biofumigation treatments did not reduce plant mortality. Pepper yields were highest in biofumigation treatments compared to CVIF, and CVIF yields were higher than fallow yields.     

Glucosinolate and isothiocyanate concentration in soil following incorporation of Brassica biofumigants

The concentration of glucosinolates (GSLs) and isothiocyanates (ITCs) was monitored in soil following the incorporation of pulverised high and low GSL varieties of rape (Brassica napus) and mustard (Brassica juncea) biofumigant crops. The concentration of both GSLs and ITCs in soil was highest immediately (30 min) after incorporation and they could be detected for up to 8 and 12 d, respectively. Irrigating with 18 mm of water over 3 h had no effect on either GSL or ITC concentrations. The amounts detected were generally related to the amount of GSL added in the incorporated plant tissue. Maximum total GSL concentration detected in the soil was 13.8 and 22.8 nmol g⁻¹ for rape and mustard, respectively, representing 7% and 13% of the original GSL present in the incorporated tissues. The non-ITC liberating GSLs (predominately indolyl GSLs) were found at lower concentrations than ITC-liberating GSLs, but tended to persist longer in the soil. Maximum total ITC concentration was 21.6 nmol g⁻¹ and 90.6 nmol g⁻¹ for rape and mustard, respectively. Calculated ITC release efficiency was 26% and 56% for high GSL rape and mustard, respectively at the time of the highest ITC concentration measured. These are the first reported measurements of GSLs in soil following biofumigant incorporation. They indicate that a significant proportion of plant GSL can persist un-hydrolysed in the soil for several days following Brassica incorporation. Further investigations of plant treatment and incorporation methods to maximise ITC release are warranted.     

Influence of cover crops on potential nitrogen availability to succeeding crops in a Southern Piedmont soil

Winter cover crops are essential in conservation tillage systems to protect soils from erosion and for improving soil productivity. Black oat (Avena strigosa Schreb) and oilseed radish (Raphanus sativus L.) could be useful cover crops in the southeastern USA, but successful adoption requires understanding their influence on N availability in conservation tillage systems. Black oat and oilseed radish were compared to crimson clover (Trifolium incarnatum L.) and rye (Secale cereale L.) for biomass production and effects on N mineralization during the summer crop growing season from fall 1998 through summer 2002 near Watkinsville, GA. Rye produced 40 to 60% more biomass, although N contents were less than the other cover crops. Oilseed radish and black oat N contents were similar to crimson clover. Black oat, oilseed radish, and crimson clover C/N ratios were less than 30, whereas rye averaged 39. Amount of N mineralized in 90 days (N _min90) measured with in situ soil cores was 1.3 to 2.2 times greater following black oat, crimson clover, and oilseed radish than following rye. No differences in N _min90 were found between black oats, crimson clover, and oilseed radish in 1999 and 2000. The amount of potentially mineralizable N (N ₀) was not different due to cover crop, but was 1.5 times greater in 2000 and 2002 than in 1999. The rate of N mineralization (k) was 20 to 50% slower following rye than the other three cover crops. Black oat and oilseed radish biomass production and soil N mineralization dynamics were more similar to crimson clover than to rye, which indicates that they could be used as cover crops in the southeast without significant changes in N recommendations for most crops.

---

土壤中水分和镉供应量对油菜器官中镉分布特征的影响

为探究油菜作为镉(Cd)污染农田修复植物的可行性,本研究以德油5号为试验材料,采用全生育期土培盆栽试验,设置高、中、低3个水平的土壤水分及4个水平的土壤镉含量,研究不同土壤水分条件下油菜对镉的吸收和富集规律。结果表明,土壤水分与镉浓度对油菜的吸镉能力影响显著,且其吸收量随着土壤水分与镉浓度的增加而增大;油菜不同器官的镉含量差异较大,其地上部分吸镉量为土壤总镉含量的0.41%～1.17%,叶片镉含量为总吸收量的46.4%～72.6%;不同水分条件下,油菜器官的镉富集量差异明显,高水、中水处理下油菜各器官的镉富集表现为叶>茎>根>角果壳>籽粒,低水处理下表现为叶>根>茎>角果壳>籽粒。综上,油菜整体具有较强的吸镉能力,但镉离子不溶于菜籽油,说明油菜可吸收土壤中的镉,又不影响菜籽油食用,是修复镉污染农田土壤的理想植物。本研究为利用油菜进行重金属土壤综合治理提供了理论依据。     

油菜秸秆还田腐解变化特征及其培肥土壤的作用

为促进油菜秸秆腐解,推进农村作物秸秆的资源化利用,减少秸秆焚烧对环境的负面影响,培养与提高土壤肥力,采用尼龙网袋和田间试验相结合方法,设置了油菜秸秆不同还田量处理和不同还田深度处理,研究了油菜秸秆腐解百分率和腐解速率变化特征,分析了油菜秸秆还田对土壤性质及作物产量的影响。结果表明,油菜秸秆还田的腐解百分率随时间延长而逐渐增大,秸秆腐解速率则早期快后期慢;随秸秆还田量增加,腐解速率降低,表现为全量还田的秸秆腐解速率<2/3量还田秸秆腐解速率<1/2量还田秸秆腐解速率<1/3量还田秸秆腐解速率;在种植水稻条件下油菜秸秆还田深度在10 cm时腐解速度最慢,在表层还田腐解速度最快,20 cm深还田腐解速度居中。相比对照处理来说,油菜秸秆还田降低了土壤容重,增加了土壤有机质含量,一定程度上提高了土壤氮磷钾含量(P<0.05)。油菜秸秆还田对水稻作物有极显著增产作用(P<0.01),增产幅度在6.02%～21.17%之间。本试验对水稻油菜轮作体系下油菜秸秆还田腐解特征进行的研究可为调控油菜秸秆还田腐解速度,改善农业生态环境提供参数依据。     

Rhizosphere Cadmium Speciation and Mechanisms of Cadmium Tolerance in Different Oilseed Rape Species

ABSTRACT

The role of rhizosphere processes in cadmium (Cd) uptake by plants and mechanisms of Cd tolerance is unexplored and a matter of debate. Pot experiments were conducted under greenhouse conditions to investigate rhizosphere Cd speciation and mechanisms of Cd tolerance in different oilseed rape (Brassica juncea L. and Brassica napus L.) species using a sequential extraction technique. A Cd-tolerant oilseed rape, Xikou Huazi, a non-tolerant oilseed rape, Zhongyou 821, and an Indian mustard (Brassica juncea L.) were used in the study. The results showed that three predominant forms of Cd in the plants were NaCl-extractable Cd, acetic acid-extractable Cd, and water-extractable Cd. The concentration of water-extractable Cd in Xikou Huazi was significantly lower than in Zhongyou 821. A significant depletion of exchangeable Cd was observed in the rhizosphere soil of oilseed rapes Xikou Huazi and Zhongyou 821, as well as Indian mustard. At 60 mg kg^?1 of soil Cd concentration, the concentrations of carbonate-bound and organically bound Cd in the rhizosphere soil of Xikou Huazi were significantly higher than in the non-rhizosphere soil. The concentrations of these two Cd speciations were higher in the rhizosphere soil of Xikou Huazi than in the rhizosphere soil of Zhongyou 821. However, for Zhongyou 821, there were no significant differences in the concentrations of these two Cd speciations between the rhizosphere and non-rhizosphere at 30 and 60 mg kg^?1 of soil Cd concentrations. A significant difference existed in rhizosphere Cd speciations and Cd forms in the plants between Cd-tolerant oilseed rape and non-tolerant oilseed rape. This difference was the main reason that Cd-tolerant oilseed rapes take up and accumulate Cd.     

Assessment of chemical composition of plants cultivated on two different soils amended with sewage sludge compost using MANOVA

Abstract

Application of organic fertilizers may replenish soil organic matter, improve soil fertility and increase plant yield and its quality. This research deals with the effects of soil amendment with sewage sludge compost (SSC) on the chemical composition of plants (white mustard, triticale and white lupine) cultivated on two contrasting soils (light vs. medium). A 3-year pot experiment was conducted and SSC at the rate of 6?Mg ha^?1 was applied to the soils.The study clearly demonstrated that SSC as an organic fertilizer had a minor influence on the modification of the chemical composition of shoots and grain cultivated in crop rotation plants and it was more evident in medium soil. The statistically confirmed effect was mainfested in higher c ontents of N and P in grain of plants in the 2^nd and 3^rd year of the experiment.     

Organic and urea nitrogen fertilizer effects on rapeseed and wild mustard competition

The competitive effects of wild mustard on rapeseed with organic amendments and urea alone or combined were studied for 2 years. Treatments consisted of three Sinapis arvensis densities and fertilizer treatments of composted cattle manure, composted municipal waste, urea nitrogen, a combination CCM+urea, a combination of CMW+urea, and a control. Weed growth was stronger in urea fertilizer and with combined organic amendments than in organic amendments alone. However, application of organic amendments could increase weed competitive ability. In the first year, urea fertilizer alone and combined with organic amendments led to the greatest rapeseed yield, but in the following year, organic amendments alone were able to increase rapeseed yield approximately equal to urea fertilizer and combined with organic amendments. Application of organic amendments alone or combined with N fertilizer could be an efficient method to increase soil productivity.     

PHENOLOGY AND SEED QUALITY RESPONSE OF RAPE (B. NAPUS) VERSUS MUSTARD (B. JUNCEA) TO SULFUR AND POTASSIUM FERTILIZATION IN NORTHWEST PAKISTAN

Inappropriate sulfur and potassium fertilization, particularly with continued soil nutrient mining and yearly fluctuations in rainfall, are major factors contributing to slow growth and low seed quality of canola in northwestern Pakistan. A field experiment was conducted in 2007–2008 on a sulfur (S) and potassium (K) deficient clay loam soil under irrigation at the research farm of NWFP (Northwest Frontier Province) Agricultural University, Peshawar, Pakistan, with an objective to determine response of phenology and seed quality of Brassica oilseed rape versus mustard to S and K fertilizer application. Twenty treatments in a randomized complete block design were consisted of two oilseed genotypes [rape (B. napus canola) and mustard (B. juncea canola)], at three rates each of S (15, 30, and 45 kg S ha^?1) and K (30, 60, and 90 kg K ha^?1), plus control (no K and S applied). Days to flowering, pod formation, seed filling duration and maturity were enhanced with K and S fertilization compared to control plots. The species B. napus took more time to flowering, pod formation, seed filling duration and maturity compared to B. juncea. Both genotypes responded positively for seed quality (oil and protein content) to K and S fertilization, but the magnitude of response varied with level and combination of K and S fertilization. Delay in the phenological stages showed negative relationship with oil and protein content in seed of both genotypes. It is concluded that a combination of 60 kg K ha^?1 + 30 kg S ha^?1 would accelerate phenological development and improve seed quality of rape and mustard in the study area.