تأثیر سطوح مصرف نهاده بر بانک بذر علفهای هرز در مزارع گندم مشهد

Introduction: According to the importance of corn in supplying the human food directly and indirectly, it is one of the most important plants among crops. One of the major problems in corn production systems, is competition with weeds that reduce corn yield significantly. Weeds not only reduce crop yields but also decrease the commercial quality and the feeding palatability of main crops. They enhance the soil seed bank of weeds, which may cause continuous weed infestation of field crops as well. Herbicide application is a reliable and highly effective method for weed control. However, demand for safe food products that have been produced with a minimum application of chemical inputs is increasing. Therefore, farmers interested in weed management have to rely on other control approaches. An alternative weed control method is the use of cover crops, which can suppress the growth of weeds by preventing them from light and by producing allelopathic compounds. Cover crops successfully have been integrated into conservational agriculture systems in many areas of the world. Legumes are used as cover crop because of their rapid growth, in addition their potential to provide further nitrogen,along with high ability to compete with weeds. Materials and Methods: In order to study the effect of cover crops (soybean and wheat) and different fertilizers sources on yield of corn and weed control, a filed experiment was conducted in randomized complete block design with three replications in 2012. Treatments included two cover crop (wheat and soybean) and three fertilizer (no fertilizer, chemical fertilizer and compost)..Fertilizer treatments was used according to soil analysis and requirement of corn (as a main plant). Weed-infestation and weed-free plots were used as controls. Study cultivars of corn, wheat and soybean were NS-640, Milan and Sari, respectively. Planting of corn was in June and cover crop was planted with corn simultaneously and between corn rows. The dominant weed species were velvetleaf (Abutilon theophrasti Medic.), johnson grass (Sorghum halepense (L.) Pers.), wild melon (Cucumis melo var. agrestis) and giant foxtail (Setaria glauca L.) in the field. In order to determine the dry weight and density of weeds, three-stage sampling was performed from the middle rows of corn. Corn yield was also measured by mechanical harvesting in middle rows and adjusting to 14% moisture. A week before the final harvest, ten plants of corn were selected randomly from the three middle rows of each plot and yield components including the number of rows in corn, number of kernels per row, weight of 1000 grains was measured. Results and Discussion: The results showed that soybean cover crop reduced weed density compared to control in weed infestated plots, but wheat was not successful in suppressing weeds and reducing their density due to poor biomass and dying at the end of growing season . So, the lowest dry matter of velvetleaf, wild melon and other weeds were related to planted corn with soybean and compost and the maximum was related to monoculture of corn with weed infestation. Results of analysis of variance indicated treatments had significant effect on grain yield. The lowest yield of corn (2733.3 Kg ha-1) was in weed-infestation control while the highest one (12124.0 and 8351.3 Kg ha-1 respectively) was in weed-free control and soybean’ cover crop plus compost. For both cover crops between fertilizer treatments, compost and chemical fertilizer had more corn biological yield than no fertilizer and differences between this two fertilizer treatments wasn’t significant. Reduction of yield under no fertilizer treatments was due to competition for nutrients, light between weed and corn. The maximum and minimum number of rows in corn and number of kernels per row respectively was obtained with monoculture of corn in weed free and weed infestation, while the maximum weight of 1000 grains was observed in soybean with applying compost. Generally, the living mulch as cover crops can reduce competition between weeds and the main crop. Conclusion: As cover crops reduce weeds growth, and there was no significant difference between chemical and organic fertilizer in corn yield, so we can use these two options for producing optimum yield in sustainable agriculture. Results showed application of soybean as cover crop, especially integrated with organic fertilizers, can be an alternative approach for herbicides and are more effective than the others.

The aims of this study were to determine energy requirement and global warming potential (GWP) in low and high input wheat production systems in western of Iran. For this purpose, data were collected from 120 wheat farms applying questionnaires via face-to-face interviews. Results showed that total energy input and output were 60,000 and 180,000 MJha(-1) in high input systems and 14,000 and 56,000MJha(-1) in low input wheat production systems, respectively. The highest share of total input energy in high input systems recorded for electricity power, N fertilizer, and diesel fuel with 36, 18, and 13%, respectively, while the highest share of input energy in low input systems observed for N fertilizer, diesel fuel, and seed with 32, 31, and 27%. Energy use efficiency in high input systems (3.03) was lower than of low input systems (3.94). Total CO2, N2O, and CH4 emissions in high input systems were 1981.25, 31.18, and 1.87kgha(-1), respectively. These amounts were 699.88, 0.02, and 0.96kgha(-1) in low input systems. In high input wheat production systems, total GWP was 11686.63kg CO2eq ha(-1) wheat. This amount was 725.89kg CO2eq ha(-1) in low input systems. The results show that 1ha of high input system will produce greenhouse effect 17 times of low input systems. So, high input production systems need to have an efficient and sustainable management for reducing environmental crises such as change climate.

Evaluation of carbon sequestration potential in corn fields with different management systems

تولید ارقام جدید نمی‏تواند به تنهایی باعث افزایش محصولات کشاورزی شود بلکه در کنار پیشرفت‏ های به‌نژادی باید روش‏های زراعی مناسب جهت تولید به‌کار گرفته شده تا حداکثر عملکرد حاصل شود. هدف اصلی از اجرای روش‏ های خاک‏ورزی حفاظتی، نگهداری مقادیر مناسب بقایا در سطح خاک جهت کنترل فرسایش آبی و خاکی مزارع، کاهش انرژی و حفاظت از منابع آب و خاک می‏ باشد. مطالعه پیش‌رو به‌‌منظور بررسی تأثیر تیمارهای مختلف خاک‌ورزی بر روی عملکرد ذرت علوفه ای، در سال 1392 انجام شد. آزمایش در قالب طرح آشیانه‌ای در سه قطعه زمین مجزا انجام شد. صفات اندازه‏ گیری شده شامل سطح برگ، وزن خشک برگ، وزن خشک ساقه، وزن خشک بوته و ارتفاع بوته و آخرین مرحله فقط وزن تر بود. نتایج تجزیه واریانس آماری حاکی از آن بود که بین نظام‏ های خاک‏ورزی از نظر سطح برگ، وزن خشک برگ، وزن خشک ساقه و وزن خشک بوته‌ی ذرت اختلاف معنی‏ داری وجود نداشت. در بین نظام ‏های خاک‏ورزی با وجود اختلاف غیر معنی‏ دار در عملکرد وزن خشک ذرت، مقدار عملکرد علوفه‌ی تر ذرت در نظام خاک‏ورزی متداول از نظر آماری بیشتر از دو نظام دیگر بود. بیشترین عملکرد علوفه‌ی تر با مقدار 71 تن در هکتار در نظام خاک‏ورزی متداول و کمترین عملکرد با مقدار 64 تن در هکتار برای نظام بدون خاک‏ورزی به‌دست آمد که با دو نظام خاک‏ورزی دیگر اختلاف معنی ‏داری داشت. نتایج این مطالعه نشان داد که نظام‏ های خاک‏ورزی اثر معنی‏ داری بر وزن خشک بوته‏ ی ذرت نداشت اما عملکرد علوفه‌ی تر در سیستم خاک‌ورزی و کمترین عملکرد با مقدار 64 تن در هکتار برای نظام بدون خاک‏ورزی به‌دست آمد که با دو نظام خاک‏ورزی دیگر اختلاف معنی ‏داری داشت. نتایج این مطالعه نشان داد که نظام‏ های خاک‏ورزی اثر معنی‏ داری بر وزن خشک بوته‏ ی ذرت نداشت اما عملکرد علوفه‌ی تر در سیستم خاک‌ورزی متداول به مقدار هفت تن در هکتار از سیستم بدون خاک ورزی و چهار تن در هکتار از سیستم کم خاک ورزی بیشتر بوده است که دلیل این اختلاف عملکرد افزایش دسترسی به آب یا دسترسی به آب بیشتر و توسعه مناسب و بهتر ریشه در سیستم خاک ورزی مرسوم می‌باشد.

Four crop rotation and management systems were studied in 1994 and 1995 in relation to growth and yield of irrigated processing tomatoes (Lycopersicon esculentum Mill.). The four treatments were three four-year rotation systems [conventional (conv-4), low input and organic] and a two-year rotation system [conventional (conv-2)]. The four-year rotation was tomato-safflower-corn-wheat(or oats+vetch)/beans, and the two-year rotation was tomato-wheat. Purple vetch (Vicia sativa L.) was grown as a green manure cover crop preceeding tomatoes in the low input and organic systems. Nitrogen was supplied as fertilizer in the conventional systems, as vetch green manure plus fertilizer in the low input system and as vetch green manure plus turkey manure in the organic system. Tomato cv. Brigade was direct-seeded in the conventional systems and transplanted to the field in the low input and organic systems. In both years the winter cover crop was composed of a mixture of vetch and volunteer oats with N contents of 2.2% in 1994 and 2.7% (low input) or 1.8% (organic) in 1995. In 1994 yields were higher in conventionally grown tomatoes because a virus in the nursery infected the transplants used in the low input and organic systems. In 1995 tomatoes grown with the low input and conv-4 systems had similar yields, which were higher than those of tomatoes grown with the conv-2 and organic systems. N uptake by the crop was greater than 200 kg N ha−1 for high yield (> 75 t ha−1) and uptake rates of 3 to 6 kg N ha−1 day−1 during the period of maximum uptake were observed. The lower yield with the organic system in 1995 was caused by a N deficiency. The main effect of the N deficiency was a reduced leaf area index and not a reduction of net assimilation rate (NAR) or radiation use efficiency (RUE). Nitrogen deficiency was related to low concentration of inorganic N in the soil and slow release of N from the cover crop + manure. A high proportion of N from the green manure but only a low proportion of N from the manure was mineralized during the crop season. In the conventional systems, the estimated mineralized N from the soil organic matter during the crop season was around 85 kg ha−1. A hyperbolic relationship between N content and total dry weight of aboveground biomass was observed in procesing tomatoes with adequate N nutrition. Lower yields with the conv-2 than with the conv-4 system were due to higher incidence of diseases in the two year rotation which reduced the NAR and the RUE. Residual N in the soil in Oct. (two months after the incorporation of crop residues) ranged between 90 and 170 kg N ha−1 in the 0–90 cm profile.

IntroductionRecent prices in soybean have spurred interest in motivating growers into input integration to improve yields across the northern savannas of Ghana. This requires more knowledge of input integration to increase soybean yield and profitability across production areas.Materials and methodA 3-yr study was conducted in three locations at Manga, Nyankpala, and Wa in Ghana's northern savanna to identify the best-yielding input combination under a rain-fed environment. The experiment used “Jenguma” soybean cultivar with lime, inoculum, and phosphorus in a 2 × 2 × 2 factorial arrangement with four replications. Eight treatment combinations (control included) were used to assess soybean yield, yield components, rain use efficiency, and economic profitability. The single-input application of lime (T1), inoculum (T2), and phosphorus (T4) was the low-input, lime × inoculum (T3), lime × phosphorus (T5), and (inoculum × phosphorus) (T6) as medium input, T7 (lime × inoculum × phosphorus) was high input, and a no-input treatment (control).ResultsThe soils were inherently low in fertility, and weather variability during the reproductive stages was a significant limiting factor to improving grain yield across locations. Grain yield was highest in 2017 at Manga and Nyankpala, but in 2019 at Wa. Except at Manga, grain yield and rain use efficiency (RUE) were highest in the high input system (T7). However, marginal net benefits (MNB) and marginal rate of returns (MRR) were highest in the low input system (T2) across locations. The low (T1) and medium (T3) input systems (except Nyankpala) were dominant for MNB and MRR due to the high cost of the lime product.DiscussionThese results suggest that smallholder farmers prefer low input (T2) with the least cost of production and the highest marginal net benefit and marginal rate of returns. Nevertheless, producers would have to evaluate their resource base and the cost of nutrient integration for sustainability.ConclusionThis paper recommends further studies on lime rates to determine profitability, lime's long-term (residual) effect, and the synergic impact of inoculum and phosphorus.

Feeding standards and feeding systems

بمنظور بررسی تأثیر نظامهای زراعی با نهاده های مختلف بر تنوع، ترکیب و تراکم علف‌های‌هرز در ذرت (Zea mays L.) آزمایشی در قالب طرح بلوکهای کامل تصادفی با سه تکرار در سال زراعی 88-1387 در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد اجرا شد. تیمارهای آزمایش شامل سه نظام زراعی کم نهاده، متوسط نهاده و پرنهاده بودند. نظام کم نهاده با 30 تن کود دامی و نظام کم نهاده با 30 تن کمپوست، بدون عملیات آماده سازی زمین و وجین دستی، نظام متوسط نهاده شامل 15 تن در هکتار کمپوست، 150 کیلوگرم در هکتار اوره، دو مرتبه عملیات آماده سازی زمین و علفکش توفوردی (در مرحله پنج برگی ذرت، به میزان 5/1 لیتر در هکتار) و یک مرتبه وجین دستی و نظام پرنهاده شامل 300 کیلوگرم در هکتار اوره، چهار مرتبه عملیات آماده سازی زمین و پاراکوات (بعد از کاشت، به میزان 2 لیتر در هکتار) و توفوردی (در مرحله پنج برگی ذرت، به میزان 5/1 لیتر در هکتار) بودند کود دامی پوسیده و کمپوست در زمان کاشت و کود شیمیایی 25 روز پس از کاشت (اوره به میزان 150 و 300 کیلوگرم در هکتار به ترتیب برای نظامهای متوسط نهاده و پرنهاده) به خاک افزوده شد. نمونه برداری از جمعیت علف‌های‌هرز در سه مرحله ابتدا، وسط و انتهای فصل رشد انجام شد. نتایج نشان داد که در بین تیمارهای مختلف مدیریت نظام زراعی، تاجریزی سیاه (Solanum nigrum) با دامنه 00/75-09/9 درصد بیشترین فراوانی نسبی را نسبت به سایر گونه های علف هرز داشت. نظام کم نهاده بر پایه کود دامی بیشترین تعداد گونه علف هرز را به خود اختصاص داد. اثر مدیریت نظامهای زراعی بر وزن خشک و شاخصهای تنوع علف‌های‌هرز معنی دار بود. بیشترین و کمترین وزن خشک علف‌های‌هرز به ترتیب در نظام کم نهاده بر پایه کود دامی و نظام پرنهاده مشاهده شد. در مرحله اول، دوم و سوم نمونه برداری، بیشترین شاخص تنوع مارگالف در نظام کم نهاده بر پایه کود دامی (به ترتیب با 3/5، 4/5 و 3/3) و کمترین میزان آن در نظام پرنهاده (به ترتیب با 8/0، 3/2 و 6/2) به‌دست آمد. بیشترین میزان شاخص تنوع شانون در مرحله اول، دوم و سوم نمونه برداری در نظام کم نهاده بر پایه کود دامی (بترتیب با 5/0، 7/0 و 6/0) و کمترین آن در نظام پرنهاده (به ترتیب با 1/0، 4/0 و 3/0) حاصل شد. دلیل کاهش تعداد و وزن خشک علف‌های‌هرز در نظام پرنهاده در مقایسه با سایر نظامها بدلیل کنترل شیمیایی آنها در طی فصل رشد و اعمال سیستمهای خاکورزی فشرده و تراکم بالای ذرت بود.

Maize yield stability under organic and conventional farming systems in sub-humid agro-ecozones of Central Kenya

SummaryThe objective of this study was to obtain detailed information on the long‐term weed suppression potential of four winter soil cover types included in an arable crop system managed at various input levels. We used weed seedbank size and composition to assess weed suppression potential. A field experiment was established in 1993 as a split‐split‐plot design with four replications, including two tillage systems [a conventional system (CS) including ploughing in the cover crops and a low‐input system (LIS) including no tillage with surface mulching of the cover crops] in the main plots, three mineral nitrogen fertilization rates for the main crop in the sub‐plots and four soil cover types (main crop residue, rye, crimson clover and subterranean clover) in the sub‐sub‐plots. Seedbank sampling took place in winter 2000/01. The weed seedbank was analysed with the seedling emergence method. Data were analysed using anova and multivariate techniques. Results indicated that the seedbank density in the LIS was about five times higher than in the conventional input system. In the CS, use of a rye cover crop resulted in a lower seedbank density with respect to the crop residue treatment (−25%), whereas in the LIS the subterranean clover cover crop decreased weed seedbank density as compared with the other cover crops and the crop residue treatment (−22% on average). Differences in species composition were mainly related to tillage system. Implications for cover crop management and the development of sustainable cropping systems are discussed.

WEED AND SEEDBANK MANAGEMENT WITH INTEGRATED METHODS AS INFLUENCED BY TILLAGE

Munger, H., Vanasse, A., Rioux, S. and Légère, A. 2014. Bread wheat performance, fusarium head blight incidence and weed infestation response to low-input conservation tillage systems in eastern Canada. Can. J. Plant Sci. 94: 193–201. Bread wheat performance, the incidence of diseases like fusarium head blight (FHB) and weed infestations may be affected by low-input systems and conservation tillage practices. This 2-yr study assessed the effects of three 24-yr-old tillage treatments (MP: moldboard plow; CP: chisel plow; NT: no-till) and two cropping systems (high-input: herbicide and mineral fertilizer; low-input: mechanical weed control and organic fertilizer) on wheat productivity, deoxynivalenol (DON) content, Fusarium graminearum inoculum production, and weed infestation in hard red spring wheat. In 2009, low-input CP and NT yields were 13 and 31% lower, respectively, than low-input MP yield, which was comparable with all of the high-input treatment yields. In 2010, yields were 23% lower in CP and NT compared with MP, and 32% lower in low-input than in high-input systems. Optimum wheat yield in low-input systems appeared conditional to adequate weed control, which was achieved with MP and CP tillage. Protein content, test weight, and 1000-kernel weight were higher in the high-input system than in the low-input system, except for test weight in 2009. DON content was not affected by tillage in either year, and was lower in low-input system than in high-input system in 2009. Fusarium graminearum inoculum measured in 2009 was similar across tillage treatments in the high-input system, whereas in the low-input system, the inoculum was lower in NT than in MP. In 2010, DON content was not affected by any treatment. Hot and dry conditions were not conducive to pathogen development, and may explain the low level of DON and the lack of treatment effect.

The Sustainable Agriculture Farming System (SAFS) Project was begun in 1988 to compare conventional 4-year and 2-year rotations receiving synthetic fertilizers and pesticides to low input and organic farming systems. In 1998 and 1999, we evaluated the influence of 10 years of organic, low input, and conventional management practices on soil chemical properties, processing tomato yields, and fruit mineral composition. The organic system had highest soil total C, N, soluble P, exchangeable Ca, and K levels as a result of 10 years of manure application and cover crop use. In both years, fruit yields were similar in the three farming systems. Organic fruits contained highest amounts of P, and Ca. Conventionally-grown tomatoes were richer in N, and Na, while the low input system had an intermediate values for N, P, and Na, and the lowest Ca concentration of the three systems.

ارزش غذایی و سودمندی های دارویی روغن کدوی تخمه کاغذی (Cucurbita pepo var. Styriaca) در گرو عملکرد دانه، نوع و میزان اسیدهای چرب موجود در آن است. در این آزمایش پاسخ گیاه به دور آبیاری، مالچ پلاستیک سیاه و منبع کودی به‌صورت اسپلیت- فاکتوریل بر پایه-ی بلوک های کامل تصادفی، با سه تکرار در تابستان 1392 در مزرعه دانشگاه همدان بررسی شد. کرت‌های اصلی، دور آبیاری (هفت و 12روزه) و کرت‌های فرعی فاکتوریل مالچ (کاربرد و عدم کاربرد) و رژیم کودی (25% کودهای شیمیایی (اوره و سوپر فسفات تریپل)+ کودهای زیستی (نیتروکسین و بیوفسفات)، 50% شیمیایی+ کودهای زیستی، 75% شیمیایی+ کودهای زیستی و مصرف 100% کودهای شیمیایی) بود. نتایج نشان داد که بیوماس کل، عملکرد میوه، دانه، شاخص برداشت، درصد و عملکرد روغن دانه تحت تأثیر برهمکنش فاکتورهای مورد بررسی و درصد و عملکرد پروتئین نیز تحت تأثیر اثرات اصلی فاکتورهای آزمایش قرار گرفتند. لینولئیک و اولئیک اسید به‌ترتیب 35/43 و 5/34 درصد از اسیدهای چرب روغن دانه را تشکیل دادند. تیمار آبیاری 12 روزه، کاربرد مالچ پلاستیک سیاه و مصرف 75 درصد کودهای شیمیایی+ کودهای زیستی، علاوه بر کاهش 25% کودهای شیمیایی و مصرف آب کمتر، با تولید 59554، 1559 و 731 کیلوگرم در هکتار میوه، دانه و روغن به‌عنوان تیمار برتر معرفی می شود. روغن تولید شده تحت این تیمار با داشتن 89/33% اولئیک اسید و 9/44% لینولئیک اسید از کیفیت بالایی برخوردار بود. بر این اساس با مدیریت صحیح نهاده های مصرفی، ضمن دستیابی به عملکرد مطلوب، زمینه های پایداری منابع تولید و توسعه پایدار فراهم خواهد شد.

Effects of diet forage proportion on maintenance energy requirement and the efficiency of metabolizable energy use for lactation by lactating dairy cows