جستجوی مقالات مرتبط با کلیدواژه « Wheat residue » در نشریات گروه « کشاورزی »

Soil is one of the factors influencing the balance of the ecosystem and countless biological and biochemical processes take place in it. In all of these processes, enzymes act as catalysts. Their presence in different cycles of soil nutrients causes the release of elements needed by plants. Therefore, the measurement of some of these enzymes can be an important indicator and criterion for evaluating soil bioavailability and consequently ecosystem measurement. Therefore, in order to investigate the extent and effect of mineral nitrogen (ammonium nitrate) and mineral phosphorus (triple superphosphate) in soils to which wheat plant residues have been added, on the enzymatic activities of urease, invertase, cellulase, alkaline and acid phosphatase were performed by a factorial experiment in a completely randomized design with three replications in the laboratory. The purpose of this study was to investigate the effect of different levels of N and P and their interactions on some enzymatic activities of soil containing plant residues of wheat.

For the purpose of this study, different levels of inorganic nitrogen were: control, 10, 25, 50 and 75 mg Nitrogen per kg soil (N, N10, N25, N50 and N75) and different levels of phosphorus including: control, 15, 30 and 45 mg phosphorous per kg soil (P, P15, P30 and P45) into a P and N poor soil. The soil was added to this soil by 5 wt.% Of crushed wheat residue, transferred to FC moisture and incubated at laboratory (relatively constant) temperature for 6 months. At the end of the incubated, the activities of urease, invertase, cellulase and alkaline and acid phosphatase were measured.

The interaction of different levels of phosphorus and inorganic nitrogen on some enzymatic activities showed that urease enzyme was highest in P30N25, P30N50, P15N25, P30N10, P30N75 and P45N10 and lowest in control treatment. Urease activity in these treatments was about 2.3 times that of the control. The highest activity of invertase was observed in P15N10, P15N25, P15N50 and lowest in P30N75. The activity of this enzyme was about 21% higher in the treatments containing phosphorus 15 and nitrogen 10 (mg/kg soil) than in the treatments containing phosphorus 30 and nitrogen 75 (mg/kg soil). The highest cellulase activity was observed in P15N10, P15N25 and the lowest activity in P45N25. Alkaline phosphatase had the highest activity in P30N10, P15N10, P30N25, P15N25 and P30N50 and lowest in phosphorus 45 and inorganic nitrogen 75 (mg/kg soil). The enzyme activity in these treatments was about 1.2 times that of P45N75. Acid phosphatase activity was highest in P15N50 and P15N25 and lowest in phosphorus 45 and inorganic nitrogen 10 (mg/kg soil) and in phosphorus 45 and mineral nitrogen 75 (mg/kg soil), respectively.

In general, application of mineral fertilizers to soil containing wheat residues increased some of the enzymatic activities according to the results of experiments for maintaining soil fertility and also balance in the rate of decomposition and emission of greenhouse gases and enzyme activity. Inorganic fertilizers at low concentrations are recommended as the catalysts for the reaction. Therefore, farmers are advised not to remove plant residues from the soil after the end of the growing season, but to balance the residual decomposition rate by adding appropriate levels of mineral fertilizers to gradually improve plant nutrition and characteristics while gradually decomposing. Physically improve the soil as well.

High degree of evaporation from soil surface (due to high temperature of environment and low relative humidity), poor soil organic content and instability of soil structure are considered indicators of arid regions of Iran. It seems that in a regional management, conservation of plant residues with irrigation operations in the absence of a negative effect on yield can be used as a way to improve the above-mentioned conditions. The management of plant residues has been interesting to researchers in recent decades due to its various effects on the physical, chemical and biological properties of soil. On the other hand, protective tillage can help to maintain more soil moisture, reduce erosion and less use of agricultural machinery, thereby achieving sustainable agriculture and reducing costs. This research was conducted to investigate the effect of application of wheat residues and green manure along with different tillage systems on corn.

This experiment was conducted in Shush, Khuzestan Province in 2015-2016, as strip-plot in randomized complete block design with three replications. The main treatment consisted of conventional and minimum tillage methods. The sub-plot treatment applied mulches such as wheat residue, two types of green manure (mung bean (Vigna radiata L.) and cowpea (Vigna unguiculata L.)) and control (no fertilizer application). The characteristics in this research included grain yield, biological yield, number of rows in corn, number of kernels per row, 100 grains weight, and weed growth indices (density, variety and dry weight in two stages: 4 to 6 leaf and maturity of corn).

Results

Maximum grain yield of corn was obtained in wheat residue (10399.27 kg ha-1). Also, there was no significant difference in plants treated with green manure of cowpea (10013.49 kg ha-1). The lowest economic yield was seen in control (7382 kg ha-1). Similar to grain yield, the highest biological yield of corn occurred with application of minimum tillage (16139.14 kg ha-1), wheat residue (17170.89) and cowpea green manure (16790.37 kg ha-1). Besides, the best treatment to reduce the number, variety and dry weight of weeds, was achieved with green manure in minimum tillage. Based on the results, the dominant weed of the field in conventional tillage in 4 to 6 leaf stage was physalis (Physalis alkekengi) while it was common purslane (Portulaca oleracea) in the minimum tillage. In maturation of corn, both in conventional tillage and minimum tillage, the dominant weed was physalis, which had the highest dry weight of weeds in every stage.

Based on the results of this research, application of wheat residues and cowpea green manure combined with minimum tillage can be a suitable way to increase corn yield and reduce weed diversity and biomass in sustainable agriculture.

Prediction of mineralization rate of organic carbon and nitrogen amounts of plant residues is important due to plant nutrient management, carbon dioxide production and environmental issues. Plant residues characteristics such as total nitrogen content (N), carbon: nitrogen (C/N), lignin content and particle size, Soil characteristics (texture, structure, pH and the microbial population) and Climate (temperature and moisture) are the most important factors affecting plant residues decomposition. Decomposition process of plant residues is influenced by substrate quality, decomposer community and environmental factors. Within a given climatic region, litter chemistry is the main determinant of litter decomposition. Litter decay and nutrient release are controlled by the litter quality, including the nitrogen (N) concentration of the litter, the carbon to nitrogen (C/N) ratio, as well as other chemical properties. To investigate the effects of size and placement depth of plant residues on organic carbon and nitrogen dynamics, a split – split plot layout based on a randomized complete block design and three replications was conducted using litter bag method. The factors were depths of incubation periods of plant residues (1, 2, 3 and 4 months), placement of plant residues (5, 15, 30 and 45 cm) and sizes of plant residues (0.2 - 0.5, 1 - 2 and 5 - 10 cm) which were located in main, sub and sub-sub plots respectively. At the end of the incubation period, the litter bags were pulled out of the pots; after the weights of the remaining plant residues in the bags were measured, the residue organic carbon was measured via the dry combustion method at 450°C for 5 h and the total nitrogen via the kjeldahl method. We analyzed the collected data during desert-lab studies by SAS/STAT software release 9.1. Statistical differences among size and placement depth of plant residues and time duration were determined using a generalized linear model (Proc GLM), P ≤ 0.05 and LSMEANS, which allows mean comparisons even when data points are missing. Results of data variance decomposition indicated that size and placement depth of plant residues had a significant effect on carbon and nitrogen loss at the probable level of 1℅ .The highest organic carbon and nitrogen loss were measured after four month of incubation and when the size and the depth of placement of plant residues were 0.2 - 0.5 and 30 cm, respectively. The lowest organic carbon and nitrogen loss were also obtained after the first month of incubation and when the size and the depth of placement of plant residues were 5 - 10 and 5 cm, respectively. After four months of incubation 49.73 and 54.07% of organic carbon and 34.48 and 39.78 of organic nitrogen of plant residues mineralized when the depths of placement of plant residues were 5 and 30cm respectively. Aridity, soil hilling and availability to nutrients are determining factors of the carbon cycle in the decomposition process. Conceptually and analytically advanced models from diverse studies suggest three factors affecting decomposition in arid ecosystems: quality and quantity of the organic matter under decomposition, the physical environment (including temperature, precipitation and soil type) and the nature and entity of the decomposing organs in the soil. From the results it was concluded that when the soil moisture level is a limiting factor for plant residue mineralization, increasing the depth of placement of plant residues enhances the rate of mineralization of organic carbon by providing sufficient moisture for plant residues decomposition. The results also showed that reducing plant residues particle size with increases the surface area and plant residues contact with the soil, enhances the rate of decomposition of plant residues.

 Conservation tillage method can lead to sustainable agriculture and reduce soil erosion, soil moisture and costs. For conservation tillage application, its effects on yield indicators and soil characteristics should be investigated. This study was carried out to evaluate the effects of conservation systems on maize production in rotation with wheat in Dasht-e- Naz Sari agro-industry. In addition to the conventional method, evaluated treatments were applied to different conditions of wheat residue (absence and presence of crushed residues). Plant height, leaf number and ear weight, potassium content, phosphorus and nitrogen, organic matter, EC, pH, soil moisture and bulk density were measured after planting and harvesting. Although the effects of conservation tillage would occur in a long term, there were no significant differences in some measurements but some changes in different indices. Direct planting of maize in wheat residues showed the highest soil phosphorus content. Also, the effect of treatments on soil moisture content and bulk density after planting showed a significant discrepancy. On the farm with shredded wheat residue and considering that reduced tillage had been applied for wheat planting, corn plant produced larger stem height. In this study, the lack of negative effectiveness of conservation system on the most of the studied quantities was observed. Considering the decrease in use of machinery in conservation methods and its economic and environmental benefits, it can be a strong point for implementation of conservation tillage in Dasht-e Naz Sari agro-industry.

Today, almost every country has some activities in the field of no-tillage or in research or application-level fields. Some researchers have declared that continuous burning residues of the previous crop reduce soil fertility and soil organic matter levels in the long term. Given the strategic importance of maize and the significant role of tillage practices and crop residue management in its production, also limited availability of water, a field experiment was conducted to determine of silage maize yield and yield components and water use efficiency (WUE), variety SC704, under different tillage management where wheat had been grown.
The experiment was laid out under different wheat residue amounts and different tillage managements in a randomized complete block design with strip plot arrangement, where each treatment was replicated three times, in Kamalan plain of Aliabad city which is situated in east of Golestan Province (Iran) in 2010 and 2011. Wheat residual (stalk) treatments were kept as main plots and tillage treatments as sub plots. Wheat residue treatments were as follows: burning the residue as R1, 50% residue (R2), and 100% residue (R3). Tillage treatments were as follows: conventional tillage (T1) (moldboard plough with depth of 25-30 cm, three times of disk harrow늌⊞), reduced tillage (T2) (application of mixed tillage equipment늌⊞), and no tillage (T3) (planting with no-till planter). For all experimental plots, surface irrigation method (strip border irrigation) was used. During two years experiment and at the end, maize aboveground mass fresh yield and yield components, water consumption and finally WUE of irrigation water were measured and determined for each plot separately.
The trial results showed that there were significant differences in terms of all surveying parameters. Comparison of fresh silage yield means between different treatments showed that the aboveground mass production in R3 was 29655.6 kg ha-1 and significantly (p>0.05) higher than in R2 and R1.Also comparison of yield means between different sub plot treatments of T showed no significant difference between T1 and T2. Comparison of WUE means between different treatments of T and R showed significant difference (p>0.05). The lowest and the highest value of WUE were R1 as7.2 and R3 as10.2 kg m-3 respectively. So that WUE values in R1 treatment was 29.4 and 21.7 percent lower than R3 and R2 treatments respectively.
In the first phase, it can be replaced T1 with T2 along with the preservation of all residues of previous crops. According to the results it can be stated that the residue keeping treatment is the most effective factor in terms of water use efficiency. Therefore keeping crop residues for increasing WUE of irrigation water is strongly recommended.

Elimination or reduction of tillage in conservation agricultural systems has led to wide variations in germination, emergence, and growth of weeds and has caused variations in the density and diversity of weeds under such systems. Maintaining crop residues on the soil surface has many potential benefits in agricultural production systems; such as reducing water and wind erosions, increasing the soil organic matter content, improving the soil structure and sowing conditions, as well as a better weed management through allelopathy or physical interference provided by the crop residues. Crop residue and tillage system cause potential changes in the soil temperature and water content, which influence soil density, structure, moisture, as well as soil temperature and nutrients. Crop residues act as mulches and can effect on weed seed germination and seedling emergence. Therefore, the objectives of current study were to evaluate the effects of no-tillage systems on: (i) narrow- and broadleaved weed densities, (ii) crop yield and (iii) water productivity (WP).
A two-year field study based on a split plot experiment in a randomized complete block design with four replications was carried out in Zahedshahr, Fars province, Iran (latitude 28˚44΄N, longitude 53˚48΄E, 1180 m altitude) during 2009-10 and 2010-11 growing seasons. The planting practices including moldboard plow, disk and leveler were practiced in conventional tillage plots and crop planting was performed using a drill seeder (made by Kohorasan Co., Iran). The no-tillage plots were directly planted without any soil disturbance and removing wheat residues of the last year using a direct planter machine (model Berteni, Argentina). Furrow irrigation was used at both systems and a water counter (model WD, size DN100) was applied to measure the amount of used water based on m3 ha-1. 1 x 1 m quadrates that were installed at the center of each plot. Crop density, narrow and broadleaved weed densities were recorded at 30 days after the beginning of crop emergence. Wheat grain yield was calculated at harvest time. Comparison of the means was conducted based on protected LSD (PLSD) at 0.05 significant levels.
Tillage systems indicated a significant effect on wheat density. The average number of crop seedlings in no-tillage plots was 27 % higher than in the conventional tillage plots. Maintaining crop residues on the soil surface provided a better site for crop germination and emergence. The response to tillage system and year effects varied depending on the weed species. Results showed that the effect of tillage systems, year and their interactions were significant on the density of Lolium temulentum and Sinapis arvensis, while in the case of Phalaris minor and Hordeum spontaneum just the tillage regimen significantly influenced the weed density. L. temulentum and S. arvensis plants showed an almost similar pattern in their response to tillage systems and year effects. The density of these two species significantly decreased under no-tillage system compared with conventional tillage operations. Moreover, their densities in conventional tillage plots were significantly greater in the second year of the experiment than the first year. The lower seedling emergence of P. minor and H. spontaneum under no-tillage circumstances is not surprising, as crop residues prevent from reaching the light on the soil surface and the light requirement for germination of these species has been reported in several studies. The water productivity of the no-tillage plots was greater than of the conventional ones at both two years of the experiment. Preservation of wheat residues on the soil surface decreases soil temperature via shading and causes reduces the evaporation rate from the soil surface. Although there was no significant difference between wheat yields in the two growing seasons under conventional tillage environment, wheat yield in no-tillage plots was significantly greater in the second year of the experiment than that of the first year. Low weed densities and high WP were observed under no-tillage conditions, although the crop yield was greater in conventional tillage plots. It seems that this yield reduction in no-tillage plots is mostly due to greater C/N ratio in no-tillage plots than conventional tillage ones.
According to the results, although wheat yield decreased under no-till system, increased water productivity, weed control and reduced cultivation costs might justify the adoption of no-tillage cropping systems by local farmers. Other principles of conservation agriculture including suitable crop rotation systems and planting cover crops must be incorporated into the no-till cropping system. As the occurrence of autumn rainfall is usual in these dry regions, employment of the stale seedbed might be another promising technique which controls early season weed species in no-tillage systems.

In order to study of intercropping of Amaranth (Amaranthus cruentus L.) and Mung bean (Vigna radiate L.) and effect of crop residue management (CRM)، field experiment was conducted in Agricultural faculty of Shahid Chamran University of Ahvaz during 2010-2011 growing seasons. This experiment had two phases، including winter part (wheat planting) and summer part (intercropping system). The experimental design was split plot based on RCB with 3 replications. Main plot including CRM (i. e. incorporation، burning and removal wheat residue) and sub-plot including plant density ratios (i. e. 0، 25، 50، 75 and 100% of each crop). Our result showed that total forage yield was changed by changing in plant density ratios. In addition، CRM had significant effect on total forage yield and also، each crop production. Intercropping systems comparison، plant density ratio 50% + 50% had the highest stem weight in residual removal treatment (766. 5). Plant density ratios 75% amaranth- 25% mung bean had the highest leaf weight in residual corporation treatment (519). Plant density ratio 50% + 50% had the highest forage yield in residue corporation treatment (1347. 6). On average، highest leaf weight، reproductive weight and total forage (dry mater) were obtained in incorporated residue treatments. But، highest stem weight was obtained in removal managements. Highest leaf / total weight ratio was obtained in 75% amaranth- 25% mung bean plant density ratio. In conclusion، although total forage yield was more influenced by amaranth than mung bean، but amaranth yield parameters had more variation than mung bean by changing in both treatments (CRM and plant density ratio).

The aim of this study was investigation the energy flow and global warming potential (GWP) of corn farm in Gorgan city. For this purpose, data were collected from three conventional planting methods (spring planting, summer planting in wheat residue and summer planting without wheat residue) by using a face-to-face questionnaire performed with farmers in summer 2012. After the required data in three parts, fuel consumption, energy consumption and global warming potential on the basis of the CO2. The results revealed that total energy consumption amount in spring panting, summer planting in wheat residue and summer planting without wheat residue was 26355.7, 28395.4 and 27783.2 MJha-1, respectively. The highest share of total input energy was recorded for nitrogen fertilizer and diesel fuel in all planting methods.The least GWP was obtained from spring planting with 2349kg Equivalent to Co2. So spring planting had less environmental effects. According to the results use of high yielding hybrids, residue management and nitrogen fertilizer is essential for increase energy efficiency and reducing Environmental effects.

Field experiment was conducted to assess the efficacy of wheat residues and different densities of sunflower in weed control during 2007 growing season. The experimental design was a randomized complete block with three replications. The experiment was set up in factorial arrangement, amount of 0, 1250, 2500, 3750, 5000 Kg ha-1 of wheat residue and burning of residue (5000 kg ha-1) were the levels of factor A and three densities of sunflower consisting of 50000, 70000 and 90000 plants ha-1 were factor B. During growth season measurement of weed biomass and weed height in 3, 6 and 9 week after planting was conducted. Increasing amounts of wheat residue and sunflower density decreased weeds biomass and height. 71.8, 73.17 and 87.48 percent of weed biomass reduction occurred with increase in wheat residue at 3, 6 and 9 weeks after planting, respectively. Also increasing sunflower density from 50000 to 90000 Plants ha-1 decreased the weeds canopy height. Sunflower grain yield increased 29.86 and 31.73 percent with increasing wheat residue and sunflower density, respectively. Applying 2500 kg.ha-1 wheat residue integrated with sunflower planting at density of 90000 plants ha -1 can give an effective control of weeds and can be an alternative to cut herbicide use.

The effects of soil tillage methods and residue management were studied at Miandoab Agriculure Station during 2003-2005. The experiment design was split block with the main plots devoted to residual management strategies (burning residue, crushing residue by disk, no treatment). Subplots were tillage methods (moldboard plowing to 20-25 cm in fall, moldboard plowing to 20-25 cm in spring, moldboard plowing to 20-25 cm in both spring and fall). Other operations were identical in all treatments. The soil cone index, percent of residue crushing, percent of residue inversion, percent of seed emergence, crop yield, percent of sugar, depth of root development and percent of soil organic carbon were measured. Results showed that tillage and residual management had no significant effect on seed emergence, percent of sugar, bulk density and soil cone index. Tillage management had a significant effect on yield and depth of root development. Fall plowing and fall-spring plowing treatments produced higher yields and root development (15%, 11%) than did the spring plowing treatment. Results also showed that soil organic carbon after harvesting was higher (14%) for the crushed and no treatment categories than for the burned residue treatment. Burning residue is not recommended, because this strategy had no positive effect on the parameters and, in some cases, reduced root yield and soil organic carbon. Water productivity in moldboard plowing at 20-25 cm in the fall treatment was higher than for the other treatments. Water productivity based on root yield was 4.32, 3. 47 and 3.66 kg/m3 for fall plowing, fall-spring plowing and spring plowing treatments, respectively.