Satisfactory Grain Research Articles

Microstructure development and mechanical behaviour of pure copper processed by the novel TWO-CAP procedure

AbstractIn this study, thin-walled open channel angular pressing (TWO-CAP) technique was applied to pure copper specimens as a novel severe plastic deformation (SPD) method. The TWO-CAP process was applied to the specimens up to four passes. After each pass, the microstructural and mechanical characterization of the material was investigated by tensile and hardness tests along with OM, SEM, EDS, TEM and XRD analyses. As a result, a highly increase in the mechanical properties was obtained, in addition satisfactory grain refinement was observed in microstructures. Strength and hardness values were positively affected from the minimizing the grain sizes after TWO-CAP process. Another reason of the improvements in mechanical properties can be explained as the increase in dislocation density. Furthermore, the effect of the TWO-CAP process on the dislocation density of the material has been demonstrated by XRD and TEM analyses in nanoscale. Moreover, the strain equation has been developed analytically and the effect of each pass on strain was calculated. Finally, the effect of the process on the stress-strain properties of the material was examined by the numerical analysis method and the study was verified.

Early Yield Forecasting of Maize by Combining Remote Sensing Images and Field Data with Logistic Models

Early forecasting of crop yield from field to region is important for stabilizing markets and safeguarding food security. Producing a precise forecasting result with fewer inputs is an ongoing goal for the large-area yield evaluation. We present one approach of yield prediction for maize that was explored by incorporating remote-sensing-derived land surface temperature (LST) and field in-season data into a series of logistic models with only a few parameters. Continuous observation data of maize were utilized to calibrate and validate the corresponding logistic models for regional biomass estimating based on field temperatures (including crop canopy temperature (Tc)) and relative dry/fresh biomass accumulation. The LST maps from MOD11A1 products, which are considered to be matched as Tc in large irrigation districts, were assimilated into the validated models to estimate the biomass accumulation. It was found that the temporal-scale difference between the instantaneous LST and the daily average value of field-measured Tc was eliminated by data normalization method, indicating that the normalized LST could be input directly into the model as an approximation of the normalized Tc. Making one observed biomass in-season as the driving force, the maximum of dry/fresh biomass accumulation (DBA/FBA) at harvest could be estimated. Then, grain yield forecasting could be achieved according to the local harvest index of maize. Silage and grain yields were evaluated reasonably well compared with field observations based on the regional map of LST values obtained in 2017 in Changchun, Jilin Province, China. Here, satisfactory grain and silage yield forecasting was provided by assimilating once measured value of DBA/FBA at the middle growth period (early August) into the model in advance of harvest. Meanwhile, good results were obtained in the application of this approach using field data in 2016 to predict grain yield ahead of harvest in the Jiefangzha sub-irrigation district, Inner Mongolia, China. This study demonstrated that maize yield can be forecasted accurately prior to harvest by assimilating remote-sensing-derived LST and field data into the logistic models at a regional scale considering the spatio-temporal scale extension of ground information and crop dynamic growth in real time.

Performance of Test Crosses of Maize Variety Sarhad White with Jalal and Kiramat for Morphological Traits

This research was carried out at Khyber Pakhtunkhwa Agricultural University Peshawar to evaluate the performance of maize inbred lines derived from maize variety Sarhad White regarding grain yield and morphological traits and identifying superior inbred lines based on test cross performance. Test crosses were evaluated in replicated trial along with two tester, one check and 16 parental inbred lines for comparison in a 7×7 partially balanced lattice square design with two replications. Results revealed highly significant differences among the genotypes for most of the traits. Jalal TC-230-a and TC-63-1 took the maximum days to tasseling and Jalal TC-101-2 showed maximum days to anthesis. Maximum day to silking and anthesis silking interval were recorded in Jalal TC-94. Maximum plant height was observed in Jalal TC-33 (164.5 cm) and Kiramat TC-9-6-1 (141.50 cm). Maximum 100 kernal weight was recorded in Jalal TC-101-2 (40.55 g). Kiramat TC-89-b produced the highest grain yield (6808 kg ha-1). From these results, it can be concluded that Kiramat TC-89-b, having highest yield, could be promoted for further selfing. Jalal TC-9-6, TC-9-6-1, TC-12-1, TC-63-1, TC-76-2b, TC-89b, TC-163, TC-205, TC-230a, TC-211 and Kiramat TC-9-6, TC-9-6-1, TC-12-1, TC-33, TC-76-2b, TC-89b, TC-94, TC-101-2, 150-c, TC-163, TC-230-a, 205, 211, 226-2 in addition to having satisfactory grain yield could be used for selfing. Among parental lines (selfed lines) 9-6-1, 9-6, 10-2, 226-2, 33, 63-1, 76-2, 163, 89-b, 205 and 211 were promising for grain yield and morphological traits.

Stability of damping capacity and mechanical properties of high-Zn-concentration Al–Zn–Mg–Sc alloy

The microstructure, damping capacity, mechanical properties, and the performance stability of high-Zn-concentration Al–Zn–Mg–Sc alloys after annealing treatment were studied. The Al–20Zn–0.5 Mg–0.5Sc alloy contained fine grains, a high number of solution atoms, Zn phases, Al 3 Sc phases, and high-density fine η and η' phases. Decreasing the Zn content led to the disappearance of the Zn phases and the decrease of intragranular η phases density and solution atom number. Increasing the Mg content did not increase the number of solution atoms but increased the size of the intragranular η phases. The Al–20Zn–0.5 Mg–0.5Sc alloy exhibited higher internal friction value and higher strength than the other two alloys because of its satisfactory grain boundaries and Al/Zn interface sliding ability at high temperature, as well as its high solid solution and second phase strengthening effects at room temperature. All annealed Al–Zn–Mg–Sc alloys exhibited excellent damping capacity and mechanical properties stability during the DMA test at the highest temperature of 360 °C due to their high structural stability. • A novel Al alloy with excellent damping capacity, mechanical properties, and performances stability was obtained. • The satisfactory GB and Al/Zn interface sliding ability led to the Al–Zn–Mg–Sc alloy exhibited well damping capacity. • The high solid solution and second phase strengthening effects led to the Al–Zn–Mg–Sc alloy exhibited high strength. • Sc addition and annealing led to the Al–Zn–Mg–Sc alloy exhibited excellent structural and properties stabilit.

Stationary rice drying: Influence of initial moisture contents and impurities in the mass grains on the physicochemical and morphological rice quality

The initial moisture contents and impurities in the grain mass can interfere with the drying operation in a stationary dryer. Thus, the objective of this study was to evaluate the effect of drying air movement in the rice mass as a function of initial moisture contents (19, 18, 17, and 16% w.b.) and impurities (1.5, 2.5, 2.0, and 3.0%) on the physicochemical properties and morphological rice quality. The moisture and impurity contents provided alterations in the movement and distribution of the drying air in the upper layers of the stationary dryers. Consequently, the physicochemical properties and morphological quality of rice were altered. In addition, the reduction in the starch and fat contents was correlated to higher percentages of crude protein, mainly upper grain layers. Thus, the rice mass at moisture content of 17% (w.b.) and impurity at 2.5% allowed major uniformity and greater drying versatility in the stationary dryer for rice quality. Practical applications The rice drying in the stationary dryer is an excellent option to reduce drying and storage infrastructure and achieve satisfactory grain quality, as long as there is an adequate control and management of the batches of grain received in terms of moisture uniformity and impurity contents. For proper rice management in the stationary dryer, it is recommended to pre-cleaning the grain mass to 2% of impurities, while the initial grain moisture content for drying must be below 18% (w.b.). The standardization of batches in terms of initial moisture content and impurities allows for an adequate flow and distribution of air in the grain mass to obtain efficiency in drying at low temperatures and maintaining grain quality. From a commercial point of view, the grains can remain in the drying process and stored in silo-dryers for the harvest period until the time they can be sold at better market prices.

Synergistic Effect of La and TiB2 Particles on Grain Refinement in Aluminum Alloy.

Synergistic effect of TiB2 (in form of Al-5Ti-1B) and La on grain refining results in Al-2Cu alloy was investigated. α-Al grains are significantly refined by Al-5Ti-1B. When trace La is added to the melt, further refinement is exhibited. Average grain size and nucleation undercooling of α-Al reduce first and then almost remain unchanged with La addition. Satisfactory grain refining result achieves when La addition level reaches 600 ppm. When more than 600 ppm La is added to the melt, La-rich particles form and the effect of solute La left in matrix on the microstructure almost no longer changes. Theoretical calculation results demonstrate that solute La segregates to Al melt/TiB2 particles interface along with Ti and Cu prior to α-Al nucleation and the synergistic effect of La and TiB2 particles on grain refinement mainly attributes to the enhancement in the potency of TiB2 particles to heterogeneously nucleate α-Al by trace La addition.

Ancient wheat species are suitable to grain-only and grain plus herbage utilisations in marginal Mediterranean environments

Thanks to their low fertilization requirements and high consumer demand, ancient wheats and old durum wheat cultivars represent an attractive option for the marginal areas of Mediterranean environments no longer cultivated due to the low grain yields attainable using modern wheat cultivars. Dual-purpose utilization may increase their value in these cropping systems, but no information is available on the suitability of ancient wheat species to this type of utilization. To fill this gap, Khorasan, einkorn, and emmer wheats, clipped at the terminal spikelet stage or left unclipped, were compared in a two-year field trial. The grains were sown in the month of October, in Sardinia (41°N, 80 m asl), Italy, on low-fertility soils and with low-medium fertilization rates. Einkorn cultivars produced the highest biomass yield (2–3 t ha−1), reflecting the longer time to the onset of the terminal spikelet stage (119–138 days). After clipping, all species recovered their ability to intercept radiation to the levels of the unclipped crops, but clipping lowered their radiation use-efficiency. Grain yield was not penalized by clipping: the increase in the harvest index compensated for the decrease in biomass. Here we show for the first time that ancient wheat species are suitable for dual-purpose utilization (herbage plus grain in the same season) rendering them valuable for marginal areas; this was because the early sowing adopted for dual-purpose utilization allowed them to take full advantage of their lateness in terms of herbage yield, and to bring flowering forward (i.e. make it earlier) so that a satisfactory grain yield was obtained, even under severe water stress. Dual-purpose utilization of ancient wheats increases the sustainability of mixed cropping systems, by making herbage available to animals in a critical period, without decreasing the grain yield attainable after grazing in the same season.

INTERCROPPING OF GRASSES OR LEGUME SPECIES IN MAIZE CROP IN THE CERRADO

In grain crop production systems, the cultivation of maize intercropped with grasses or legumes, together with soil management, can provide sustainability without reducing maize yield in the low altitude Cerrado. Thus, this study aimed to evaluate the effects of sowing maize intercropped with grasses or legume species, in two soil management systems, on the agronomic characteristics and yield of maize, in the first crop season in physically limited soil in the Cerrado. The experiment was developed in the agricultural years of 2015/16, 2016/17 and 2017/18, in the municipality of Selvíria, in the state of Mato Grosso do Sul, in typical dystrophic Red Latosol, with clay texture. The randomized block experimental design was used, in a 2x5 factorial scheme, consisting of soil management systems (no-tillage and minimum tillage) and maize intercropped or not (sole maize; maize + Urochloa ruziziensis; maize + U. brizantha; maize + Crotalaria spectabilis; and maize + Cajanus cajan). The intercropping of maize with legumes or grasses sown simultaneously in the interrow spacing, when implemented and conducted properly, did not affect the average maize yield. Regardless of soil management and maize intercropping systems, the high soil density and penetration resistance, observed in the experimental area, were not impediments to satisfactory maize grain yield.

Desempenho agronômico de cultivares de trigo para safrinha no Planalto de Santa Catarina, Brasil

O aumento na produção brasileira de trigo para suprir a demanda interna do cereal está associado ao aumento da área de cultivo em regiões ou épocas historicamente pouco exploradas. Neste sentido, o presente trabalho teve como objetivo estudar o desempenho produtivo de cultivares de trigo para cultivo em safrinha na região do Planalto Catarinense. O experimento de campo foi conduzido entre os meses de fevereiro e junho de 2018. Cinco cultivares de trigo (BRS 264, BRS 394, BRS Parrudo, Tbio Audaz e Tbio Sonic) foram semeadas em 14 de fevereiro e 01 de março. Os parâmetros morfológicos das plantas foram determinados no período de antese. No período de maturação, foram determinados os componentes da produção e produtividade de grãos. Adicionalmente, determinou-se a duração do período entre emergência e florescimento e entre florescimento e maturação das plantas. A cultivar BRS Parrudo não apresentou desenvolvimento satisfatório para cultivo em safrinha, com sintomas de anomalias na formação da espiga. As demais cultivares estudadas apresentaram crescimento e produção de grãos satisfatória para a semeadura realizada em 14 de fevereiro.

Effect of La addition on microstructure evolution of hypoeutectic Al–6Si alloys

Solidification experiments were carried out for Al–6Si alloys with different La addition levels. The results demonstrate that the average sizes of the α-Al grains and the eutectic Si have a tendency of first decreasing and then almost keeping constant with the La addition. About (0.04–0.06) wt% La addition is enough to achieve a satisfactory grain refinement and modification. An analytical model based on the Wilson equation, the Miedema model and the thermodynamics was proposed to investigate the mechanisms of the α-Al grain refinement and the eutectic Si modification in the hypoeutectic Al–6Si alloys with the trace La addition. The La effect on the grain refinement of α-Al and the modification of the eutectic Si are mainly attributed to the increase in the efficiency of the heterogeneous nucleation substrates to nucleate α-Al and the amount of La atoms in the eutectic Si. The grain refinement and the modification results achieve the maximum when the La concentration is near its maximum solid solubility in the primary α-Al phase.

Effect of Water Saving Irrigation Management Practices on Rice Productivity and Methane Emission from Paddy Field

Irrigation water supply is one of the vital components for sustainable rice farming, which is becoming a limiting resource in the changing climatic condition. An experiment was conducted at the research field of Bangladesh Agricultural University, Mymensingh during dry season from January-June of 2017 to investigate the suitability of Alternate Wet and Dry Irrigation (AWDI) for sustainable rice production and reducing methane emission. The modern rice variety BINA Dhan 10 was used as test crop. There were five irrigation treatments viz. T1 (saturated condition), T2 (continuous flooded, 5 cm standing water), T3 (AWDI-10 cm; irrigated when water level fell 10 cm from surface), T4 (AWDI-15 cm; irrigated when water level fell 15 cm from surface) and T5 (AWDI-20 cm; irrigated when water level fell 20 cm from surface). Results of the field trial showed satisfactory grain yield and low seasonal methane emission along with significantly high irrigation water savings (%) in AWDI treated field plots. Among the treatments, T3 (AWDI-10 cm) and T4 (AWDI-15 cm) showed higher yield performance (6250kg.ha-1 and 5810 kg.ha-1, respectively) with lower CH4 emission (reduced up to 36% and 40%, respectively) compared to continuous flooded treatment (T2, CF 5 cm water). In AWDI field plots less irrigation frequency (6 - 9) was required which significantly saved the amount of irrigation water (12% - 24%). Although T5 (AWDI-20 cm) showed the highest water savings (24%) and lowest CH4 emission (reduced up to 50%); however the lowest grain yield (4283 kg.ha-1) was found under this treatment. On the other hand, continuously irrigated (T2, 5 cm standing water) field plot showed lower yield (4783 kg.ha-1) but significantly higher methane emissions compared to other treatments during rice cultivation. Water productivity index was also found higher in AWDI treated field plots compared to continuously irrigated field plot. At the reproductive stage of rice plant well-developed aerenchyma tissue was observed in root cortex under the continuous irrigated field plot, which indicates higher diffusion pathway of methane gas from root rhizosphere to the atmosphere compared to other treatments. Therefore, alternate wet and dry irrigation water management practice may be recommended at farmers’ level for sustainable rice production and reducing methane emission during dry winter Boro season which will reduce the cost of production by water saving as well as energy saving.

Critical concentration of available soil phosphorus for grain yield and zinc nutrition of winter wheat in a zinc-deficient calcareous soil

The decrease in cereal grain zinc (Zn) caused by phosphorus (P) application has attracted wide attention. However, optimizing P fertilization for both satisfactory grain yield and grain Zn concentration is still a problem due to a poor understanding of the relationship between P application rates and available soil P, and that of available soil P and soil Zn availability, relevant soil factors, and plant Zn uptake and utilization. A location-fixed field experiment was initiated in 2004 with winter wheat (Triticum aestivum L.) grown at five P rates of 0, 50, 100, 150, and 200 kg P2O5 ha−1, and soil and plant samples were collected during the three growing seasons of 2013–2016. Winter wheat grain yield increased, and the grain Zn concentration decreased with increasing available soil P in a linear-plus-plateau manner. The grain yield plateau, averaging 6009 ± 155 kg ha−1, was reached at an available soil P concentration of 10.2 ± 2.5 mg kg−1, and the grain Zn plateau, averaging 22.4 ± 0.9 mg kg−1, was reached at an available soil P of 14.2 ± 1.8 mg kg−1. Shoot Zn uptake after flowering was not affected, while Zn remobilization from vegetative parts to grains and the Zn harvest index increased with P application at available soil P levels below 11.6 mg kg−1. The available soil Zn increased, and root mycorrhizal colonization was unaffected at lower available soil P levels. The decrease in wheat grain Zn concentration with increasing P application at lower available soil P levels was primarily explained by yield dilution effects, not the changes in available soil Zn and root mycorrhizal colonization. Under the experimental conditions, the available soil P would have to be as low as 0.7 ± 0.4 mg kg−1 to achieve the target grain Zn concentration of 40 mg kg−1, and at this level, the grain yield would only be 4127 ± 252 kg ha−1.

YS-16: A high yielding dual purpose sorghum variety

Sorghum is an important dual purpose (grain and fodder) crop in Punjab, Pakistan. It is a good substitute for maize and is important as poultry feed because it is a good source of carbohydrates and proteins. A previous variety, YSS-98, became susceptible to foliar diseases and subsequently failed to provide satisfactory grain and fodder yields. A new genotype, YS-16, was developed with high grain and fodder yields and tolerance to foliar diseases. This genotype was sent to the expert subcommittee and approved with the name YS-16. The variety was selected through continuous selection from a germplasm received from ICRISAT India during Kharif-1987 and planted at the Maize & Millet Research Institute, Yusafwala, Sahiwal. This sorghum variety has the potential to produce a grain yield of 6,220 kg/ha, which is not only higher than the check variety but also higher than commercial hybrids. YS-16 was better in varietal yield trials, adaptability yield trials, at different farms, and in national uniform yield trials during 2007, 2008, 2009 and 2010. YS-16 also proved superior in stalk yield to check variety YSS-98 in varietal trials. The maturation period of YS-16 is 125 to 135 days. Due to its high sugar contents (Brix 18%), its stover is more palatable to milch animals. It is suitable for medium soil. YS-16 is the best variety recommended by the Punjab Seed Council due to height, sweetness, remaining green at maturity, higher grain yield and better lodging resistance due to strong root anchoring.

The effects of plastic-film mulch on the grain yield and root biomass of maize vary with cultivar in a cold semiarid environment

Plastic-film mulch is an agricultural technology widely used for maize (Zea mays L.) production in northern China, but the effects of the interaction between cultivar and plastic-film mulch on the grain yield and biomass production have not been studied. Five maize hybrids, Jinsui 4; Jixiang 1; Pingyu 8; Xianyu 335 and Yuyuan 5, were assessed in 2014 and 2015 in plastic-film mulched and non-mulched ridge-furrow plots in a cold semiarid environment. In 2014, the grain yield of the five cultivars varied from 685 to 898gm−2 with no mulch, and from 966 to 1228gm−2 under mulch. In 2015 (drier and warmer than in 2014), the grain yield varied from 179 to 353gm−2 without mulch, and from 548 to 1021gm−2 with mulch. By incorporating the variation in grain yield over cultivars, mulch treatments and cropping years, Jixiang 1 was the highest yielding cultivar: in 2014 the grain yield reached 898gm−2 under no mulch, compared to 1228gm−2 under mulch, while in 2015 the grain yield was 329gm−2 under no mulch compared to 1021gm−2 under mulch. Cultivar and mulch independently affected the aboveground biomass and harvest index of maize. Jixiang 1 attained high yields as a result of average aboveground biomass, but high harvest index. Differences in maize water use efficiency (grain yield per unit of evapotranspiration) as affected by mulch and cultivar paralleled those of grain yield due to minor effects of mulch and cultivar on growing-season evapotranspiration. The effects of plastic-film mulch on maize root biomass in the upper 0.6m soil profile and root/shoot ratio varied with cultivar. Averaging years and mulch treatments, Jixiang 1 had the smallest root biomass in the upper 0.6m soil layer and Jixiang 1 and Jinsui 4 had smaller root/shoot ratios than the other three cultivars. We conclude that the effects of plastic-film mulch on the grain yield, root biomass and root/shoot ratio varied significantly with cultivar. A moderate aboveground biomass and high harvest index may give satisfactory grain yield in plastic-film mulched or non-mulched fields in hydrothermally-limited areas. A wide variation of root/shoot ratio with maize cultivar and cropping year indicated that using a fixed root/shoot ratio to estimate the root carbon input to the soil would induce large uncertainty.

Combining user involvement with innovative design to develop a radical new method for managing N fertilization

In France, a single science-based model has dominated winter wheat N fertilizer management for 40 years. Despite scientific progress, it remains challenging to minimize N losses whilst maximizing grain yield and achieving satisfactory grain protein content. A mismatch between the science-based method and its implementation has been demonstrated. We thought that involving users early in the design process would lead to explore more relevant methods regarding the diversity of N issues and implementation conditions. We used a three-step design process: (1) a diagnosis of the uses of existing methods and tools, (2) a design process combining participatory workshops, generation of new knowledge and model-based prototyping, and (3) a test of the prototype in the users’ conditions. We identified the fixing of a target yield a priori as one of the major problems with the current N fertilization method. We thus established an exploratory conceptual axis: “a fertilization method without target yield”. Design workshops led to a new method based on (1) the regular monitoring of crop N nutrition, (2) the acceptance of periods of crop N deficiency, and (3) the simulation of short-term soil N availability with a crop model. New knowledge was generated, and the Azodyn model was used to build decision rules for N applications, based on viability theory. The prototype was tested by two groups of farmers. We show that, by combining the three steps used here, it was possible to develop an innovative fertilizer method radically different from the dominant paradigm, and positively received by users.

Yield, water and nitrogen use efficiencies of sprinkler irrigated wheat grown under different irrigation and nitrogen levels in an arid region

A major challenge in crop production is to achieve the goal of increasing both yield and resource use efficiency. Irrigation water and nitrogen (N) are scarce and expensive resources constraining wheat production in arid regions. There is limited information on how irrigation and N supply can be simultaneously manipulated to achieve higher yield, water productivity (WP), and nitrogen use efficiency (NUE) of wheat in arid regions. A two-year field experiment was conducted to investigate the effects of irrigation and N rates on yield, WP and NUE of wheat in a hot, arid environment at Bikaner, India. The experimental treatments comprised of six irrigation [100% (ETm; full evapotranspiration), 90% (ETd1), 80% (ETd2), 70% (ETd3), 60% (ETd4), and 50% (ETd5) of ETc (crop evapotranspiration)] levels, and four N [0 (N0), 40 (N40), 80 (N80), and 120 (N120)kgha−1] rates. Moderate deficit irrigation (ETd2) had greatest WP and caused a 17% reduction in water consumption with only a 5% reduction in yield compared to full irrigation (ETm). The N application improved yield and WP. The NUE declined with a reduction in water application and an increase in N rates. The yield and WP response to N rates modified with irrigation levels.The significant increase in grain yield was recorded with N120 at ETm and ETd1, with N80 at ETd2 and ETd3, and with N40 at ETd4 and ETd5 irrigation levels. The significant increase in WP was recorded with N80 at ETm, ETd1, ETd2 and ETd3, and with N40 at ETd4 and ETd5 irrigation levels. The results suggested that moderate deficit irrigation (ETd2) along with 120kgNha−1 could ensure satisfactory grain yield and WP of wheat in arid regions. The study also indicated that the adoption of an appropriate deficit irrigation and N rate combination can be an effective means to reduce non-beneficial water consumption, achieve higher yield, and improve WP and NUE for wheat in an arid environment.

Fertilizer and Weed Management Options for Direct Wet Seeded Rice in Dry Season

Direct seeding of rice is an emerging technology. However, direct seeded rice culture in the main field is hindered by enormous weed infestation and it lacks judicious fertilizer management. So, experiments were conducted during dry seasons of 2010 and 2012 with three fertilizer packages and four weed control measures. Rice seed was sown in the field using drum seeder in wet soil. The results revealed that weed density and weed biomass were strongly influenced by weed control methods and fertilizer rates. Weed density was higher in unweeded plots with 140:36:43 kg NPK ha-1. Among the species Echinichloa crusgalli (L.) P. Beauv. was the dominant species. Three hand weeding controlled maximum weeds. Uses of herbicide for controlling weeds were above 80 and 70% effective. Strong negative correlation was recorded between grain yield and weed density. Herbicide with one hand weeding and BRRI weeder in combination with 160:46:53 kg NPK ha-1 produced about 81- 104% higher grain yield than no weeding. Weed free plot produced 112% higher yield with 160:46:53 kg NPK ha-1. Besides, herbicide with one hand weeding and BRRI weeder treated plot produced similar yield irrespective of fertilizer doses. The strong positive and linear relationship was found in case of yield and yield components. Herbicide with one hand weeding and 120:26:33 kg NPK ha-1 gave higher net return (1145 $/ha). The benefit cost ratio was also higher in herbicide based weed management with reduced rate of fertilizer. Direct seeded culture using herbicide with one hand weeding and 120:26:33 kg NPK ha-1 could be an option for reducing production cost in dry season along with satisfactory grain yield.Bangladesh Rice j. 2016, 20(1): 65-75

Effect of Herbicide Dose and Water Management on Weed Control Efficiency and Yield Performance of Boro Rice

An experiment was conducted at the Experimental Farm of the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Salna, Gazipur during November 2011 to May 2012 to determine the effect of pre-emergence herbicide Pretilachlor @ 75%, 100%, 125%, 150%, 175% and 200% of the recommended dose under two water management regime i.e. continuous flooding and field capacity on weed suppression and yield performance of Boro rice cv. BRRIdhan28. One weed free and one control (unweeded) treatment were also imposed for treatment comparison. The experiment was laid down in Split Plot design with three replications. Standard management practices for transplanted rice were followed. Continuous flooding was found to contribute better weed control efficiency than field capacity. At 60 DAT, the highest weed control efficiency of 65.75% was found in the treatment receiving Pretilachlor @ 125% of the recommended dose under continuous flooding and the least (54.76%) was found in the treatment receiving 75% of the recommended dose under field capacity. Continuous flooding contributed to more tillers thanfield capacity, and herbicide up to 125% of the recommended dose enhanced tillering in rice. At 75DAT the highest number of tillers (17.53 hill-1) were found in the plots receiving Pretilachlor @ 125% of the recommended dose under good water management (W1T3), while the lowest (11.10 hill-1) was recorded in W2T6 treatment receiving Pretilachlor @ 200% of the recommended dose under field capacity. The highest tiller mortality (27.90%) was observed in W1T3 treatment, whereas the least (8.06%) was observed in W2T5 treatment receiving the same herbicide @175% of the recommended dose under field capacity. Application of Pretilachlor at recommended dose under continuous flooding contributed to the highest crop dry matter production (1144.60g m-2) thus leading to the highest grain yield of 6.31 t ha-1 being followed by the treatment receiving Pretilachlor @ 125% of the recommended dose under same water management yielding 5.95 t ha-1 along with the highest harvest index of 0.58. Results revealed that Pretilachlor at recommended dose might be considered as viable option for weed management in transplanted Boro rice cultivation for effective weed management and satisfactory grain yield provided that appropriate water management is adopted. Journal of Science Foundation 2014;12(2):39-46DOI: http://dx.doi.org/10.3329/jsf.v12i2.27737

Grain yield and water use efficiency of maize as influenced by different irrigation regimes through sprinkler irrigation under temperate climate

In Vojvodina region, water deficit during the growing season is a major factor limiting maize production. Therefore, to achieve the ideal soil water content in this region, it is of crucial importance to optimize irrigation. The effects of different irrigation levels with sprinkler irrigation system on crop yield, yield components, water use, water (WUE) and irrigation water use (IWUE) efficiency of maize (Zea mays L.) were investigated in Vojvodina (northern Serbia), on a Calcaric Chernozem soil in temperate environment for 3 consecutive years (2006–2008). Maize was subjected to four irrigation regimes, as follows: non-limited irrigation (I100), 75% of non-limited irrigation (I75), 50% of non-limited irrigation (I50), and rainfed (non-irrigated) as the control (I0). The irrigation treatments were arranged in a complete randomized block design with 4 replicates. Results showed that maize grown in rainfed conditions had high annual variability, mainly due to amount of rainfall and its distribution during the crop-growing seasons. A significant irrigation effect was found for yield, yield components and others investigated parameters under study. Water stress had significant impact on yield response: as an average of the three years, a grain yield increase of 47.8, 32.8, and 22.9% was observed in I100, I75 and I50 treatments compared to rainfed (I0) treatment, respectively. Yield increased linearly with seasonal crop evapotranspiration and irrigation amount. Furthermore, WUE is maximized with a moderate water deficit (I50), while IWUE is the highest in I100 treatment. The deficit irrigation stress index, DISI, decreased with increasing irrigation rate. The results revealed that irrigation is necessary for maize cultivation because rainfall is insufficient to meet the crop water needs in Vojvodina. In addition, the study indicated that the irrigation regime of 25% water saving (I75) could ensure satisfactory grain yield of maize and increment of WUE.

Effect of Different Levels of Phosphorus and Method of Application on the Growth and Yield of Wheat

An experiment was conducted to evaluate the productivity of wheat under different levels of phosphorus and method of application at Department of Agronomy, Sindh Agriculture University, Tandojam. Experiment was laid out in a RCBD (factorial) with three replications. The treatments were four phosphorus levels (P1 = 0 Kg?ha–1 + Recommended Nitrogen, P2 = 30 Kg?ha–1 + Recommended Nitrogen, P3 = 60 Kg?ha–1 + Recommended Nitrogen and P4 = 90 Kg?ha–1 + Recommended Nitrogen) and two placement methods (A1 = Drilling method and A2 = Broadcast method). The statistical analysis of phosphorus levels and placement exhibited significant differences to the maturity days, plant height, tiller production, spike length, grains per spike, seed index, harvest index and grain yield ha–1. However, the interactions of P levels and placement in all crop characters were non-significant except the grain yield/ha–1. The results revealed that application of 90 kg P ha–1 prolonged 143 days for maturity, taller plants (100.16 cm), more tiller plant–1 (13.50), lengthy spikes (12.83 cm), more grains spike–1 (51.33), heavier seed index (48.16 g), better harvest index (50.82%) and satisfactory grain yield (4240.50 Kg?ha–1). The unit increase in grain yield was positively correlated with the increased values of observed crop parameters by extending the values of maturity r = 0.85, plant height r = 0.94, tillers plant r = 0.96, spike length r = 0.95, grains spik–1 r = 0.97, seed index r = 0.95 and harvest index r = 0.97. It was concluded that 90 kg P ha–1 was superior level of phosphorus if, applied with seed drilling for obtaining satisfactory grain yield of wheat crop.