International Journal of Plant Production
Volume:10 Issue: 3, Jul 2016

This work aimed to study the intrinsic tolerance of Greek lentil accessions to imazamox herbicide by combining bioassays, pot and field experiments. Initially, 31 genotypes were evaluated in Petri dish bioassays for their tolerance to six concentrations of imazamox. The average root length of 10 lentil seedlings/dish at seven days after herbicide application was used for non-linear regression analysis and the GR50 values (the amount of the herbicide required for 50% root length reduction of the seedlings) were estimated to calculate the resistance ratio (R/S) of each cultivar. The results of the in vitro test clued the selection of nine accessions for further study in pot experiment, to assess their tolerance to four rates [0 (control), 20, 30, 40 g ai ha-1] of imazamox post-emergently applied at the seven true-leaf stage (V7 stage). Five weeks after treatment, the number of survived plants was recorded and the above-ground dry weight was determined in each pot. There was no direct correlation in the results of in vitro test and the pot experiment, suggesting no matching between the two methods. The evaluation of five accessions (cultivars with high commercial interest and accessions sporting tolerance in pot experiment) in field experiment demonstrated different but increased susceptibility to imazamox. Specifically, compared to the untreated control, the imazamox treatments reduced plant growth, delayed flowering and maturity and reduced yield, dry weight, 1000-seed weight and harvest index. Yet the protein concentration was increased in herbicide treatments. The findings of the study showed clearly that the evaluated lentil accessions lack genes with resistance to imazamox and different methods have to be used for assessing any potential tolerance.

The dynamic and static deficit (DDI, SDI), partial root drying (DPRD, SPRD) and full (FI) irrigation strategies were applied in Agria and Ramos potato cultivars in a semi-arid area. FI received 100% of the potential evapotranspiration (ET); SDI and SPRD received 75% of ET during the growth period; DDI and DPRD received 90% of ET in the first third, 75% of ET in the second third and 50% of ET in the last third of growth period. Results showed that fresh tuber yield and tuber nitrogen (N) content were negatively correlated meaning that by increasing the tuber N content, tuber yield decreased. PRD irrigation strategy had significantly the highest tuber N content than FI and DI. Dry matter water productivity (WPDM) was significantly different between the irrigation strategies. The DI strategies had significantly higher WPDM than FI and PRD ones. DDI and DPRD increased WPDM by 26 and 19% compared to SDI and SPRD, respectively. WPDM in Ramos (1.08 kg m-3) was higher than Agria (0.82 kg m-3). The newly introduced Dry Matter-Water Content Index (DMWCI) was higher in PRD and Agria than DI and Ramos, respectively. Conclusively, the DI treatments are the recommended water savingirrigation strategies under these experimental conditions in terms of highest WPDM and greater dry matter allocation to tubers, though the PRD irrigation strategy had higher tuber N content. Ramos is the favored potato cultivar for processing industry based on its higher WPDM and tuber dry matter content than Agria.

Nitrogen (N) in plants is generally diagnosed by a soil test and plant tissue analysis. However, such analyses are costly in terms of time and money and are not easily accessible by researchers and extension workers, let alone farmers. Alternative cost-effective methods are required for rapid analysis of the N status of crops and to guide N management in wheat. The objective of this study was to assess whether the SPAD values using a leaf chlorophyll meter could be used to apply N at the maximum tillering (MT) stage of irrigated spring wheat grown under light soils of South Asia. Experiments were conducted over two years under light soils at the Wheat Research Centre (WRC), Dinajpur, Bangladesh. Treatments were 80, 100 and 120 kg N ha−1, applied two-thirds as basal and one-third at the crown root initiation (CRI) stage along with additional 10, 20 and 30 kg N ha−1 (first year) and 0, 10, 20 and 30 kg N ha- (second year) at MT. Rates at MT were determined on the basis of SPAD values, which fell below the critical value of 37.5, recorded at 45 days after sowing (DAS). SPAD values recorded at 55 and 65 DAS were positively correlated with grain yield (GY), indicating that the application of extra N at MT influences wheat GY. Our results have two major implications: (i) SPAD values based on a leaf chlorophyll meter can be used for N application and (ii) extra 30 kg N ha-1 at MT is recommended for achieving maximum GY of irrigated spring wheat under the light soils of South Asia.

The present study investigated the impact of environmental pollution, represented in soil, irrigation water and air heavy metals, on the growth and production of Egyptian clover cultivated at south Greater Cairo, Egypt. Plants were sampled through five quadrats (0.5 0.5 m), distributed equally in four cultivated farms in unpolluted and polluted sites, at the harvesting time. In addition, soil, air and irrigation water were collected from each farm. Significant differences in air, soil and irrigation water between the polluted and unpolluted sites were recognized. Plant density, shoot and root lengths; as well as biomass and yield were remarkably lower in the polluted site. In contrast with chlorophyll b; chlorophyll a and carotenoids contents were lower in clover cultivated in the polluted site. However, chlorophyll a/b ratio was significantly higher in plants from the polluted site. It was found that, As, Cr, Ni, Zn, Ag and V were significantly higher in clover shoots than roots, while Pb, Cd, Cu, Fe, Mn and Co concentrations were higher in the roots. The bioaccumulation and translocation factors of most heavy metals were greater than unity indicating high potential of the study species for phytoremediation in polluted areas. Egyptian clover accumulated toxic concentrations of Fe, Pb, Ni, Zn, Cd, Cr and Co, which have adverse effects directly on livestock and indirectly on human health through its flow in the food chain. In order to use Egyptian clover as a forage crop, its cultivation should be avoided in polluted areas.

Wheat-corn cropping system is one of the most important grain production systems in the world. However, the integrative impacts of soil tillage on crop yield, N use efficiency (NUE) and greenhouse gases (GHGS) emissions are not well documented in this system. Thus, a twoyear field experiment was carried out in a typical wheat-corn cropping system with four tillage regimes during the wheat season, including no-tillage (NT), rotary tillage (RT), sub-soiling tillage (ST) and sub-soiling with rotary tillage (SRT) in a randomized block design with three replicates. No-tillage was conducted for all treatments during corn season. Over the two years, the highest yields of wheat, corn and annual were found in the SRT treatment, while the lowest annual yield was found in the NT treatment averagely. Two-year average annual yield in the SRT was 19643.9 kg ha-1, which was 4.8, 5.9 and 7.7% higher than that in the ST, RT and NT treatments, respectively (P

The introduction of ecological sanitation (ECOSAN) toilets in villages near Bangalore has created opportunities for safer sanitation and recycling of human excreta, as fertilizers, in rural and peri-urban areas. Field experiments were conducted at the University farm on French beans and Maize as the test crops in succession for 2 consecutive years in the same field. Different treatment combinations tried include human urine, with and without gypsum, Farm yard manure (FYM), chemical fertilizers and control. The fertilizer value of human urine were assessed and supplied to the crops based on the nutrient content. The results revealed that yield of two crops were significantly highest in treatment receiving human urine FYM followed by human urine alone. Generally the results showed that human urine performed well than the commercially available chemical fertilizers (urea) applied as a source of N for crops and does not pose any significant hygienic threats and leave any significant flavor in food products.

Adoption of drip irrigation in Kerala State of India is very low and potential exists to increase its adoption in the State. A field survey was conducted in two districts to determine the major factors influencing farmers’ adoption of drip irrigation and to draw conclusions that will help in developing policy and institutional interventions to encourage the adoption. The results indicated that adoption index of farmers is higher in Kozhikode, when compared with the Thrissur district. However, with respect to different crops, adoption index is not statistically significant. Socioeconomic characteristics such as age, education, experience, land holding size, etc. have a positive influence on drip irrigation adoption index by farmers. Farmers have realized yield improvement in the range of about 13% to 47% through drip irrigation, when compared to surface method of irrigation for arecanut, coconut and nutmeg. High productivity and income from cultivation of crops like coconut, arecanut and nutmeg have acted as an incentive to adopt the costly system of drip irrigation in the case of both Kozhikode and Thrissur farmers. The number of drip irrigation components and type of emitters indicated a significant and linear response for drip irrigation adoption. The reported constraints experienced by farmers include rainfall, clogging of drippers, high initial cost, inadequate subsidy, difficulty in getting subsidy, etc. This information will help to prioritize the factors that affect adoption decisions and provide insights for improving the crop and water productivity.

Salinization of soil is primarily caused by capillary rise from saline shallow groundwater or application of saline irrigation water. In this investigation, the transient state analytical model was modified to predict water uptake from saline shallow groundwater, actual crop evapotranspiration, soil water content, dry matter, seed yield and soil salinity under different saline groundwater depths, irrigation water salinities and deficit irrigation for quinoa. Considering the effect of salinity on soil saturated hydraulic conductivity and maximum root depth in presence of shallow saline groundwater, the model resulted in good agreement between the measured and predicted saline groundwater uptake, soil salinity increase at different groundwater depths (300-800 mm) and water salinity (10-40 dS m-1). Therefore, the modified model is applicable for quinoa yield and soil salinity prediction and it could be a valuable tool for soil salinity management in presence of shallow saline groundwater. Furthermore, prediction of quinoa yield by the modified model can be used for better irrigation water salinity management under different saline groundwater depths, irrigation water salinities and deficit irrigation.

This study was aimed at evaluating the effect of crop rotation and various tillage systems on the chemical and biological properties of soil in the years 2013-2015. The first order factor included cropping systems: a) crop rotation (pea – winter wheat – spring wheat) and b) monoculture of winter wheat, whereas the second order factor were tillage systems: 1) conventional (CT), 2) reduced (RT) and 3) No-tillage (NT). In the autumn season, in the CT system, shallow ploughing (at the depth of 10–12 cm) and pre-winter ploughing (25–30 cm) were applied for pea and spring wheat crops, whereas shallow ploughing and pre-sow ploughing (20–22 cm) were applied for winter wheat crop; in the RT system, only a cultivator was applied for spring wheat and pea crops as well as a cultivator and a tillage set for winter wheat; in the NT system glyphosate was applied on all plots as well as a cultivator and a tillage set were used before winter wheat sowing. The study demonstrated that the soil sampled from plots with crop rotation contained more organic C and available forms of P, K and Mg and that it was characterized by a higher activity of dehydrogenase, phosphatase and urease than the soil sampled from monoculture. In addition, it was characterized by a higher number of earthworms than the soil from monoculture. The RT and NT systems affected an increase in the contents of organic C and total N and in the enzymatic activity of soil, compared to the CT system.

Energy and water availability were identified as the first order controls of evapotranspiration (ET) in ecohyrodrology. With a ~1,000 km precipitation gradient and distinct wet-dry climate, the North Australian Tropical Transect (NATT) was well suited for evaluating how energy and water availabilities constrain water use by vegetation, but has not been done yet. In this study, we addressed this question using Budyko framework that quantifies the evapotranspiration as a function of energy-limited rate and precipitation. Path analysis was adopted to evaluate the dependencies of water and carbon fluxes on ecohydrological variables. Results showed that the major drivers of water and carbon fluxes varied between wet and dry savannas: down welling solar radiation was the primary driver of the wet season ET in mesic savanna ecosystems, while soil water availability was the primary driver in inland dryland ecosystems. Vegetation can significantly regulate water and carbon fluxes of savanna ecosystems, as supported by the strong link of LAI with ET and GPP from path analysis. Vegetation structure (i.e. the tree:grass ratio) at each site can regulate the impact of climatic constraint on ET and GPP. Sites with a low tree:grass ratio had ET and GPP that exceeded sites with high a tree:grass ratio when the grassy understory was active. Identifying the relative importance of these climate drivers and vegetation structure on seasonal patterns of water use by these ecosystems will help us decide our priorities when improving the estimates of ET and GPP.