Meta-analysis of the Effects of Salinity Stress on Cotton (Gossypium spp.) Growth and Yield in Iran

Research on the impact of inputs has a long history in the country; however, because of the dispersion and diversity in the results of various experiments, it is difficult to achieve a general conclusion. In this study, a meta-analysis approach has been used to overcome this problem in order to achieve a single result by integrating and re-analyzing the findings of independent experiments. For this purpose, scientific articles published by researchers of the country regarding the effect of salinity stress on cotton yield were investigated. Articles were selected so that, in their meta-analysis of data required to perform there. The data necessary for the implementation of the meta-analysis is present in them. The results of this study showed that from 1996 to 2017; 15 papers and thesis were published on the effects of salinity stress on yield, early maturing and number of bolls in upland cotton (Gossypiumhirsutum L.). With increasing salinity stress, yield and number of bolls decreased. The standardized values for salinity stress effect on cotton yield were significant in all five treatments (control via salinity, control via 2-3 dS m-1, control via 4-5 dS m-1, control via 6-7 dS m-1, control via 8-9 dS m-1) compared to control (P<0.001). The standardized values of the effect of salt stress on cotton aging were significant in all five treatments compared to control. The standardized values of the effect of salt stress on cotton aging were significant in all five treatments compared to control. Results showed increasing salinity stress can cause early maturing in cotton. The standardized values for the effect of salinity stress on number of bolls per cotton plant, in the comparison of the total treatments of salinity stress, 2-3 dS m-1, 6-7 dS m-1 and 8-9 dS m-1 were significant compared tocontrol (P<0.001). In general, the results of this study showedthat salinity stress can reduce yield of cotton by reducing thenumber of bolls and also can cause early maturing on cotton

Environmental and socioeconomic assessment of agroforestry implementation in Iran

peer reviewedAgroforestry has been recognized as a sustainable strategy over conventional agriculture that can mitigate environmental impacts, enhance ecosystem services, maintain natural resources, and simultaneously improve smallholders’ livelihoods in rural areas. Agroforestry will be most effective in agricultural lands that are more vulnerable in terms of environmental and socioeconomic aspects. Therefore, it is necessary to identify the priority areas that are more susceptible to agroforestry. The objective of this study was to evaluate where and to what extent Iran's farmlands were subjected to increased environmental and socioeconomic pressures that can be alleviated through the implementation of agroforestry practices. To do so, two climatic, four soil, and four socioeconomic indicators were selected, and their maps were generated as well. Then, pressure maps of these indicators were created by applying the critical threshold of each indicator to the corresponding map. Finally, all the pressure maps were accumulated on a map called the Agroforestry Suitability Map (ASM). The locations that have more than five pressures on the current map were designated as priority areas for the development of agroforestry. The main findings showed that rise in temperature and soil organic carbon (SOC) deficit were the dominant pressures that affected the study area. Furthermore, about 17% of the total farmlands were recognized as the priority areas. The priority areas were mostly located in arid and semi-arid regions, which indicates the greater vulnerability of these regions to climatic and socioeconomic conditions. Our results highlighted that the farmlands of Kermanshah, Khuzestan, and Lorestan provinces, located adjacent to the Zagros Mountains, are the most suited areas for agroforestry implementation, respectively. The study findings could assist decision makers in mitigating the negative effects of environmental pressures and in providing a wide range of other beneficial services through the establishment of agroforestry systems in the recognized priority areas

More food or better distribution? Reviewing food policy options in developing countries

Peer Revie

Ecological Sustainability of a Wheat-cotton Agroecosystem in Khorassan

In order to develop a sustainability index (SI) for quantifying the sustainability of a wheat-cotton agroecosystem, a study was conducted in 2003 in the Khorassan province. Data of socio-economic, agronomic and ecological indicators were collected using 518 questionnaires. Results showed that only 18.6 percent of farmers gained the half or more of SI scores. The mean SI score was 44.0 which indicate that these agroecosystems are not sustainable. Results of this study are in consistent with other reports in other regions of the country. Livestock production, crop production, and water and irrigation indicators had the lowest score (6, 31, and 37, respectively). The backward stepwise regression analysis indicated that SI can be predicted from a linear combination of field size, wheat yield, crop residue management, crop income and education and extension services, while application of chemical fertilizers did not add to the prediction ability of SI. Results also showed that any progress in farmers’ education, economic viability, crop production management and water use efficiency could improve overall sustainability of these agroecosystems substantially

Quantification of the cardinal temperatures and thermal time requirement of opium poppy (Papaver somniferum L.) seeds to germinate using non-linear regression models

The response of plant development rate (including germination rate) to temperature might be described as a non-linear function. We compared 3 non-linear regression models (Dent-like, segmented and beta) to describe the germination rate-temperature relationships of opium poppy (Papaver somniferum L.) over 6 constant temperatures to find cardinal temperatures and thermal time required to reach different germination percentiles. Two replicated experiments were performed with the same temperatures. An iterative optimization method was used to calibrate the models and different statistical indices (mean absolute error, coefficient of determination (R2), intercept and slope of the regression equation of predicted vs. observed germination rate) were applied to compare their performance. The segmented was found to be the best model to predict germination rate (R2=0.92, MAE=0.0011 and CV of 1.4-3.6%). Estimated cardinal temperatures were similar for different germination percentiles (P<0.05). Base on the model outputs, the base, the optimum and the maximum temperatures for germination were estimated as 3.02, 27.36 and 36.31°C. The thermal time required to reach 50 and 95% germination was 57.27 and 87.55degree-days, respectively. Model predictions of the time required for seed germination agreed reasonably well with the observed times (MAE=0.56 day, R2=0.887). All model parameters may be readily used in crop simulation models. © 2011 Elsevier B.V.The authors gratefully acknowledge the financial support of Alcaliber S.A.Peer Reviewe

The subsurface application of pistachio waste compost and foliar spraying of organic matter can induce the flower yield and the quality of saffron (Crocus sativus L.) corms affected by restricted nutrient conditions

Correct use of organic waste in the form of composting can play a constructive role in reducing environmental pollution and increasing saffron sustainable production. Recently, pistachio waste compost has been considered as a soil conditioner, especially in arid and semi-arid areas. Along with improving the organic structure, foliar application of amino acids through the recommendation of reputable companies is another sustainable solution that can further strengthen the relationship between trade and agriculture. The current study was conducted in Anbari Agricultural Seeds Company, Mashhad, Iran during 2019–2021. The experiment was performed with three replicates based on a randomized complete block design arranged in factorial-split including 12 main plots [Organic fertilizer (control, pistachio compost (P), wheat straw (W), cow manure (M), P + W, and P + M) × Foliar spraying (control and 2 L. ha−1 DRIN: a commercial organic compound)] and 2 sub-plots (first and second sampling). The minimum number of saffron flowers and stigma weight were observed under no-organic fertilizer; while all organic sources led to increase these traits. The values increased by 27% and 31%, respectively, resulting pistachio compost compared to control treatment. Applying organic sources resulted in a higher crocin and safranal. At the same time, foliar spraying had a significant effect in increasing crocin and safranal concentrations. Organic fertilizers and foliar spraying caused a significant effect in terms of N, P, and K concentration in daughter corms. when control treatment was considered, foliar spraying increased sucrose by 24% compared to non-spraying. Furthermore, sucrose content was recorded to be improved following all organic amendments. Similar responses were observed regarding arginine, glutamic acid, alanine, and aspartic acid. Overall, applying pistachio compost concurrent with spraying of DRIN is recommended for saffron sustainable production, especially under nutrient-restricted conditions

Water stress effects on growth, development and yield of opium poppy (Papaver somniferum L.)

The effects of pre-anthesis water deficit and cycle length were examined in Papaver somniferum L., cultivated for alkaloid production, in two locations in southern Spain. The vegetative period was shortened by extending the photoperiod through supplemental lighting in the field, while water deficit in pre-anthesis was induced by avoiding irrigations and installing rain shelters. The treatments were: IN (irrigated-normal photoperiod), IL (irrigated-hastened flowering), DN (water deficit in pre-anthesis-normal photoperiod) and DL (water deficit in pre-anthesis and hastened flowering). The artificial photoperiod hastened the flowering by 15 and 21 days, for irrigated and deficit treatments respectively. Seasonal evapotranspiration (ET) ranged from 398 (DN) to 505mm (IN). There was evidence of root water uptake deeper than 1.5m. Stomatal conductance was reduced (16%) during water stress, and did not recover in post-anthesis after resuming irrigation. Head yields (capsule+seeds+7cm stem) ranged between 3.8 and 4.3tha-1; water deficit and short vegetative period both reduced the biomass accumulated, although the effect on yields in these treatments was counterbalanced by a higher harvest index. Early flowering had a detrimental effect on alkaloid concentration in the capsule. Alkaloids yield ranged between 27 and 37kgha-1. Water use efficiency (WUE) ranged between 0.78 and 0.96kgm-3 ET for yield and between 63.4 and 73.7gm-3 ET for alkaloids. Water stress increased slightly the Water Use Efficiency. A shorter vegetative phase had no effect on WUE for biomass or yield, but decreased the WUE for alkaloids production. © 2010 Elsevier B.V.We also appreciate the Ministry of Science, Research and Technology of I.R. Iran for providing scholarships for Abdolmajid Mahdavi Damghani, Behnam Kamkar and Majid Jami Al-Ahmadi as their sabbatical leave.Ministry of Science, Research and Technology of I.R. IranPeer Reviewe

Water stress effects on growth, development and yield of opium poppy (Papaver somniferum L.)

The effects of pre-anthesis water deficit and cycle length were examined in Papaver somniferum L., cultivated for alkaloid production, in two locations in southern Spain. The vegetative period was shortened by extending the photoperiod through supplemental lighting in the field, while water deficit in pre-anthesis was induced by avoiding irrigations and installing rain shelters. The treatments were: IN (irrigated-normal photoperiod), IL (irrigated-hastened flowering), DN (water deficit in pre-anthesis-normal photoperiod) and DL (water deficit in pre-anthesis and hastened flowering). The artificial photoperiod hastened the flowering by 15 and 21 days, for irrigated and deficit treatments respectively. Seasonal evapotranspiration (ET) ranged from 398 (DN) to 505 mm (IN). There was evidence of root water uptake deeper than 1.5 m. Stomatal conductance was reduced (16%) during water stress, and did not recover in post-anthesis after resuming irrigation. Head yields (capsule + seeds + 7 cm stem) ranged between 3.8 and 4.3 t ha-1; water deficit and short vegetative period both reduced the biomass accumulated, although the effect on yields in these treatments was counterbalanced by a higher harvest index. Early flowering had a detrimental effect on alkaloid concentration in the capsule. Alkaloids yield ranged between 27 and 37 kg ha-1. Water use efficiency (WUE) ranged between 0.78 and 0.96 kg m-3 ET for yield and between 63.4 and 73.7 g m-3 ET for alkaloids. Water stress increased slightly the Water Use Efficiency. A shorter vegetative phase had no effect on WUE for biomass or yield, but decreased the WUE for alkaloids production.Deficit irrigation Photoperiod Evapotranspiration Water use efficiency