Chemical properties of long-term irrigated Fluvisols of the Beli Drim river valley in the Klina region (Serbia)

The impact of long-term (> 100 yr) irrigation on soil chemical properties was studied on eight plots in the Beli Drim river valley in Kosovo and Metohija near Klina, Serbia. For these studies, soil samples from shallow profiles were collected from only one or two depth zones of the Ah horizon; and from moderately deep and deep profiles, from two to three depth zones for the purpose of comparing irrigated field and non-irrigated meadow lands. Water from the Beli Drim River and surface gravity systems (irrigation furrows or border strip irrigation) were used for irrigation. Chemical variables included determination of pH-H2O, content of CaCO3, content of humus, hydrolytic acidity, sum of basic cations, cation exchange capacity, and base saturation. On irrigated soils, the results of chemical analysis showed on average a small increase in pH-H2O (0.07 pH units), as well as a significant decrease in humus content (2.00-4.75%), sum of basic cations (4.98-12.98%) and cation exchange capacity (12.8%) compared to the non-irrigated land of the study area. Long-term irrigation had no effect on hydrolytic acidity and base saturation in the Ah horizon of the investigated lands. Namely, the mentioned variations in the chemical properties of the investigated soils show that slight processes of reduction in the humus content and reduction of the content of base cations occured. Data on the chemical properties of the investigated soils indicate that the destructive processes of reduction in the humus content and leaching of base cations must be controlled in order to achieve a stable sustainable system of high productivity and prevent their further deterioration.

Soil quality of the tea and apple-growing sites in Mindat District, Chin state, Myanmar: A preliminary study

In this study, two sites from tea and apple growing sites were collected from Pyay village and Nine Mile village, Mindat district, Chin state of West Myanmar under a humid subtropical climate. The results of physicochemical properties of observed soils were neutral pH, favorable moisture, silty clay loam texture, very high content of organic carbon, organic matter and total nitrogen. However, the tea growing soil was very poor in phosphorus and potassium content. Moreover, both soils lack of available potassium. The content of heavy metals in both soils was not varied from each other and followed the order: Fe (iron) > Cu (copper) >Zn (zinc) > Pb (lead) > Cr (chromium) and was below the maximum allowed concentrations (MAC). Therefore, the studied soils are generally favorable for cultivation under the condition of application of phosphorus and potassium fertilizers. However, due to the regular application of fertilizers and pesticides, it is necessary to monitor these soils for PTE levels. Further research is recommended, which must include analyses of the physicochemical properties of soils to a two depths of 0-30 and 30-60 cm, especially for the area where fruit plants are grown. In addition, higher density of soil samples and sub-samples are necessary to produce a reliable dataset that will allow proper statistical analysis.

Perspectives for cultivation of diversified crops in a rice (Oryza sativa L.)-based crop rotation in the Kyzylorda region, Kazakhstan

In the Aral Sea basin of Kyzylorda region, Kazakhstan, rice (Oryza sativa L.) is a main crop and annually occupies more than 45% of the total area of agricultural crops. However, about 90% of Syr Daria River waters is consumed for agricultural purposes, mainly for irrigation of paddy fields. In addition, there is an annual variability in the volume of water during the growing season, which creates certain threats to ensuring guaranteed water supply to irrigated lands and may pose a desertification risks. In addition, in the studied region, due to insufficient application of phosphorus fertilizers nutrient imbalance has been observed in the soil. The aim of the research was to develop sustainable production of rice by introduction of diversified cultures such as barley, soybean and rapeseed: Hordeum vulgare (L.), Glycine max (L.) and Brassica napus (L.), respectively, in a rice-based crop rotation and application of the different doses of mineral fertilizers in the Kyzylorda region. The results of the study showed that application of phosphorus as the main fertilizer at a dose of 90 kg ha-1 gives a significant increase in yield. Studied barley and rapeseed crops showed better adaptability to the specific agroecological conditions. These crops are recommended to be introduced into the rice crop rotations in order to produce rice using environmentally friendly technology.

Mapping environmental and climate variations by GMT: A case of Zambia, Central Africa

Zambia recently experienced several environmental threats from climate change such as droughts, temperature rise and occasional flooding and they all affect agricultural sustainability and people wellbeing through negative effects on plants and growing crops. This paper is aimed at showing variations in several climate and environmental parameters in Zambia showing spatial variability and trends in different regions of Zambia's key environmental areas (Zambezi River and tributaries), Livingstone near the Victoria Falls and central region with Muchinga Mountains. A series of 10 maps was plotted using data from TerraClimate dataset: precipitation, soil moisture, Palmer Drought Severity Index (PDSI), downward surface shortwave radiation, vapor pressure deficit and anomalies, potential and actual evapotranspiration and wind speed with relation to the topographic distribution of elevations in Zambia plotted using GEBCO/SRTM data. The data range of the PDSI according to the index values ranged from minimum at -5.7 to the maximum at 16.6 and mean at 7.169, with standard deviation at 4.278. The PDSI is effective in quantifying drought in long-term period. Because PDSI index applies temperature data and water balance model, it indicates the effect of climate warming on drought by correlation with potential evapotranspiration. The maximum values for soil moisture of Zambia show minimum at 1 mm/m, maximum at 413 mm/m, mean at 173 mm/m. This study is technically based on using the Generic Mapping Tools (GMT) as cartographic scripting toolset. The paper contributes to the environmental monitoring of Zambia by presenting a series of climate and environmental maps that are beneficial for agricultural mapping of Zambia.

Application of two measures of adaptation to climate change for assessment on the yield of wheat, corn and sunflower by the aquacrop model

Frequent occurrence of droughts over the last two decades, as well as increases in the air temperature increase have led to the rise farmers' concerns that field crop production would not be possible without irrigation. The aim of this research is to assess how two adaptation measures, sowing dates and irrigation and water excess impacts the yields of wheat, maize and sunflower in Serbia. In order to assess the future of climatic condition five representative locations have been selected for the analysis (Novi Sad, Valjevo, Kragujevac, Negotic and Leskovac). For the analysis of future climatic conditions, results of the ensemble of nine regional climate models from the Euro-CORDEX database were used. The period between 1986 and 2005 was used as a reference, while time slices in the future are: 2016-2035 (near future), 2046-2065 (mid-century) and 2081-2100 (end of the century). Analyses were made for the scenario of GHG emmisions RCP8.5. Aquacrop model v.6.1 was used for the yield, sowing period, and irrigation requirement assessment. The analysis and the results have indicated that earlier start of the growing season of maize and sunflower for 5, 11 and 19 days in near future, mid and end of the century, respectively, whereas optimal sowing period for rainfed wheat will vary from September 20 to November 30, depending on rainfall occurrence, and for irrigated one in optimal sowing period (beginning of October). The warmer climate will shorten the growing cycle of all studied crops. However, the shortening significantly differs among locations. The growing cycle of maize shortened from 34 up to 48 days in Valjevo in near future through the end of the century, while in Negotin it could be less only for 6 days. The increase in air temperature and earlier start of the growing season will enable the most sensitive phenophases, flowering and fruit formation, to appear in a period of more favorable weather conditions, together with the increase in CO2 concentration, can help mitigate the negative impact of the climate change, so that there will be no reduction in sunflower yields. Slight increment of sunflower yields could be expected by the end of century (2.3 - 13.8%), whereas yield of maize will remain on the present level. The increase of wheat yield could be expected only in the near future (up to 8.3 %), but also it can be reduced at some locations by the end of the century. Irrigation water requirements of all studied crops will remain at the same level the same level as the present, but only if sowing applied in the optimal period. Although it is known that irrigation changes microclimatic conditions, ie., the air humidity increases, and the air temperature decreases (the so-called oasis effect), which can affect the extension of the vegetation period, and thus the increase in yield. Such subtle changes in the microclimate cannot be "recognized" by models, so even simulated yields cannot be fully (accurately) predicted. This research come to the conclusion that in addition to irrigation, shifting the sowing dates earlier can have an impact on mitigating the consequences of climate change in crop production, which is of great importance for areas where there is not enough water for irrigation. The risk of drought will exist on shallow and sandy soils as well as on overwetted lands that cannot be plowed until drained to be sown in optimal terms and all crops sown in the late spring.

Properties and groundwater level of humogley soil of southern Bačka

The paper examines hydromorphic soils from the class of gley soils, soil type humogley. The examined soils are located in the protected part of the inundation of the middle course of the Danube. According to the chemical properties of the examined soils, the pH value ranges from 7,64 to 8,15 on average, and with depth there is an increase in alkalinity. The total salts of the examined soils had increased values in the humus horizon and ranged from 0,06 to 0,09%. The texture classes of the humus horizon of these soils are: clay loam to sandy clay loam, while the lower sub-horizons of the gley are textural classes of sandy loam, loamy sand and sand. The influence of the Danube water level on the groundwater level results in high correlation coefficients, which range from 0,67 to 0,88. The groundwater in these soils had the highest level from 28 cm to 70 cm depth, and the lowest level was from 110 to 175 cm deep. The amplitude of groundwater variation during the year in the examined humogley soils ranges from 66 to 132 cm. Groundwater quality classes according to U.S. Salinity Laboratories are unfavorable and range from C3S1 to C4S1, ie salt to very salty water with low sodium content, and according to the FAO classification the water quality is such that there is a moderate need for restriction. High groundwater level above the critical level, as well as watering the soil with water of this quality can have an impact on salinization of the surface horizon of humogley soil of the examined area.

Soil organic carbon stocks in relation to the altitude in Serbia

The research was conducted to determine the soil organic carbon (SOC) stocks in relation to the altitude in Serbia. The database included a total of 1,140 soil profiles. SOC were investigated at different the altitudes (0-200 m, 200-500 m, 500-1,000 m, 1,000 - 2.000 m) and at two soil depths (0-30 cm and 0-100 cm). Statistical correlation was done for five regions where locations were grouped according to the spatial distribution. The results showed that the highest mean values of SOC were measured on the terrain that includes mountains with the altitudes of 1,000-2,000 m and covers an area of 11.5% of the territory of Serbia. The lowest obtained result is related to the lowland areas with the largest number of locations. Greater variability in the results of SOC stocks were found at the higher altitudes and the greatest on the low mountains of 500-1,000 m altitude. There is a medium to strong statistical dependence of the altitude with the SOC stocks at two soil depths (0-30 cm and 0-100 cm). The result indicate that the relationship between SOC stocks and altitude varies between the regions. This study shows that altitude is an important factor affecting SOC stocks.

Screening of new sources of 'Hordeum vulgare' genes for adaptive breeding in Aral Sea basin, Kazakhstan, for diversification of agriculture

The specifics of the soil and climatic conditions of the Aral sea region, Kazakhstan, primarily associated with salinization, various types of droughts, uneven distribution of precipitation during the growing season, and late spring frosts, make it necessary to create crop varieties with resistance to biotic and abiotic environmental factors. In this regard, the expansion of the area under crops of nontraditional salt-tolerant grain crops in the Kyzylorda region is one of the main directions of increasing the sustainability of agriculture in the region. Studies have shown that among the grain crops cultivated in the region, spring barley (Hordeum vulgare L.) is a reliable crop that can make the most of the region's bioclimatic resources to form sustainable yields. The purpose of this study is to create a new promising source material of barley based on a comprehensive study of collection material of various ecological and geographical origin by applying various methods of classical breeding. Based on a comprehensive assessment of the collection material of barley, a working collection of 250 varieties with agronomic resistance to environmental stress factors of the Aral Sea region was created. The selected samples are recommended for use in practical breeding in order to increase the adaptive potential of modern barley varieties.

Maize irrigation requirement on Zemun chernozem in the last half of the century

The aim of this paper is to examine the water regime of chernozem under maize crops in the last half century (1966-2019) and to determine whether during that period and to what extent, there was an increase or decrease in maize irrigation requirements. The mathematical plant model FAO CROPWAT 8.0 was used for the calculation. The calculation was performed on the basis of monthly values of reference evapotranspiration (ETo) for the period 1966-2019, calculated by the modified Hargreaves method, daily values of precipitation from the meteorological station Surcin, data on the selected plant, which are in accordance with FAO56. The soil is chernozem on the Zemun les terrace. The analysis was performed by dividing the research period into three subperiods: the first twenty (1966-1985), the second twenty (1986-2005) and the last fourteen (2006-2019) years. It was found that the average values of potential evapotranspiration of maize were increasing, starting from the first (500mm) to the third (562mm) subperiod, while the average values of actual evapotranspiration, as well as the average amount of effective precipitation in the vegetation period of maize, decreased. Consequently, the average water deficit, i.e. maize irrigation requirements was increased by 56%, starting from the first (205mm) to the third (319mm) subperiod of the research. The increase in the water deficit also caused an increase in the projected reduction in maize yield related to its genetic capasity, which averaged 31% in the first subperiod and 47% in the third. Analysis of the results on a monthly and decadal level showed that maize irrigation requirements lasts from June to August, with a maximum in the second decade of July. In all three summer months, an increase in maize irrigation requirements was registered from the first to the third subperiod of the research, with the maximum increase during July. The conducted research, which generally gives an insight into the state of the water regime of Zemun chernozem in the last half century, shows that the conditions of maize production in the natural rain regime are deteriorating and that the irrigation requirement is increasing.