Impacts of the continuous maize cultivation on soil properties in Sainyabuli province, Laos

Quality assessment and evaluation of irrigation water and soil used for maize (Zea mays L.) production in Boloso Sore district, southern Ethiopia

Poor quality of irrigation water and soil are among the major factors determining maize productivity in Ethiopia. This study assessed and evaluated the quality of irrigation water and soil under maize production in Soke and Woybo irrigation schemes in Boloso Sore district, Ethiopia. Four water samples per site per season were collected from the first point of the irrigation schemes and farm gate for dry and rainy seasons in 2019/2020. Soil samples of 108 were collected from 36 points, from which 18 composited samples were taken for laboratory analysis. Results show that irrigation water of the two schemes is non-saline (electrical conductivity <0.2 dS m^-1) and in the normal pH range (6.5-7.5). Maximum concentration of cations in irrigation water was in the order of sodium (22.3 mg l^-1) > potassium (7.3 mg l^-1) > calcium (6.2 mg l^-1) > magnesium (3.1 mg l^-1). Moderate to severe sodicity (sodium adsorption ratio of 10.9) was also recorded. Sulfate, nitrate, and phosphate contents in water were trace, and increased during rainy seasons in downstream. Textural classes of soils are clay loam to clay, and less compact to restrict root penetration (bulk density ≤1.4 g cm^-3), have slow infiltration rate (≤0.13 cm h^-1), and medium level of total available water (≤178 mm m^-1). Soils are strongly acidic to neutral (pH: 5-6.5), salt-free, and have low soil organic carbon (≤2.1%), low total nitrogen (≤0.1%), low available phosphorus and sulfur, and low Ca²⁺: Mg²⁺ ratio. It can be concluded that the irrigation water in the study area has cation imbalance (poor quality) which affects soil quality and maize productivity. Likewise, soils of the study area have poor quality. Lime application, efficient fertilizer use, and organic matter applications can be suggested. Further study on optimizing fertilizer rates and irrigation levels has to be conducted to improve maize productivity.

Suitable site selection by using full consistency method (FUCOM): a case study for maize cultivation in northwest Turkey

The agricultural land evaluation procedure is a valuable guide for growing plants where they are best suitable, and it has a critical role in actualizing sustainable plans for providing food security for the growing population. In agricultural land suitability analysis, different multi-criteria decision-making methods are applied. The main objective of this study is to introduce the potential usage of a new multi-criteria decision-making method the Full Consistency Method (FUCOM) in agricultural land suitability analysis. The study was carried out in the northern part of the Karamenderes plain in NW Turkey. Nine land characteristics (soil texture, soil depth, organic matter content, electrical conductivity, pH, slope, drainage, CaCO3%, and cation exchange capacity) were used for the land evaluation study. The weighting values of the land characteristics were calculated by the FUCOM. According to the results, 223 ha (6.26%) were highly suitable, 2650 ha (74.40%) were moderately suitable, 508 ha (14.26%) were marginally suitable, and 181 ha (5.08%) were not suitable for maize cultivation. The weighted values of the parameters were also tested with Analytic Hierarchy Process (AHP) and the Best-Worst Method (BWM). There is a general compatibility between the methodologies. The data obtained from these methods showed that analysis consists of a very positive relationship with each other. The comparisons of these methodologies showed that FUCOM's prioritization order simplicity in parameter weighting and ability to reduce the processing intensity would provide a significant contribution and advantage to the land evaluation experts and planners. It is recommended that the Full Consistent Method could be reliably used in agricultural land suitability analysis.

Assessment of the Interrelationships of Soil Nutrient Balances with the Agricultural Soil Emissions and Food Production

Sustainable and adjusted soil management practices are crucial for soil quality, namely in terms of the nutrient budget. On the other hand, soil characteristics are interlinked with agricultural sustainability and food supply. In other words, soil quality influences agricultural performance and food chains, but it is also impacted by agricultural activities. In this context, this research aims to evaluate the spatial correlations of the soil nutrient balance around the world and analyse how this variable is interrelated with agricultural soil emissions, agricultural output, and food supply. To achieve these goals, data from the FAOSTAT database were considered. This statistical information was analysed with spatial autocorrelation approaches to identify spatial clusters around the world that can be considered as a basis for designing common policies. To perform panel data regressions to identify marginal effects between variables, data were first evaluated using correlation matrices and factor analysis. The results highlight that there is space for common strategies worldwide to preserve soil quality, as in some parts of the world the problems are similar. In these frameworks, the international organizations may have a determinant contribution.

Metagenomic Analyses of Plant Growth-Promoting and Carbon-Cycling Genes in Maize Rhizosphere Soils with Distinct Land-Use and Management Histories

Many studies have shown that the maize rhizosphere comprises several plant growth-promoting microbes, but there is little or no study on the effects of land-use and management histories on microbial functional gene diversity in the maize rhizosphere soils in Africa. Analyzing microbial genes in the rhizosphere of plants, especially those associated with plant growth promotion and carbon cycling, is important for improving soil fertility and crop productivity. Here, we provide a comparative analysis of microbial genes present in the rhizosphere samples of two maize fields with different agricultural histories using shotgun metagenomics. Genes involved in the nutrient mobilization, including nifA, fixJ, norB, pstA, kefA and B, and ktrB were significantly more abundant (α = 0.05) in former grassland (F1) rhizosphere soils. Among the carbon-cycling genes, the abundance of 12 genes, including all those involved in the degradation of methane were more significant (α = 0.05) in the F1 soils, whereas only five genes were significantly more abundant in the F2 soils. α-diversity indices were different across the samples and significant differences were observed in the β diversity of plant growth-promoting and carbon-cycling genes between the fields (ANOSIM, p = 0.01 and R = 0.52). Nitrate-nitrogen (N-NO₃) was the most influential physicochemical parameter (p = 0.05 and contribution = 31.3%) that affected the distribution of the functional genes across the samples. The results indicate that land-use and management histories impact the composition and diversity of plant growth-promoting and carbon-cycling genes in the plant rhizosphere. The study widens our understanding of the effects of anthropogenic activities on plant health and major biogeochemical processes in soils.