Molecular Soil Biology 2024, Vol.15, No.5, 216-226 http://bioscipublisher.com/index.php/msb 222 Vertisols: The combined application of inorganic fertilizers (NPK) and organic manure (farmyard manure) is effective in Vertisols. This practice improves soil physical properties, root growth, and water-use efficiency, leading to higher yields (Hati et al., 2006). Tropical Cropping Systems: In tropical systems, soil calcium enrichment through liming and gypsum application, along with appropriate nitrogen fertilization, can enhance root growth and overall yield. This strategy is particularly effective in integrated cropping systems where maize is double-cropped after soybeans (Souza et al., 2023). 6 Environmental and Climate Factors 6.1 Climate conditions and their impact on soybean irrigation Climate conditions, including temperature, rainfall patterns, and overall climate variability, significantly influence soybean water requirements. In temperate regions, the amount and distribution of precipitation during the growing season are critical for soybean yield. For instance, a study conducted over three years demonstrated that different irrigation regimes significantly impacted soybean yield and water productivity, particularly under varying precipitation conditions. The study found that irrigation is essential in semi-dry and dry years when seasonal precipitation is below 300 mm, while in wet years, yields were comparable to those achieved with irrigation due to favorable precipitation distribution (Gajić et al., 2018). In regions characterized by high annual precipitation but with periods of soil water deficit, supplemental irrigation during the reproductive stage (R1-R8) has been shown to positively affect soybean growth and yield. This is particularly important as rainfed conditions resulted in a 35% reduction in yield compared to irrigated treatments (Montoya et al., 2017). Additionally, combined heat and drought stress can drastically reduce soybean yields, with irrigation playing a crucial role in mitigating these stresses. For example, in the USA, irrigation alleviated both water and heat stresses, although dependencies on temperature and precipitation remained (Luan et al., 2021). Elevated atmospheric CO2 and temperature also affect soybean water use. Studies have shown that elevated CO2 levels can enhance crop biomass and yields, potentially altering water use efficiency. However, these effects are modulated by air temperature and nitrogen management, indicating the complex interplay between climate factors and crop water requirements (Lenka et al., 2020). 6.2 Soil erosion and conservation techniques Soil erosion and degradation are significant concerns in irrigated and fertilized soybean fields. Various conservation techniques can be employed to prevent soil degradation and maintain soil health. One effective approach is the use of plant growth-promoting microbes (PGPMs) and nanoparticles (Si-ZnNPs), which have been shown to enhance soybean growth and productivity under water deficit and salt-affected soil conditions. These treatments improve leaf potassium content, photosynthetic pigments, and relative water content, thereby reducing oxidative damage and enhancing overall plant health (Osman et al., 2021). In addition, proper nitrogen fertilizer management is crucial in preventing soil degradation. For instance, excessive soil moisture from extreme precipitation events can lead to nitrogen loss and reduced crop yields. Field trials have demonstrated that pre-plant nitrogen fertilizer applications, combined with rescue nitrogen applications, can mitigate these effects and improve yields in subsequent soybean crops (Kaur et al., 2017). Drip irrigation is another effective technique for preventing soil degradation in low rainfall regions. Drip irrigation helps maintain plant water status, which is critical for dry matter production and yield. Studies have shown that drip irrigation can prevent yield decreases in years with low rainfall, highlighting its importance in maintaining soil health and productivity (Chomsang et al., 2021). 7 Economic Considerations of Irrigation and Fertilization 7.1 Cost-benefit analysis of irrigation practices The economic viability of different irrigation methods for soybean cultivation varies significantly based on regional climatic conditions and the specific irrigation practices employed. For instance, in the temperate humid
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