Fertilizer Source Affects Crop Yield Under Different Tillage Practices: A Meta-analysis

Farmers are clearly realizing how important sustainable agriculture practices are, to ensure the future of food security while maintaining healthy environment. Organic farming and conservation agriculture are considered as promising alternatives to the conventional managements for crop production taking into consideration the environmental impacts. Organic farming techniques have been extended for more than 6 folds, while conservation agriculture practices have been extended for more than 4 folds, in the last 20 years. The application of mineral fertilizers is extensively adopted to ensure the highest crop productivity, even if their misuse and massive application led to expensive and dangerous circumstances for the environment and human health. On the other side, several studies reported that the use of organic sources of nutrients is considered a suitable strategy for matching the production of safe and healthy foods and enhancing the restoration of soil fertility while mitigating the negative effects of climate change. Accordingly, environmentally friendly practices such as the replacement of chemical or inorganic (M) fertilization with other substitutes, such as mixed inorganic/organic (MO) or sole organic (O) fertilizers should be considered. Furthermore, integrating organic fertilizer application with conservation tillage practices could be a more suitable option for sustainable agriculture. Conservation tillage practices such as reduced tillage (RT) and no-tillage (NT) have advantageous effects over the conventional tillage (CT) regarding time and energy demanding. In addition, they affect soil health positively through improving soil structure, increasing soil organic matter, maintaining soil moisture, as well affecting water and nutrient use efficiency, which consequently influencing crop production. Such practices may prevent further losses, even it can be used to re-establish degraded lands. Several researches reported that under certain farming and environmental conditions, the yields of sustainable and conventional farming practices could be equal, even if the effects of organic fertilization and conservation tillage practices are not well understood, given the wide range of factors affecting agricultural activities. Improving the knowledge concerning the combination of organic nutrient sources under different tillage intensities may represent an important tool to help farmers for decision-making regarding different farming managements. This study focuses on evaluating the effects of organic fertilizers applied alone or in combination with mineral fertilizers compared with conventional fertilized crop, overall assembled studies, and when subjected to different soil tillage regimes.