Njiru L G, Yegon J R, Mwithiga G, Micheni A, Gitari N J, Mairura F S
University of Embu, Department Water and Agricultural Resource Management, P.O. Box 6-, 601600, Embu, Kenya.
Kenya Agricultural and Livestock Research Organization, Food Crops Research Institute, P.O. Box 27 - , 60100, Embu, Kenya.
Heliyon. 2023 Oct 14;9(10):e20926. doi: 10.1016/j.heliyon.2023.e20926. eCollection 2023 Oct.
Soil macronutrient and micronutrient availability is particularly critical in semi-arid agro-ecological zones that are characterized by poor soil fertility and low rainfall regimes. An experiment was initiated in Siakago, Embu County to investigate the effects of tied-ridges, conventional tillage and input applications on soil nutrient fertility using a randomized complete block design with a split-split plot arrangement for 4 seasons (2018-2021). The treatments comprised of two main plot tillage systems, three cropping systems allocated to the sub-plots and four soil input management treatments assigned to sub-sub plots. ANOVA was used to test the effects of different treatments including tillage, crop system and soil fertility management using Genstat software. The data was also subjected to Principal Component Analysis procedures using R ("" and "") to examine the inter-relationship patterns between different soil fertility parameters and to reduce the data into independent soil fertility components. There were significant main effects due to crop system (Soil Mn), tillage and crop system interaction (SOC and TSN) and soil fertility management (TOC, TSN, Ca, Zn). Soil inputs significantly influenced soil carbon concentrations (p = 0.002), with the lowest values observed in the control (0.2 %), followed by sole fertilizer (0.35 %), manure + fertilizer (0.41 %) and the fully decomposed manure treatment (0.61 %). The soil-extracted manganese values recorded significant effects due to crop system, while soil-extracted Zn values were significant due to soil fertility management. Multivariate analysis results revealed the structure of soil nutrient distribution. Tied ridging can improve soil micronutrient availability through reduced soil erosion, conservation of soil organic matter, which can improve soil micronutrient availability. Soil conservation practices such as tied-ridging integrated with organic input applications can enhance multiple nutrient availability for improved crop performance and human nutrition in dryland farming systems where farmers lack soil moisture, technologies and resources to enhance crop nutrient availability.
在以土壤肥力差和降雨少为特征的半干旱农业生态区，土壤大量养分和微量养分的有效性尤为关键。在恩布县的西亚卡戈开展了一项实验，采用随机完全区组设计和裂区设计，在4个季节（2018 - 2021年）研究垄作、传统耕作和投入施用对土壤养分肥力的影响。处理包括两种主区耕作系统、分配到副区的三种种植系统以及分配到副副区的四种土壤投入管理处理。使用Genstat软件进行方差分析，以检验不同处理（包括耕作、作物系统和土壤肥力管理）的效果。还使用R软件（“”和“”）对数据进行主成分分析程序，以检查不同土壤肥力参数之间的相互关系模式，并将数据简化为独立的土壤肥力成分。作物系统（土壤锰）、耕作和作物系统相互作用（土壤有机碳和总氮）以及土壤肥力管理（总有机碳、总氮、钙、锌）产生了显著的主效应。土壤投入显著影响土壤碳浓度（p = 0.002），对照处理中观测到的最低值为0.2%，其次是单施化肥（0.35%）、粪肥 + 化肥（0.41%）和完全腐熟粪肥处理（0.61%）。作物系统对土壤提取的锰值有显著影响，而土壤肥力管理对土壤提取的锌值有显著影响。多变量分析结果揭示了土壤养分分布结构。垄作可以通过减少土壤侵蚀、保护土壤有机质来提高土壤微量养分的有效性，进而改善土壤微量养分的有效性。在旱地农业系统中，农民缺乏土壤水分、技术和资源来提高作物养分有效性，垄作等土壤保护措施与有机投入施用相结合，可以提高多种养分的有效性，从而改善作物生长性能和人类营养状况。
