Zero Tillage Improves Soil Properties, Reduces Nitrogen Loss and Increases Productivity in a Rice Farmland in Ghana

Issaka Issaka,Zhang Zhang,Zhao Zhao,Li Li,Kanu Kanu,Wang Wang,Asenso Asenso

doi:10.3390/agronomy9100641

Issaka Issaka, Zhang Zhang + Show 5 more

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https://doi.org/10.3390/agronomy9100641

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Journal: Agronomy	Publication Date: Oct 15, 2019
Citations: 4	License type: CC BY 4.0

Affiliation: South China Agricultural University

Abstract

Soil fertility in Ghana continues to decline due to the overdependency on farm machinery to till the land coupled with the continuous application of mineral fertilizer, which has a resultant effect on agricultural non-point source (AgNPS) pollution. A two-year field experiment was conducted to evaluate the effects of different tillage methods on soil properties, nitrogen loss reduction and rice productivity of a gleysol, developed over granite. Five tillage methods—namely, zero tillage direct seeding (ZTDS), zero tillage transplanting (ZTTS), reduced tillage direct seeding (RTDS), reduced tillage transplanting (RTTS), and conventional tillage (CT)—were studied in a Randomized Complete Block Design (RCBD) with three replicates. After two cropping seasons, soil bulk density was in the order of (ZTTS = ZTDS) ˃ RTDS ˃ RTTS ˃ CT. ZTDS and ZTTS were associated with significantly higher levels of nutrients in the top soil (0–20 cm) as compared with the rest of the treatments. Plant height was in the order of CT > RTTS = ZTTS > RTDS > ZTDS. The highest grain yield was recorded by both CT and ZTTS significantly different from the rest of the treatments. ZTDS recorded the highest stover yield for both years. Subsequently, CT was associated with high release of potential pollutant loads which could lead to AgNPS pollution, as is evident from the high nutrient loss. Considering the high nutrient concentration at 0–20 cm, the reduced nutrient movement and the corresponding yield improvement, ZTDS and ZTTS are recommended for farmers in Ghana to ensure sustainable rice production, reduce AgNPS pollutant movement and ultimately provide an eco-protective and friendly environment for sustainable rice production.

Highlights

Rice plays a critical role in contributing to food security, income generation, poverty alleviation and socioeconomic growth in Ghana [1]
The soil bulk density of the different conservation tillage treatments did not differ significantly when soil monitoring was performed in January–April, 2016
The results of this study reveal that soil bulk densities for all of the conservation tillage techniques were significantly higher than conventional tillage (CT) (Figure 3a) at the beginning of the experiment

Summary

Introduction

Rice plays a critical role in contributing to food security, income generation, poverty alleviation and socioeconomic growth in Ghana [1]. Between the years of 2000 and 2010, hectares of land under rice cultivation increased from 0.09 to 0.16 million hectares, while productivity fluctuated between 1.7 to 2.7 tons per hectare [2]. The production of rice in Ghana relies on the use of farm machinery and increased usage of inorganic fertilizers [1]. Ghana is an example of a country with land dynamics suitable for Agronomy 2019, 9, 641; doi:10.3390/agronomy9100641 www.mdpi.com/journal/agronomy. Agronomy 2019, 9, 641 mechanization, with the rapidly increasing farm sizes in recent years leading to medium-scale farmers (5–100 ha) cultivating the largest share of national cropland [3]. Results from the 2013 IFPRI/SARI survey of medium-to-large farmers in Northern Ghana, showed that over half of tractor owners cited land expansion as the primary motivation for their investment [4].

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