Can Retention of Crop Residues on the Field Be Justified on Socioeconomic Grounds? A Case Study from the Mixed Crop-Livestock Production Systems of the Moroccan Drylands

Tamer El-Shater,Yigezu A Yigezu

doi:10.3390/agronomy11081465

Abstract

Conservation agriculture (CA) involving zero tillage, crop diversification, and residue retention is considered a panacea for several interrelated problems in agricultural production. However, in the mixed crop-livestock production systems of the drylands, crop residues have great significance as sources of animal feed, posing a major challenge in the promotion of CA. While the economic benefits and the drivers of adoption of zero tillage and rotation have been well documented, the literature on the economics of residue retention (RR), especially in the drylands, is scanty. By applying the endogenous switching regression model to a case study of 2296 wheat fields in Morocco, this paper provides evidence on the socio-economic impacts of residue retention. Between 30% and 60% and above 60% of crop residues were retained respectively on 35% and 14% of wheat fields. These levels of residue retention led to 22% and 29% more yields, 25% and 32% higher gross margins and 22% and 25% more consumption of wheat, respectively. Retention of above 60% residue reduces both downside risk and variability of yield while lower levels of residue retention have mixed effects. Residue retention is economically and biophysically beneficial even for owners of livestock as the monetary value of the additional grain yield more than offsets the cost of purchasing an equivalent amount of feed from the market—all providing good economic justification for residue retention. Our findings show that economic reasons are not barriers for adoption of residue retention, but risk factors and absence of alternative feed sources might. The policy implication of our results is that there are high incentives for Morocco and other similar countries in North Africa and West Asia to invest in the development and/or import of alternative feed sources, introducing crop insurance, and raising the awareness of the economic, biophysical and environmental benefits of residue retention among farmers.

Highlights

Conservation agriculture (CA) has received special attention and is being widely promoted throughout Africa under the assumption that it can help revert soil degradation [1,2,3,4]
We argue that short-term economic advantages/disadvantages might be critical in farmers’ decisions on whether to adopt crop residue retention and providing empirical evidence is useful in informing the overall effort to promote conservation agriculture in the drylands
Given the issues discussed in the methods section, we followed [40] to carry out a falsification test and the results showed that the instrument has a negative and significant effect on the adoption decision but has no significant effect on the yield, gross margins and wheat consumption of the non-adopters, thereby giving us confidence on the validity of the instrument [37]

Summary

Introduction

Conservation agriculture (CA) has received special attention and is being widely promoted throughout Africa under the assumption that it can help revert soil degradation [1,2,3,4]. As one of the three pillars of CA, RR enhances the biological processes above and below the soil surface [5]. Residue retention is strongly recommended for reducing surface run-offs, improving rainwater infiltration, and suppressing and controlling the growth of weeds [5,6,7]. When coupled with Zero tillage, residue retention increases infiltration of rainwater—an important benefit in the dry areas where moisture stress is the major limiting factor [10,11]. We argue, and provide empirical evidence, that all these benefits of RR to the soil, and to the crop would increase yield, gross margins, and household wheat consumption from own production while enhancing yield stability and reducing the risk of obtaining low yields. Given the importance of crop residue as feed in the drylands, we carried out a cost–benefit analysis of RR for livestock owners

Objectives

Methods

Results

Discussion

Conclusion