Increasing paddy yields and improving farm management: results from participatory experiments with good agricultural practices (GAP) in Tanzania

Kalimuthu Senthilkumar,Jonne Rodenburg,Jerome Mghase,Bonaventure J Tesha

doi:10.1007/s10333-018-0666-7

Kalimuthu Senthilkumar, Jonne Rodenburg + Show 2 more

Open Access

https://doi.org/10.1007/s10333-018-0666-7

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Abstract

Rice is an increasingly important commodity in sub-Saharan Africa. In Tanzania, the rice yield gap is as high as 87%, due to a combination of production constraints and sub-optimal crop management. Reducing this yield gap may be partly achieved through the introduction and dissemination of good agricultural practices (GAP). We conducted 18 farmer-managed on-farm trials in Tanzania, to test a set of GAP components against conventional farmers’ practices (FP) for two consecutive growing seasons in 2013 and 2014. The objectives were: (1) to understand farmers’ capabilities in implementing GAP; (2) to acquire better insights into the merits, relevance and suitability of individual GAP components; and (3) to provide a case study showing that exposure to good practices combined with the farmers’ own experimentations can serve to improve and, trigger a positive change in the participating farmers’ crop management. Compared to the farmers’ own practices, average yield increases of 1 t paddy ha−1 in 2013 and 2.7 t ha−1 in 2014 were achieved when following GAP. These yield advantages were mainly obtained by a higher panicle number, improved harvest index and improved weed control. Farmers experienced difficulties with land levelling, planting or sowing in lines and using rotary weeders, but they were convinced that these technologies are important to boost their rice yields. The case of Tanzania shows that paddy yields can be substantially improved by GAP and that adoption of GAP by smallholder rice farmers can be triggered by stimulating experimentations with such practices on their own farms.

Highlights

Rice (Oryza sativa and O. glaberrima) is an increasingly important staple food in sub-Saharan Africa (SSA)
The objectives of our study were: (1) to compare a set of good agricultural practices (GAP) to conventional farmers’ practices (FP) to quantify the possible yield advantages with GAP; (2) to understand farmers’ capabilities in implementing GAP on their farms and to obtain their opinions on GAP component technologies compared to conventional practices; and (3) to provide a case study showing that on-farm farmer participatory experiments with such practices can serve to improve and prioritise rice-farming extension efforts and, trigger a positive change in the participating farmers’ crop management
When compared with the critical levels below which nutrient deficiency for individual nutrients occur for rice production (Fairhurst et al 2007), we found that the N, P, K, Mg, S and B are below the

Summary

Introduction

Rice (Oryza sativa and O. glaberrima) is an increasingly important staple food in sub-Saharan Africa (SSA). With rice yield gaps in SSA ranging from 30 to 90% (van Oort et al 2015), Tanzania is among the countries with the largest difference between the potential or water-limited yield and the actual yield. With such low yields, smallholder rice farmers in Tanzania, who grow rice both for their own subsistence and for the (local) market, are often stuck in a poverty trap. The current rice production practices of smallholder farmers in Tanzania include soil tillage using hand-held hoes and the use of low-yielding local varieties.

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