Potential benefits of intercropping corn with runner bean for small-sized farming system.(Report)

INTRODUCTION

Feed cost comprises from 50 to 70% of total farming expenses in Turkey (Ergun et al., 2002). Crops and livestock are interdependent elements, thus, income of farmers can be improved by utilizing the production factors for the combination of crops and dairying (Widodo et al., 1994). In order to reduce feed costs and create more sustainable management systems for moderate-sized, family operations, value-promoted livestock enterprises must be integrated with existing cropping enterprises.

One of the most important factors affecting Turkish farming systems is the lack of cheap, abundant and high quality feedstuff. The feeding of low-quality forages such as crop residues (wheat, barley straw) and low-quality hays with protein (meal) or energy supplementation (grain barley) to wintering ruminants is a common practice in Turkey. However, these low-quality forages may limit performance of dairy and fast-growing beef cows due to their high gut-filling capacity (Minson and Wilson, 1994). Dairy cows can only produce high milk yields and beef cows can only reach their maximum potential if their intermediary metabolism is supplied with sufficient nutrients (Ergun et al., 2002). Thus, high-quality forages have to be produced.

Corn silage has become more popular as a high-quality forage for ruminant animals in many parts of world as well as in Turkey. Corn silage has become a major constituent of ruminant, especially dairy, rations in recent years (Anil et al., 2000). Cereal forages are mainly used as an energy source in ruminant rations, possessing mainly carbohydrates but often with inadequate protein for high levels of production (Anil and Phipps, 1998). Thus, cereal forages often require additional protein supplementation for high milk and meat production. Protein-rich forages such as legumes can be ensiled and utilized to complement high energy corn silage.

Intercropping has been traditionally practiced in many parts of world (Anil et al., 2000; Karadag, 2004) as well as in Turkey (Karadag, 2004) and has some advantages over monocultures (Anil and Phipps, 1998; Karadag, 2004). One of its obvious advantages may be to increase forage protein, the principle being improvement of forage quality through the complementary effects of two or more crops grown simultaneously on the same area of land (Anil et al., 2000). Intercropping supplies efficient resource utilization, reduces risk to the environment and production costs, and provides greater financial stability, making the system more suitable particularly for labor-intensive, small farmers (Anil and Phipps, 1998).

Therefore, the objectives of this study were to evaluate potential benefits of intercropping of corn with runner bean for a small-sized farming system, based on LER and silage yield and quality of corn intercropped with runner bean, in arid conditions of Turkey under an irrigation system.

MATERIALS AND METHODS

Place of experiment

This experiment was carried out in the Van-Gevas region, at the border of Turkey and Iran (38[degrees]18'N, 43[degrees]07'E, altitude of experimental field 1,720 m, mean temperature 8.8[degrees]C and average rainfall 516.9 mm). Soil of the experimental field was slightly alkaline, and poor in terms of organic matter, nitrogen and phosphorous contents.

Experimental design and treatments

This experiment was established as a …