Abstract: The experiment consisted of two sorghum based inter-cropping system i.e. sorghum+guara and sorghum+cowpea in 1-row, 2-row and 3-row strips including sole cropping of all the component crops. Total fodder yield and mean land equivalent ratio (LER) was fairly high in all inter-cropping treatments but the highest LER 1.89 was recorded for sorghum-cowpea 3-rows inter-cropping system. This showed that 70-89 percent yield advantage was gained due to inter-cropping. However, maximum fodder yield of sorghum was obtained after three months of sowing from all the inter-cropped treatments.
Introduction
The available fodder production is approximately 52-54 percent less than actual requirement (Bhatti, 1988). Moreover, with the rapid increase in farm population, and limited land for cultivation, inter-cropping is being looked upon as an excellent strategy for increasing productivity per unit area and intensifying land use. Inter-cropping has long been practiced in tropical countries and its popularity all over the world is increasing because of its sound advantages. Cordero and McCollum (1979) reported that land equivalent ratio from 1.2 to 11.4 from inter-cropping maize and soybean. To utilize the land effectively and increase green fodder yield and improve the nutritive worth of sorghum fodder. Its inter-cropping and multiple cropping with legumes seems to have a great promise. It also reduces the chemical fertilizer requirements. With these objectives investigations were carried out to find the best sorghum-legume inter-cropping systems for high fodder yield from legume-cereal mixture.
Materials and Methods
The experiment was conducted at Faculty of Agriculture, Gomal University, D.I.Khan during 1993. The experiment was laid out in split plot design with four replication. The sub-plot size 3.20×6 m2. The sorghum variety "Giza-3" and local varieties of guara and cowpea were studied. The date of harvesting were the main plots, whereas the sole/inter-crops were arranged in the sub-plot. The dates of harvesting were as under:
| D1 | 23-07-93 |
| D2 | 06-08-93 |
| D3 | 22-08-93 |
| D4 | 03-09-93 |
| D5 | 17-09-93 |
| D6 | 02-10-93 |
The sole/inter-crops included in the trial were as under:
| T1 | Sole sorghum single row |
| T2 | Sole sorghum two row strips |
| T3 | Sorghum two row strips + guara one row |
| T4 | Sorghum two row strips + guara two rows |
| T5 | Sorghum two row strips + guara three rows |
| T6 | Sorghum two row strips + cowpea one row |
| T7 | Sorghum two row strips + cowpea two rows |
| T8 | Sorghum two row strips + cowpea three rows |
| T9 | Sole guara |
| T10 | Sole cowpea |
Conventional planting in rows 40 cm apart as control was maintained for inter-cropping, sorghum was sown in 2-rows strips 20 cm apart with gapes of 60 cm between strips (20/20 cm) for fodder. The usual seed rate of sorghum (25 kg/ha) for fodder was used. The recommended seed rate of guara, cowpeas was used for sole and as well as for inter-crops. Total number of rows in each sole plot of guara, cowpea were 8 and row to row distance was 40 cm. A basal dose of 50 kg P205 and 70 kg nitrogen/ha was applied. Half of nitrogen was mixed with soil before sowing and remaining half was applied at first irrigation. The data was analysed by using analysis of variance technique and Duncan’s multiple range test at 5 and 1 percent level of significance to test the treatments differences (Steel and Torrie, 1980).
Results and Discussion
Total fodder production efficiency: The results showed that total fodder yield of sorghum+ inter-crops were significantly influenced by inter-cropping systems dates and their interaction (Table 1). The 2-row sorghum+3-row cowpea produced higher total fodder yield as compared to other treatments. Among the dates of harvesting, the last harvest produced higher yield. While the maximum fodder yield was produced by T8 on 17-9-93. The differences in the total fodder yield might be attributed to variable degree of competition between the component crops grown in association with each other by Waghmaref and Singh (1984), Gabra and Sherif (1985), Bhagat et al. (1986), Shahani (1990), Rout et al. (1990) and Salim (1992).
Land equivalent ratio: The land equivalent ratio was significantly influenced by different inter-cropping as well as their interaction with dates (Table 2). It is evident from the table that LER for different inter-cropping systems and planting patterns ranged between 1.70 to 1.89.
| Table 1: | Total fodder production at 15 days interval |
| Table 2: | Land equivalent ratio of fodder based legume at 15 days interval |
| Means followed by different letter(s) in each column are significantly different according to Duncan’s multiple range test | |
This indicates that there were 70 to 89 percent yield advantage from different inter-cropping treatments sorghum+3-row cowpea recorded the highest LER of 1.89. This might be due to beneficial behaviour of crops and less competition of both crops for nutrients, light and moisture (Babu et al., 1988; Menezes, 1988; Conniff, 1989; Tripathi, 1989; Rout et al., 1990).