Abstract: A field study pertaining to different intertillage practices on maize was conducted in spring 1998. Different intertillage practices comprised of no intertillage + no earthing-up, no intertillage + earthing-up, intertillage twice with Tarphali + no earthing up, intertillage twice with Tarphali + earthing-up, manual weeding + no earthing up, intertillage twice with spade + earthing-up. The significant maximum grain yield (4.3 t ha–1) of maize and net income (Rs. 27713) was obtained by intertillage twice with spade and earthing-up as against the minimum grain yield (3.02 t ha–1) with net income of Rs. 20385/ha in case of no intertillage + no earthing up treatment.
Introduction
Although soil and climatic conditions of Pakistan are ideal for maize production, yet its productivity per hectare is very low as compared to other maize growing countries of the world. The major constraints of low productivity are malnutrition, poor agronomic practices etc. Among the intertillage practices, earthing up is of great value as it helps in making efficient use of irrigation water, minimizing lodging of the crop and extensive development of root system (Chaudhry, 1983). By contrast intertillage promotes soil tilth, controls weed infestation, and improves water conservation ability and air circulation of the soil (Khan, 1994). Sakhunkhu (1985) pointed out that different tillage practices did not affect markedly, plant height, plant population per unit area and grain yield of maize, while better yield of sugarcane was also observed by deep tillage (Hussain, 1997). In an other experiment earthing-up in maize proved superior to maize crop grown without earthing-up operation (Prasad et al., 1988).
Keeping all this in view the present study was designed to determine the effect of different intertillage practices on growth and yield of spring maize cultivar 'Golden' under irrigated conditions of Faisalabad.
Materials and Methods
The study pertaining to different intertillage practices on growth and yield of maize was conducted at the Agronomic Research Area, University of Agriculture, Faisalabad during Spring 1998. Replicated three times the experiment was laid out in Randomized Complete Block Design with a net plot size of 3.60×10.00 m. Different intertillage practices comprised of no intertillage + no earthing-up, no intertillage + earthing-up, intertillage twice with Tarphali + no earthing up, intertillage twice with Tarphali + earthing-up, manual weeding + no earthing-up, intertillage twice with spade + earthing-up. the crop was sown on a well prepared seed bed with the help of single row hand drill in the pattern of 90 cm apart double row strips on March 7, 1998. Fertilizer was applied at 150, 100-100 kg NPK ha–1. All phosphorus and potash and 1/3 nitrogen was applied at sowing, while the remaining N was applied in two equal splits with 1st irrigation and at tasseling stage. The crop was harvested on June 6, 1998. First intertillage with Tarphali and spade was done on March 24 and second one on March 30. While earthing-up was done on April 15 in the respective treatments. However, manual weeding with sickle was done on March 28, 1998. Observations like number of plants m–2, plant height at harvest, cobs per plant, grains per cob, 1000-grain weight and grain yield were recorded. The data collected were analysed statistically using Fisher's analysis of variance technique and Least Significant Differences test at 5% level of probability was applied to compare the treatment means (Steel and Torrie, 1984).
Results and Discussion
The data presented in Table 1 revealed that number of plants m–2 was not affected significantly by different intertillage practices. The non-significant difference among the treatment means attributed to maintaining a uniform interplant spacing in each treatment at the time of thinning. These results are in accordance with those of Sakhunkhu (1985).
Plant height at harvest was affected significantly by different intertillage practices (Table 1). The maximum plant height of 195.66 cm was recorded in treatment T6 (intertillage twice with spade + earthing up) followed by T4, T3 and T2, respectively. These treatments, however, did not differ significantly from one another but were superior to T1 (no intertillage + no earthing up). The maximum plant height in T6 was due to better condition available for plant growth and development. These results are in accordance with those reported by Nizami and Shafiq (1988) and Prasad et al. (1988).
Number of cobs plant–1 were significantly affected by the intertillage practices (Table 1). Maximum number of cobs per plant (1.50) was recorded in plots intercultured twice with spade + earthing up. The minimum number of cobs (1.03) were found in case of control treatment. However, T3 and T4, exhibited statistically similar number of cobs plant–1. These results are in accordance with those of Prasad et al. (1988) and Rafiq (1989).
Number of grains per cob was also affected significantly by different tillage practices. The maximum number of grains cob–1 (306.17) was achieved from the plots with intertillage manually + earthing up (T6) and was at par with T3, T4 and T. On the other hand the crop grown without any intertillage (T1) produced the minimum number of grains cob–1 (259.20). However, the difference between T1, and T2 was found nonsignificant. The lesser number of grains per cob was attributed due to poor growth and development of the plants in control treatment as a result of more weeds infestation. These results support the finding of Prasad et al. (1988) and Rafiq (1989).
The maximum 1000-grain weight (183.00 g) was recorded in T6 (intertillage twice with spade + earthing up) closely followed by T4 (intertillage twice with Tarphali + earthing up)producing 1000-grain weight of 182.9 g.
| Table 1: | Growth, yield and yield components of maize as affected by different intertillage practices |
| NS = Non-significant (1) = Any treatment means not sharing a letter differ significantly at 5% level of probability (LSD) | |
| Table 2: | Economic analysis of different intertillage practices in spring maize |
| Table 3: | Marginal analysis |
On the other handmanual weeding + no earthing up (T6) produced significantly heavier grains than control treatment but was on a par with T3 and T4 treatments. The higher 1000-grain weight in T6 and T4was due to better use of irrigation water, less weed infestation, better use of nutrients etc. These results are supported by the findings of Nizami and Shafiq (1988) and Prasad et al. (1988), it is clear from Table 1 that difference in grain yield of maize among some of intertillage treatments was also significant. Maize crop given intertillage twice with spade+earthing upproduced significantly higher grain yield (4.39 t ha–1) thanrest of treatments except T4 producing 1000-grain weight of182.9 g. On the other hand manual weeding+ no earthing (T5) produced significantly heavier grains than control treatment but was on a par with and T3 and T4 treatments. The higher 1000-grain weight in T6 and T4 was due to better use ofirrigation water, less weed infestation, better use of nutrientsetc. These results are supported by the findings of Nizami and Shafiq (1988) and Prasad et al. (1988). It is clear from Table 1 that difference in grain yield of maize among some of intertillage treatments was also significant. Maize crop given intertillage twice with spade + earthing up produced significantly higher grain yield (4.39 t ha–1) than rest of treatments except T4 (intertillage twice with Tarphali+earthing up) which s howed a grain yield of 4.14 t ha–1. The control treatment (T1) being statistically at par with T2, produced the minimum grain yield (3.02 t ha–1). The higher grain yield recorded in intertillage with spade/Tarphali+earthing up treatments was attributed to higher number of grains cob–1 and heavier grain weight than control treatment. Increase in seed yield of maize because of tillage practices was also reported by Rafiq (1989) and Adil et al. (1995).
The physiological efficiency of a maize plant to convert the total dry matter into economic yield is reflected by its harvest index (H.I.). Different intertillage practices significantly differed with respect to HI value. The maximum harvest index (35.82%) was recorded in intertillage twice with Tarphali+earthing up (T4) which was on a par with T3 and T4 treatments. The minimum harvest index (29.97%) was recorded in control treatment. Increase in harvest index with deep tillage was also reported by Nizami and Shafiq (1988). Keeping in view the overall performance of the maize crop as influenced by different intertillage practices, it is concluded that intertillage twice with spade or Tarphali + earthing up appeared to be a better practice for obtaining good grain yield of spring maize.
Economic analysis: The economic analysis togethr with all relevant calculations are given in Table 2 and 3. Perusal of the table indicated that all the intertillage treatments exhibited the higher net income per hectare than control treatment (T1). Interculture twice with spade+earthin up had the highest net benefits of Rs. 27713 ha–1 however, marginal rate of return was only 35.8% while inter-tillage twice with Tarphali+earthing up had net benefits of Rs. -27025 ha and marginal rate of return 222% (Table 3). These results revealed that intertillage twice with spade+earthing up and intertillage twice with Tarphali+earthing up are economical treatments than other treatments at existing prices and labour wages. Almost similar results were reported by Hussain (1997) in case of sugarcae cultivation.