Response of irrigated tomato (Solanum lycopersicum Mill) to mulch application rates

The rapid decline in available water for crop production has led to the adoption of irrigation schedules for the management of available water resources. However, the loss of water soil and extreme global warming conditions often result in water stress conditions between the schedules. Thus the application of mulch for the conservation of soil moisture in irrigated farming is fast which is becoming popular among smallholder farmers in most tropical environments. In this study, a two-year greenhouse experiment was conducted to evaluate the effect of Pennisetum purpureum(Pp) mulch on tomato which is grown in daily irrigation.

Food and agriculture production are key indices of a nation's growth and development. Though great achievements in agriculture have been attained around the world...continuing growth in the human population will always necessitate an increase in competition for water among various users to meet the rising demand for food. Consequently, an increase in water demand over limited resources has led to the continued decline in water resources has led to the continuous decline in water resources for agriculture production. And that's the reason behind an urgent need for water management in agricultural production. And this could depend upon the desired frequency of irrigation per crop type, crop variety, and also environment.

On other hand, mulch application is a practice that could enhance irrigation water management and soil moisture content, with a consequent effect on plant growth. Mulching has been reported to play an important role in irrigation water management and also in crop production.

• The study was conducted in 2015 (Year 1) 
• 2016 (Year 2) in the greenhouse (Latitude 07° 27ʹ 06.4ʹʹ N and Longitude 03° 53ʹ 46.1ʹʹ E) of the Department of Soil Resources Management, University of Ibadan, Nigeria.
• The average minimum and maximum temperature of the greenhouse during the study were 20℃ and 30℃, respectively.
• The soil used for the study was obtained from the Teaching and Research Farm, University of Ibadan, Nigeria. The farm has been used for maize and vegetable cultivation for several decades. The soil is an Alfisol classified as Typic kandiustalf, It was locally classified as the Ibadan series (Smyth and Montgomery, 1962). Soil samples were randomly collected at 0-30 cm and homogenized before being taken to the laboratory for routine analyses using standard procedures.
• The baseline chemical properties and particle size distribution of the soil are presented in Table 1. The soil organic carbon was 46.6 g k-1 and 45.2 g k-1 in years 1 and 2 respectively, while corresponding values for total nitrogen were 0.6 g k-1 and 0.5 g kg-1, respectively. The soil pH was acidic in both years of the study but higher in year 1 than in year 2. The textural class of the soil was loamy sand as shown by its high sand content.

Result(effect):

The effects of irrigation frequencies and mulch application rates on tomato stem diameter in years 1 and 2 are illustrated. Stem diameter only differed significantly among the irrigation frequencies at 6 WAT. Results showed that peak values at 9 WAT were statistically similar, but lower by 1.4% in IF3 and IF5 relative to IFdaily in year 1, In year 2, stem diameter only differed significantly among the irrigation frequencies at 9 WAT and was lower in IF3 and IF5 by 2.8% and 4.9% compared with daily, respectively. Among mulch rates, stem diameter differed significantly and was in the order of Pp4 > Pp3 > Pp2 > Pp1 > Pp0 in years 1 and 2, respectively...

Conclusion:

The growth and yield of tomatoes were significantly affected by irrigation frequency across mulch application of rates. While the reduction in irrigation frequency reduced fresh fruit weight tomato, with the 5days of irrigation interval causing a substantial decrease in tomato yield, the 3-day irrigation interval which was comparable to daily irrigation in the production of yield.

 Furthermore, there was a marked improvement in tomato yield following mulch application, and the application of Pp3 appeared promising in improving tomato yield over the two years. In general, the contributions in irrigation and mulch combination to improving tomato yield exceeded those of their application, and IF3+Pp4 was not substantially different from IFdaily+Pp4, which was superior in yield production. That's why IF3+Pp4 appears most effective for irrigation water management and the improvement of tomato yield. Therefore, irrigating tomatoes at 3 days intervals and mulching with Pennisetum purpureum at 4 t ha-1 could provide an additive effect on water management and tomato yield.