Soil Hydrothermal Regimes, Biological Activity and Nutrient Availability under Various Mulches and Weed Management Practices in Tomato

Abstract

The impact of different mulching materials and weed management practices on soil properties were evaluated by a field study conducted at College of Horticulture, Rajendranagar during 2015 with tomato as test crop. The experiment was laid out in randomized block design with seven treatments consisting of control (unweeded check), pendimethalin (PE) @1.0 kg a.i. ha-1 + hand weeding at 30 DAT, black polythene mulch, reflective polythene mulch, paddy straw mulch,  paddy husk mulch, hand weeding two times (20 DAT & 40 DAT) and replicated thrice. The mean temperature was higher by 1.7°C under black polythene mulch compared to control (bare soil) and it was less by 1.8 °C under paddy straw mulch. Soil moisture content under black polythene mulch was significantly higher by 31.21%, 36.07% and 24.19% respectively at 20, 40 DAT and at harvest.  In the initial stages i.e., at 20 DAT, reflective polythene mulch (28.81%) and paddy husk mulch (24.52%) were also equally effective in maintaining soil moisture on par to that of black polythene mulch. Significantly highest dehydrogenase activity (8.62 and 6.17 μg of TPF released g-1day-1 respectively), acid phosphatase activity (121.81 and 92.15 μg of PNP released g-1hr-1 respectively) and alkaline phosphatase activity (135.19 and 106.10 μg of PNP released g-1hr-1 respectively) were recorded under paddy straw mulch at 40 days after transplanting and after harvest. Similarly, significantly highest bacterial count (7.49 log10 CFU g soil-1 and 7.34 log10 CFU g soil-1), fungal count (4.53 log10 CFU g soil-1 and 4.36 log10 CFU g soil-1) and actinomycetes count (5.42 log10 CFU g soil-1 and 5.26 log10 CFU g soil-1) at 40 DAT and after harvest respectively were high under paddy straw mulch. Availability of nitrogen and phosphorus was high under reflective polythene mulch while that of potassium under straw mulch. Weed management either through pre-emergence application of pendimethalin @1.0 kg a.i. ha-1 + hand weeding at 30 DAT or by hand weeding two times (20 DAT & 40 DAT) did not influence the soil properties significantly.