RESUMEN
Tillage is the physical manipulation of soil into optimum conditions, which enhance the soil health for better crop productivity. A field investigation was carried out to evaluate conservation agriculture effect on soil nutrient conservation and set up in spilt plot design. Zero tillage (M3) witnessed significantly (P<0.05) greater nitrogen availability (288.17, 251.39 and 239.70 kg ha-1), K2O (229.04, 209.80 and 193.73 kg ha-1) than conventional tillage (M1) at soil depths 0-7.5, 7.5-15 and 15-30 cm, respectively. In green manuring practices, horse gram (C3) recorded OC (0.53, 0.51 and 0.47 %), available sulphur (23.38, 20.61 and 18.10 mg kg-1) followed by sun hemp. The interaction combination of M3C3 recorded highest soil nutrient status. Significantly lowest microbial population were found in M1, was due to faster decomposition organic matter resulted in unfavourable condition for survival. Overall adopting M1 alone (1 Ploughing + 2 harrowing + 1 intercultural operation) adversely affect soil health.
RESUMEN
This study conducted in Kerala, evaluated the role of conservation tillage (zero tillage (ZT), minimum tillage (MT), and conventional tillage (CT)) with five treatment combination of potassium (12 kg/ha, 20 kg/ha, 40 kg/ha) and magnesium sulphate (60 kg/ha and 80 kg/ha) on total DMP, physiology and grain yield of the test variety Anaswara (cowpea). In pot culture study, application of K: MgSO4, 10:80 kg/ha resulted in highest total chlorophyll content. While higher chlorophyll a content was obtained with the levels 20:60 kg/ha, and highest total DMP was recorded with the application at 40:100 kg/ha. Different levels of K and MgSO4 nutrition positively influenced 100 seed weight and grain yield, while there found no significant difference on chlorophyll b content, days to flowering, and grains/pod with any of the treatments imposed. Higher values for test weight and grain yield were recorded with K: MgSO4 40:60 kg/ha. In field experiment, tillage practices failed to produce notable difference in chlorophyll a, chlorophyll b, total chlorophyll contents, chlorophyll a/b ratio, grains per pod and test weight. Early flowering (45 DAS) and highest total DMP up to 75 DAS were recorded under CT. ZT produced highest LAI, while highest grain yield was noted under MT practice (734.5 kg/ha). Nutrient treatments failed to produce significant differences in chlorophyll b and chlorophyll a/b ratio. However, application at 40:80 kg/ha produced highest LAI, and higher content of chlorophyll a and total chlorophyll content (1.34 mg/g). K:MgSO4 applied at 40:60 kg/ha recorded highest grain yield. LAI was recorded highest under ZT with K:MgSO4 at 40:80 kg/ha. MT + K:MgSO4 at 40:60 kg/ha reported highest chlorophyll a/b ratio (4.71). K: MgSO4 applied at 40:60 kg/ha produced highest grain yield (806 kg/ha). In interactions, MT + K: MgSO4 at 40:60 kg/ha registered highest grain yield (914.8 kg/ha). Overall, in terms of grain yield, the test crop responded well to MT with application of K: MgSO4 at 40:60 kg/ha.
RESUMEN
The field experiments were conducted on sandy loam soil at New Delhi, during 2007 and 2008 to investigate the effect of conservation tillage, irrigation regimes (sub-optimal, optimal and supra-optimal water regimes), and integrated nutrient management (INM) practices on soil biological parameters in wheat cultivation. The conservation tillage soils has shown significant (p<0.05) increase in soil respiration (81.1 percent), soil microbial biomass carbon (SMBC) (104 percent) and soil dehydrogenase (DH) (59.2 percent) compared to the conventional tillage soil. Optimum water supply (3-irrigations) enhanced soil respiration over sub-optimum and supra-optimum irrigations by 13.32 percent and 79 percent respectively. Soil dehydrogenase (DH) activity in optimum water regime has also increased by 23.33 percent and 8.18 percent respectively over the other two irrigation regimes. Similarly, SMBC has also increased by 12.14 percent and 27.17 percent respectively in soil with optimum water supply compared to that of sub-optimum and supra-optimum water regime fields. The maximum increase in soil microbial activities is found when sole organic source (50 percent Farm Yard Manure+25 percent biofertilizer+25 percent Green Manure) has been used in combination with the conservation tillage and the optimum water supply. Study demonstrated that microbial activity could be regulated by tillage, water and nitrogen management in the soil in a sustainable manner.