M. Osman

EFFICIENT TILLAGE AND NUTRIENT PRACTICES FOR SUSTAINABLE PEARL MILLET PRODUCTIVITY IN DIFFERENT SOIL AND AGRO-CLIMATIC CONDITIONS

SUMMARY Long-term field experiments were conducted at Agra, Solapur and Hisar from 2000 to 2008 to identify efficient tillage and nutrient management practices and to develop predictive models that would describe the relationship between crop yields and monthly rainfall for rainfed pearl millet grown on arid and semi-arid Inceptisol, Vertisol and Aridisol soils. Nine treatments comprising a factorial combination of three tillage practices, viz., conventional tillage (CT), low tillage + interculture (LT1) and low tillage + herbicide (LT2) and three fertilizer treatments viz., 100% N from an organic source (F1), 50% organic N + 50% inorganic N (F2) and 100% inorganic N (F3) were tested in a split-plot design at the three locations. Studies revealed that tillage and fertilizer treatments, and their interactions, significantly influenced pearl millet grain yields at the three locations. Prediction models describing the relation between grain yield and monthly rainfall indicated that rainfall occurring in June, July and August at Agra; June and July at Solapur; and June and August at Hisar significantly influenced pearl millet grain yield attained by different treatments. The R 2 values of the model ranged from 0.64 to 0.81 at Agra; 0.63 to 0.92 at Solapur, and 0.75 to 0.89 at Hisar. When averaged over all the treatment combinations, mean pearl millet grain yields varied from 1590 to 1744 kg ha −1 at Agra; 1424 to 1786 kg ha −1 at Solapur; and 1675 to 1766 kg ha −1 at Hisar while their corresponding sustainability yield indice (SYI) varied from 35.4 to 42.2%, 19.9 to 45.6% and 64.1 to 68.3%, respectively. At Agra (Inceptisol), CTF3 resulted in significantly higher mean net returns (Rs 11 439 ha −1 ), benefit-cost ratio (2.33), rainwater use efficiency (RWUE) (3.52 kg ha −1 mm −1 ) and the second best SYI (39.9%). At Solapur (Vertisol), the LT1F3 resulted in significantly higher net returns (Rs 12 818 ha −1 ), benefit-cost ratio (3.52), RWUE (3.89 kg ha −1 mm −1 ) and the fourth best SYI (42.6%). At Hisar (Aridisol), the LT1F3 treatment gave higher net returns (Rs 3866 ha −1 ), benefit-cost ratio (1.26), RWUE (5.05 kg ha −1 mm −1 ) and the fourth best SYI (67.8%). These treatment combinations can be recommended for their respective locations to achieve maximum RWUE, productivity and profitability.

Effects of Long-Term Fertilizer Application and Rainfall Distribution on Cotton Productivity, Profitability, and Soil Fertility in a Semi-arid Vertisol

Long-term fertilizer experiments were conducted on cotton (Gossypium hirsutum) for 21 years with eight fertilizer treatments in a fixed site during 1987–2007 to identify an efficient treatment to ensure maximum yield, greater sustainability, monetary returns, rainwater-use efficiency, and soil fertility over years. The results indicated that the yield was significantly influenced by fertilizer treatments in all years except 1987 1988, and 1994. The mean cotton yield ranged from 492 kg ha−1 under the control to 805 kg ha−1 under 25 kg nitrogen (N) [farmyard manure (FYM)] + 25 kg N (urea) + 25 kg phosphorus (P) ha−1. Among the nutrients, soil N buildup was observed with all treatments, whereas application of 25 kg N + 12.5 kg P ha−1 exhibited increase in P status. Interestingly, depletion of potassium (K) was recorded under all the fertilizer treatments as there was no K application in any of the treatments. An increase in soil N and P increased the plant N and P uptake respectively. Using relationships of different variables, principal component (PC) analysis technique was used for assessing the efficiency of treatments. In all the treatments, five PCs were found significant that explained the variability in the data of variables. The PC model of 25 kg N (FYM) + 25 kg N (urea) + 25 kg P ha−1 explained maximum variability of 79.6% compared to other treatments. The treatment-wise PC scores were determined and used in developing yield prediction models and measurement of sustainability yield index (SYI). The SYI ranged from 44.4% in control to 72.7% in 25 kg N (FYM) + 25 kg N (urea) + 25 kg P ha−1, which attained a mean cotton yield of 805 kg ha−1 over years. Application of 25 kg N (FYM) + 25 kg N (urea) + 25 kg P ha−1 was significantly superior in recording maximum rainwater-use efficiency (1.13 kg ha−1 mm−1) and SYI (30.5%). This treatment also gave maximum gross returns of Rs. 30272 ha−1 with benefit–cost ratio of 1.60 and maintained maximum organic carbon and available N, P, and K in soil over years. These findings are extendable to cotton grown under similar soil and agroclimatic conditions in any part of the world.

Statistical Assessment of Sustainability of Finger Millet Yield through Rainfall and Soil Fertility Variables using Regression and Principal Component Models in Rainfed Semi-Arid Alfisol

ABSTRACT Field experiments were conducted in farmyard manure (FYM) and maize-residue (MR) blocks during 1984–2011 with the objective of identifying a superior treatment for attaining maximum finger millet yield and soil fertility at Bangalore. The treatments tested in the FYM block were Control; FYM@10tha−1; FYM@10tha−1 + 50% nitrogen, phosphorus, and potassium (NPK); FYM@10tha−1 + 100%NPK; 100%NPK; and in the MR block, Control; MR@5tha−1; MR@5t ha−1 + 50%NPK; MR@5tha−1 + 100%NPK; 100%NPK. FYM@10t/ha + 100%NPK gave a maximum mean yield of 3207 kg/ha in the FYM block, while MR@5t/ha + 100%NPK gave 2548 kg/ha in the MR block. Regression and principal component (PC) models of yield were developed through soil fertility and rainfall variables to assess the treatments. Maximum yield predictability of 60% and 65% under regression, and 76% and 75% under the PC model were observed for the FYM and MR blocks, respectively. FYM@10t/ha + 50%NPK was superior, with maximum gross returns of Rs.41286/ha and benefit–cost ratio (BCR) of 2.27 in the FYM block compared to MR@5t/ha + 100%NPK (gross returns of Rs.34530/ha and BCR of 2.09) in the MR block with maximum soil fertility, and are recommended for adoption under semi-arid Alfisols.

Clay Mineral Application and its Effect on Establishment and Growth of Custard Apple in Alfisols of Semi-Arid Environment

A study was conducted to assess the effects of clay mineral application @ 0, 1.2, 2.4 and 4.8 kg/pit on different morphological and physiological parameters in custard apple under Alfisols in semi-arid conditions. There was no significant effect of clay mineral on height and spread in both North-South and East-West directions of custard apple trees up to 300 days after planting (DAP); while it had a significant effect at 439 and 704 DAP for height and number of branches; and canopy spread. A similar impact was noticed in case of stomatal conductance and relative water content and canopy temperature at 158 DAP. Height was significantly related with number of branches (439 and 704 DAP); north-south and east-west spread (704 DAP); and girth (704 DAP). Number of branches had a significant relation with north-south and east-west spread (704 DAP); girth (704 DAP). Significant relations of east-west and north-south spread (704 DAP) with girth; stomatal conductance and relative water content at 158 DAP were observed. Height was significantly related with number of branches, while rainfall was related with height and number of branches. Based on regression analysis, the influence of clay minerals on different parameters was assessed. Application of 4.8 kg/pit of clay mineral was found to be efficient in improving height and number of branches of custard apple under Alfisols in semi-arid conditions.

Long-Term Effects of Soil and Nutrient Management Practices on Soil Properties and Additive Soil Quality Indices in SAT Alfisols

A long term experiment was conducted for 11 years to study the effects of soil and nutrient management practices on soil fertility and additive soil quality indices in rainfed Alfisol, at Hyderabad, India. The treatments were comprised of conventional tillage (CT) and minimum tillage (MT) as main factors, sorghum stover (dry) @ 2 t/ha (SS), fresh gliricidia loppings @ 2 t/ha (GL) and no residue (NR) application on surface as sub-treatments and N levels @ 0, 30, 60 and 90 kg N/ha as sub- sub treatments in castor-sorghum yearly rotation. The results indicated that after 11 years, MT significantly improved organic carbon (OC), available N, available K, exchangeable Mg, available S, microbial biomass carbon (MBC), dehydrogenase activity (DHA), labile carbon (LC), bulk density (BD) and mean weight diameter (MWD) of soil aggregates. Application of sorghum residue and gliricidia loppings showed significant increase in OC by 6.28% and 3.7%, respectively over NR. Statistical regression functions indicated that soil parameters viz., MBC, LC, MWD, OC, S, Fe and DHA influenced by long term soil management practices significantly influenced the crop yield. The physical (PSQI), physico-chemical (PCSQI), chemical (CSQI), biological (BSQI) and additive SQIs (ASQI) were significantly influenced by management treatments. On an average, the percent contribution of these component soil quality indices towards ASQI was in the order of BSQI (32.1%) > CSQI (26.1%) > PSQI (25.7%) > PCSQI (16.2%). Crop yields were significantly correlated with these indices and thus emphasized their importance in increasing the productivity in these semi arid Alfisol soils.

Irrigation Requirement of Crops under Changing Climatic Scenarios in a Semi-arid Region of Northern Karnataka

The groundwater status of Vijayapura district is under semi-critical to over-exploited category and optimal application of irrigation water is needed for the sustainable water management in this region. In the present study, the rainfall, temperature, evapotranspiration variability and irrigation requirement of major crops was analyzed for three future scenarios, namely, 2020’s (2010 to 2039), 2050’s (2040 to 2069) and 2080’s (2070 to 2099) with respect to the baseline period (1976-2005). The ENSEMBLE data corresponding to four different emission scenarios was used. Rainfall and temperature are important factors governing the irrigation requirement and the rainfall is predicted to increase from 590 mm during baseline period to 611, 646 and 677 mm under RCP 4.5 (medium emission scenario) and 617, 674 and 742 mm under high emission scenario (RCP 8.5). The maximum temperature is predicted to increase by 0.8, 1.6, 2.00C under RCP 4.5 and 0.9, 2.0, 3.60C under RCP 8.5. The minimum temperature is predicted to increase by 1.0, 1.8, 2.30C under RCP 4.5 and 1.1, 2.5, 4.20C under RCP 8.5 respectively. Correspondingly, the evapotranspiration values (ET0) are estimated to increase from 1851 to 1877, 1900 and 1916 mm under RCP 4.5 and 1876, 1912 and 1958 mm under RCP 8.5. The irrigation requirement of rabi sorghum is predicted to increase from 434 to 440, 447 and 449 mm under RCP 4.5 and 438, 445 and 453 mm under RCP 8.5. Similarly, the irrigation requirement of rabi maize is predicted to increase from 667 to 678, 688 and 694 mm under RCP 4.5 and 679, 694 and 712 mm under RCP 8.5, respectively. No considerable increase in the irrigation requirement for kharif crops was predicted in Vijayapura. In order to ensure long-term and sustainable groundwater utilization in the region, proper estimation of crop water requirement and its application are needed.

Estimation of Soil Loss Under Changing Climatic Scenarios in Semi-Arid Watersheds

Spatial and temporal estimation of soil loss is very essential for the sustainable planning and management of watersheds. In the present study, an attempt was made to estimate the soil loss spatially and temporally using RUSLE from a dry semi-arid watershed (Goparajpalli in Warangal District) and a wet semi-arid watershed (Seethagondi in Adilabad District) under changing climatic scenarios using PRECIS data. In the dry semi-arid watershed, the annual rainfall varied from 390 to 1181 mm with a mean value of 735 mm and a mean erosivity of 6260 MJ mm/ha/h/y. The mean annual rainfall during the base line period (1961–1990), mid (2021–2050) and end centuries (2071–2098) in this watershed were 738, 835 and 777 mm, respectively. The mean erosivity during these periods were 5657, 9253 and 7170 MJ mm/ha/h/y and soil loss from crop land were 2.39, 4.02 and 3.14 t/ha/y, respectively. In the wet semi-arid watershed, the annual rainfall varied from 508 to 1351 mm with a mean value of 950 mm and a mean erosivity of 6789 MJ mm/ha/h/y. The mean annual rainfall during base line, mid and end centuries in this wet semi-arid watershed were 956, 1088 and 1124 mm and erosivities were 10547, 14437 and 14755 MJ mm/ha/h/y, respectively. Similarly, the soil loss from crop land during these periods were 9.18, 13.11 and 14.11 t/ha/y. Even though, the soil loss from the dry semi-arid watershed was relatively lower than the wet semi-arid watershed, it showed an increasing trend in the mid century and a decreasing trend in the end century whereas, in the wet semi-arid watershed, it showed an increasing trend in both mid and end centuries. Considerable spatial variation in the mean annual soil loss was observed in both the wet and dry semi-arid watersheds during base line period, mid and end centuries.

Improving the Productivity of Rainfed Farming Systems of Small and Marginal Farmers in Adilabad District, Telangana

On-farm trials were conducted during 2010 and 2011 to evaluate the effect of different interventions on productivity and profitability of rainfed farming systems of small and marginal farmers in Seethagondhi cluster, Adilabad district. Averaged across six farmers’ fields, the cotton equivalent yield (CEY) of cotton + pigeonpea intercropping was 7.99 q/ha with farmers’ practice. The CEY increased by 17.5% due to herbicide use for weed control, 28.3% with application of recommended NPK, and 35.8% with use of both herbicide and recommended NPK compared to farmers’ practice. Use of herbicide for weed control coupled with application of recommended NPK gave higher net return ( 10,300/ha) compared to other management practices. Among the farming systems of marginal farmers, integrated farming system involving crop production (cotton + pigeonpea intercropping) and livestock rearing (4 bullocks, 3 desi cows and 1 buffalo) gave higher net return ( 40,180/year) compared to other farming systems. Similarly, among the three farming systems of small farmers, integrated farming system involving crop production (cotton + pigeonpea intercropping) and livestock rearing (2 bullocks, 1 desi cow and 40 goats) performed better with a net return of 89,937/year compared to other farming systems.