Soil Chemical Analysis

In recent years conventional production technologies in the rice–wheat (RW) system have been leading to deterioration of soil health and declining farm profitability due to high inputs of water and labour Conservation agriculture (CA)-based resource-conserving technologies (RCTs) vis-a-vis zero-till (ZT), raised-bed planting and direct-seeded rice (DSR) have shown promise as alternatives to conventional production technologies to overcome these problems The integration of CA-based RCTs with precision agriculture (PA)-based technologies in a systems perspective could provide a better option for sustainable RW production systems In this study we attempted to evaluate conservation and precision agriculture (CPA)-based RCTs as a double-ZT system integrated with laser-assisted precision land leveling (PLL) in the RW system A field experiment was conducted in the western IGP for 2 years to evaluate various tillage and crop establishment methods under PLL and traditional land leveling (TLL) practices to improve water productivity, economic profitability and soil physical quality Irrespective of tillage and crop establishment methods (TCE), PLL improved RW system productivity by 74% in year 2 as compared to traditional land leveling Total irrigation water savings under PLL versus TLL were 12–14% in rice and 10–13% in wheat PLL improved RW system profitability by US$113 ha −1 (year 1) to $175 ha −1 (year 2) Yields were higher in conventionally transplanted rice followed by direct-drill-seeded rice after ZT In wheat, yields were higher in ZT when followed by DSR than in the conventional-till (CT) system RW system productivity under double ZT was equivalent to that of the conventional method Among different TCE, conventional puddled-transplanted rice-CT wheat required 12–33% more water than other TCE techniques Compared with CT systems, double ZT consumed 12–20% less water with almost equal system productivity and demonstrated higher water productivity The CT system had higher bulk density and penetration resistance in 10–15 and 15–20 cm soil layers due to compaction caused by the repeated wet tillage in rice The steady-state infiltration rate and soil aggregation (>025 mm) were higher under permanent beds and double ZT and lower in the CT system Under CT, soil aggregation was static across seasons, whereas it improved under double no-till and permanent beds Similarly, mean weight diameter of aggregates was higher under double ZT and permanent beds and increased over time The study reveals that to sustain the RW system, CPA-based RCTs could be more viable options: however, the long-term effects of these alternative technologies need to be studied under varying agro-ecologies

Evaluation of precision land leveling and double zero-till systems in the rice–wheat rotation: Water use, productivity, profitability and soil physical properties

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Laser Land Leveling: A Precursor Technology for Resource Conservation

Effects of reduced nitrogen rate on cotton yield and nitrogen use efficiency as mediated by application mode or plant density

Stagnating yield and declining input use efficiency in irrigated wheat of the Indo-Gangetic Plain (IGP) coupled with diminishing availability of water for agriculture is a major concern of food security in South Asia. The objective of our study was to establish an understanding of how wheat yield and input use efficiency can be improved and how land leveling and crop establishment practices can be modified to be more efficient in water use through layering of precisionconservation crop management techniques. The “precision land leveling with raised bed” planting can be used to improve crop yield, water and nutrient use efficiency over the existing “traditional land leveling with flat” planting practices. We conducted a field experiment during 2002-2004 at Modipuram, India to quantify the benefits of alternate land leveling (precision land leveling) and crop establishment (furrow irrigated raised bed planting) techniques alone or in combination (layering precision-conservation) in terms of crop yield, water savings, and nutrient use efficiency of wheat production in IGP. The wheat yield was about 16.6% higher with nearly 50% less irrigation water with layering precision land leveling and raised bed planting compared to traditional practices (traditional land leveling with flat planting). The agronomic (AE) and uptake efficiency (UE) of N, P and K were significantly improved under precision land leveling with raised bed planting technique compared to other practices.

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Layering precision land leveling and furrow irrigated raised bed planting: Productivity and input use efficiency of irrigated bread wheat in indo-gangetic plains

High irrigation efficiencies may be achieved if water is delivered uniformly across the field. Topography index (TI) was used to asseSs the smoothness of the land surface of the selected farmers fields of village Masauta, district Ghaziabad, U.P. during 2002–03. No direct relationship was found between TI and field size, however, earthwork requirement per unit area, for laser leveling was found increasing with increasing field sizes (least for small farmers, and highest in case of large farmers). Application, storage and distribution efficiencies showed a decreasing trend with increasing values of TI. Laser leveling improved all the three efficiencies (application, storage and distribution) in all the cases; however, the percent enhancement of irrigation efficiencies was found to be higher at higher values of TI. After laser leveling, application, storage and distribution efficiencies increased from 58.85 to 64.4%, 50.6% to 69.5% and 70.3% to 81.5% in the field having TI of 5.8 cm whereas these increased from 32.2% to 67.15%,30.0% to 66.7% and 38.9% to 78.5% in the field with TI of 26 cm, respectively. Laser leveling increased wheat yields, the increase in yield was however more significant in fields with high TI values, before leveling. (14.6% increase from the field having TI as 5.8 cm but 32.2% increase in case of the field haVing TI of 26 cm).

Laser Leveling - A tool to increase irrigation efficiency at field level

Venturi injector is a commonly used device for fertilizer application through drip irrigation. The injection rate of a venturi injector mainly depends upon the suction created due to the difference between its upstream and downstream pressures. A commercially available venturi was evaluated for injection rate under the range of operating pressures from 1.0 to 2.0 kg.cm−2 using normal irrigation water and fertilizer solution. Maximum injection rate of the venturi with irrigation water was 106.4 l.h−1 at operating pressure of 2.0 kg.cm−2. Maximum injection rate (105.8 l.h−1), when urea fertilizer dissolved in irrigation water in the ratio of 0.25:1 (urea: water) was at the upstream and downstream pressure of 2.0 kg.cm−2 and 0.1 kg.cm−2, respectively. However, for muriate of potash (MOP) dissolved in irrigation water in the ratio of 1:1 (MOP: water), minimum injection rate of venturi was 1.44 l.h−1 at upstream pressure of 1.6 kg.cm−2 and downstream pressure of 0.5 kg.cm−2. Injection rate was observed to be inversely proportional to the concentration of the fertilizer solution. However, it was directly proportional to the pressure gradient i.e. decrease in pressure gradient across the venturi decreased the injection rate.

Effect of System Pressure and Solute Concentration on Fertilizer Injection Rate of a Venturi for Fertigation

Generation of wastewater in huge amounts is putting a lot of pressure on irrigation engineers for its safe disposal or reuse in agriculture. Though wastewater could contribute to major and minor nutritional requirement of crops, but the presence of microbial contaminants and toxic elements limits its use. Utilization of wastewater for irrigation through drip irrigation system seems to be a good choice to reduce the chances of contamination due to restricted quantity of water application. Since clogging in such a situation would be the main problem, its remediation is required for enhanced utilization of wastewater through drip irrigation system. Physical and chemical characteristics of wastewater were determined and compared with ground water. While higher EC, pH, Mg, and carbonate were observed in ground water, wastewater contained higher turbidity, total solids, HCO3, and Ca. Population of total coliforms (2.72x104 to 5.2x107) and E. coli. (1.8x103 to 2.64x106) were detected in wastewater. The hydraulic performance of drip emitters was studied for two years (2009 and 2010) with municipal wastewater and ground water using gravel media (F1), disk filter (F2) and combination of gravel and disk filters (F3). Filtration using F3 gave emitter discharge exponent close to 0.5 with R2 value of 0.99. Emitter flow rate decreased with increase in time of operation of the system. Coefficient of variation less than 4% with wastewater and ground water showed excellent performance in surface placed drip lateral after two years of operation. After filtration with F3, coefficient of variation (CVq) of 4.0% with wastewater and 6.46% with ground water was observed under subsurface (15 cm deep) placement of laterals.

Hydraulic Performance of Drip Irrigation System with Municipal Wastewater

A field experiment was conducted during 3-winter seasons of 2001-2002 through 2003-2004 to study the effect of fertigation daily, alternate day, weekly and monthly on an Indo-American hybrid 'Creole Red' of onion (Allium cepa L.) crop and NO 3 -N of soil. Analysis of soil samples indicated considerable influence of fertigation frequency on NO 3 -N distribution in soil profile. The NO 3 -N in lower soil profiles (30-60 cm soil depth) was marginally affected in daily, alternate day and weekly fertigation 41.9, 42.0, 43.6 ppm, respectively. However, fluctuations of NO 3 -N concentration in 0-15 cm, 15.0-30 cm, 30-45 cm and 45-60 cm soil depth was more in monthly fertigation frequency. After the crop season 29.85% NO 3 -N was leached through the profile in monthly fertigation. Daily, alternate day and weekly fertigation did not significantly affect yield of onion, 29.2 tonnes/ha, 28.0 tonnes/ha, 27.4 tonnes/ha respectively. The highest yield was recorded in daily fertigation (29.2 tonnes/ha) followed by alternate day fertigation (28 tonnes/ha) while the lowest in monthly fertigation (22.4 tonnes/ha). Application of 57.7 cm irrigation water and 3.4 kg/ha urea in daily fertigation resulted in maximum yield of onion (29.2 tonnes/ha) with least amount of leaching of NO 3 -N (23%).

Effect of fertigation frequency on onion (Allium cepa) yield and soil nitrate-nitrogen

Hydrus–2D model was selected for simulation and modeling of soil water under subsurface drip system in ‘Kufri Anand’ potato (Solanum tuberosum L.) crops grown during winter (rabi) season 2002–03 through 2004–05. Potato was sown at a depth of 15 cm in the raised ridges prepared during the third week of October at ridge spacing of 30 cm×60 cm, respectively. The study consisted of three different irrigation levels of 60, 80 and 100% of the crop evapotranspiration (ie 0.6V, 0.8V and 1.0V) and five depths of placement of drip tapes including one at the surface and the others at 5, 10, 15 and 20 cm soil depths. Drip tape of 0.3 mm thickness was buried manually at different depths. It was observed that by changing the position of water source from surface to subsurface, the wetted width was increased by 25–50%. Maximum potato yield of 33.3 tonnes/ha was recorded at 10 cm depth of drip tape at 100% of the crop evapotranspiration.

T. B. S. Rajput

Papers

Laser Leveling - A tool to increase irrigation efficiency at field level

Effect of System Pressure and Solute Concentration on Fertilizer Injection Rate of a Venturi for Fertigation

Hydraulic Performance of Drip Irrigation System with Municipal Wastewater

Effect of fertigation frequency on onion (Allium cepa) yield and soil nitrate-nitrogen

Simulation and modeling of water movement in potato (Solanum tuberosum)