Residual Soil Moisture Research Articles

Tillage and Nitrogen Rate Effects on Corn Production and Residual Soil Characteristics

Core Ideas Strip tillage had relative production advantage over other tillage practices in corn production. Strip tillage showed greater water use efficiency than conventional tillage. No‐tillage showed higher residual carryover soil moisture, NO3–N and total N. ABSTRACTSuccessful corn (Zea mays L.) production in semiarid and arid southwestern United States is limited by available resources, especially water and N, and management of such limited resources need efficient on‐farm tillage and N management decisions. A 3‐yr study was conducted at New Mexico State University Agricultural Science Center, Tucumcari, NM, to evaluate the effectiveness of three tillage strategies (conventional, strip, and no‐tillage) and two N rates (196 and 308 kg ha−1) on corn yield, water use, and carry‐over residual water and N characteristics. Tillage × N‐rate interaction had no significant impact on corn yield, water use, and residual soil characteristics (P > 0.05). No‐tillage showed consistent lower grain and stover yield in all three years. Strip tillage (ST) had a relative grain yield advantage over other tillage practices in 2 out of 3 yrs. Strip tillage showed higher harvesting index and greater water use efficiency (WUE) than conventional tillage (CT). No‐tillage (NT) had 20 to 45% greater residual carry‐over soil moisture than CT during the 3‐yr study period. Percent change (draw‐down) in soil profile moisture and NO3–N in each site‐year were higher in CT than other tillage treatments at both 0 to 30 and 30‐ to 60‐cm depth increments. No‐tillage resulted in higher residual carry‐over NO3–N and total N at both incremental depths in each tested year, without exception. Overall, implementation of ST in the semiarid regions has significant advantage over other tillage practices in improving the resource use efficiency in corn production.

Soil Moisture Monitoring Using Remote Sensing Data and a Stepwise-Cluster Prediction Model: The Case of Upper Blue Nile Basin, Ethiopia

In this study, a residual soil moisture prediction model was developed using the stepwise cluster analysis (SCA) and model prediction approach in the Upper Blue Nile basin. The SCA has the advantage of capturing the nonlinear relationships between remote sensing variables and volumetric soil moisture. The principle of SCA is to generate a set of prediction cluster trees based on a series of cutting and merging process according to a given statistical criterion. The proposed model incorporates the combinations of dual-polarized Sentinel-1 SAR data, normalized difference vegetation index (NDVI), and digital elevation model as input parameters. In this regard, two separate stepwise cluster models were developed using volumetric soil moisture obtained from automatic weather stations (AWS) and Noah model simulation as response variables. The performance of the SCA models have been verified for different significance levels (i.e., α = 0.01 , α = 0.05 , and α = 0.1 ). Thus, the AWS based SCA model with α = 0.05 was found to be an optimal model for predicting volumetric residual soil moisture, with correlation coefficient (r) values of 0. 95 and 0.87 and root mean square error (RMSE) of 0.032 and 0.097 m3/m3 during the training and testing periods, respectively. While in the case of the Noah SCA model an optimal prediction performance was observed when α value was set to 0.01, with r being 0.93 and 0.87 and RMSE of 0.043 and 0.058 m3/m3 using the training and testing datasets, respectively. In addition, our result indicated that the combined use of Sentinel-SAR data and ancillary remote sensing products such as NDVI could allow for better soil moisture prediction. Compared to the support vector regression (SVR) method, SCA shows better fitting and prediction accuracy of soil moisture. Generally, this study asserts that the SCA can be used as an alternative method for remote sensing based soil moisture predictions.

Development of a steady-state model to predict daily water table depth and root zone soil matric potential of a cranberry field with a subirrigation system

Maintaining a steady water table depth (WTD) to ensure an optimal soil matric potential in the root zone (RMAP) is vital when growing cranberry under a subirrigation system; owing to losses and other hydrological processes. The excessive rising or falling of the WTD may threaten the plant transpiration either by saturation or lack of moisture in the root soil. A steady-state model was developed for a uniform soil column to predict WTD and RMAP under different weather conditions. The model is based on van Genuchten (VG) and Brooks and Corey (BC) analytical soil water retention functions coupled with Mualem, Brooks and Corey, and Gardner hydraulic conductivity models. The results show that the model is capable of predicting satisfactorily both WTD and RMAP. The VG model performed with a 78.13% accuracy for the WTD and an 88.59% precision according to the Kling Gupta Efficiency coefficient (r2 = 0.90, β = 1.00, and γ = 0.99) for the field storage. Meanwhile for the RMAP the Mualem and Gardner hydraulic conductivity models, predictions were successful 71.87% and 75.00% of the time, respectively. The BC model had a 78.13% success for the WTD, 86.93% accuracy in estimating the field water storage according to Kling-Gupta efficiency coefficient (r2 = 0.89, β = 1.00, and γ = 1.00) and the BC and Gardner hydraulic conductivity models had 65.63% and 71.88% success, respectively. A sensitivity analysis of the model, by means of the Morris method, reveals that for both models, the lower boundary condition impacts significantly both variables which are, however, less affected by the field capacity and the residual soil moisture content. The lower boundary condition interacts with the slope of the soil water retention functions, the height of the capillary fringe, the saturated conductivity, and the saturation moisture content which have non-linear effects. An uncertainty analysis shows that both variables for both models are normally distributed.

Integrated breeding approaches for improving drought and heat adaptation in chickpea (Cicer arietinum L.)

AbstractChickpea (Cicer arietinum L.) is a dry season food legume largely grown on residual soil moisture after the rainy season. The crop often experiences moisture stress towards end of the crop season (terminal drought). The crop may also face heat stress at the reproductive stage if sowing is delayed. The breeding approaches for improving adaptation to these stresses include the development of varieties with early maturity and enhanced abiotic stress tolerance. Several varieties with improved drought tolerance have been developed by selecting for grain yield under moisture stress conditions. Similarly, selection for pod set in the crop subjected to heat stress during reproductive stage has helped in the development of heat‐tolerant varieties. A genomic region, called QTL‐hotspot, controlling several drought tolerance‐related traits has been introgressed into several popular cultivars using marker‐assisted backcrossing (MABC), and introgression lines giving significantly higher yield than the popular cultivars have been identified. Multiparent advanced generation intercross (MAGIC) approach has been found promising in enhancing genetic recombination and developing lines with enhanced tolerance to terminal drought and heat stresses.

Longer mesocotyl contributes to quick seedling establishment, improved root anchorage, and early vigor of deep-sown rice

Dry direct seeding of rice (DDSR) is practiced as a technique to address drought in tropical Asia, as it requires less water than transplanting. However, rice has a narrow range of optimal sowing depth, and deep sowing often causes poor seedling emergence. The objective of this study was to elucidate differences among rice cultivars in their tolerance to deep sowing (i.e., the ability to show vigorous seedling emergence from deep soil) and the traits associated with this vigor. Two-year on-farm research in rainfed lowlands showed mean seeding depths of 16.1–35.0 mm (a coefficient of variation of 27%–49%). The deep-sowing tolerance differed significantly among 16 cultivars in research station field experiments. The emergence of seedlings from sowing at a depth of 85 mm was >80% in tolerant cultivars versus <1% in cultivars popular with farmers. Deep-sowing tolerance was attributable primarily to the elongation ability of the mesocotyl and, to a lesser extent, of the 1st internode. In a pot experiment that simulated drought around the time of sowing, seedlings that germinated from deeper soil had greater emergence and greater shoot and root growth than those that emerged from shallow soil, as the deeper seeds could acquire residual soil moisture. Our results suggest that improving the tolerance of rice to deep sowing should stabilize seedling establishment in DDSR. Cultivars that tolerate deep sowing will allow further development of the deep sowing technique and reduce the risk of sowing failure caused by drought during seedling emergence in water-scarce environments.

Impact of High Temperature and Drought Stresses on Chickpea Production

Global climate change has caused severe crop yield losses worldwide and is endangering food security in the future. The impact of climate change on food production is high in Australia and globally. Climate change is projected to have a negative impact on crop production. Chickpea is a cool season legume crop mostly grown on residual soil moisture. High temperature and terminal drought are common in different regions of chickpea production with varying intensities and frequencies. Therefore, stable chickpea production will depend on the release of new cultivars with improved adaptation to major events such as drought and high temperature. Recent progress in chickpea breeding has increased the efficiency of assessing genetic diversity in germplasm collections. This review provides an overview of the integration of new approaches and tools into breeding programs and their impact on the development of stress tolerance in chickpea.

An investigation into a resource and environmentally sustainable system: zero-tillage lentil and garlic production in Nepal

ABSTRACTLentils and garlic are primarily grown under conventional tillage (CT) practice; however, both crops have been fetching lower profits due to the high cost of both cultivation as well as the required inputs. For securing more benefits and using residual soil-moisture, farmers have started the zero-tillage (ZT) practice in a rice-based cropping system. In general, it is imperative to compare these two systems (ZT and CT) to assess their energy consumption, and their broader environmental and financial performance. In this study, we found that the total energy input was reduced by 38% with ZT as compared to CT (3.96 GJ ha–1) for lentil cultivation; in contrast, for garlic, CT’s energy consumption was 11% of that of ZT (113.55 GJ ha–1). Energy output increased by 13% and 4% with ZT, in comparison to CT, for lentil and garlic, respectively. Similarly, ZT reduced CO2e (carbon dioxide-equivalent) emissions by 50% and 98%, as compared to CT, for lentil and garlic cultivation, respectively. The maximum financial benefit was seen to be obtained with ZT: the production cost was reduced by 28% and 33%, as compared to CT practices, for lentil and garlic, respectively. The return-cost ratios from ZT and CT were 3.39 and 2.18 for lentil, and 7.64 and 3.52 for garlic, respectively. We can, therefore, conclude that ZT is an energy-efficient, environment-friendly, and cost-effective practice of lentil and garlic production.

Response of Lentil (Lens culinaries) to Post-rice Residual Soil Moisture Under Contrasting Tillage Practices

Soil moisture stress and excessive soil wetness are the main abiotic factors limiting lentil (Lens culinaries Medik) growth and productivity in the humid tropics. Field experiments were conducted during the post-monsoon to winter seasons (November–March) of 2012–2013 to 2013–2014 on a clay loam soil (Aeric Haplaquept) of Eastern India to cultivate rainfed lentil, utilizing the carry-over soil moisture and residual soil fertility, in rice fallow during post-rainy season. Our objective was to determine the effects of three tillage treatments, viz. No tillage with standing rice stubbles (NT), minimum tillage with standing rice stubbles (MT) and conventional tillage (CT), imposed on post-rice soil conditions, on the root-zone soil moisture storage, actual evapotranspiration (ETa) of lentil, actual time and intensity of crop stress exposed, as well as growth, seed yield, and water use efficiency of lentil. The soil moisture storage within the root-zone was 17.1–18.6 cm for NT and MT and 13.8–14.3 cm for CT during the time of sowing and the values declined to 7.5–10.0 cm during harvesting of lentil. Treatment CT declined > 40% of its readily available water at pod-formation stage. Soil moisture storage depletion from sowing to maturity at 0–40 cm depth was found 4.8, 3.4 and 6.9 cm under NT, MT, and CT, respectively. The leaf relative water content (RWC), chlorophyll concentration, crop growth rate (CGR) and biomass were significantly (P < 0.05) higher in NT and MT than CT. Leaf area, chlorophyll concentration and RWC varied significantly (P < 0.05) at critical crop growth periods under different tillage as compared to soil moisture stress. The ratio of CGR to LAI was 1.5 times more under NT and MT than under CT. The ETa was 11.41, 11.16 and 10.28 cm, respectively, for CT, NT and MT with a mean seed yield of 938, 1292 and 1225 kg ha−1 across both the years. Treatments NT and MT had significantly (P < 0.05) higher water use efficiency producing 35.3 kg ha−1 more seed yield per cm of water as compared with CT. The increase in yield was primarily ascribed to the favourable soil moisture content, which increased the plant growth rate (96% as compared with CT), thereby helping the crop to overcome the terminal drought during the later stages of the growth of lentil. Contrasting tillage practices modified the crop coefficient (Kc) values by altering evaporation and transpiration coefficients with mean Kc values for initial, development, mid-season and maturity stages were 0.32, 0.43, 1.12 and 0.39, respectively, under post-rice residual soil moisture. Our study concluded that when long-duration puddled-transplanted monsoon rice (~ 150 days) was the preceding crop in rice fallow situations, NT and MT are better alternatives to CT for the production of lentil.

Influence of land configuration on rain water use efficiency, yield and economics of cowpea (Vigna unguiculata L.) in maize-cowpea sequence cropping under rainfed condition of Northern Transitional Zone

The main aim of land configurations is in situ conservation of soil moisture by increasing the opportunity time for augmented water use efficiency and drain out excess water. The field study was conducted for two years under rainfed conditions of Dharwad on residual soil moisture and fertility. Cowpea produced higher grain yield (13.4 q ha-1), haulm yield (25.6 q ha-1) and harvest index (34.4 %) with Broad Bed and Furrow (BBF) method of planting. Similarly, BBF method resulted in higher soil moisture content (32.09 % at 40 DAS) and rain water use efficiency (RWUE) of 5.96 kg ha-mm-1. The RWUE had a significant and highly positive correlation with soil moisture at 40 and 55 DAS (with r value of r=0.94** and r=0.96**, respectively). BBF method of planting also registered higher gross return (Rs.42725 ha-1), net return (¹ 27515 ha-1) and benefit-cost ratio (2.82). Cowpea can be grown successfully after summer maize on existing BBF configuration for higher yield and rain water use efficiency.

Effect of No-Till and Raised-Bed Planting on Soil Moisture Conservation and Productivity of Summer Maize (Zea mays) in Eastern Himalayas

Productivity of summer maize (Zea mays) is relatively low in hill ecosystem of north-eastern region (NER) of India due to scanty rainfall, lack of irrigation and low residual soil moisture. Conservation tillage along with suitable land management system can improve the soil moisture regime and performance of maize. Field experiment was conducted for 2 years (2012 and 2013) with six combinations of tillage and land configuration practices, viz. CT–FB: conventional tillage (CT) with flatbed planting (FB), CT–RF: CT with ridge and furrow planting (RF), CT–RB: CT with raised-bed planting (RB), NT–FB: no-till (NT) with FB, NT–RF: NT with RF and NT–RB: NT with RB. Results revealed that significantly higher soil moisture content (22.8–23.4% and 21.0–25.3%) was found in NT–RB system as compared those under CT–FB (19.0–19.4% and 17.0–21.2%) at 0–60 cm soil depth in both years 2012 and 2013, respectively, at all the period of moisture estimation. The NT–RB system being on a par with NT–RF recorded significantly higher root length, rooting density, leaf area index and biomass accumulation as compared to other treatments. The average (2 years) maximum number of cobs ha−1 (63,518 cobs per plant), cob weight (272 g per cob), green cob (11.2 M ha−1) and fodder yield (50.5 Mg ha−1) were also recorded under NT–RB system. So, it is recommended to grow summer maize under NT–RB system for higher soil moisture conservation, improved plant growth and subsequently good fodder and green cob yield in the hills of NER.

Climate change impact on river flow extremes in the Upper Blue Nile River basin

Abstract This paper aims to study climate change impact on the hydrological extremes and projected precipitation extremes in far future (2071–2100) period in the Upper Blue Nile River basin (UBNRB). The changes in precipitation extremes were derived from the most recent AFROCORDEX climate data base projection scenarios compared to the reference period (1971–2000). The climate change impacts on the hydrological extremes were evaluated using three conceptual hydrological models: GR4 J, HBV, and HMETS; and two objective functions: NSE and LogNSE. These hydrological models are calibrated and validated in the periods 1971–2000 and 2001–2010, respectively. The results indicate that the wet/dry spell will significantly decrease/increase due to climate change in some sites of the region, while in others, there is increase/decrease in wet/dry spell but not significantly, respectively. The extreme river flow will be less attenuated and more variable in terms of magnitude, and more irregular in terms of seasonal occurrence than at present. Low flows are projected to increase most prominently for lowland sites, due to the combined effects of projected decreases in Belg and Bega precipitation, and projected increases in evapotranspiration that will reduce residual soil moisture in Bega and Belg seasons.

Growth, yield attributes and yield of irrigated spring wheat as influenced by sowing depth

Abstract In South Asia, including Bangladesh, most farmers sow wheat under residual soil moisture after rice is harvested, but the upper layer of soil dries quickly after soil has been prepared for wheat sowing. Crop seeds that are sown either deeply or shallowly can result in failed emergence, low dry matter accumulation, and reduced grain yield. Therefore, appropriate sowing depth is crucial for seedling emergence and successful crop establishment. Considering this, a two-year field experiment was conducted at the research field of the Agricultural Research Station of the Bangladesh Agricultural Research Institute at Dinajpur during the dry, rabi (winter) season of 2013-14 and 2014-15, at four sowing depths, i.e., 2, 4, 6 and 8 cm, to identify the most appropriate sowing depth for higher grain yield. Wheat seeds sown at a depth of 4 cm resulted in significantly highest number of seedlings and seminal roots, tallest plants as well as largest roots and plant biomass followed by sowing at a depth of 6, or 2 cm. Depth of sowing also significantly affected the yield and yield-related attributes, all performing best at a depth of 4 cm. The highest number of spikes m-2, grain yield, straw yield and harvest index were observed when seeds were sown at depths of 4 or 6 cm, relative to 2 or 8 cm. Therefore, a sowing depth of 4 to 6 cm is recommended for wheat cultivation in South Asia, including Northern Bangladesh.

Tillage and cropping sequence effect on physico-chemical and biological properties of soil in Eastern Himalayas, India

Poor soil quality and low fertility are major limitations to agricultural intensification and increasing crop productivity under rainfed hill ecosystems of North Eastern Region (NER) of India. Intensive tillage and adoption of mono-cropping of rice (Oryza sativa L.) or maize (Zea mays L.) leads to depletion of soil fertility and crop productivity. A three year field experiment (2007–2010) was conducted at mid altitude of Meghalaya, India with eight cropping sequences [maize-rapeseed (Brassica campestris L. var. toria.), maize-pea (Pisum sativum L.), rice (Oryza sativa L.)- rapeseed, rice-pea, ricebean (Vigna umbellate Thunb.)-rapeseed, ricebean-pea, soybean (Glycine max L. Merr) – rapeseed and soybean-pea] under two tillage systems; conservation tillage (CST) and conventional tillage (CT). The objectives were to assess impact of tillage and cropping sequence(s) on soil quality and fertility after three years of the experiment. Soil moisture content and infiltration rate were significantly improved under CST relative to those under CT. The soil organic carbon (SOC) concentration was significantly higher under CST (23 g/kg) relative to that under CT (21.2 g/kg) at 0–15 cm soil depth. Available nitrogen (N), phosphorous and potassium, soil microbial biomass carbon (SMBC) and dehydrogenase activity (DHA) were also significantly higher in CST than those under CT. The cropping sequences did not affect the bulk density (ρb) and SOC significantly. However, available N, SMBC and DHA concentration were significantly higher under soybean-pea and soybean-rapeseed sequences as compared to others. During 2009–10, where rainfall received during the winter season was negligible, 4–70% higher yields of winter crops were observed under CST than those under CT. Thus, adoption of CST and soybean based cropping sequences offers an alternative to raise crops during the winter season on residual soil moisture and improve soil quality in eastern Himalayas.

Agroecological integration of shade- and drought-tolerant food/feed crops for year-round productivity in banana-based systems under rain-fed conditions in Central Africa

Yield gaps in banana-based production systems have increased in the past two decades due to declining soil fertility, drought and biotic stresses. Sustainable, environmentally sound and economically viable strategies for intensification in these systems are urgently needed. Agroecological practices, such as the integration of shade- and drought-tolerant crops, nitrogen-fixing and cover crops could potentially improve soil fertility and moisture retention, reduce the weed burden, narrow yield gaps and increase overall plot/farm productivity in these systems. In Malaysia, leguminous crops like Pueraria phaseoloides, Calopogonium caeruleum and Centrosema pubescens are often cultivated as cover crops (to suppress weeds, and reduce moisture loss and soil erosion) in young rubber and oil palm plantations with low shade levels. Even in mature oil palm plantations with less than 30% light intensity, various shade-tolerant crops are grown, e.g., elephant foot yam, turmeric and arrow root. In humid tropical Africa, Colocasia (taro) and Xanthosoma (cocoyam) are reported to tolerate shade conditions and hence often planted under perennial banana/plantain plantations. Drought tolerance is a less common feature of most annual crops grown in the humid tropics. A few root and tuber crops (e.g., cassava, taro, yam and sweetpotato) remain in the field during the dry season in Central Africa and are then harvested according to household needs. This paper also reports on crops (Mucuna, lablab and chickpea) with potential for integration into banana-based systems during the dry season, if planted during the last month of the rainy season. These crops are reported to use the residual soil moisture content for continued growth during the dry season months. The paper concludes with detailed descriptions (from a literature review) on drought- and shade-tolerance characteristics of various crops which have long been integrated in Central African banana-based cropping systems, crops with a more recent cultivation history and crops with potential for system integration.

Front line demonstration on lentil using improved varieties for increasing productivity under lateritic soil of West Bengal

Front Line Demonstrations (FLD) on lentil using improved varieties WBL-58 and WBL-77 were conducted during winter seasons of the year 2013-14 and 2015-16 respectively in the adopted villages of Rathindra KVK, PSB, Visva-Bharati, Sriniketan, Birbhum to show the higher production potentiality. The demonstrations were carried out in 32 farmers’ fields of 5 ha area and 79 farmers’ fields of 20 ha area during the year 2013-14 and 2015-16 respectively in irrigated medium land situation. The lateritic soils were sandy loam in texture having low in pH (6.0-6.4), O.C (0.39-0.47 %) and available P2O5 (16-19 kg /ha) and medium in N and K content. Lentil seeds @ 30 kg /ha was sown in the month of November after harvesting of short duration paddy. The technology of improved variety viz. WBL-58 and WBL-77 increased the average productivity by 26.5 % and 40.88 % and increased the net return by Rs. 7,900.00 with an improved B:C ratio of 2.71 instead of 2.27 and Rs. 15,240.00 with an improved B:C ratio of 3.74 instead of 2.95 than those of local check variety Asha during the both the years respectively. Beside that soil health and soil nitrogen was also improved along with better nodulation in the demonstration plots. Thus the technology of improved variety of lentil may be accepted economically for better utilization of the residual soil moisture after short duration rainy paddy.

Agro-physical assessment of different pea (Pisum sativum) cultivars in lowland rice (Oryza sativa) fallow under no-till system for enhancing cropping intensity and productivity in mid hills of northeast India

The cropping intensity of North Eastern Region (NER) of India is low (134%) mainly due to non-utilization of fallow lands after harvesting of rainy season rice (Oryza sativa L.). Pea (Pisum sativum L.) is one of the most potential leguminous field crops for crop diversification and enhancing productivity of rice based cropping systems in NER. Thus, a field experiment was conducted during 2012-13 and 2013-14 to evaluate the performance of pea cultivars under no-till (NT) condition after harvest of lowland rice in mid-hills (Umiam, Meghalaya, 950 m above sea level, 25°30’N latitude and 91°51’E longitude) of North East India.Twenty one pea cultivars were tested in rice fallow conditions under NT with the residual soil moisture. Out of 21 genotypes, 11 were pole type (PT) and 10 were dwarf type (DT). Among the cultivars, Arkel (95 days) followed by IPFD 4-6 (129 days) and IPFD 1-01 (130 days) were the most early maturing, and IPF 14 (150 days) and IPF 2-13 (150 days) were the most late maturing genotypes. Among all the cultivars, leaf area index, chlorophyll index, number of nodules/plant and nodule weight/plant were higher in Arkel among PT and IPFD 4-6 among DT cultivars. Among all PT cultivars, the higher seed yield, crude protein and total P content was recorded in Arkel (2.37 t/ha, 23.4% and 0.94%), VL-42 (2.33 t/ha, 23.2% and 0.91%) and MUD P 15 (2.29 t/ha, 22.3% and 0.84%); while among DT cultivars, these values were higher in IPFD 4-6 (2.25 t/ha, 20.7% and 0.75%), IPFD 1-01 (2.23 t/ha, 20.6% and 0.72%) and IPFD 99-13 (2.18 t/ha, 20.1% and 0.69%, respectively) than others. Aphid and rust were the most prominent insect and disease, respectively. Among PT cultivars, IPF 99-26 followed by MUD P 15 and among DT cultivars, Prakash and IPFD 5-10 showed maximum resistance against pea aphid. VL-42 was the most disease resistant variety followed by Arkel among the PT and Vikash followed by IPFD 99-13 among the DT cultivars. Thus, the study revealed the opportunity of pea cultivation in lowland rice fallow with suitable cultivars and appropriate technologies in mid-altitude of Meghalaya.

Farmer knowledge and perception of production constraints in Northwest Cambodia

Upland farming in Northwest Cambodia has developed rapidly over the last 20 years, with limitations to the plough based system now apparent, including soil degradation and reductions in yield and profitability. A survey was conducted in order to prioritise the main constraints to production, to aid in future research planning, and to identify potential beneficial modifications to the current system. Three hundred and ninety one farmers were interviewed regarding their current farming system constraints, knowledge of conservation agriculture and their future plans in the Districts of Samlout in Battambang Province and Sala Krau in Pailin Province. Perceived major problems in the farming system were extreme climate events such as droughts and heavy rain, declining crop yields, and cash flow shortages, particularly in the pre-monsoon period. This is a plough based farming system, yet 66% of farmers had heard of conservation agriculture, and 59% wanted to learn more about conservation agriculture practices. Two thirds of farmers were interested in how to grow crops in the post-monsoon dry season on residual soil moisture. The survey highlighted opportunities for farmer education and adoption of farming system modifications to improve productivity and sustainability of the farming system in Northwest Cambodia, and assist with climate change adaptation.

Evaluating the role of watershed properties in long‐term water balance through a Budyko equation based on two‐stage partitioning of precipitation

AbstractIn this paper, a four‐parameter Budyko equation is derived for mean annual water balance by applying the proportionality relationship to a two‐stage partitioning of precipitation. The four dimensionless parameters include the Horton index (H, defined as the ratio of evaporation to total wetting) and λ (the ratio of initial evaporation to total wetting) for slow runoff, and β (the ratio of initial wetting to total wetting) and γ (the ratio of total wetting to its potential) for fast runoff. The derived four‐parameter equation balances model parsimony and representation of dominant hydrologic processes and provides a framework to disentangle the roles of climate variability, vegetation, soil, and topography on long‐term water balance in gauged watersheds. The four parameters are determined for 165 watersheds by using observations of precipitation, potential evaporation, streamflow, and soil properties. Based on the principal component regression analysis, average time interval between rainfall events, slope, normalized difference vegetation index, and wilting point are identified as the dominant controlling factors on H and λ; saturated hydraulic conductivity and the difference between field capacity and residual soil moisture are identified as the dominant controlling factors on β; and γ is controlled by effective soil water storage capacity, frequency of rainfall events, and climate seasonality. The combination of four‐parameter Budyko equation and the principal component regression equations provides a model to assess the long‐term responses of evaporation and runoff to climate and watershed property changes in ungauged watersheds.

Effect of Front Line Demonstrations of Chickpea Cv. RSG-888 on Farmers’ Field in Rainfed Condition of Rajasthan, India

In the present study performance of chickpea variety (RSG-888) against local check was evaluated through front line demonstrations conducted at farmer’s field during rabi season of 2013, 2014 and 2015. A total of 56 demonstrationswere laid on 9.0 ha in 20 villages across six blocks of Pali district. Sowing was done using residual soil moisture of dry condition from second week October to first week of November every year [1]. Package of practices as developed for the region were strictly followed. Recommended seed rate i.e. 70 kgha-1 against existing farmers’ practices of using 100 kg ha-1 (local check) was broadcasted and nutrients i.e. N, P, and S in the ratio of 20:30:40 kg ha-1 were applied. The variety performed much better compared to local check (Pratap Channa) and an average grain yield of 16.7 q/ha was recorded which was 67.00% more than the local check. Straw yield also recorded an increase of 44.20% over local check. In spite of increase in yield both in grain and straw, technological and extension gaps existed which was 7.2 and 5.3 q/ha, respectively. The extension gap can be bridged by popularizing package of practices where in stress need to belaidon use of proper seed rate and balanced nutrient application. Economics of growing released high yielding variety of chickpea RSG-888 recorded a net income of Rs. 39208/, per hectare which is 83.30% more compared to net income from local check (Pratap Channa) Meena and Singh [2].

Scientific Evaluation of the Putative Traits for Optimization of Potash Application to Groundnut Under Water Stress Condition in Odisha

A field experiment entitled “Physiological and biochemical basis of growth, yield and drought tolerance in groundnut by application of potash” was conducted at central farm OUAT, Bhubaneswar under AICRP on groundnut, Department of Agronomy during Rabi-Summer 2014-2015. The physiological studies were carried out in the department of Plant Physiology, College of Agriculture, Bhubaneswar. Groundnut variety Devi was taken for study and the experiment was laid out in a Randomized Block Design with 8 treatments and replicated thrice. The treatments were comprised off T1: control(no NPK) T2: farmers practice (N:P:K:: 18:46:30 kg/ha) T3: RD of NPK @ 20:40:40 kg/ha T4: NPK @ 20:40:60 kg/ha T5: NPK @ 20:40:80 kg/ha all at sowing T6: NPK @20:40:20 kg/ha at sowing and 20 kg/ha at flowering (30 DAS) T8: NPK @ 20:40:40 kg/ha at sowing and 40kg/ha at flowering (30 DAS). The result revealed that plant height, number of branches, number of leaves, number of nodules, TDM were improved by the level and timing of K application. Among the treatments application of 60 and 80 kg/ha in split registered significant increase of the above growth character in groundnut crop which reflected a higher value of LAI, LAD, CGR and RGR. The physiological traits for stress tolerance of a crop significantly influenced by the level of K and timing of its application. A significant increase of these traits was noticed when the level of K was increased up to 80 kg/ha and applied to groundnut crop in splits except RWD which decreased significantly with increase in the level of K application. The highest value of these biochemical characteristics of groundnut crop were recorded at 80 kg/ha when applied in splits at sowing and flowering. The seed yield in groundnut increased significantly with increase in the level of K application due to increase in number of pods per plant, shelling percentage and kernel weight and the highest yield registered among the treatments at 80 kg/ha when applied in split. In view of the positive and beneficial effect of K application in groundnut crop it may be concluded that improvement in the productivity of groundnut crop under residual soil moisture condition can be possible through split application of K up to 80 kg/ha.