Modeling for the Prediction of Soil Moisture in Litchi Orchard with Deep Long Short-Term Memory

Soil moisture is an important factor determining yield. With the increasing demand for agricultural irrigation water resources, evaluating soil moisture in advance to create a reasonable irrigation schedule would help improve water resource utilization. This paper established a continuous system for collecting meteorological information and soil moisture data from a litchi orchard. With the acquired data, a time series model called Deep Long Short-Term Memory (Deep-LSTM) is proposed in this paper. The Deep-LSTM model has five layers with the fused time series data to predict the soil moisture of a litchi orchard in four different growth seasons. To optimize the data quality of the soil moisture sensor, the Symlet wavelet denoising algorithm was applied in the data preprocessing section. The threshold of the wavelets was determined based on the unbiased risk estimation method to obtain better sensor data that would help with the model learning. The results showed that the root mean square error (RMSE) values of the Deep-LSTM model were 0.36, 0.52, 0.32, and 0.48%, and the mean absolute percentage error (MAPE) values were 2.12, 2.35, 1.35, and 3.13%, respectively, in flowering, fruiting, autumn shoots, and flower bud differentiation stages. The determination coefficients (R2) were 0.94, 0.95, 0.93, and 0.94, respectively, in the four different stages. The results indicate that the proposed model was effective at predicting time series soil moisture data from a litchi orchard. This research was meaningful with regards to acquiring the soil moisture characteristics in advance and thereby providing a valuable reference for the litchi orchard’s irrigation schedule.

Determinants in the Adoption of Alternate Wetting and Drying Technique for Rice Production in a Gravity Surface Irrigation System in the Philippines

Alternate Wetting and Drying (AWD) is a well-known low-cost water-saving and climate change adaptation and mitigation technique for irrigated rice. However, its adoption rate has been low despite the decade of dissemination in Asia, especially in the Philippines. Using cross-sectional farm-level survey data, this study empirically explored factors shaping AWD adoption in a gravity surface irrigation system. We used regression-based approaches to examine the factors influencing farmers’ adoption of AWD and its impact on yield. Results showed that the majority of the AWD adopters were farmers who practiced enforced rotational irrigation (RI) scheduling within their irrigators’ association (IA). With the current irrigation management system, the probability of AWD implementation increases when farmers do not interfere with the irrigation schedule (otherwise they opt to go with flooding). Interestingly, the awareness factor did not play a significant role in the farmers’ adoption due to the RI setup. However, the perception of water management as an effective weed control method was positively significant, suggesting that farmers are likely to adopt AWD if weeds are not a major issue in their field. Furthermore, the impact on grain yields did not differ with AWD. Thus, given the RI scheduling already in place within the IA, we recommend fine-tuning this setup following the recommended safe AWD at the IA scale.

Evapotranspiration Partition and Dual Crop Coefficients in Apple Orchard with Dwarf Stocks and Dense Planting in Arid Region, Aksu Oasis, Southern Xinjiang

Crop coefficients are critical to developing irrigation scheduling and improving agricultural water management in farmland ecosystems. Interest in dwarf cultivation with high density (DCHD) for apple production increases in Aksu oasis, southern Xinjiang. The lack of micro-irrigation scheduling limits apple yield and water productivity of the DCHD-cultivated orchard. A two-year experiment with the DCHD-cultivated apple (Malus × domestica ‘Royal Gala’) orchard was conducted to determine crop coefficients and evapotranspiration (ETa) with the SIMDualKc model, and to investigate apple yield and water productivity (WP) in response to different irrigation scheduling. The five levels of irrigation rate were designed as W1 of 13.5 mm, W2 of 18.0 mm, W3 of 22.5 mm, W4 of 27.0 mm, and W5 of 31.5 mm. The mean value of basal crop coefficient (Kcb) at the initial-, mid-, and late-season was 1.00, 1.30, and 0.89, respectively. The Kc-local (ETa/ET0) range for apple orchard with DCHD was 1.11–1.20, 1.33–1.43, and 1.09–1.22 at the initial, middle, and late season, respectively. ETa of apple orchard in this study ranged between 415.55–989.71 mm, and soil evaporation accounted for 13.85–29.97% of ETa. Relationships between total irrigation amount and apple yield and WP were developed, and W3 was suggested as an optimum irrigation schedule with an average apple yield of 30,540.8 kg/ha and WP of 4.45 kg/m3 in 2019–2020. The results have implications in developing irrigation schedules and improving water management for apple production in arid regions.

Nutritional Composition of Green Robusta Coffee (Coffea canephora) Beans under Organic and Integrated Nutrition with Varying Shade and Irrigation Management Practices in Western Ghats of India

Background: Cultural practices and environment may affect the physical, chemical, microbiological and nutritional qualities of the raw beans. With the advent of nutritional labelling regulations (FDA, 1973), many coffee bean processors have incorporated nutrition information on their products for label declaration. The current field experiment aimed to study to know the influence of nutrient management practices, irrigation and shade pattern on nutrient status of green coffee beans and yield of robusta coffee. Methods: This field-laboratory experiment was carried out at nine selected robusta coffee estates located at Western Ghats of India, i.e., Koppa region of Chikkamagaluru District, situated in the south western part of Karnataka State. The experiment was laid out in randomized block design (RBD) with 25 plants per treatment (plot size- 112 m2) with four replications. Representative coffee fruits from the experimental blocks were collected during harvesting period (February-March). After harvesting of the fruits they were wet processed to remove pulp and mucilage from the fruits. Further, they were sun dried up to 10 percent moisture level and stored using standard methods. Result: The green coffee bean N and P concentration remained higher (3.1 and 0.37%) in INM mode of nutrition compared to that of exclusive organics (3.0 and 0.36%). Within organic mode of nutrition, the shade pattern and irrigation schedule imparted difference in N assimilation. The bean K content did not vary between the INM and organic nutrition modes as depicted by similar (1.8%) values. However, within organic mode of nutrition, the shade pattern and irrigation schedule imparted difference in K assimilation. The average bean yield remained higher (1230 kg ha-1) in INM mode of nutrition compared to that of exclusive organics (1101 kg ha-1).

Response of Yield, Water Use Efficiency and Economics of Broad Bean to Irrigation and Phosphorous Level in Lower Indo-Gangetic Plains of Eastern India

The field experiment was conducted during the winter seasons of 2009–10, 2010–11 and 2011–12 on a sandy loam soil of lower Indo-Gangetic plains of Eastern India to optimize irrigation schedule and phosphorus level on broad bean. The treatments comprised of three irrigation levels viz. 30, 60 and 90 mm of cumulative pan evaporation (CPE) and four phosphorus levels viz. 0, 30, 60 and 90 kg P2O5 ha-1 were laid out in a split plot design. The results showed that irrigation at CPE 30 mm and phosphorus at 90 kg P2O5 ha-1 registered significantly the highest average seed yield of 4.76 and 5.37 t ha-1, respectively. The interaction effects revealed that irrigation at CPE 30 mm with 90 kg P2O5 ha-1 recorded significantly mean maximum yield (5.69 t ha-1) and gross return (Rs. 45520 ha-1), net return (Rs. 28870 ha-1) and BCR (1.73). In limited water availability, higher seed yield (5.13 t ha-1), maximum WUE (37.18 kg ha-1 mm-1), higher gross return (` 41040 ha-1), net return (Rs. 25590 ha-1) and BCR (1.66) were found with irrigation at CPE 90 mm with 90 kg P2O5 ha-1. Significant linear relationships were detected between yield with applied irrigation water (R2=0.964) and phosphorus (R2=0.989). Thus imposition of irrigation at CPE 90 mm coupled with 90 kg P2O5 ha-1 could be recommended to broad bean growers for deriving higher yield, WUE and income.

Effect of Irrigation and Herbicides on Most Tenacious Weed Cyperus rotundus in Wheat

To manage the Cyperus rotundus (Purple nut sedge.) is a troublesome, economically damaging weed, widely naturalized in the tropical and subtropical regions of the world. A field experiment was done at Students Instructional Farm of Chandra Shekhar Azad University of Agriculture & Technology, Kanpur (U.P).The study was conducted to investigate the competitive effects of C. rotundus in wheat (Triticum aestivum L.) under varying irrigation regimes and herbicides in field conditions at Kanpur during Rabi 2017-18 and 2018-19 in a split plot design. The experiment was laid out in split-plot design with four irrigation schedule viz. irrigation at CRI and active tillering stage (I1), irrigation at CRI + jointing + booting (I2), CRI + active tillering + booting + flowering stage (I3) and irrigation at CRI + jointing + booting + flowering + milking stage (I4) were assigned to main plots and weed management practices viz. W1-weedy check, W2-two hand weeding at 20 and 40 DAS, W3-sulfosulfuron @25 g/ha , W4- pendimethalin (pre emergence) fbWCPL-15(clodinafop- propargyl 15 %) @400 g/ha , W5- carfentrazone ethyl 20% + sulfosulfuron 25%WG @ 100 g/ha , W6- halauxafen + penxasulam 23.5% @ 75 g/ha , W7- halauxafen - methyl 1.21% w/w + fluroxypyr @ and W8- clodinafop- propargyl 15% + metsulfuron 1% @ 400 g/ha were allocated to sub plots. Application of two irrigations at CRI and active tillering stage (I1) significantly reduced the density of C. rotundus and their fresh and dry weight with highest weed control efficiency (WCE) over irrigation at CRI+ jointing+ booting+ flowering+ milking stage (I4), irrigation at CRI + active tillering + booting + flowering stage (I3) and irrigation at CRI + jointing + booting (I2). However, maximum yield was recorded with the application of five irrigation at CRI+ jointing+ booting+ flowering+ milking stage (I4). Among herbicidal treatments, lowest density, fresh and dry weight of C. rotundus with the highest WCE resulted in higher yield of wheat was recorded with the application of carfentrazone ethyl 20% + sulfosulfuron 25%WG as post emergence (35 DAS) at 100 g/ha as compared to other treatments. However, none of the herbicidal treatments as effective as hand weeding twice at 20 and 40 DAS.

Dual Crop Coefficient Approach in Vitis vinifera L. cv. LOUREIRO

Vineyard irrigation management in temperate zones requires knowledge of the crop water requirements, especially in the context of climate change. The main objective of this work was to estimate the crop evapotranspiration (ETc) of Vitis vinifera cv. Loureiro for local conditions, applying the dual crop coefficient approach. The study was carried out in a vineyard during two growing seasons (2019–2020). Three irrigation treatments, full irrigation (FI), deficit irrigation (DI), and rainfed (R), were considered. The ETc was estimated using the SIMDualKc model, which performs the soil water balance with the dual Kc approach. This balance was performed by calculating the basal coefficients for the grapevine (Kcb crop) and the active soil ground cover (Kcb gcover), which represent the transpiration component of ETc and the soil evaporation coefficient (Ke). The model was calibrated and validated by comparing the simulated soil water content (SWC) with the soil water content data measured with frequency domain reflectometry (FDR). A suitable adjustment between the simulated and observed SWC was obtained for the 2019 R strategy when the model was calibrated. As for the vine crop, the best fit was obtained for Kcb full ini = 0.33, Kcb full mid = 0.684, and Kcb full end = 0.54. In this sense, the irrigation schedule must adjust these coefficients to local conditions to achieve economically and environmentally sustainable production.

Study on the Water Supply and the Requirements, Yield, and Water Use Efficiency of Maize in Heilongjiang Province Based on the AquaCrop Model

Agricultural irrigation depends heavily on freshwater resources. Under the context of increasingly severe water shortages, studying the relationship among crop water requirements (ETc), actual crop evapotranspiration (ETa), irrigation water requirements (Ir), yield, and water use efficiency (WUE) would be beneficial to improve the agricultural application of irrigation water. Based on the daily data of 26 meteorological stations in Heilongjiang Province from 1960 to 2015, this study used the calibrated AquaCrop model to calculate the ETc, ETa, Ir, and yield of maize (Zea mays L.) in different hydrological years (extremely dry years, dry years, normal years, and wet years) along with WUE to evaluate the mass of yield produced per unit mass of crop evapotranspiration (ET) under rainfed and irrigated scenarios. The results showed that ETc and ETa decreased first and then increased from the west to the east during the four types of hydrological years. Irexhibited a decreasing trend from the west to the east. Compared with the irrigation scenario, the rainfed scenario’s average yield only decreased by 2.18, 0.55, 0.03, and 0.05 ton/ha, while the WUE increased by 0.32, 0.4, 0.33, and 0.21 kg/m3 in the extremely dry years, dry years, normal years, and wet years, respectively. The results indicated that in the normal and wet years, the WUE was high in the central regions, and irrigation did not significantly increase yield; further, we determined that irrigation should not be considered in these two hydrological years in Heilongjiang Province. In the extremely dry and dry years, irrigation was necessary because it increased the yield, even though the WUE decreased. This study provides a theoretical basis for studying the regional irrigation schedule in Heilongjiang Province.