No abstract

Monitoring nitrogen (N) and phosphorous (P) losses on farmland is essential for the prevention of agricultural non-point source pollution (NPS). This study was conducted on typical dry farmland in southern China to determine the effect of conservation tillage and conventional tillage (CT) on soil physical and chemical properties, nutrient movement, as well as on N and P losses. Four conservation tillage techniques (i.e., no-tillage direct seeding (NTDS), no-tillage transplanting (NTTS), minimum tillage direct seeding (MTDS), and minimum tillage transplanting (MTTS)), as well as one CT technique, were carried out in a randomized complete block design with three replicates each. The results suggest that MTDS and NTDS improved soil physical and chemical properties by ensuring adequate retention of these properties at the 0–20 cm soil depth. Low levels of N and P losses in runoff and drainage water were recorded under NTTS and NTDS compared to CT. Our results, therefore, suggest that conservation tillage approaches, such as MTDS and NTDS, are the most suitable tillage techniques for improving soil nutrients and reducing agricultural N and P losses while providing an eco-friendly and sustainable agricultural practice.

The goal of this research is to use a WORKSWELL WIRIS AGRO R INFRARED CAMERA (WWARIC) to assess the crop water stress index (CWSIW) on tomato growth in two soil types. This normalized index (CWSI) can map water stress to prevent drought, mapping yield, and irrigation scheduling. The canopy temperature, air temperature, and vapor pressure deficit were measured and used to calculate the empirical value of the CWSI based on the Idso approach (CWSIIdso). The vegetation water content (VWC) was also measured at each growth stage of tomato growth. The research was conducted as a 2 × 4 factorial experiment arranged in a Completely Randomized Block Design. The treatments imposed were two soil types: sandy loam and silt loam, with four water stress treatment levels at 70–100% FC, 60–70% FC, 50–60% FC, and 40–50% FC on the growth of tomatoes to assess the water stress. The results revealed that CWSIIdso and CWSIW proved a strong correlation in estimating the crop water status at R2 above 0.60 at each growth stage in both soil types. The fruit expansion stage showed the highest correlation at R2 = 0.8363 in sandy loam and R2 = 0.7611 in silt loam. VWC and CWSIW showed a negative relationship with a strong correlation at all the growth stages with R2 values above 0.8 at p < 0.05 in both soil types. Similarly, the CWSIW and yield also showed a negative relationship and a strong correlation with R2 values above 0.95, which indicated that increasing the CWSIW had a negative effect on the yield. However, the total marketable yield ranged from 2.02 to 6.8 kg plant−1 in sandy loam soil and 1.75 to 5.4 kg plant−1 in silty loam soil from a low to high CWSIW. The highest mean marketable yield was obtained in sandy loam soil at 70–100% FC (0.0 < CWSIW ≤ 0.25), while the least-marketable yield was obtained in silty loam soil 40–50% FC (0.75 < CWSIW ≤ 1.0); hence, it is ideal for maintaining the crop water status between 0.0 < CWSIW ≤ 0.25 for the optimum yield. These experimental results proved that the WWARIC effectively assesses the crop water stress index (CWSIW) in tomatoes for mapping the yield and irrigation scheduling.

Drought and water scarcity due to global warming, climate change, and social development have been the most death-defying threat to global agriculture production for the optimization of water and food security. Reflectance indices obtained by an Analytical Spectral Device (ASD) Spec 4 hyperspectral spectrometer from tomato growth in two soil texture types exposed to four water stress levels (70–100% FC, 60–70% FC, 50–60% FC, and 40–50% FC) was deployed to schedule irrigation and management of crops’ water stress. The treatments were replicated four times in a randomized complete block design (RCBD) in a 2 × 4 factorial experiment. Water stress treatments were monitored with Time Domain Reflectometer (TDR) every 12 h before and after irrigation to maintain soil water content at the desired (FC%). Soil electrical conductivity (Ec) was measured daily throughout the growth cycle of tomatoes in both soil types. Ec was revealing a strong correlation with water stress at R2 above 0.95 p < 0.001. Yield was measured at the end of the end of the growing season. The results revealed that yield had a high correlation with water stress at R2 = 0.9758 and 0.9816 p < 0.01 for sandy loam and silty loam soils, respectively. Leaf temperature (LT °C), relative leaf water content (RLWC), leaf chlorophyll content (LCC), Leaf area index (LAI), were measured at each growth stage at the same time spectral reflectance data were measured throughout the growth period. Spectral reflectance indices used were grouped into three: (1) greenness vegetative indices; (2) water overtone vegetation indices; (3) Photochemical Reflectance Index centered at 570 nm (PRI570), and normalized PRI (PRInorm). These reflectance indices were strongly correlated with all four water stress indicators and yield. The results revealed that NDVI, RDVI, WI, NDWI, NDWI1640, PRI570, and PRInorm were the most sensitive indices for estimating crop water stress at each growth stage in both sandy loam and silty loam soils at R2 above 0.35. This study recounts the depth of 858 to 1640 nm band absorption to water stress estimation, comparing it to other band depths to give an insight into the usefulness of ground-based hyperspectral reflectance indices for assessing crop water stress at different growth stages in different soil types.

Several tillage and planting methods have been proposed to enhance the soil bulk density, biological community, and grain yield of rice. In this work, we present the impact of plowing methods with different rice crop establishment approaches, i.e., moldboard plowing with mechanical transplanting (MPMT), rotary tillage with mechanical transplanting (RTMT), moldboard plowing with direct seeding (MPDS), and rotary tillage with direct seeding (RTDS), on soil bulk density, microbial community, enzymatic activities, and grain yield of ratoon rice (RR). The results showed that MPDS improved soil bulk density in 0–30 cm depth in both years and both harvesting times (1H: 1st harvest and 2H: 2nd harvest). The results also showed that microbial community significantly improved under MPDS compared to the other treatments in both years and in 1H and 2H. Additionally, enzymatic activities showed a positive effect under MPDS in both years and in 1H and 2H. MPDS subsequently improved rice grain yield by 18.05% and 17.27% in 2017 (1H and 2H), and 14.86% and 18.64% in 2018 (1H and 2H), respectively. In conclusion, MPDS appears to be a more suitable approach to obtaining high soil eminence and health, as well as sustainable RR production.