In order to determine the effect of newly developed biodegradable liquid mulch (BDLM) on soil temperature, seed germination, and seedling growth of upland cotton, an experiment was carried out at the Agricultural Experiment Station of Zhejiang University in 2018 and 2019. The results showed that BDLM exhibited significant improvement with respect to soil temperature, cotton seed germination rate, stem and leaf biomass (P＜0.05) compared with bare soils. In comparison with plastic mulch, BDLM had no significant effects on soil temperature and cotton seed germination rate. In order to evaluate the effect of BDLM residues on cotton seedling growth under different soil types, a pot trial was carried out in a growth chamber. The results revealed that BDLM residues had significant effect on cotton seed germination rate. The interaction of soil types and BDLM residues had significant effects on chlorophyll content, leaf area index (LAI) and soil moisture content (P＜0.05). The highest chlorophyll content was observed from loam soils with BDLM residues, and the highest leaf area index was observed from clay soils with plastic residues, and lowest moisture content was observed from traditional loam soils. In conclusion, BDLM has positive effect on cotton growth, however further researches should be proposed during cotton harvesting stage.

5-aminolevulinic acid (ALA) has been used as a plant growth regulator and can affect physiochemical processes, including carbon fixation and nutrient assimilation. Here, we investigated the effect of ALA on sulfur metabolism and glucosinolate (GSL) biosynthesis in rape (Brassica napus L.) seedlings, which were treated with 0, 0.5, 1.0, 5.0, and 10.0 mg/L ALA supplemented in a Hoagland solution. After 28 d of treatment, the effect of ALA on thiol and GSL contents and transcriptional profile of associated genes was analyzed. Results showed that low ALA concentrations increased cysteine, GSL, and total soluble thiol contents, and upregulated expression of genes such as BnSULTR1.1, BnSULTR2.2,and BnAPK1 that regulate sulfur uptake and metabolism. ALA also increased the GSL content, particularly the aliphatic GSLs, due to the improvement of sulfur metabolism and assimilation to methionine. Other GSLs biosynthesis stages, such as desulfo-GSL glycosylation, were also significantly improved by the ALA applications as indicated by the increased expression of BnUGT74B1 and BnUGT74C1. High ALA concentrations negatively affected sulfur metabolism and GSL synthesis by inflicting photo-oxidative stress that damaged cellular components. Moderate ALA concentrations promoted sulfur acquisition, assimilation, and GSL biosynthesis.

In order to clarify the influence of different hill spacings and seedling numbers on dry matter accumulation and yield formation of machine-transplanting hybrid rice, two different rice varieties, F you 498 and Yixiangyou 2115 were selected as plant materials, and a randomized block experiment with three replicates was conducted to analyze the effects of field collocation pattern on tillers, dry matter production, yield and its component factors of rice. Based on the production practice, the reasonable seedling rate of hybrid rice is 0.42 million per hectare in Sichuan Province, and three field collocation patterns were set as: 1) high hills with low seedlings, 1.5 seedlings transplanted at 30 cm × 12 cm spacing; 2) middle hills with middle seedlings, 2.1 seedlings transplanted at 30 cm × 17 cm spacing; 3) low hills with high seedlings, 2.9 seedlings transplanted at 30 cm × 23 cm spacing. The results showed that the tiller numbers of single hill and population increased first and then decreased with the rice development process. The tiller number of single hill in every development period improved as the hill spacing increased, and the earring- tiller percentage of Yixiangyou 2115 was higher in low hills with high seedlings. The leaf area of single hill and dry matter mass of rice increased as the spacing enlarged, and Yixiangyou 2115 had larger leaf area and dry matter mass of single hill in low hills with high seedlings. Under the three different field collocation patterns, the differences of tiller numbers, dry matter accumulation and transportation, and yield were not significant, which indicated that the decrease of hill numbers per unit area did not influence the productive ear numbers and yield with the same basic seedlings. Reduce hills but not reduce seedlings, and low hills with high seedlings can also achieve high and stable yield.

As is well-known, the iodine deficiency disorders (IDD) have tremendous adverse effects on the growth and development of human beings. The universal salt iodization (USI) has been introduced for the control and elimination of IDD in many countries. However, excessive iodine intake caused by USI may lead to new diseases such as hyperthyreosis, high level iodine goiter and thyroid cancer. Meanwhile, other investigations indicated that organic iodine is much safer than inorganic iodine added in salt.
A new strategy has been confirmed by pot and hydroponic experiments to cultivate the iodine- rich crops through biofortification for iodine supplement. This study aims to testify the feasibility of cultivating iodine-rich crops in a large scale under natural conditions, thus exploring a potential way for the prevention and elimination of the IDD.
Randomized block experiments were conducted in the farmland in Sha’an Village of Bihu Basin, which located in Lishui City of Zhejiang south mountain area, to explore the biofortification effect of seaweed iodine fertilizer on iodine contents of rice, vegetables and fruits in the field. The seaweed iodine fertilizer was prepared by mixing the smashed kelp with diatomite according to patent formula. The treatments of exogenous iodine were as follows：0, 0.375, 0.750, 1.500, 3.000, and 4.500 kg/hm². Spectrophotometric method was used to detect the iodine contents of crops and soil samples, and one-way analysis of variance was applied to analyze the difference of iodine contents among all treatments.
The results suggested that the iodine content in the edible parts of all the tested crops were significantly enhanced (P＜0.05) after biofortification by the seaweed iodine fertilizer, including rice, loofah, cucumber, tomato, eggplant, watermelon, edamame, cowpea, etc. The iodine content of rice grain on a dry mass basis increased from 0.019 mg/kg to 0.403 mg/kg after iodine biofortification, while the iodine content of the vegetables and fruits on a fresh mass basis may be enhanced from 0.01-0.05 mg/kg to 0.130 mg/kg after iodine application. Besides, the iodine translocation factors from the roots to the edible parts of cowpea and edamame were relatively higher than the others. A daily consumption of 0.38 kg fresh iodine-rich vegetables or fruits and 0.40 kg iodine-biofortified rice can offer 150 μg/d iodine for adults, which can meet the daily iodine intake recommended by the World Health Organization (WHO).
In conclusion, the iodine content varied significantly in different parts of rice, and increased gradually from roots to straws and grains. Low concentration (0.375 kg/hm²) of exogenous iodine had little effect on the iodine content of the edible parts of crops, while high concentration (≥3.000 kg/hm²) of exogenous iodine could reduce the iodine content of the edible parts of crops. Upon overall consideration of the costs and benefits for the plantation, 1.500 kg/hm² should be an optimal exogenous iodine dosage for the cultivation of iodine-rich crops in the field.

Eggplant (Solanum melongena L.) is one of nutritious vegetables welcomed by consumers. However, the diseases occurred on eggplants, particularly soil-borne diseases became increasingly severe, which hampered sustainable development of eggplant production. Based on our investigation, eggplant rotation is able to reduce the occurrence of diseases significantly, but its mechanism has not been explained clearly.
In this study, we collected soil samples from different fields cultivated by eggplant continuous cropping and rotation to analyze their nutrients, enzymatic activities and microbial community structure using high throughput sequencing technique.
The results showed that the contents of available P, Ca, Mg and Mn decreased significantly, and the activities of polyphenol oxidase (PPO), urease (UE), alkaline protease (ALPT) decreased; the number of bacterial operational taxonomic units (OTUs) reduced but fungal OTUs increased, and the bacterial and fungal diversity indexes decreased and the dominance index increased in fields with four-year continuous cropping (eggplant-eggplant-eggplant-eggplant, EEEE), as compared with different eggplant rotation fields. However, there were significant differences in the nutrients, enzymatic activities and microbial community structure from different soil samples between the four-year eggplant rotation fields [eggplant-rice-rice-eggplant, ERRE or eggplant-green bean (the early half of the year)+bottle gourd (the latter half of the year)-green bean (the early half of the year)+bottle gourd (the latter half of the year)-eggplant, EGBE] as well. Compared with the EGBE, the pH and the contents of total P, available P, exchangeable Ca, Mg and Mn increased significantly, but the salinity and available boron (B) reduced significantly; the activities of peroxidase, acid protease, neutral protease decreased significantly but the catalase, UE and ALPT increased significantly; the number of bacterial OTUs increased significantly but fungal OTUs decreased; the bacterial and fungal diversity indexes increased and the dominance indexes decreased in ERRE.
In sum, ERRE is a good and worthy way for rotation by comprehensively considering soil pH, salinity, nutrients, enzymatic activities and microbial community structure in this study. The above results lay a theoretical foundation for choosing suitable cultivation system of eggplants in mountain regions.

Cadmium (Cd) is one of the most important inorganic pollutants in the soil of China and can be readily assimilated into plants and transported to human bodies through food chain. Rice is the staple food in China and also the major source of dietary Cd intake by people. Therefore, it’s important to decrease the uptake and accumulation of Cd in rice for human health. The capacity of iron plaque to sequester heavy metals is well known, besides its possible role as a buffer and reservoir in heavy metal uptake. It is well documented that exogenous Na₂SeO₃ or Na₂SiO₃ can depress the Cd absorption in rice by changing its content in the iron plaque, but the comparative study of exogenous Na₂SeO₃ or Na₂SiO₃ on Cd uptake in different rice cultivars is limited. The aim of this study is to explore the effects of Na₂SeO₃ and Na₂SiO₃ on depressing Cd assimilation in different rice cultivars.
In this study, a pot experiment was conducted to explore the effects of Na₂SeO₃ or Na₂SiO₃ on Cd uptake in two rice cultivars with different grain Cd accumulation abilities. The seedlings were cultured in the soil with 5 mg/kg Cd (CdCl₂·2.5H₂O) coupled with or without 1 mg/kg selenium (supplied as Na₂SeO₃) or 150 mg/kg silicon (supplied as Na₂SiO₃·9H₂O), and were sampled at 42 days after transplanting and at mature stage, respectively. The biomass of roots and shoots, soil pH, Cd contents in the iron plaque, roots, shoots and grains at mature stage were measured.
The results showed that exogenous Na₂SiO₃ significantly increased the pH of rhizosphere and depressed the root growth of the two rice cultivars. Exogenous Na₂SeO₃ improved the root biomass of Chuanguyou2348, but had no significant effect on the root biomass of Yixiangyou2115. The Cd content in the iron plaque of Chuanguyou2348 was significantly higher than that in Yixiangyou2115. The Cd content in the iron plaque was decreased by 8.5% and 14.1% in Yixiangyou2115, 12.9% and 39.4% in Chuanguyou2348 with the application of Na₂SeO₃ and Na₂SiO₃, respectively. Exogenous Na₂SeO₃ or Na₂SiO₃ also decreased the Cd content in the root and shoot of the two rice cultivars, and the Cd translocation coefficient from root to shoot decreased as well. Compared with the control, exogenous Na₂SeO₃ or Na₂SiO₃ also decreased the total Cd accumulation significantly, but their effects on the percentage distribution in different parts of rice were quite different. In Yixiangyou2115, Na₂SeO₃ and Na₂SiO₃ mainly increased the percentage of Cd in the iron plaque, but increased the Cd accumulation percentage in both the iron plaque and roots of Chuanguyou2348. Correlation analysis showed that Cd content in the iron plaque had positive correlation with Cd accumulation in rice roots and shoots, which indicated that iron plaque was a reservoir for Cd.
It is concluded that exogenous Na₂SeO₃ or Na₂SiO₃ significantly affects the root growth of rice, decreases the Cd content and accumulation in rice root and shoot, then decreases the Cd content of the grain at mature stage in both the cultivars. Chuanguyou2348 has a larger decline than Yixiangyou2115 under the two treatments, and Na₂SiO₃ treatment shows better effect than Na₂SeO₃.

Soybean is an important grain and oil crop in China. However, with the decrease of economic benefits and cultivated area, it depends on imports heavily due to the unbalanced supply and demand. Intercropping systems are widely used because they can increase crop yield, nutrient use efficiency, and land productivity. In particular, legume/crop intercropping systems can increase nitrogen fixation, reduce nitrogen input, enhance nitrogen use efficiency, and thereby increase crop yield. Maize/soybean relay strip intercropping system is the major planting pattern in the southwest of China, which can increase soybean yield and land output. The objective of this study is to investigate the effects of different interspecific spacings of maize/soybean intercropping on biomass, dry matter allocation and yield of soybean with different nodulation characteristics, and make a progress for the research of yield and nutrient utilization in maize/soybean relay strip intercropping system.
To explore the effects of soybean varieties and row spacings on soybean nodule growth, biomass accumulation and distribution, we carried out a field experiment with two-factor randomized block design, and applied three kinds of row spacing between maize and soybean (B₁: 45 cm, marked as IS45; B₂: 60 cm, marked as IS60; B₃: 75 cm, marked as IS75) and two soybean varieties (A₁: weak-nodulation Gongxuan No. 1, A₂: strong-nodulation Nandou No. 25).
The results revealed that the effects of shade on soybean decreased with the increase of row spacing between maize and soybean. With the increase of row spacing, the nodule number and dry mass of soybean increased from the third trifoliolate stage to full bloom stage of soybean. The soybean nodule number and dry mass reached its maximum at beginning seed stage, with the following order: IS60＞IS75＞IS45. Compared with A₁, the nodule number was lower and the nodule dry mass was greater in A₂. From the third trifoliolate stage to full bloom stage, shoot dry matter accumulation declined with the decrease of row spacing and mainly distributed to stems and leaves; in addition, the dry matter accumulation of stems, leaves and shoots was lower in A₂ in comparison with A₁. From beginning seed stage to full maturity stage, the shoot dry matter increased rapidly, but the allocated rate of stems and leaves decreased; however, the allocated rate of pods increased and reached its peak at full maturity stage and B2 treatment. The output rate and contribution rate of vegetative organ for A₂ were greater in contrast with A₁, and the grain yield of A₂ was 2.94% higher than that of A₁. In addition, under different row spacing treatments, the grain yield of B₂ was 9.77% and 2.67% higher than that of B₁ and B₃, respectively.
In sum, the yield of soybean reaches the maximum under the 60 cm row spacing. In contrast to weak-nodulation soybean cultivar, the grain yield increase of strong-nodulation soybean can be responsible for the increase of pod per plant and 100-grain mass.

Waxy maize is an important economic crop in Zhejiang Province. Agronomic traits, especially the yield and yieldrelated traits of waxy maize are the focus of attention paid by both waxy maize breeders and producers. Most agronomic traits of waxy maize are quantitative traits affected by environment, variety-by-location interaction, variety and location-by-year interaction. It is very important to understand the contribution rates of each factor to agronomic traits of waxy maize, so as to screen appropriate varieties for Zhejiang Province.
In this study, a regional variety test with random complete block design was implemented in multiple locations from 2013 to 2015. Totally, 29 waxy maize varieties and eight test locations were arranged with three blocks in each location. The yield and seven yield- related traits, ear length, ear diameter, net ear rate, rows per ear, row grains, fresh 1 000-grain mass, and seed producing rate were investigated. Based on the location effects, variety effects, year effects, location-by-year interaction effects, variety-by-location interaction effects, predicted by a mixed linear model, the stability and adaptability of the 29 varieties were analyzed, and the eight locations were comprehensively evaluated using productive level, precision, distinguishing ability, representation and stability. SAS and QTModel softwares were applied for the analysis.
The results of variance analysis showed that the location effects, variety effects, year effects, year-by-location interaction effects and variety-by-location interaction effects were significant for yield trait, and the variety-by-location interaction effects for seven yield-related traits were not significant. Wherein, 67.6% of variance for rows per ear was from variety effects, 36.3% of variance for yield from location effects. Additionally, the location related effects explained 6.9% 62.0% of the total variance for each agronomic trait. In accordance with the contribution rate of location?related effects, the traits from high to low contributions were the yield, seed producing rate, row grains, fresh 1 000-grain mass, net ear rate, ear diameter, ear length, rows per ear, respectively. The results for comprehensive evaluation on location showed that productive levels in the eight locations were diverse; the trial precisions in the eight locations were high, showing that the trials were all valid. In these test locations, Jiashan, Hangzhou and Chun’an possessed high distinguishability; Dongyang, Jiangshan, Chun’an and Hangzhou possessed high representativeness; Dongyang and Jiashan possessed high stability and productive level.
On evaluation of variety stability and yield-ability, according to the results of multiple comparisons by Tukey method for yield trait, the varieties marked by “a” were regarded as appropriate ones, and among them, those with yield mean value equal to or larger than the average of all appropriate ones were determined as the most appropriate varieties. Based on the variety effects and variety-by-location interaction effects, the stability of the variety was estimated. As a result, “Ketiannuo 2” was the most appropriate variety for Zhejiang Province.